PsychARTICLES an Opponent-Process Theory of Motivation Temporal Dynamics of Affect

8/13/2019 PsychARTICLES an Opponent-Process Theory of Motivation Temporal Dynamics of Affect

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1 sychological Review1 9 7 4 , Vol. 81, N o. 2 , 1 1 9 - 1 4 5

A N OPPONENT-PROCESS THEORY OF M O T I V A T I O N :I. T E M P O R A L D Y N A M I C S O F A F F E C T1

RICHARD L . SOLOMON *University of Pennsylvania

JOHN D. CORBITBrown University

A new theory of mot ivat ion i s descr ibed a long wi th i t s appl icat ions toaddiction and avers ion. T h e theory assumes that many hedonic, affective,o r emotional states are automatically opposed by central ne rvous systemmechanisms which reduce the intensity of hedonic feelings, both pleasantand aversive. T he opponent processes fo r most hedonic states are strength-ened by use and are weakened by disuse. These s imple assumpt ions leadto deduct ions of many known facts about acquired mot ivat ion. In addit ion,th e theory suggests several new lines of research on mot ivat ion. It arguesthat the establishment of some types of acquired motivation does not de-pend on condi t ioning and is nonassociat ive in nature . T he relationshipsbetween condit ioning processes and pos tula ted opponent processes are dis-cussed. Finally, it is argued that th e data on several types of acquiredmot ivat ion, ar i s ing f rom ei ther p leasurable or avers ive s t imulat ion, can bef ru i t fu l ly reorganized and under stood wi th in the f r amew ork p rov ided byth e opponent-process model .

First, we describe the kind of phenome-non wh ich has caught our at tent ion. Tw ofictitious examples will suffice. In the first,a wom an at work discovers a lump in herbreast and immedia te ly is terrified. S hesits still, in termi t t en t ly weeping, or shepaces the floor. Af t e r a few hours , sheslowly regains her composure, stops cry-ing, and begins to wo rk. At th is poin t , sheis still tense and d i s turbed , but no longerterrified and dis tracted. S he ma nifests thesymptoms usually associated with intenseanxie ty . Whi le in this state she calls herdoctor for an appointment . A few hou rsla ter she is in his office, still tense, stillf r i gh t e ne d : She i sobviously a very unhappywom an . T he doctor makes his exam inat ion .This research was supported by U. S. PublicHealth Service G r a n t MH-04202 to the first au-thor and Gran t MH-16608 to the second author.We are grateful to Bur ton S. Ros ner , Francis W.Irwin, and Martin E. P. Seligman for their pains-taking and he lpful edi t ing of an ear l ier draf t ofth is paper. Final ly , we are indebted to DorotheaJameson Hurvich a n d L e o M . H u r v i c h , whosedevelopment of the Hering theory into thei r co-

herent , opponent-process color v is ion theory firstsuggested to us a new way of th ink ing abou t af-fect and hedonic process.2 Reques ts fo r repr ints should be sent to R i c h a r dL . So lomon, D epar tment of Psycho logy , Univer -sity o f P e n n s y l v a n i a , P h i l a d e l p h i a, P e n n s y lv a n i a19104.

He then in fo rms her that there is no possi-bil i ty of cancer , that there is nothing toworry about , and that her problem is justa clogged sebaceous gland requiring nomedical at tent ion.A few minutes l a ter , the woman leavesthe doctor's office, sm iling, greeting strang-ers, and wa lk ing wi th an unusual ly buoyantstride. Her euphoric mood permeates allher act ivi t ies as she resumes her n orm alduties . She exudes joy, which is not incharacter fo r her. A few hours later , how-ever, she is work i ng in her normal , per-functory w a y . Her emo t ional express ion isback to normal . S he once more has thepersonal i ty immediately recognizable by allof her fr iends . Gone is the euphoria , andthere is no h i n t of the ear l i er t er r i fy ing ex-perienceof that day.In the second example, a couple have justbegun sexual fore play , and i t is quite plea-surable. After a fewm oments of aconstantlevel of mutual s t imula t ion ,th e pleasure de-creases som ewhat . N orm al ly , this decl inewould elicit behavior calculated to increasethe in tens i ty of m u t u a l s t imula t ion and tomain ta in the high level of p leasure . U n-fo r tuna te ly , a t tha t moment a te lephonerings. O ne par tner l eaves and goes intoanother room to answer i t , and the otherpa r t ne r lies a lone in the bed. T h e aban-

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120 R J C J J A R I J L. S O L O M O N AN D J O H N D . C O K B I T+ 1 0 0

INTENSITY OFPRIMARY

AFFECT

INTENSITY OFAFFECTIVE

AFTE R- RE ACTIO N

1

PEAK OF PRIMARYAFFECTIVE REACTION

ADAPTATION PHASE^STEADY LEVEL

DECAY OF AFTER-REACTION

PEAK OF AFFECTIVEAFTE R- RE ACTIO N

ONTIM

StandardPattern ofAffectiveDynamicsFIGURE 1 . The s t a n d a r d p a t t e r n of affec t ivedynamics , show i ng t he f i ve d i s t i nc t i ve f e a t u r e s :the peak of the p r i m a r y a f fec t ive reac t ion , th eadapta t ion phase , the s teady level , the peak of theaf fec t ive a f t e r - reac t i on , and , finally, the decay ofth e a f t e r - reac t i o n . (The heavy b l ack b a r r e p r e -sents t he t i me dur i ng w hi ch t he a f f ec t - a r o u s in gs t i m u l u s i s p re sen t . The ord i na t e repre sen t s t w ohedon ic sca les , each depart ing f rom n e u t r a l i t y ,o nefo r th e p r i m a r y affec t , th e o t h e r for the a f f e c t ivea f t e r - r e a c t i o n . )

cloned par tner exper iences a qu ick dec l ineof th e pleasure, then becomes tense and i r -r i t a ted , and s t rongly c raves a r e s u m p t i o nofth e sexual s timula t ion . Time goes by , how -ever , and the o ther par tner does no t r e t u r n .Final ly , the abandoned par tner gets out ofbed, absen tminded ly tu rn s on the t e lev i s ionset , and becomes absorbed in a news broad-cast. Go n e is the i r r i t ab i l i ty and intensecrav ing . There is no h i n t , in overt beha-v i o r , of the pleasurable sexual experienceof a few minutes ago. A type of dispas-s iona te no rmal i ty now pervades .

W e c a n disti l l from these tw o ex a m p l essome i m p o r t a n t em p i r i c a l f ea t u re s c o m m o nto m a n y h ed o n i c , em o t i o n a l ,or affect ive ex -periences . First, fo l lowing th e sudden in -t r o d u c t io n of ei ther a p leasurable or avers ives t im u lu s , an affective o r hedonic react ionbegins a n d qu ick ly r i ses to a peak . I t t h e nslowly decl ines to a steady level w h e r e itr e m a i n s if the s t i m u l u s q u a l i t y a nd in tens i tyis ma in ta ined . The n , a t the sudden te rmi-n a t io n of the s t imulus , the affect ive rea c t i o nquick ly d i sappears and gives way to aqua l i -ta t ively very di f feren t type o f af fec t ive re-ac t ion which reaches its own p ea k of in ten-s i ty and then s lowly d i sappears wi th t ime.

Figure 1 diagrams these changes in he-donic or affective state and i l lus t rates what

we call th e standard pattern of affective dy -namics. The pa t te rn has five dis t inct ivef e a t u r e s : (a) the peak of the p r imary h e-donic process o r s tate , precip i ta ted by stim-ulus onset; (6) a period ofhedonic or affec-t ive adaptation du rin g which the in tensi tyof the hedonic s ta te decl ines , even thoughs t i m u l u s intensity is m a i n t a i n e d ; (c ) asteady level of the hedonic process whichcont inues as long as s t imulus in tensi ty ism a i n t a i n e d ; (d ) a peak of affective after-reaction w h i c h q u i c k l y fol lows s t imulus t e r -mina t ion , and whose qua l i ty i s hedon ica l lyvery di ffe rent from that of the p r i m a r y he-donic state; a n d e ) final ly, th e af te rs ta tedecays and subsequent ly d isappears .

This s tandard pa t t e rn descr ibes bo th f ic-t i t ious exam ples . In the f i rs t , the in i t ia l ,pr imary hedon ic o r affect ive process w a s u n -p leasan t and the a f te r - reac t ion was p leasan t .In the second , the p r imary p rocess waspleasant and the a f te r - reac t ion was unp leas -ant . The d ata of psychology con tain l i ter-ally d o z en s of examples of t h i s k i n d . F orb r e v i t y w e wil l first describe some of themore in te res t ing o r im por tan t cases chosenf rom v e ry dif feren t areas of psychologicalresearch . W e c a n t h e re fo re d em o n s t r a t ethe grea t genera l i ty o f the s tandard pa t t e rnof affective dynamics . Then w e wi l l de-scribe a theoret ical model for the underly ingmechan ism.E X A M P L E S OF E M P I R I C A L P H E N O M E N ATo BE E X P L A I N E DTable 1 presen ts seven exa m ples of emo-t iona l , affective, hedon ic , o r m o t i v a t i o n a lp h e n o m e n a . S o m e a re behav io ra l , some exper ien t ia l . S ome a re ex p e r i m en t a l ,o thers a re observa t iona l , der ived f rom com-mon everyday exper iences . F inal ly , someare p rec ip i t a ted by p leasan t , and some byu np l e a s a n ts t i m u l i .Example 1 descr ibes behav io r changesseen in a dog subjected to in tense avers ives t im u la t i o n . The example d raws on se lec ted

parts of studies reported by Katcher, So l o -mon, T u r n e r , L o L o r d o , O v e r m i e r , a n d Res-corla (1969) and C h u r c h , L o L o r d o , Over-m i e r , S o l o m o n ,an d Turner (1966). A d o gin a Pav lov harness was s t imula ted by sev-


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O P P O N E N T - P R O C E S S T H E O R Y O F M O T I V A T I O N 121T A B L E 1

S E L E C T E D E X A M P L E S O F H E D O N I C - A F F E C T I V E P H E N O M E N A

E x a m p l e

Dogs in Pavlovharness, 10-secondshocks, grossbehav io rDogs in Pavlovharness, 10-secondshocks, electro-cardiograph re-

sponsesEpstein 's para-chut is ts , free f a l l ,gross behavior,physiologyOpiate users, intra-v eno u s in j ec t ion ,moods and feelingsD o g s and M & Ms ,

gross behav iorLove , in te rpersona ls t i m u l a t i o n , moods ,feelingsI m p r i n t i n g , the a t-t a c h m e n t ofcreatures to t h e i r mothers

