Acta Psychologica 59 (1985) 209-225 North-Holland

209

THE INDEPENDENCE OF REACTION AND MOVEMENT TIME IN PROGRAMMED MOVEMENTS

Jim PHILLIPS and Denis GLENCROSS *

The Flindem Unroersiy OJ South Austrulirr. Austrdiu

Accepted October 1984

The issues of controlled vs automatic processing. and programmed vs preprogrammed movements deal with two problems. whether subjects can control their performance, and whether RT is related

to task difficulty. The subjects’ control over the relationship of RT and movement was examined.

Two experiments are reported in which the relationship between RT and MT is investigated using

instructional set and speed-accuracy tradeoff techniques. The two issues considered were: (1)

whether subjects could separate their RT and MT in a top-down approach: (2) whether RT could

be independent of MT and accuracy. The two experiments separated RT and MT using instruc- tional set and feedback bands in a simple horizontal aiming movement. A relationship was found

between RT and movement accuracy. The implications for preprogramming and programming are

briefly discussed.

The programming-preprogramming distinction has been used to ex- plain situations where reaction time (RT) is not related to movement complexity. This experiment examined subjects’ ability to dissociate RT from movement complexity. This would show whether subjects could shift their level of control of movement, and what effect it would have on movement.

The motor programming approach uses reaction time data to ex- amine movement complexity. More complex movements require more preparation, and so they have longer latencies. Klapp (1980) and Henry (1980) have debated which RT paradigm should be used. Klapp stated that subjects can preprogram, that is, prepare a response in advance when using a simple RT paradigm.

The debate centres about the subjects’ ability to control their pre-

* Mailing address: J. Phillips, Cognition and Performance Laboratory, Dept. of Psychology, The Flinders University of South Australia, Bedford Park, South Australia, 5042, Australia.

OOOI-6918/85/$3.30 0 1985, Elsevier Science Publishers B.V. (North-Holland)

paration. If subjects can control their preparation, then it will be more difficult to interpret RT data. If preparation is done in advance. RT will not be related to response complexity (Klapp et al. 1974). A movement latency could be influenced by advance preparation and movement complexity. A movement latency involves the interaction of strategy (advance preparation) and structural requirements (movement complexity).

Another way of considering the programming-preprogramming is- sue, is in terms of controlled or automatic processing. One of the major ways of distinguishing between controlled and automatic processing is in terms of use of processing capacity in relation to task difficulty. A controlled task requires more capacity with increasing task difficulty. while an automatic task does not. When considering programming and preprogramming, programming involves a relationship between RT and movement, whereas preprogramming does not involve a relationship between RT and movement. Programming may be considered con- trolled processing. Underwood (1982) has suggested that advance processing is a major cause of automaticity. In this case advance preparation or preprogramming may be akin to automatic processing.

Neumann (1984) has distinguished two approaches to the issues of controlled and automatic information processing. The more common approach involves direction of processing, for example Schneider and Shiffrin (1977). In this approach processing is either controlled by the subject (top-down), or the environment (bottom-up). In motor control Turvey (1977) has discussed whether control is the responsibility of lower or higher levels. The second approach involves levels of control, where processing varies with the level at which parameters are specified. In motor control this approach has been discussed by Glencross (1977, 1980). The two approaches differ to the extent which subjects can alter their processing. In the first approach a behaviour is either modifiable and strategic (top-down) or unmodifiable and structural (bottom-up). In contrast, processing is more modifiable by the subject according to the levels of processing approach.

This experiment examined whether subjects could modify their processing by changing a programmed response into a preprogrammed response. This is done by taking a situation where processing is more controlled and making it more automatic. In other words taking a task where RT is related to movement, and making RT independent of movement.

J. Philhps. D. Glencross / Independence of R T und MT 211

One area where RT is related to movement complexity is movement duration. Longer movement times require longer reaction times. This experiment attempted to remove this relationship by asking subjects to control RT using speed-accuracy techniques, while controlling MT. If RT could be made independent of movement complexity, then prepro- gramming or automaticity of a previously programmed response could be demonstrated.

Independence of RT and MT

There has been some interest in the literature, concerning the relation- ship between reaction time and movement time. Reaction time and movement time have been seen as the result of independent processes. Factors, such as choice, which influence RT have not influenced MT (Brewer 1976; Lally and Nettelbeck 1977). Similarly, factors affecting MT, such as index of difficulty, have not influenced RT (Fitts and Peterson 1964; Fitts and Radford 1966; Glencross 1976). In general, most early studies have reported a very small relationship, if any, between RT and MT, even when considering individual differences (Henry 1961). More recently, some experiments have found relation- ships between RT and MT.