First fe ws t i m u l a t i o n sStateA( i n p u t present)

ter ror , panic

large cardiacaccelerat ion

ter ror ,a u t o n o m i cnervous systemarousale u p h o r i a , r u s h ,p leasu re

pleasure , ta i l wag-ging, ch e w i n g

ecstasy, excite-m e n t ,h a p p i n e s spleasure , cessationo f fear , nodistress

State B( i np u tgone)s teal th ( subdued ,caut ious , inac-t ive , hesi tant)slowdecelera t ion,smal l overshoot

s t u n n e d , stony-faced

crav ing , aversivew i t h d raw a lsigns, shor td u r a t i o ntenseness , mo t ion-

lessloneliness

loneliness, distresscries, shortd u r a t i o n

A f t e r many s t imula t ionsState A '( i n p u t present)

u n h a p p y (an-noyed,anx ious ,af ra id)small accelerationor none

tense, eager,expec tan t

loss ofe u p h o r i a ,no rm a l feeling,relief

n o r m a l , comfort-ab le , conten tpleasure , nocries

S t a t e B '( i n p u t gone)jo y (euphoric ,active, social),h a p p yquickd ecelera tion,large overshoot

exh i la ra t ion ,jub i la t ion

intense craving,abstinenceagony, longd u r a t i o n

grief, separa t ionsyndrome , longdura t ionloneliness, intensecries, longd u ra t i o n

eral 10-second shocks. The dog appearedto be terrified during the first few shocks.It screeched and thrashed about, it s pupilsdilated, it s eyes bulged, it s hair stood onend, it s ears la y back, it s tail curled betweenit s legs. E xpu l s ive defecation and urina-t ion, along with many other symptoms ofintense autonomic nervous system act ivi ty ,were seen. A t this point , the dog was freedfrom the harness , it m oved s lowly about l i e room, appeared to be s teal thy , hesi tant ,an d u n f r i e n d l y . I ts s ta te h ad sudden l ychanged from ter ror to s teal thiness .We n ow arbitrari ly label the state duringshock (the terror s tate or the peak of thepr ima r y reaction to shock) State A. T hes teal thy state, right af te r shocks were ter-

minated ( the after-react ion) , will be calledState B. In that way , w e can temporarilyignore whether w e have correctly labeledth e states. W e know that State A was no tS ta te B . Indeed, State A wa s very differ-ent from State B, judging by the many be-havioral changes observed when the dog wassuddenly re leased . Fu r therm ore , S ta te Bgradual ly disappeared. I n a few minutes ,the clog appeared to he no rm al , l ike its pre-vious, preshock , na tura l , se l f : act ive , alert ,and socially respons ive . When th i s hap-pened, it was impossible to tell by lookingat the dog that either S ta t e A or B had j u s tt ransp i red . T he evidence w as gone. T hedog had progressed from normalcy to Ato B, and back to normalcy. This sequen-


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122 R I C H A R D L . S O L O M O N ANDJOHN D . C O R B T T250

200

150-BASELINE

0 2.5 5.0 75 10.0Time Afte r Shock Onset S e c )

100-

90-

80

BASELINELINE 4maP ^>,--- >--O-Vi(8 ma

0 10 20 30 40 50Time AfterShockTermination Sees)F I G U R E 2 . Heart rate changes as a f u n c t io n ofshock onset , ma i n t enance , and t e r m i n a t i o n . (Thereis a decl ine fo l lowing th e init ial peak reac t ion toshock onset. There is a decelera to ry overshootf o l l ow i ng shock terminat ion , a n d th en th e h e a r t

rate slowly re tu rns to basel ine ra te . Note that th eeight-milliampere shock produces a bigger heartra te increase and a bigger dece le ra t ion than doesthe fou r -mi l l i ampere sh o ck . ) (Ad a p ted f r o m a nar t ic le by Ru sse l l M . Ch u r ch , V in cen t LoLordo,J. Bruce Overmier, Richard L. Solomon, and Lu-cil le H . Turner ap p ea r in g in the A u g u s t 1966Journal o f Comparative and Physiological Psy-chology. Co p y r ig h ted by t he A m e r i c a n P s y c h o -logical Association, Inc. , 1966.)t ia l pa t te rn wil l be seen in all of the ex-amples given in Table 1 . ft is, we believe,the basic pattern for the dynamics of a f f e c t .H o w e v e r , E x a m p l e 1 has not yet beenfully described. When th e same dog wasbrought back for the same t rea tment dayafter day , its behavior gradua l ly changed.D uring shocks, th e signs of terro r disap-

peared. Ins tead , the dog appeared pa ined ,annoyed, or anxious, but not terrified. F orexample, it whined rather than shr ieked, andshowed no fu r the r ur in a t ion , defecation, orstruggling. Then, wh en released suddenlyat the end of the session, the dog rushedabout , jumped up on people , wagged i ts ta i l ,in wha t we called at the time a fit of joy .Finally, several m inu tes la ter , the dog wasits n or ma l self : fr iendly , but not racingabout . Here again, the sequence w as nor-mal S ta te A Sta te B normal , whereS ta te A accompanied the a rous ing input ,and State B directly followed the suddent e rminat ion of tha t in pu t , and then slowlydied out.W e wish to emph asize that the quali ta-t ive and quanti ta t ive features of Sta tes Aand B d u r i n g later shocks were not the sameas those for S ta tes A and B d ur in g the f irs tfew shocks. This pattern ofchanges , occur-r ing as a consequence of repeated exposuresto the s t imulus input which causes A , a lsois , .we believe, typical of the basic patternof affective dyn am ics . B ecause th e laterStates A and B were not ident ica l to theearlier states, we label th e later ones A' andB',respectively.Look a t Example 2 in Table 1. A dogw as in an experiment in which it s heartbeatw as measured by an electrocardiograph dur-ing repeated shocks to its hind feet. Theobservat ions are from C hu rch e t a l. (1966).D urin g the firs t few shocks , there was alarge cardiac accelerat ion; in some dogs itwas an increase of 1 50 beats per min ute .A t s hoc k t e r min a t ion ,the rate suddenly de-creased, and w i th in 5 seconds it descendedbelow the base line ra te . It often f e l l as lowas 20 to 30 beats per m i n u t e below baselinerate. The n, it slowly recovered to base-line rate, over a period of as long as 30 to60 seconds. The below-baseline excurs ionhas been called vagal oversh oot. I t is awell-s tudied phen omen on . F ig ur e 2 is takenfrom C hur c h et al. (1966) and demonstratesthese dy nam ic events . The f igure a lso sug-gests that th ere may be a re la t io nsh ip be-tween intensity of the A state and the mag-nitude and duration of the B state. N owwe can define baseline, Sta te A , State B ,and the return to baseline using an electro-


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OPP ONENT-PROC ES S THEOR Y OF MOTIVATION 123cardiograph measurement instead of grossobservat ions of emotional behavior.

States A a n d B changed markedly af te rseveral sessions. S hock onset now causedlittle, if any, increase in hear t rate . Any in-crease w as m o m e n t a r y . T he rate often de-creased even while the shock was stil l on.However , when shock was suddenly te rmi-nated, the overshoot was m u c h largerthan it was on early shock trials. Heartrate in some individual cases descended to50 to 60 beats per minute ( somet imes morethan 50 beats per minute be low base l inerate), and recovery to basel ine took as longas two to five minu te s . As Katcher et al.(1969) put it, The deceleratory heart-rateovershoot p roduced b y s t im ulus te rmin at ionshows shortened latencies . . . and greatermagnitude over t r ials [p. 172]. Thus,S ta tes A and B h av e c h a n g e d : A' seems tobe weaker than A , B' stronger than B, andB' longer lasting than B. But , as in theprevious examples , we can st i l l ident i fy thesequence: basel ine > A > B baseline.E x a m p l e 3 comes from Epste in 's (1967)repor t of physiological , emotional-expres-sive, and social react ions of parachutis ts .When parachutists make their first ju mp ,they are often terr if ied, ju d g ing by tele-metered autonomic responses and photo-graphed facial expressions. W hen they landsafely, they look stony-faced or s tu nne d forseveral minutes , then gradual ly resume nor-m alcomposure. After the parachutists havemade severa l jumps and are experts, theirresponses are different. When jumping,they are no longer ter r i f ied. They ma y beanxious, tense , or even eager . A fter theyland safely, they feel exuberant , exh i lara ted ,and good. They l ike the feel ing, and themood lasts som etimes for hou rs. S uchparachutis ts love to jump because of thisafter-feeling. Aga in, we see that the qual i-ta tive and qua nt i ta t ive a t t r ibu tes o f StatesA and B have changed wi th the repet i t ionof el icit ing cond it ions. How ever , tw o verydif feren t states are st i l l observable ,a nd w i t heach st imulat ion input , we can identify thes equen c e : baseline > A B base l ine .E x amp le 4 represents states in opiate use(Ja ffa , 1965; M a u r e r & Voge l , 1967) .E a r l y in a h is to ry of opiate use , th e use r

exper iences th e rush (an intensely plea-surab le feel ing) direct ly af ter the opiate in-jec t ion , fo l lowed by a per iod of less intenseeuphor ia. Then, wi th f u r th e r passage oft ime , the user suffers aversive, painful , andfr ightening somat ic wi thdrawal symptoms,together with a feeling of craving. Hereagain, we see a baseline A > B base-line sequen ce. How ever, w ith opiates, Bm ay last a long time, sometimes for severaldays.Afte r repea ted d osages of opiates o verseveral weeks, State A begins to weaken ,and at the same t ime State B begins to in-tensify and takes longer to re turn to base-l ine. State A' is called normal ratherthan euphor ic. The rush is no longer ex-per ienced. Y et , State B' is more physio-logically d is tu rb ing than B was, and lastsm u c h longer than d id State B . The cravingaspect of State B' is now extremely intense ,aversive, and enduring. It is called absti-nence agony. It can be m o n t h s before B'r e tu r ns to basel ine . Perhaps it never reallydoes. It is a ghastly experience.T he repeated use of some drugs resul tsin th e behaviora l phenomenon of addict ion.People find themselves craving a substancein which they prev ious ly had little interest.I t is the most vivid instance of acquiredmotivat ion , because of its intensity andd u r a t i o n . It also provides a fru i t fu l , em -pir ical mode l for analyz ing many k inds ofacquired motivation. Indeed,welater show,wi th examples taken from love and affection,social at tachment , and impr in t ing in birds,tha t addiction does not differ in principlef rom any acquired motivat ional system. W ecan easi ly descr ibe opiate , alcohol, barbi-turate , amp heta m ine , or cigare tte addict ion( see S o lomon & C orb it , 1973) w i th in theempir ical f r a m e w o r k of the analysis w e haveproposed . They a ll h a v e f o u r a t t r i b u t e s :(a ) The B' state lasts a lo ng t ime ; (& ) th eB' state is in tense ly aver s ive ; (e) th e elici-ta t ion of S ta te A or A' is effective in caus-in g imme d ia t e r e mo v a l o f State B or B';and (rf) the user learns to employ the drugwhich elicits States A and A' in order toget rid ofState B or B'.A lasting cycle of ad d ic t io n wi l l not a r i s e ,even though A and B are repeatedly exper i-