Experiments reporting a relationship between RT and MT have usually involved instructional sets to control performance in some way. For example, Falkenberg and Newell (1980) required subjects to con- trol movement velocity, whilst movement latency was not emphasised. They found a significant relationship between movement velocity and movement latency. Klapp et al. (1974) required subjects to control their movement durations. Subjects were also instructed to make their reac- tion times as fast as possible. Klapp et al. found a strong relationship between RT and MT. Quinn et al. (1980) required subjects to control their movement times when examining the effects of target size and movement amplitude on reaction time. Quinn et al. found the major determinant of reaction time was movement time. In view of the independence of RT and MT reported in the earlier cited studies, it may be that RT and MT are related when controlling movement.

Some studies of individual differences have found a relationship between RT and MT. However, these results may also be attributed to control of movement. Inomata (1980) used payoffs to control RT, or

MT, or both RT and MT. Inomata found significant relationships between RT and MT when subjects were asked to produce fast MT, or to produce both fast RT and MT.

Although most studies have found a positive relationship between RT and MT, sometimes a negative relationship has been reported. An experiment involving choice and movement suggests the relationship between RT and MT is arbitrary. Danev et al. (1971) examined the relationship in a paced task. Subjects had to react and press 4 buttons within a fixed time interval. When subjects produced a fast RT they compensated with a slow movement. A slow latency was compensated for by a fast movement. This suggests the relation of RT and MT may be modified.

What does this pattern of conflicting evidence mean? It suggests that the findings of a relationship between RT and MT were due to control of movement. If movement is not controlled, RT and MT tend to be independent. Given preparation is required when controlling movement duration, is it possible to make RT independent of movement duration?

There will be two issues: whether it is possible to control the relationship of RT and MT, and whether RT is alsa independent of movement accuracy. If RT is independent of both aspects of the movement (movement duration and accuracy), then subjects will have preprogrammed the response.

Wickelgren (1977) has described methods of controlling RT. One method involves the use of feedback to inform subjects when their reaction times were outside a desired time band. It is hypothesised that RT should be separate from MT when subjects are given feedback to control RT and are instructed to keep MT constant.

Hypotheses

(1) If RT and MT are not separate (viz., if they are structurally linked), movement time will covary with RT: Fast RT will produce fast MT. If subjects are asked to control both RT and MT when they are not separable, then subjects may choose to control either RT or MT. (2) If RT and MT are separable (viz., they are linked merely by instructional set), then movement time will not vary with RT: (a) RT feedback bands will have no effect on MT. Once RT and MT have been separated, programming and preprogramming may be examined. If

J. Phrllips, D. Glencross / Independence o/R T und MT 213

subjects preprogram their movements, movement accuracy will not vary with reaction time: (b) RT feedback bands will have no effect on movement accuracy. If subjects program their movements, then move- ment accuracy will be inversely related to RT: (c) Fast RT will produce less accurate movements.

Experiment 1

Method

Subjects

There were 16 Ss, ranging in age from 12 to 40 years, with a mean age of 23.7 years. Fourteen S’s were right-handed and two were left-handed, as determined by a verbal questionnaire. Ss were paid $3 for their participation.

Appurutus und tusk The task involved a movement in response to a reaction signal. After each response

Ss were given feedback on their reaction times. A Gonogo reaction task was used. After a foreperiod (1.5 set or 1.75 set), Ss moved

in response to a 800 Hz tone in the preferred ear. Ss did not move in response to a 800 Hz tone in the non-preferred ear. A Gonogo task was used in preference to a simple or choice RT task as it allowed preprogramming (no response uncertainty), but controlled for stimulus uncertainty (Zelaznik 1978).

The movement consisted of a 15 cm horizontal arm movement, moving a graphics pen from a start position to a target of 2.5 cm diameter. Ss used their preferred hand. Right-handed Ss moved to a target 15 cm to the right of the start position, while left-handed Ss moved to a target 15 cm to the left of the start position. The distance of the graphics pen from the target was recorded using a Tectronix graphics tablet.

Feedback relating to reaction time was given after each trial, using a LED lighting display. The LEDs were located 31 mm apart in a 83 mm by 50 mm black box, which was placed about 40 cm in front of the S. There were two specified times which formed the upper and lower limits for a reaction time. There was a bandwidth between these two times in which S’s did not receive feedback of their reaction times. A red light shone after a response if the reaction time was faster than a specified time and a green light shone if the reaction time was slower than a specified time. There were 4 feedback bandwidths used: 125-175 msec, 150-200 msec, 175-225 msec, and 200-250 msec.