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12 4 R I C H A R D L . S O L O M O N AN D J O H N D . C O K U I Tenced , if the proper t i e s of affect ive responseto a d r u g a re such that B fades out to base-l ine v e r y q u i c k l y . This is t rue because an-other dosage of the drug is never needed ino r d e r to get r id of the avers ive B state. Itquickly gets rid of i tself. This is the case inExample 5, a c o m m o n t y p e of p leasurab les i tua t ion . A labora tory dog is s i t t ing de-j e c ted ly in a cage. It is s u d d e n l y h a nd e done M & M candy . It wags its ta i l , movesabout , chews , a n d swallows. This ref lec tsS ta t e A. I t smacks its l ips a few t imes ,cur l s its tongue across its l ips , then becomesmot ionless an d tense. I t or i en t s toward th ee x p e r i m e n t e r and focuses its eyes on the ex-perimenter's hand (the one which held thes ingle M & M ). Assu m e this to ref lec tState B . Then, if a no t h e r M & M i s no tf o r t h c o m i n g , the B s ta te dies o u t a f t e rabout 15 to 30 seconds. The clog movesaway , wa lks a round the cage , sn i f fs here an dt h e r e , begins to ignore t h e e x p e r i m e n t e r ,then s i t s again. It has r e t u r ne d to i ts or igi -nal s ta te . Here a ga i n , t e r m i na t i o n o f o neh e d o n ic event has p rec ip i t a t ed ano the r s t a t enot present pr io r to the onset of s t im ula -t i o n , and the second state d i sappea red byi tself mere ly wi th the passage of t ime . Inthis case, A is pleasant , so we infer B to bequal i ta t ive ly di ffe rent , and probably cravingis th e best term for it . Th e so-called pea-nu t phenom enon in hu m ans i s comparab le .Once you start ea t ing peanut s , it is h a r d tostop unless th e cycle is i n t e r r u p t e d for aper iod longer than th e t i m e r e q u i r e d for thepeanut craving, o r B state, to die out . Thishas been called a mini -add ic t ion .3 I nd e e d ,th e case of the couple in t e r rup ted dur ingmutual sexual s t imula t ion, descr ibed in theI n t r o d u c t i o n , is ce r t a in ly s imi l a r .

In Example 6, the pleasurable input gen-era tes a condi t ion in which the B s ta te typi-cally lasts a lot longer than tha t for anM & M o r a peanut , and so the f a v o r a b l econdi t ions fo r a d d i c t i o n a re p r e s e n t . A b o yand gi r l fal l in love . T h i s S t a t e A ischa rac te r i zed b y p l e a s u r a b le e x c i t e m e n t , f r e -q u e n t s e x u a l feel ings , a p r e v a i l i ng m o o d ofecs tasy, happiness , and good feel ings . Whenth e lovers , whose m u l t i m o d a l m u t u a l s t i m u -

3 This t e rm w a s f i r s t suggested by E l i o t S t e l l a ra t a cockta i l party.

la t ion wi l l cause S ta te A, are separa ted fromeach other , they wi l l feel lon ely , sad, and de-pressed (State B). Even wi th an t i c ipa t ionsof reunion ( symbol i c , condi t ioned a ro u s e r sof S t a t e A ) lonel iness m ay preva i l . Ac tua lreunion wi l l s imul t aneous ly e rase B and re -ins t a t e A jus t a s desc r ibed in At t r ibu te cof addic t ion to opia tes .A f t e r severa l years o f repea ted mutua ls t imula t ion , t he qua l i t a t ive and qu ant i t a t ivechanges in A and B are a m a t t e r of publ i clore . S t a t e A' is chara cter ized ( i f a l l hasgone we l l ) as c o n t e n t m e n t , n o r m a l c y , an dcomfor t . B ut State B' is now potent i a l lyof h igh in t ens i ty and long dura t ion . If itshould occur, it is often called grief or, asBowlby (1952) has descr ibed it in ch i ld ren ,th e separation syndrome. I t r e q u i r e s alo t of t i m e fo r this B' state to decay . T hepar tne rs have become add ic t ed to one an-o th e r , and when sepa ra ted they exper i encew i t h d r a w a l s y m p t o m s . As in al l the pre-v i o u s f ive examples , no te tha t t he suddent e r m i n a t i o n of the s t i m u l u s t h a t a r o u s e s Aor A' leads to the o c c u r r e nc e of B or B'be fo re th e e v e n t u a l r e t u r n to emot iona l base-l ine or norm alcy . In th i s case , t he t e rmin a-t ion o fA', even though A' does no t m a n i f e s ti tself as i n t e ns e l y as did A , is fol lowed bya m o r e p o w e r f u l a n d m u c h m o r e p r o t r a c t e dB' state. This is the same pat tern seen inall the p rev ious examples , whe the r the Astate is p leasurab le o r avers ive .E x a m p l e 7 is one of i m p r i n t i n g . F f wetake the duckl ing as our s u b j e c t , it showsthe same pa t t e rns of affect revealed in opia t ea d d ic t i o n . Firs t , r ight a f t e r ha tch ing the reare very few dis t ress cr ies . Indeed , thed u c k l in g m a y appear to be qui t e happy wi thi t s new envi ronment . Then, i f t he duck l ingis exposed to a whi te , moving objec t , i tlooks inten t ly a t i t. Also, i f there we re anydis t ress voc al iza t ions , they ten d to d i sap-pea r . However, if the m o v i ng o b j e c t is t h e nr e m o v e d from v iew ( H o f f m a n , 1968; Hoff -m a n , S t r a t t o n , N c w b y , & B a r r e t t , 1 9 7 0 ) ,there i s a burs t of dis t ress crying w h i c hm ay last fo r severa l minu tes an d then dis-appear. W i th success ive p res enta t io ns a n dr e m o v a l s o f t h e i m p r i n t i n g s t i m u l u s , th ef r equen cy an d i n t e n s i t y o f d i s t r e s s c r y i n gwi l l increase .


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O P P O N E N T - P R O C E S S T H E O R Y O F M O T I V A T I O N 125The efficacy of the p resen ta t ion of themoving s t imulus in e l imina t ing th e d i s t resscries appears to be op t imal at the outset .

Then th e duck l ing can be shaped to push apole in order to present itself with the im-print ing s t imulus . At that poin t , of cou rse,th e duck l ing is exhibi t ing all c r i t e r i a foraddic t ive beh avior . I t i s hooked on thei m p r i n t i ng ob jec t , th e p resence of which isa posi t ive re in fo rce r and the absence ofwhich is an avers ive event .

Note that the ethological description ofimpr in t ing as the sudden es tab l i shmen t o f fo l lowing behavior , released by an ade-qua te impr in t ing s t imulus , i s u t t e r ly inap-prop riate in the light of our analysis . Themoving object releases some affective StateA , p re s u m a b l y an uncondi t ioned , pleasantemotional react ion to the moving s t imulus .The removal o f the s t imulus then p rec ip i -t a tes S ta te B , wh ich i s an ave rs ive even t .S ta te B intensif ies wi th repea ted s t imula-t ions. D uck l ings wi l l then wo rk on an avo id -ance schedule to p rev en t th e disappearanceof th e i m p r i n t i n g o b j ec t , j u s t as the opiateadd ic t wil l develop an t ic ipa to ry beha v io rwhich prevents the occurrence of a t leas tthe more in tense wi thd rawal symptoms .

E M P I R I C A L G E N E R A L I Z A T I O N SFirst, in all seven empi r ica l examples , aswel l as in the f ic t it ious o n es in our I n t r o d u c -t ion, the sudden onsetof some new s t imulusa ro u s ed an affect o r hedonic s ta te not p res -

ent pr ior to onset . The state terminatedw h e n the s t imulus t e rmina ted . Then , a news tate appeared , qualitatively unlike ei therthe p res t imula t ion s ta te or the state pro-duced by the onset and m a i n t en a n c e of thestimulus. Fin ally, this new posts t imulusstate persisted for a w h i l e and died out.The basel ine state ev en t u a l l y r e t u rn ed . Innone of the examples did the subject 's af-fective s t a t e r e t u rn d i r ec t l yt o base l ine uponcessa t ion of s t i m u l a t i o n . B a s e l i n e was re-gained v ia some new state which becamemanife s t a t s t i m u l u s t e r m i n a t i o n , and t h enslowly d ied away .Second , in some cases th e states changedin th e i r qua l i ty an d in tens i ty with successive,repeated s t imula t ions . W h en ev e r t h i s o c -

c u r r e d , the A states became weaker and theB states st ronger and longer lasting.These two phenomena , the dynamic he-don ic response pat tern , and its modificat ion

withrepeated experience, were seenwhetherthe A state w as p leasu rab le o r aversive.THE E X P L A N A T O R Y M O D E L

In our op in ion , the simplest theoret icalmodel that organizes these typical mot iva-t ional phenomena (and count less other phe-nom ena of innate and acquired mo tivat ion)isan opponent-process system. It was bor-ro w ed from p rev ious ly deve loped accoun tsof sensory dynamics (Hurvich & Jameson ,1957) . T h e p r i m a ry a process for a givenhedonic state is aroused by its adequates t imulus . We then imagine a single oppo-n e n t loop generat ing the secondary b processand hav ing an hedonic sign opposite to tha tof the state aroused by the inpu t . T he loopgenera t ing th e b p rocess is act ivated when-ever any inpu t evokes a sufficient hedon icconsequence. T he b process is sluggish, soit has a re la t ively long la tency , recrui tsslowly, and dies out slowly. Finally, theb process is s t rengthened by use and weak-ened by disuse.Because many fo rmal p roper t i es of thepa t te rns of both sensory and affective phe-n o m e n a seem so s imilar , we must show atth e outset that they are n o t iden t ica l andthat the standard pat tern of affective dy-namics is n o t a d irect consequence of thepa t te rn of senso ry dynam ics . Otherwise ,one could explain allhedon ic or affective dy -namics in term s of sensory events . Forexample , in the case of the w o m a n w ho dis-covered the lump in her breast , one mightargue that her steady-level anxiety state wasless intense than her in i t ia l peak of terrorat the discovery of the lump because ofsensory ada pta t ion ; that is , the perceivedpresence of and m a g n i t u d e of the l u m pdec reased . W e can refu te such an i n t e r p r e -t a t ion , leaning heavi ly on the fact that th etime course of typ ica l senso ry dynamics isof a completely di f feren t o rder of m a g n i t u d ef rom that of the s tandard pa t t e rn of affec-t ive dynamics re f lec ted in Figure 1 a ndTa b l e 1 . S ensory changes usu a l ly occur in


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126 R I C H A R D L . S O L O M O N ANDJOHN D . C O R B I Ta ma t t e r of mil l iseconds, seconds, and min- occur in minu te s , hour s , days , weeks , andutes, whereas the emo t iona l changes usua l ly mo n th s . T h e r e is, therefore , a theoret icalPbnel A. THE PROCESSINGSYSTEM

nodoUL J L

^nvironmentalstimulus:adog

yesf

Cognitive-Perceptualcategorical,all-or-nonedetectornetwork

J L^ ,CognitivePerceptualsignal;ye s -nodetection

Affect iveor Hedonic

^f fect ivesignal

Panel B. THE AFFECTIVE STAGE OF THE SYSTEM

FIRST nL COMPONENT

^Cognitive-PerceptualsignalProcess a :a f f e c temotionhedonic tonefeelingmood

s

a-signal

-t -0

>

SECONDCOMPONENT

Process b =

THIRDCOMPONENTSummingdevicea + b,whereb is - )

/

1

opponent-a f f e c topponent-emotionopponent-hedonic toneopponent-feelingopponent-mood


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O P P O N E N T - P R O C E S S T H E O R Y O F M O T I V A T I O N 127necessity for a d is t inc t opponent-processmechanism fo r affect and motivation in -dependent of mechanisms for sensory dy-namics.

Figure 3 illustrates th e typeo fsystem thatw e h a v e in mind. Panel A shows tw ostages of in fo rmat ion processing, a cogni-tive-perceptual stage that converts the stim-ulus to an informational signal, and anaffective or hedonic stage that converts th einformat ional signal to an affect ive signal.The affective system in Figure 3 receivesasquare wave input,and fol lows itwith a dy-namic affective response of the standardpattern shown in Figure 1 .Perhaps an example will clarify the pointof Figure 3. The sight of a dog is a fear-arousing stimulus for acat. The dog repre-sents a complex, multidimensional display,and the perception of the dog is categorical,al l-or-none. The stimulus sequence is asfo l lows: The dog enters the cat's environ-m en t , remains for a while, and then leaves.The cognitive-perceptual sequence is: Thedog is detected, continues to he detected aslong as it remains, and then ceases to bedetected when it leaves. There is no adap-tat ion (i.e., the dog does not become lessd o g l i k e ) , nor is there any appreciable sen-soryafter-reactionat stimulus removal (i.e.,no negative [antidog?] afterimage). Theaffective sequence, in contrast, will show theprimary reaction and after-reaction compo-n en t s: intense fear at first, subsiding to asteady level,and then, whenthe dog isgone,th e appearance of another state, very dif-feren t f rom the f i rs t . The after-reaction( r e l i e f ? ) then gradually dies out.Figure 3, Panel A, shows that the affec-t ive system follows its square wave inputw i t h an output having th e complex dynamicfeatures of Figure 1 . How can we accountfo r this behavior? T he affective system inPanel A is shown as a single stage. Now,w e will open the black box fo r this stagean d look inside. O ur proposal for themechanism responsible for affective dynam-ic s is shown in Figure 3, Panel B. Here,the affect ive stage is analyzed into its threeco mp o ne n t parts. The cognitive-perceptualstage has acted as a categorical detector.T h e i n f o r m a t i o n a l signal enters the affec-

t ive system as i n p u t to th e first component,the a process, which has a short time con-stant. The signal from the a process acti-vates the second component or b process,which responds with a slow rise and a slowdecay. The third component is a summingdevice that adds th e a and b signals, and i tgenerates as its output the affective signal,w h i c h shows the sequence of the peak pri-mary reaction A, adaptation, steady level,after-react ion B, and decay of B. Thus,w e see that the input f rom the perceptual-cognitive stage has an affective, hedonic sideeffect, Process a. When it does, the oppo-nent loop is activated, calling into play theopponent process (which has a hedonicquali ty in some w ay opposite to , and verydif feren t f r o m , that o fProcess a). T h e o p -ponent process, which we call Process breduces the hedonic intensity of the statewhich the input initially aroused. When theperceptual-cognitive input ceases, the op-p o ne n t process reveals itself as pure StateB , because the b process takes a while todecay.

The opponent process is a slave processIt is activated indirectly via the activationof th e a process. Presumably, th e slaveprocess has an evocation threshold, a la-tency , a recruitment or augmentation time,and a decay func t ion , all characteristic ofa given opponent-process system. We willalso see later that the opponent process can,under proper conditions, be activated byevents inmemory,as aconsequence of Pav-lovian conditioning procedures.The block diagram of the affect-controlsystem in Figure 3 yields the temporal dy-namics of affect shown in Figure 4, PanelA. There we first see a baseline state.Then the affect-arousing stimulus is pre-sented and itstays on for 10seconds. Next,it issuddenly terminated. Thissimple eventsequence activates th e underlying opponentprocesses. First, there is a quick rise o fProcess a to apeak intensity. Shortly af te r -ward, there is aslow recruitment of Processb . When th e s t im u lu s is terminated, Pro-cess a quickly goes to zero, but Process b ,h a v i n g a sluggish decay property, persever-ates and dies o u t slowly. T h e resultantmani fes t dynamics of affect are a conse-


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128 R I C H A R D L. S O L O M O N AND J O H N D . C O R B I T

AMANIFESTAFFECTIVE 0RESPONSE

B

UNDERLYINGOPPONENTPROCESSES

STIMULUSEVENT

Panel A.

FIRST FEW STIMULATIONSPanel B.

AFTER MANY STIMULATIONS

g b

TIME

FIGURE 4 . Panel A: The opera t ion of the summi ng dev i ce for the f irs tfew s t i mul a t i ons . (The s u m m a t i o n of the unde r l y i ng opponen t p rocesses ,a and b , yields th e m ani fes t a ffec t iv e response . ) P anel B : The ope ra t i onof th e summing device a f ter many repea ted s t imula t ions .quence of subtracting th e b process from th ea process . The subtraction of the two qu an-t i t ies yie lds Manifes t S ta te A when a > band yields Manifes t Sta te B w h e n b > a .The intensity of the manifes t s ta te is givenby the quan t i ty |a b \ .W h e n w e subtract the un de r ly in g pro-cesses, a and b from each other , we obta in

the manifes t affective response patternshown in Figure 5. Imm edia te ly a f te rs t imulus onset , a is large and b is zero, thusyield ing a peak of S ta t e A. As b is s lowlyrecruited, th e quanti ty \a b\ decreases,yielding a dec l ine in the m a g n i t u d e of S ta t eA . Th i s is the adaptat ion phase shown inF ig ur e 1 , th e s tandard pa t te rn of affective

+100

toNeutral oca

J5to 100

First Few StimulationsPEAK OF A

ADAPTATION^STEADY LEVEL OF A

4 OF BPEAK OF B

ONTIME

F I G U R E 5 . The m an i fe s t t empo ra l dynami cs g ene ra ted by t he opponen t -process system during the f i rs t few s t imula t ions . (The f i ve fea t ure s o ft h e af fec t ive r es pons e a re l ab e l ed . )


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O P P O N E N T - P R O C E S S T H E O R Y O F M O T I V A T I O N 12 9dynamics . W h e n th e b process reaches anasymptote, there wi l l be a steady level ofState A . Then , when the s t imulus is ter-minated, th e intensity of a goes quickly tozero, but the b process dies away slowly.A t t h i s m om en t , b > a , y ie ld ing the peakand subseque nt decay of S ta te B. At t h i spoint ,State B ispu re b .T he theory represented in Figures 3 and4 gives a rough, qualitative account of allof th e data ofTable 1 , for the first few st im-ulat ions only. First, it explains peaks ofintensity of affect or hedonic qual i ty at st im-ulus onse t : T h e opponent process has notyet had enough t ime to get into action. S ow e see phenomena like terror, th e rush,ecstasy, etc. Or, rate the pa infu lness of a30-second shock. The peak pa in fu lness isat onset. For example, see the peak ofheart rate in Figure 2 .T he other major event explained by thetheory is the emergence of the after-reaction,postulated to be a funct ion of the opponen tprocess , which becomes manifes t after thete rmina t ion of s t imu lus inpu t . This emer-gence is due to pu re b persevera t ing in t i m eafter the a has quickly disappeared. TheB state slowly decays, and baseline is even-tually at tained.In each of the seven empirical examplesof Table 1, th e mani fes tB state was, in someunspecified way, related to A, but not thesame as A. The model designates th e rela-t ionship as oppositeness. But in w hat waycan we say, for example, that lonel iness isopposi te to the pleasure produced by thepresence of a loved one ? S ure ly , they arehedonically opposed. Th is conce pt is bui l tinto the theoretical model. If A is pleasant,then B must be unp leasa nt . If A is a posi-t ive re inforcer , then B is a negat ive rein-forcer. Other affective attributes of A andB rema in an empirical quest ion. The modeltells us how to identify the a t t r i bu t es ofoppositeness. All one has to do, for anygiven A state, is observe the a ttrib ute s ofaffect wh i ch are revealed at the peak of B.Therefore, the model puts a cons train t onw hat we cal l oppositeness . For exam ple,th e opposite of love must be the a t t r ibu tesof grief. To say that , Hate is the oppositeof love is s imply wrong, when at the death

of a loved one, one experiences grief, nothate . The k ind s of opposi teness w hich aregenerated by each A state are still, in m anycases, waiting to be studied and named.Here is a vast , neglected area of investiga-t ion.W e pos tu la ted tha t the /;process is aslaveprocess. That means tha t at first it cannotbe aroused direct ly by ordinary sensory in-puts, but instead can arise only indirectlyvia th e arousal of an a process (see Figure3) and the subsequent activation of the op-ponent loop. This fits common sense. Tryto imagine being grief-s t r icken without hav-ing loved someone. Try to imagine cravingand abstinence agony without drug use.Try to imagine the exhilaration of the para-chutist without any j u m p . On the otherhand , we wil l point out later that it may bepossible to arouse a b process directly byelectrical or chemical st imulation of thebra in , or to el iminate it by surgery, or tocondition it by Pavlovian procedures. In-itially, however , it is a slave process, inac-cessible to direct environmental inputs, butindirectly arousable via hedonic and affec-tive processes elicited by env i ronm en t a linputs .S T R E N G T H E N I N G O F O P P O N E N T P R O C E S S E S