Stimulus generation and data collection were controlled by a PDP 1 l/34 computer.

Procedure There was a preliminary task, which trained the Ss’ speed of movement (movement

time), and then 4 conditions of the experimental task were presented. The preliminary MT training involved a simple RT task. Ss responded to a tone in

the ear on their preferred side by moving to a target on their preferred side. Ss were

asked to make fast, accurate movements. Ss were encouraged to complete the move- ment in less than 250 msec, and were given verbal feedback when their movement time was longer than 250 msec on a trial. The data from this task were not analysed. After 20 trials of this task, Ss were told they were moving at the required speed, and were advised to move consistently at that speed throughout the experiment.

The experimental task involved a go-no-go situation with 2/7ths no-go trials (catch trials). Ss were instructed to control their RT. and at the same time keep their movements as accurate as possible at the speed of 250 msec. Ss were asked not to vary their movement time or accuracy between conditions. There were 4 conditions with RT bandwidth times of: 125-175 msec, 150-200 msec, 175-225 msec. and 200-250 msec. Feedback was given on each trial using the LED display. The order of the 4 bandwidth RT to be produced by the Ss was randomised from block to block. For each RT bandwidth condition there was a practice block of 28 trials, followed by a block of 56 test trials.

The purpose of the experimental procedure was to determine if Ss could control RT and at the same time keep MT constant. If the relationship of RT to MT wax due to instructional set, then they should be separable.

270 C S-----X Controlled RT (N = 6) N c WNot Controlled RT (N = 8)

260

150 200 175 200

Feedback Bands (mseC)

Fig. 1. Reaction times for the two sub-groups. Separation of subjects into groups on the basis of

their control of reaction times.

J. Phillrps, D. Glencross / Independence of RT and MT 275

There was no change in mean reaction time with the different feedback bands, thus Ss showed no ability to control RT, (F(3,45) = 1.908. p > 0.05). This is to be con- trasted with mean movement times. Ss were unable to keep their movement times constant. There was a significant change in mean movement time, (F(3.45) = 4.485, p < 0.05).

When Ss were asked to control their RT and keep MT constant, but they did not, an analysis of covariance was performed on the RT data using MT as a covariate. There was still no effect of RT feedback on reaction time, (F(3,44) = 1.621. p > 0.05). The covariate MT removed a significant proportion of the variance (F(1,44) = 14.783, p -c 0.001). This shows that RT and MT were related.

Ss were asked to control RT keeping MT constant. Could Ss have either controlled RT or kept MT constant? It was necessary to select between Ss that showed control of RT from those that did not. This involved selecting Ss that showed a linear increase in RT with the changing bandwidths. To select Ss who controlled their reaction times, the means for each S were considered. These were multiplied by linear polynomials (3, 1. - 1, - 3) and the sums calculated to give an indication of the linear increase in reaction time. The size of the linear trend was ranked for all 16 Ss, and then Ss were split at the

Co-----<) Controlled FIT ( = 6) N C W Not Controlled FIT (N = 6)

N-C

260

l --+--1

PC I

240 I

c 230-l % E 220-

z E ZlO- c

; zoo-

E B 190-

I

& 160-

2 170-

160 1

/’ /’

I’

,P,’ /’

/’ I’

OR / //

/’

Feedback Bands (msec)

Fig. 2. Movement times for the two sub-groups. The effect on mean movement time of separating

subjects on the basis of their control of reaction time.

median. There was then a group that controlled RT (i.e.. showed a linear increase in RT). and a group that did not control RT (i.e., no linear trend in RT).

As may be seen in fig. 1, Ss who controlled their reaction time showed a large change in RT with RT feedback band. Ss who did not control RT (the non-control group), did not show a change in RT with RT feedback. Of course this was to be expected because of the procedure used to select S’s into those who controlled RT and those who did not.

The effects of RT on the other dependent variables may be examined. As RT covaried with MT, it would be expected that selecting Ss on the basis of their control of RT would influence MT. As may be seen in fig. 2. Ss who controlled their RT showed generally faster movement times, while Ss who did not control their RT showed little change in MT.

The results do not support the hypothesis that Ss can separate RT and MT when instructed to do so. When examining Ss who controlled RT, these Ss showed changes in both RT and MT. Ss chose between making a fast response in terms of short RT. and short MT, and making a slow response in terms of long RT, and long MT.