B Y R E P E A T E D S T I M U L A T I O NW e have not yet explained th e changes inhedonic dynamics brought about by repeatedaffect-arousing stimulations over a relativelylong period of t ime. There are important

differences between the A and B states onth e left side of Table 1 as comp ared to theright side. F ortu na tely, one postulate bringsorder into the d a t a : The opponent processis strengthened through use and weakenedthrough disuse, but the pr imary affectiveprocess is not seriously affected by use. Ab process wil l acquire more power if fre-quently elicited. It will show a sho rterlatency of response to a, a quicker rise, ahigher asymptote, and a longer decay t ime.In contrast , an a process is a relativelystable, unc ond i t ioned react ion. This seemsreasonable for a system which is designedto m i n i m i z e dev ia t ions from affective neu -t r a l i ty . W hy should an opponent processnot act like a defensive or i m m u ni za t i o n pro-


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130 R I C H A R D L. S O L O M O N AN D J O H N D . C O R B I TAfterManyStimulationsnn JUUO

Neutraleo

1001

STEADY LEVEL OF A'-=^>- .- - - _ - _ . _ Baseline

PXEAK OF B'

ONTIME

F I G U R E 6. The man i fe s t t empora l dynamics genera ted by the opponent-process system a f t e r many repea ted s t imulat ions . ( T h e m a j o r features ofthe modified pa t t e rn a re labeled.)

cess , which produces ant ibodies more e f f i -ciently and in larger numbers in the faceof repeated challenge? In the same vein,disuse should weaken a b process, and itshould slowly return to i ts original magni-t u d e whenever its aprocess has not occurredfo r a long t ime.

Figure 4 , Panel B , shows how the oppo-nen t processes will interact after the b pro-cess has been strengthened by repeated use.A comparison of Panels A and B explainswhy the left-hand portion of Table 1, de-scr ibing early st imu lation, differs from ther ight-hand port ion of Table 1 , describing later st imulations.The effect of repeated experiences on thehedonic response is confined to strengthen-ing the bprocess . D uring later s t imulat ionsth e b process increases at a fas ter rate ats t imulus onset and reaches a greater asymp-totic inten sity. In additio n, the b processrequires a much longer time to decay afterthe later s t imulus terminat ions. A s a con-sequence of these changes in the b process,the resul tant pat tern of the affective reactionchanges so that th e peak of A is cons ider-ably at tenuated, and the peak of B becomesmu ch greater and longer lasting. Figu re 4,Panel B, shows these s imple algebraic sum-

mat ions of the a and b processes after m anyrepeated s t imulat ions.Figure 6 shows the pat tern of emo tionaldynamics af te r many repeated s t imulat ionsand should be contrasted with the pat ternshown in Figure 5. Three phenomena arecorollaries of the use postulate. First, th epeak of A' will be less intense because th elatency of the b process is decreased and itsin tensity is increase d. S econd, the steadylevel of A', |a b\, during maintaineds t imulation will be close to baseline and per-haps even below it in some cases. Th ird,th e peak o f B' should be intense and longlast ing, compared to what i t was duringearly s t imulat ion (Figure 5 ) .The events in Figure 6 do not follow froma simple affective contrast model . If a p r i n -ciple of simple hedonic or affective contrastwe re o pera t ing , then the peak of B inFigure5 should be greater in intensi ty than it is inFigure 6, because the intensity of A directlyprior to s t imulus terminat ion is greater in

Figure 5 than it is in Figure 6. However ,i f we run down the descript ive adject ivesfo r States A, B, A ', and B' in Table 1,even as loosely defined as they are, theopponent-process model works well , and as imple contrast model fails.


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O P P O N E N T - P R O C E S S T H E O R Y O F M O T I V A T I O N 131M ore convincingly, the ob jective datafrom the electrocardiograph experimentswith dogs fit the opponent-process model.In Table 1 we saw the following:

A, large accelerat ion;B, small overshoot , short durat ion;A ', small or absent accelera t ion;B', large ov ershoot, longer lasting.These findings fit the postulate that repe-titions of affect-arousing st imulation, in thiscase shocks, will strengthen the opponentprocess which dampens the pr imary cardiacacceleration process. Fu rtherm ore, there

are many s igns of qual i ta t ivechanges; e.g.,signs ofpleasure and euphoria appear in theperiod following terminat ion of the shocksession, although they were absent in earliersessions. Ou r m odel canno t yet deal pre-cisely w ith these qua litativ e changes whichare produced by many repetitions of thesame s t imulus. A' is less intense than A ,and B' is more intense and longer lastingthan B. The model deduces these quantita-tive changes (F igu re 4). In many cases,however , A' is qualitatively different fromA , even though they have the same hedonicsign. Similarly B' and B are sometimesqualitatively different, even though theyhave th e same hedon ic sign. W hen th emodel is fully developed, it must contain arationale for these qu ali tat ive changes.The observations on the right-hand sideof Tab le 1 also support the assumption thatma n y repeti t ionsofpleasures will strengthenthe i r aversiv e oppo nent processes. Av ersivestates, m anife sting themselves after the sud-den termination of pleasurable inputs, be-come more intense with repeated experi-ences. M ild loneliness later becomes grief.Mild craving later becomes abstinence agonyand intense craving. In addition, aftermany repeti t ions th e steady level of plea-sure produced by the continued presence ofthepleasurable s t imulus input has decreased.The confirmed opiate user experiences a loss of euphoria, and the rush is gone.The pleasure -affective systems seem even-tually to yield to opponent processes whichkeep departures from hedonic equil ibr iumrelatively sma ll. The ave rsive opponentprocess, when it is manifest , is more intense

and longer lasting than it once was. S o fre-quently repeated pleasure has its costs, psy-chologically, in an increased potentiality fo rdispleasure.Similarly, for A' states aroused by aver-sive input, there is a cost, but this costis an increased potentiality for pleasure.Table 1 lists in the column under B' theopponent affects for the aversive A' states.W o r d s like joy, exhilaration, and goodfeeling appear. These are the emotionalcosts of aversiveness. The m odel thu s re-quires that any prolonged or repeated de-partures from hedonicor affective neutral i ty ,regardless of hedonic sign, have a cost.Any significant departure from hedonic oraffective neutrality should have correlatesin increased auton om ic and central nerv oussystem activity aimed at reducing that de-par ture . The cost of this activity will notonly be psychological, but alsowill be physi-ological (metabol ic , hormonal , and n eura l ) .We are assum ing that prolonged exerciseof an opponent-process system, whether itbe pleasurable or aversive, might cause

physiological stress in the same sense thatSelye (1950) uses th e term stress. That is ,many physiological resources might be re-quired in order to keep the opponent pro-cess strong. If we follow Selye's argument,we would expect that such a constant de-mand might lead to the exhaustion of a par-t icular ove rwo rked opponent-process systemor to the debilitation of other defensivesystems.Thus we come to a m ajo r implicat ion ofour opponent-process model: There proba-bly are stresses caused by pleasurable stim-ulat ion just as there are stresses causedby aversive stimulation. Therefo re, thereshould be adaptational costs as a conse-quence of both k inds of stresses. Fur the r -more , if we look fo r them, we should finddiseases of adaptation jo r both, due to thecorrelated, phy siologica l side effects of long-duration often-elicited intense b processes.In the past, psychologists have identifiedpsychological stress with aversion, pain, andunpleasantness. Theories of mental disease,psychosomatic disease, and behavior disor-ders usually emphasize that aversivenessmeans stress, stress means aversiveness, and


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132 R I C H A R D L . S O L O M O N AN D J O H N D . CORBITboth cause emotional d isorders , psychoso-mat ic illnesses, and behav io ra l m al fun c t ions .O ur opponent-process theory of mot iva t ionpu ts all th is to quest ion. From our po in tof vie w , s t resses caused by avers ive s t imu-la t ion are only one half of the story. Thereshould be emotional d isorders , psychoso-mat ic diseases,and beha v io r d i so rders causedby long-las t ing, repeated , and intense b p ro-cesses in genera l , whether these opponen tprocesses are p leasu rab le or avers ive .

Take the case of the parachu t i s t s . Theiroperan t beh av io r , wh en B' is st rong, wi l l b ere inforced by the pleasurable experience ofB'. Bu t the cost o f n eu t r a l i z i n g the inna teaversiveness of a fall through space mightbe h igh , both physio logical ly and emot ion-ally, j u s t as Epstein (1967) has postulated.Even so , one might imagine , i f there wereno other p leasurable sensory i n p u t s else-where ava i lab le to the i n d i v i d u a l , t h a t h em i g h t p u t himself thro ugh repeated avers ives t imula t ion in o r d e r to exper ience the plea-surable B'state w h i c h w o u l d b e bo th in tenseand lasting. From our point of view, th istype of apparen t masochistic behavior is nota m en t a l d i s o rd e r but is, ra ther , a reflectionof th e normal fu n c t i o n i n gof a heal thy , au to-mat ic , affect-contro l system. Th us , a lso ,f rom th is point of v iew, there is noth ing ab-n o r m a l or st range about addict ion. It isonly a social ly v iv id example of the n o rm a lhedon ic and m o t i v a t i o n a l func t ion ings of anefficiently operat ing af fec t-control sys tem.Mot iva t iona l sys tems invo lv ing p leasu r-ableA statesand avers ive A states are simi-lar . In both cases the onse t , main tenance ,and te rmina t ion o f the s t im u lu s resul ts in acer ta in amount of p leasu re and a certa ina m o u n t of d i sp leasu re . They differ m a i n l yin whether p leasu re o r displeasure comesfirst. In the case of the p leasu rab le Astates, we can assume tha t th e s u b s eq u en tavers ive B state func t ions as a d r ive tha tenerg izes the per fo rmance o f operan t s , andtha t the pleasurable A states may positivelyre inforce these operan ts . E lectr ical self-s t imula t ion of reward ing b ra in s i t es , chemi-cal self-s t imulat ion with opiates , and loverelat ionships should work th is way. In con-t ras t , when the A state is avers ive , andw h e n the A state s t imulat ion is absen t , no th -

ing func t ions as a d r ive to energ izean oper-an t u p o n w h i c h the A state is con t ingen t .S o w e have the problem of how to get thebehavior s tar ted . T h e B state for an aver-sive A state is not an energ izer . Ins tead ,it is a posi t ive re in fo rce r . There is thus ani m p o r t a n t asymmetry b e t w een m o t i v a ti o n a lsys tems for pleasurable and avers ive As ta tes. S ome ou ts ide energ iz ing inf luencei s needed to get behav io r s t a r ted when th eo p e ra n t is fo l lowed by an avers ive A state.Examples o f such behav io rs inc lude thrill-seeking beh aviors , such as p a ra c h u t e j u m p -ing , mounta in c l imbing , au tomobi le rac ing ,etc . , a l l of which involve an avers ive com-ponen t , fol lowed by a p leasu rab le fee l ingo fexh i la ra t ion . W h y should o ne ini t ia te anact iv i ty when i ts immediate effect is aver-sive, i . e . , wh en a p un ishm ent con t ingencyex is t s? S ome compet ing ou t s ide inf luence ,such as social pressure f rom peers , is re-q u i r ed . Ho w ev e r , af te r many repea tedst imulat ion s , such ou ts ide influences ma ynot be needed . Because th e aversive A stateis t h en w ea k and the subsequent , posi t ivelyr e in f o r c in g B state is strong, the A statewil l funct ion as a pos i t ive re in fo rcer . W eknow that th is can happen when a w e a kshock s ignals the onse t of food for cats( M a s s e r m a n , 1943). No te tha t an out-side inf luence is not n eed ed w h en the Astate is pleasurable. These o p e ra n t s areenerg ized by the a v e r s i v e B state.