The relationship of RT and MT was resistant to instructional set. Rather than RT and MT being influenceable in a toppdown fashion, it appeared that control of RT was linked to control of MT. Previous experiments such as Klapp et al. (1974). and Quinn et al. (1980) showed control of MT influenced RT; this experiment showed control of RT influenced MT.

Experiment 2

The first experiment attempted to separate RT from MT using RT feedback and instructional set. There were two issues. Would control of both RT and MT be possible? If RT and MT could be separated, this would enable a comparison of programming and preprogramming accounts of the relationship of RT to movement accuracy. However, RT and MT were not separated, and so a further experiment was conducted in order to separate RT and MT, using practice, and RT and MT feedback. The first experiment had little success demonstrating preprogramming using a go-no-go task. and so this experiment used a simple RT task, where there would be no response uncertainty or stimulus uncertainty to impair advance preparation.

The literature has suggested that RT and MT are the result of independent processes that were linked due to the control of MT. However. the prior experiment failed to separate RT and MT using specific instructions and feedback. If the relationship of RT to MT is a structural one (bottom-up), then it will not be possible to separate RT from MT in a further experiment. However, if the relationship of RT to MT is a strategic one (toppdown), then it should be possible to separate RT from MT.

To demonstrate that the separation of RT and MT was not only possible. but not dependent upon augmented feedback at asymptotic performance, there should be little reliance by the S on feedback.

J. Phdl~ps, D. Glencross / Independence of RT and MT 217

Method

Subjects There were 8 Ss, whose ages ranged from 18 to 25. There were 7 right-handed and 1

left-handed Ss. Ss were paid $3 each for the first two sessions, and were paid $4 each for the last two sessions.

Apparatus and task The apparatus and task were similar to that used in experiment 1. The task involved

a movement in response to a reaction signal. After each response Ss were given either feedback on their reaction time or feedback on their movement time. Although Ss were given feedback either on their RT or on their MT, they were however expected to control both their RT and their MT.

The task was a simple aiming movement to a small circular target (2.5 cm diameter). The task used a simple RT procedure. Ss responded to a 800 Hz tone by moving a stylus a distance of 15 cm to the 2.5 cm target. After each response, Ss were given visual feedback on the speed of their performance, as in the previous experiment. Ss used their preferred hand. Right-handed Ss moved to a target 15 cm to the right of the start position, whilst left-handed Ss moved to a target 15 cm to the left of the start position.

Feedback was delivered through the same LED display, as in the previous experi- ment, however, feedback could now be delivered either concerning duration of reaction time or duration of movement time.

Procedure There were 4 experimental conditions corresponding to the combination of the 2 RT

feedback bands and the 2 MT feedback bands. There were three parts to each experimental condition. The first two parts involved training an S to produce RT and MT separately, while the third part involved training an S to control both RT and MT at the same time. For the first two parts Ss were trained to criterion. If Ss did not attain criterion performance, they did not continue. One S was excluded on this basis.

The first part focussed on the control of RT. Movement time was not controlled at this stage. Ss held the pen down in the start position. After a delay of 1.5 set or 1.75 set, there was a 800 Hz tone signalling the S to move to the target. Ss were asked to hit the target 9 out of 10 times, however control of RT was more important. After each trial feedback was presented visually using LEDs. If the S’s reaction time lay within the training band (150-200 msec or 200-250 msec). then the lights stayed off. If the S’s RT was slower than the training band, a red light was presented. If the RT was faster than the training band, then a green light was presented. Ss were given blocks of 16 trials. Ss were trained to a criterion of two successive blocks in which both mean and median RT lay within the training band.

The second part of a condition focussed on controlling movement time. The movement was the same as for when training reaction time. Procedure was the same as that for training reaction time, however, now Ss were given instructions and feedback to control their movement time. Ss were trained to a criterion of two successive blocks in which both mean and median MT lay within the training band.

Before Ss could control RT and MT at the same time, they had to demonstrate that they could control RT and MT separately. Ss progressed to the third part of an experimental condition. only if they had reached criterion performance, controlling reaction time separately. and controlling movement time separately. The remainder of the experiment involved controlling both reaction time and movement time together at a combination of feedback bands. Ss were only given feedback on one aspect of performance in each block of trials. Ss were given feedback on their RT for the first block of 16 trials, and then were given feedback on their MT for the second block of 16 trials. Feedback for a RT or MT condition was the same as that given when Ss controlled RT or MT separately. However, Ss were now required to control both RT

and MT at the same time. Ss were trained to criterion performance, or until they had completed 12 blocks of 16 trials (192 trials). Criterion performance required that both mean and median RT and mean and median MT be within their respective training bands for 4 consecutive blocks of trials.