R E L A T I O N OF THE T H EO R YT O OTHER C ON C E PTSTo the reader wel l versed in the his toryof theor ies of learn ing , tw o aspects of ourm o d e l shou ld no w b e apparen t . First, th ep h en o m en a of acqu i red mot iva t ion p roducedmerely by the repet i t ion of affect-arousingst imul i are nonassociat ive in na tu re . Forex a m p l e , th e person repeatedly dosed withm o rp h i n e d o es n o t h a v e to k n o w a n y t h i n g

and is not requ i red to be sub jec ted to P a v -lovian s t imulus con t ingenc ies , nor to con-t ingencies between operants and ou tcomes ,in o rd e r to develop an increas ing tendencyto suffer w h e n th e m o r p h i n e is w i t h d r a w n .T he m o d e l is therefo re very dif feren t f romprev ious theo r ies o f acqu i red mot iva t ion ,


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O P P O N E N T - P R O C E S S T H E O R Y O F M O T I V A T I O N 133all of which have emphasized associat ionalprocesses.S econd, the m ode l, in relating i ts hypo-thetical mechanism to the phenom ena ofoperant con di t ioning, expl icit ly assumes thatoperants are energized only by aversivestates and that they can be reinforced ei therby the onset of pleasurable states or by thete rmina t ion of aversive states. This is thecase whether th e pleasure or aversivenesscomes from A states or B states. For ex-ample , th e re inforc ing effects of shock ter-minat ion wi l l not only be due to the elimi-nat ion of the aver s i ve A state but also, andperhaps more important ly , it will be dueto the subsequent pleasurable B state.Woodwor th a n d Schlosberg 's (1954) con-cept of safety, M ow rer's (1960) con-cept of re l ief , and D enny ' s (1971) conceptof relaxation are all emphasizing this con-cept of re inforcement in aversive s i tuat ions.T he assumption that operants are ener-gized only by aversive states fits most com-fortably wi t h the theoretical posit ion takenby Hull (1943 , 1952) and elaborated byM owrer ( 1947 ) , M i l l e r (1948), Spence( 1 9 5 6 ) , an d B r o w n ( 1 9 6 1 ) . T h e assump-tion that operants can be reinforced by theonset of pleasurable states fits easily withthe posi t ion taken by Y o u n g (1955) and byPfa f fman (1960). O f course, th e assump-t ion that operants are reinforced by theterminat ion of aversive states is most l ikethe drive-reduct ion posi t ion maintained es-pecially by Hul l (1943) and by M owrer(1947). These assumptions are really notat issue for us. W e take all three to beaxiomat ic , a point of departure, and we goon from there to spell out the dynamics ofpleasurable and aversive states.

C O N D I T I O N A B I L I T Y OF A S T A T E SA N D B STATES

T he opponent-process theory would en-compass an even larger array of data onacquired motivat ion if it could be safelyassumed that A states, or B states, or bothcould be brought under the control of pre-viously neutral s t imul i as a consequence ofexperience. A Pavlovian condi t ioning pro-cedure then would result in the establish-

m e n t of condi t ioned s t imul i which couldevoke either state as a conditioned response.Assume that w e have a valid measure-ment of the intensi ty of affect produced byth e onset and maintenance of a 10-secondshock in dogs and t ha t we can measure th eopponent process when it reveals itself di-rectly after shock terminat ion. No w we re-peatedly pair a condi t ioned s t imulus ( tone)with shock onsets. If a Pavlovian condi-tioning process is effective, then the condi-t ioned s t imulus would then become an A-state elicitor. W e call such a conditionedst imulus a C S A . (In the Pavlovian frame-work such a condi t ioned s t imulus would becalled a C S + . ) If wepresent a test trialwith C SA , wi t h no shock presented, w eshould s e e C S Aarouse a conditioned StateA (or a weak re la t ive) . W hen C S A is sud-denly terminated, w e should see S ta te Bappear, peak, and then decay to baseline int ime. The hedonic recovery from such atest with CSA alone should therefore ap-pear to be biphasic.C ontrast this with wh at should occur ifw e establish a condi t ioned s t imulusby pair-ing a signal with the peak ofState B, whichwill occur directly following shock termi-nat ion. That paradigm is Pavlovian back-ward conditioning: The conditioned stim-ulus always fol lows terminat ion of theunco nditioned stim ulus closely int ime. Sucha conditioned stimulus should become a Pav-lovian C S , or in our terminology, a C S n .It should beable to elicit a conditioned statevery similar to S tate B . A test with CSs(wi t hou t a shock preceding it) should resul tin th e condi t ioned State B appearing at theonset of CSa. Then , after C S u terminat ion,State B should decay monotonical ly , andbaseline should be reestablished. In otherwords , a monophasic recovery followingC S n terminat ion should occur , whereas abiphasic recovery ought to occur followingC S A terminat ion . W h y a monophasic re-covery for B ? Because, if the b process isa slave process with respect to a , and yetthe resultant states are also conditionable,then w e ought to be able to arouse th e bprocess directly by onset of a C SB , but then,after CSB has terminated , all State B cando is die away . But a C S A ,if successful in


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134 R I C H A R D L . S O L O M O N A N D J O H N D . C O R B I T

2016-12-

8 -4-

- C S +

+10 +15 +2 0 +2T+30,Pos-CSre-CS CS

Successive5-Second PeriodsFIGURE 7 . Data f r o m Rescorla an d LoLordo(1965). (Th e so l id l i nes an d dots show th e b i-phas i c re sponse fo l l ow i ng te rmi na t i on of the f e a r -a rous i ng condi t i oned s t i mul us [CS]. In t h i s g rapht h e C S + i s a C S A . T he dot ted l ines and opencircles show th e monot on i c recove ry fo l l ow i ng thet e r m i n a t i o n of the fea r -suppress i ng condi t i oneds t i m u l u s . I n t h i s g r a p h th e C S i s a C S u . )

elici t ing the cond i t ioned a process , wi l l alsoindirect ly arouse its oppo nent process.Therefo re , S ta te B wil l be seen immediatelyaf te r CSA is sudden ly t e rmina ted , y ie ld inga b iphas ic recovery . But a peak of State Awill never be seen after aCSB ist e r mina t e d:On l y a re t u rn of State B to basel ine wil loccur .

In comtnonsense t e rm s , w h a t the oppo-nent-process theory is saying for the caseof condi t ioned fear is pecul iar . The suddent e rm i n a t i o n of a danger signal (CSA)should cause the condi t ioned subject to actas though it had received a safety signal.But the sudden te rmina t ion of a safety sig-na l ( C S n ) shou ld n o t cause th e cond i t ionedsub jec t to act as though it had received aclanger s igna l . An ana logous asym m et ryshould of course exist for appet i t ively con-di t ioned s t imul i , though we are no t a w a reof th e exis tence of exper imenta l da ta onth i s po in t .Some Pavlovian condi t ioning data fitthese expectat ions very w el l for avers ivest imulat ion. Rescorla and LoLordo (1965)t ra ined dogs to avoid shocks on a S i d m a nnons igna l ized avo idance schedu le (shock-shock interval 10 seconds , response-shock in terval= 30 seconds). The avoid-ance response rate was used as a m ea s u reof fear in tens i ty . W hen the dogs' avoid-

ance response rate h ad stabi l ized , they weretes ted du r ing avo idance per fo rmance wi th aCSA w h i c h h ad p rev ious ly been pa i red wi thshock onsets dur ing separa te Pav lov ianfea r -condi t ion ing sessions. Th e onset of theCSA d u r i n g th e shock-free tests resul ted ina large increase in the avo idance responserate . This w a s in te rp re ted to m ea n t h a t th eavoidance response was energized by the in-c rem en t o f condi t ioned fear caused by thepresen ta t ion of the CSA. T h e mos t inter-es t ing phenomenon to us is the fact tha trecovery from a CSAtestwasbiphasic . Theavoidance response rate, w h en CSA was te r -minated , dropped quickly below basel ine,then recovered slowly to baseline in 30 to45 seconds (see Figure 7 sol id l ine withsolidcircles).Rescor la and L o L o r d o (1965) used a dis-c r imina t ive cond i t ion ing fea tu re , w i th acond i t ioned s t imulus pa i red wi th a longshock-free inter t r ia l in terval . When th econdi t ioned s t imulus was tested d u r i n g theclogs' avoidance performance, i t suppressedth e avoidance response rate . Then, w h e nthe cond i t ioned s t imulus was t e rmina ted , thera te s lowly re tu rned to baseline in 30 to4 5 seconds (see Figure 7, dot ted l ines withhol low circles) . T h e recovery f rom th econd i t ioned s t imulus w as exact ly what w eshould expect i f the condi t ioned s t imulushad been condi t ioned to the B state. In-tu i t ively , o ne migh t th ink that th e t e r m i -nat ion of the cond i t ioned s t imulus , wh ichis , a f te r all , a safety signal, ought to causea sudden intensif icat ion of fear above theoriginal fear baseline. This does no t hap-p en , an d adds s t rength to the theoret icalanalysis wehavepresented . How ever , thereis a ser ious problem in applying the modelto these data on Pavlovian di ffe rent ia l con-di t ioning. T h e cond i t ioned s t imulus w asalways presented fo l lowing an in te r t r i a l in -te rva l of m i n u t e s or longer . Th erefo r e ,by no stretch of the imaginat ion could w econsider the condi t ioned s t imulus to havebeen regularly paired with the peak of B,because the peak of B would have occurredvery shor t ly af ter the previous shock termi-na t ion . How, the n , can we manage th i sconcep tua l p rob lem ? I f we a re to s taywi th in the conf ines of our m o d e l , w e m u s t


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O P P O N E N T - P R O C E S S T H E O R Y O F M O T I V A T I O N 135m a k e t w o assumpt ions . First, af ter m a n ycondi t ion ing t r i a l s d u r i n g w h i c h h u n d red sof shocks have been sustained, the bprocessw o u ld be very s t rong and last a long time(p e rh a p s fo r m a n y m i n u t e s , o r even fo rhours). Second, we m ust assume contem-poraneous cond i t ion ing ,an event state con-d i t ion ing process , where the condi t ioneds t im u lu s is the event and the state is B.This is an assumpt ion for which we haveno empirical support .T he f indings of Moscovi tch and LoLordo(1968) add more unambiguous support forthe cond i t ioning of a B s ta te . U sing thesame exper imenta l s i tua t ion as did Rescor laa n d L o L o rd o ( 1 9 6 5 ) , they employed a Pav-lovian backward-cond i t ion ing parad igm toestablish a CSB. According to our analy-s i s , th i s shou ld pa i r the CSB onset wi th thepeak of B and create a max imal ly powerfulCSB. R e c o v e r y from a short-durat ion tes twi th such a CSB shou ld be mono ton ic , be-cause there is no m ec h a n i s m w h ereb y the bprocess could engender the a process. Thisis indeed what happens , as shown in Figure8. Tests w i t h CSB caused a reduct ion inavoidance response rate to a level about 1/5of t h a t d u r i n g th e base l ine per fo rmance .Recovery to basel ine af te r CSs te rmina t iontook more than 30 seconds (see Moscovitch& LoLordo , 1968, p . 675 , Figure 1), and itw as m o n o t o n i c . M o s c o v it c h an d L o L o r d or e fe r r ed to the backward cond i t ioned s t imu-lus as a safe ty signal ; they reported theirdogs to be re l a x ed ; t h e re w ere n o indi-cat ions of f reez ing o r fr ight [p .675]. Thisrelaxation occurred in spite of the fact thatth e dogs were still in the avo idance- t ra in ings i tua t ion, w h i c h w as f r igh ten ing enough tomotivate a steady rate of avo idance re-sponses (abou t six per m i n u t e ) . So theirb a c k w a r d cond i t ioned s t imulus met a l l thecr i te r ia for a cond i t ioned s t imulus for a Bstate.To convince oneself that B-state condi-t i on ing has indeed occurred , i t might notbe sufficient merely to show that the back-w ard cond i t ioned s t imu lus wi l l suppress anongo ing S idman avo idance response . Thedecrease could reflect a reduc t ion of fear , adecreased expectation of shock, or bothra ther than some p leasan t hedon ic state wi th

3 -21-

J5 -10 -5Pre-CS

+15 20 25 30,Post-CSFIGURE 8. Data f rom Moscovi tch and L o L o r d o

(1968). (Here we see the response to a Pavlo-vian backward cond i t ioned s t im ulu s [C S]. Therecovery f rom t he condi t ioned s t i m ul us p re sen ta -t ion is m o n o t o n i c and is a C5n.)positive reinforcement properties. Two linesof ev idence wo u ld help . First, the gross be-havior of the subjects , such as ta i l waggingin th e presence of the backward cond i t ioneds t im u lu s , would suggest a qualitatively dif-fe rent state from that which the avoidancesi tuat ion no rm al ly evokes . S econd, thedemons t ra t ion that a backw ard conditioneds t imulus wou ld subsequen t ly re in fo rce th edeve lopment of a new operan t in a non-fearful situation might strengthen the con-vict ion that the condi t ioned s t imulus wasreally a CSB of a p leasurable sort .We have seen that Pavlovian laws seemto apply well to the conditioning of bothA states and B states precipitated by aver-sive s t imula t ion . We should then expectthe same laws to hold for A states and Bs tates precip i ta ted by pleasura ble sensoryevents . Firs t , th e c o n d i t io n ed s t i m u l u seven ts for p leasu rab le A states should beposi t ive re inforcers , should be able to rein-force operants , and finally shou ld b e ableto counter and sometimes even temporari lyeliminate the B state. Therefore, in opiateadd ic t ion , p resen ta t ion o f a d rug con ta iner ,a syringe, a needle prick , or a room full ofsatisfied addicts should all tend to funct ionas C SA s wh ich wou ld oppose the B stateby arous ing a condi t ioned A state . S uchcondi t ioned opposi t ion would of course beweaker than that produced by the opiatei tself , but i t shou ld be detectable. M any


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136 R I C H A R D L . S O L O M O N AN DJ O H N D . C O R B I Top ia te addicts actual ly give themselves sham in jec t ions . Even the fami l i a rsocial surroundings where the drugs are ob-t a ined and used should have CSA proper -ties. They should temporar i ly reduce crav-ing and abstinence panics. C linical evidenc esuggests that this is indeed the case ( M a u -rer &V ogel, 1967; Wikler, 1971).T he action of 83 events should be evenmore interest ing in addict ion, because theyshould augment the B state an d producemore intense craving. S uch C S n S wo u ld bethose paired with th e peak of B, the mostintense craving state . Thu s, w e would ex-pect a variety of social and personal eventsto become conditioned arousers of craving.In general, they should be events and placesassociated with lack of the addictive drug.A ja i l cell, confinement , lack of mo ne y , allof these should be able to arouse a condi-t ioned B state to augment an existing un-condit ioned B state. Perhaps the occur-rence of the condit ioned B state mightprecede the actual emergence of the unco n-di t ioned B state. This condit ioning phe-nomenon should lead to increased f requencyof dosage. For someone trying to kick ahabit , the carefu l avoidance of these C S nevents , which elicit B states, should be veryhelpfu l .T h e conditioning process results in theaddict being hemmed in to agreat ex tent .If w e assume that the events in Figures 7and 8 occur also for the addict ions, then in-creased craving would be a consequence ofcondi t ioned s t imulus events , no matterwh e th e r a C S A o r a C S u were presented.In the case of the C S A, the craving shouldoccur fo l lowing the te rminat ion o f the CSA(see th e biphasic recovery inFigure 7). Inth e case of CSB, the craving should occurd u r i n g and after the CSs presentat ion (seethe monotonic recovery inFigure 8 ). Thus,the Pavlovian condit ioning of A states andB states, during th e acquisi t ion of an ad-dictive cycle , overdetermines the crav ing fo rthe drug . Th e add ict, even if he tr ies tore inforce himself symbolically, i .e . , with avar ie ty of CSA onsets, wi l l experience anincreased aversive B state af terward.Co nd i t i o ne d b processes can become verypower fu l re lat ive to a processes , just as un-

condi t ioned b processes can become verypower fu l . Take the work of Kimmel(1971), w ho used the galvanic skin re-sponse as an anxie ty index. In analyz ingthe phenomena of galvanic skin responsecond i t ion ing wi th aver s ive uncondi t ioneds t imul i , he found t h a t the m a g n i t u d e of an-t icipatory galvanic skin responses in re-sponse to C S A S often increased on the veryear ly t r ials of condit ioning. How ever , onlater t r ials they decreased, even though thesame uncondi t ioned s t imulus r e inforce r wasbeing regular ly presented. Kim m el cal ledth i s p h e no me no n the inh ib i t ion of emot ionalbehav io r , a mani fes ta t ion of the organisms'adaptive ad jus tment . His idea is that thefear of the uncondi t ioned s t imul i has be-come manageable by the action of a fear -inhibi t ion mechanism. Kimm el 's conceptsseem to be close to our own, if we changethe inhibi t ion concept to an hedonic oppo-nent-process concept . W e d o n o t k no wexper imenta l ly whe the r the p h e no me na d e m-ons t ra ted by Kimmel a l so mani fes t th e m-selves in appet i t ive condit ioning. W e sus-pect that they do .The obse rvat ions of Kimmel (1971),taken in co n ju nc t io n w i th an opponent -process t h e o r y , suggest a variant of the ex-per iment by Rescor la and LoLordo (1965)which w o u l d be a very strong test of theopponent -process theory . On e wo uld t r a indogs to p e r f o r m a regular S i d m a n avoid-ance response . Then, d u r i n g th e condi t ion-ing phase of the expe rim ent, a long seriesof tr ials with the uncondit ioned st imulusalone could be presented. The oret ical ly ,this should strengthen the b process forfear. Then th e d iscr iminat ive condi t ioningphase of the expe r imen t could be c arr iedo u t j u s t as Rescor la an d LoLordo d id .W h e n t he C S A i s presented on a test tr ialwhi le the dogs are per forming this avoid-ance response, t h e C S An o w , in contrast towhat Rescor la and LoLordo found , sh o u ldbe relatively impotent in energizing theavoidance response. In o the r words , theC S A onset would be a weak fear elicitor( K i m m e l , 1971). In contrast , the te rmi-nat ion o f C S A a s well as the presentat ionof the CSB, wh en presented dur in g avoid-ance responding, should power fu l ly suppress


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O P P O N E N T - P R O C E S S T H E O R Y O F M O T I V A T I O N 137avoidance behavior. This suppressive ef-fect should persist for a relatively long timeafter terminat ion of the test with CSB.These deductions stem from the assumptionthat th e long series of pre t rea tment trialswith the uncond it ioned st im ulu s a lone hasstrengthened th e b process, so that when theconditioned st imuli are f inal ly in troducedin the later discriminative con ditioning, C S Awill be paired with a shock which elicitsvery lit t le fear (b is large, so a m i n u s b issma l l ) , but CSB will be paired with theintense peak of the B state which is theopponent of fear ( joy , euph or i a ) .

A fur ther deduction from opponent-pro-cess theory suggests a way to reverse whathas heretofore been a strong empirical gen-eralization. In most discriminat ive-condi-t ioning experiments th e elicitation power oft h e C S + grows quickly as a funct ion oft r ia ls of condit ioning, but the inhibitoryproperties of the CS requi re many moretria ls to manifest themselves. In the vari-ant of the Rescorla and L o L o r d o (1965)experiment which w e suggested as a strongtest of our opponent-process model, the re-verse should be true if discriminative con-ditioning is started after a long series oft r ia ls on which the uncondit ioned st imulusalone has been presented. The effective-ness of the uncondit ioned st imulus shouldbe greatly a t tenuated wh en condit ioning isstarted, and a conditioned stimulus pairedwith an ineffective uncon dit ioned st imulusshould acquire excitatory properties veryslowly. In contrast , a condit ioned st imuluscoming direct ly after uncondit ioned st imu-lus termination would be associated with anintense B state. S uch a condit ioned st im-ulus should quickly acquire C SB properties.The postulates of an opponent-processtheory of affect, combined wi th Pavlovianlaws for the condit ioning of A states and Bstates, give us a new way of looking at thephenomena of acquired mot iva t ion .

A N A L Y S I S O F S E L E C T E D M O T I V A T I O N A LP H E N O M E N A IN LIGHT OF THEO P P O N E N T - P R O C E S S T H E O R Y

There are many areas of psychologicalresearch which can be prof i tably reanalyzed

within the confines of the opponent-processmodel . F or example, w e have found themodel useful in increasing our unders tand-ing ofad dict ion, chi ldhood at tachments, loveand affection, imprinting in precocial birds,rewarding and punishing electrical stimula-tion of the b rain, so-called thrill-seek ingbehavior, th e dynamicsoffear and avoidancebehavior, the pleasures and displeasures as-sociated with thermoregulatory behavior,some aspects of masochistic behavior, de-pression and euphoria , and taste cravingsand obesity, to ment ion a few. W e haveselected only two of these phenomena forintensive and detailed analysis in order todemonst ra te th e applicability and use of theopponent-process model to deduce new phe -nom ena and experiments. In the first, theA state is pleasurable , and in the second itis avers ive .Addiction and Stimulation of A and BStates with Drugs

W e have discussed th e main fea turesofan opponent-process theory ofaffect. Theseare as fo l lows: (a ) Process a; (b) Oppo-nen t Process b , a slave process ; (c ) thestrengthening of the b process as a functionof repe t i t ions of the a process ; and (d) thecondi t ioning of A and B states by Pavloviancontingencies.W e believe any addict ion can be betterunders tood by reference to these features.Firs t , the addict ive substance must be capa-ble of giving pleasure, at least sometimedu ring i ts early use. Actual ly, there maybe some aversive effects from the first fewdoses, but these are overshadowed by thepleasure effects coming ei ther from th e drugitself or from other avai lable reinforcers.If not, the dosage will not be repeated. Ifdosage is repeated, the opponent process willbegin to strengthen. W ithdraw al symp-toms and craving wil l intensify and becomelonger lasting. They will be aversiveenough and persistent enough so that th euser will try ways of getting rid of them.It is here that w e have to qualify thetheory with a specificity assumption. W eassume that, because th e b process is theopponent of a, th e quickest and most effec-


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138 R I C H A R D L . S O L O M O N ANDJOHN D . C O R B I Ttive way of getting rid of the B state is touse the substance which direct ly producesth e A state. W e do n o t know, however ,w hy this should be so, but i t is the way ad-dict ive drugs work. Thus, behavior re-sul t ing in the obtaining and use of theA-arousing substance wil l be s t rongly re-inforced because it produces A and it simul-taneously terminates B . This will lead tofu r the r st rengthening of the b process.Therefore , am oun t s of the substance wil lha ve to be increased in order for the sum,(a b ) , to be greater than zero, or abovebaseline. This is the drug tolerance phe-nomenon (Jaffe, 1965; Wilder , 1953). In-crease of dosage then will reinforce all thebehavior upon which it is cont ingent , andthe b process wil l be fu r ther st rengthenedby more f reque nt use. This is the addict ivecycle.D urin g ear ly doses, w hen the quant i ty|a b\ is large, previously neutral st imulishould become conditioned to A if they di-rectly precede the onset of S tate A. The ywil l become C SA st imul i , Pavlovian el ici torsof the A state or components of i t . Thesest imuli , as C S A S for a pleasurable D r u gS ta te A , wil l be positive secondary reinforc-ers, capable of reinforcing new operants.As the b process becomes stronger, th ePavlovian condi t ioning of previously neutralst imuli which directly follow a-process ter-minat ion , and which also directly precedethe peak of B, should readi ly occur. W ewill then see the emergence of s t rong CSBs,aversive in quality. They wi l l be the con-dit ioned st imul i for the craving and with-drawal symptoms. Thus they wil l be sec-on da r ynegat ive re inforcers and wil l energizeescape and avoidance behaviors . As theCSBs become st ronger they wi l l becomem o r e anticipatory, and so redosage and re-s t imula t ion will start to occur at shorterin tervals . The addict then w il l be usingthe drug part ly to remove condi t ioned B -state arousals precipi tated by the presenceof C SBs. Th erefo re, increased dosage fre-quency , until some asymptote is reached,should occur whenever : (a) The b processbecomes stronger, and (b ) C S s S are estab-l ished by Pavlovian condi t ioning cont ingen-cies . Increased frequ enc y of dosage should

occur even if drug am oun t s per dosage donot sub stan tially change. Finally, if the ad-dict, under the influenceof other mot ivat ion,stops using th e drug, th e b process willweaken gradual ly wi th th e passage of t ime.The dynam i cs of behavior change whichwe have outlined are typical of most addic-t ions (see Solomon & C orbi t , 1973). N a t u -ral is t ic observat ions appear to fit the deduc-t ions from the opponent-process model.C o u l d the opponent-process model for ac-quired motivat ion help us to understand bet-ter the problems of the addict w ho wantsto q u i t ? C o u l d w e devise a regime to helph im q u i t ? In a wel l-addicted drug user ,th e m aj o r behavioralengineeringtask wouldseem to be to weaken B'. This is the statewhich energizesthe strong escape and avoid-ance beha viors wh ich termin ate craving eacht ime it occurs. T he well-addicted druguser is exhibit ing avoidance behavior muchof the t ime rather than escape behav ior . Hewould ra ther not experience the B sta te; heindulges so f requen t ly that he rarely lets i toccur , and if it occurs, he quickly gets ridof it with another dosage. How ever , inorder to weaken B', the addict must lessenth e constant , repeated challenges to the op-ponent process. One way is to stop arous-ing A, i .e . , cold turkey withdrawal , totalcessation all at once. Ano ther w ay is todecrease th e intensi ty and f requency of Ainputs . In other words, fade out A by grad-ually cut t ing down on drug use.There is an analogy in color vision. Takea saturated red, and very gradual ly d imini shthe satu ratio n un til i t is gray. A greenaf ter image does not occu r , but the t ime offade-out has to be equa l to, or longer than,the du ra t i on of the green af ter image w henred is sudd enly t erminated ra ther than fadedo u t . If the t ime of fade-out is shorter thanthat , there wi l l be a green after image be-cause some finite quant i ty of the opponentprocess wil l still be opera t ive due to i ts ownin tr ins ic decay t ime. The refore, reasoningby analogy, in order to weaken the b processin addic t ion by a fade-out technique, wemust f i rs t know how long the craving wouldhave lasted had the addict gone through coldt u r key w i t h d r a w a lun t i l th e c rav i nghad dis-appeared . This could be a very long t ime,


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O P P O N E N T - P R O C E S S T H E O R Y OF M O T I V A T I O N 139and i t m ust be es t ima ted . If the fade-ou ttechn ique invo lves a gradual decrease ofdrug use frequency and am oun t , wh ich l as tsfo r a shorter period than the cold turkeyper iod , th e techn ique is b o u n d to fai l . Thatis because, after the last small dose is takenand t e rm i n a t ed , the B' state would s t i l l comein st rongly enough to energize behaviorlead ingto another redosage.

The opponent-process model warns ofstill another problem for the add ic t w h ow a n t s to qu i t . E ven if the d rug user weresuccessful in reducing th e a m o u n t of B,there is still th e positive re in fo rc ing effectof A to contend w ith . Together w i th so-cial reinforcers , it was probably im portantin i t ia l ly in reinforcing the user's behav io r .Now the a process again has a chance to re-inforce drug use, because th e quan t i tya b\ gets larger as b gets smal ler . Thusa st rong posi t ive re inforcer (A) for d ru guse wil l again become available for any ex-perienced user la te in the cold turkey with-d ra w a l or the fade-ou t reg imen . Thist rade-off , deduced by the model , makes the kicking of an add ic t ion very difficult.Late in addict ion , the avers ive craving stateenergizes the behavior more forcefully, butaf te r par t i a l w i thd rawal , the positively rein-forc ing state reinforc es the sel f-adm inis t ra-tion o p e ra n t s .How does one hand le the p rob lem o fc o u n t e r i n g a positive r e in f o r c e r ? First, bythe action of punishment . To weaken thedrug-use behav io r at a t ime when |a b \is large, punishment is one indicated al ter-nat ive. P unishm ent probably should n o t beused ear ly in wi thd rawal , o r ea r ly in fade-out, because the drug-use behavio r is com-posed of avoidance and escape operantsdr iven by the avers ive B' ( t h e w i t h d ra w a lagony and c ra v i n g ) . P u n i s h m en t at thatt ime migh t intensify the operants , as i t fre-quent ly does for any operants contro l led byavers ive s ta tes ( the v icious ci rcle phenome-n o n ) . Perhaps late in w i t h d r a w a l , strongrewards fo r abs t inence migh t be used to -gether wi th punishment for drug taking.B u t such rewards wou ld have to be hedon i -cally s t ronger than is the d rug-p roducedrew a rd A at the t i m e w h en a is st rong andb is weak.

Another technique suggested by the op-ponent-process theory of mot ivat ion is theuse ofantagonistic dru gs. It should be pos-sible to b reak the addict ive cycle with adrug which antagonizes or eliminates theavers ive b process. The addict medicatedwi th such a b process antagonist would sti l lexperience the pleasurable A state, but thew i t h d r a w a l agony and craving would begone. He migh t , under the impetus of othermot iva t iona l inf luences , become a casualuser ra ther than a driven addict . An evenm o r e effective therapy could be developedif we had two drugs , an o-process antago-nist as wel l as a ^-process antagonist . Thef o r m e r could be relatively short acting, butthe lat ter would have to be long acting ino rd e r to coun terac t the long-lasting aversiveb process.

The opponent-process model deduces thatthere will be great difficulty in el iminat ingthe addictive cycle. Even though all thecondi t ions fo r w ea k en i n g th e b process areopt ima l , t roub le can ensue . In addict ion ,State B

PsychARTICLES an Opponent-Process Theory of Motivation Temporal Dynamics of Affect

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