There were two feedback bands used for training RT (150P200 msec and 200-250 msec) and two feedback bands used for training MT (150-200 msec and 200-250 msec). Ss were given feedback either for RT for a block of trials, or for MT for a block of trials, but not for both at once. Feedback could not be given for both RT and MT, nor could feedback be mixed between RT and MT for a block of trials. On a particular block of trials, feedback could be present or absent for RT. If feedback was present for RT. it would be absent for MT; and if feedback was absent for RT, it would be present for MT. To test whether Ss were approaching asymptotic performance the last two blocks of trials for each S were analysed. The design was a balanced 2 X 2 X 2 X 2 repeated measures design of the form, RT feedback band X MT feedback band X type of feedback X block of trials. Each combination of RT feedback band X MT feedback band was performed in a separate session. The order of the 4 conditions was counterbalanced using a latin square.

The mean number of trials to reach criterion for RT and MT pretraining may be seen in table 1. As can be seen, when examining trials to criterion, it was easier to learn to

Table 1 Mean number of trials to criterion performance

Feedback bandwidths (msec)

RT MT

Feedback for training segment

RT MT

pretraining pretraining

RT+MT training “

150-200 150-200 36

150-200 2OOC250 42

200-250 15OC200 52

200-250 200-250 62

’ Maximum number of trials was 192.

42 142

44 144

36 156

34 152

J. Phillips. D. Glencro.~ / Independence of RT and MT 219

produce fast RT. It was also easier to reach criterion movement time after being trained to produce slow RT.

The number of trials to reach criterion for each combination of RT and MT may also be seen in table 1. There was little difference in number of trials to reach criterion. Slower RT and faster MT conditions tended to be more difficult.

Reaction times The results for the last 4 blocks of trials for each S were used in the data analysis.

This was done as the aim was to show whether control was possible rather than show how many trials it took to reach a separation. These 4 blocks of trials were either the blocks in which the S reached criterion performance, or the last 4 out of 12 blocks of trials. It was predicted that Ss could control RT and this control would be independent of MT. The results showed that control of RT was independent of control of MT. However, it appeared that this independence was due to practice. Control of RT was independent of presence of augmented RT feedback. Control of RT was not influenced by the form of feedback given, RT feedback or MT feedback.

240 -

230

220-

180

170 :

160

MT Feedback / Band 150-200 :

MT Feedback

210-

zoo-

190-

240 -

230 -

220 -

I

150.2w 200 250

FIT Feedback Band Block 1

170-

160-

MT Feedback

1soroo 1. -

200 250

Fig. 3. The interaction of the effects of RT feedback with MT feedback with practice on mean

reaction times.

220 J. Phillips, I). Glencros.~ / Independmce of RT cd MT

The analysis of variance reveals a significant effect of RT feedback band, (F(1,7) = 42.565, p < 0.001). Ss produced faster RT in the fast feedback band. There was no effect of MT feedback on mean RT, (F(1,7) = 0.001, p > 0.05). There was no interac- tion of RT feedback band and MT feedback band, (F(1.7) = 2.339. p > 0.05). It appeared that control of RT was independent of control of MT. The effect of practice was examined to find whether Ss had reached asymptotic performance. There was no effect of blocks of trials practice on reaction time, (F(1.7) = 0.027, p > 0.05). However, the interaction of RT feedback band. MT feedback band, and practice approached significance, (F(1,7) = 4.193, p -C 0.08). As may be seen in fig. 3. movement time feedback band affected control of RT, but this effect was reduced with more blocks of trials. Ss did not rely on augmented feedback. There was no effect of presence of feedback on reaction time, (F(1.7) = 0.625, p > 0.05).

Movement time

The mean movement time was examined. It was predicted that Ss could control MT, and this effect would be independent of RT control. The results showed that Ss

250

240

I

230 -

;i I r 220-

E I=

+e ZlO-

E z

s C 200. : I

190.

150 200 200 - 250

Feedback Band (msec)

Fig. 4. The interaction of the effects of MT feedback with practice on mean movement time.

J. Phillips, D. Glencross / Independence of R T and MT

. Ideal Pertormance

221

I ,

150 200 250

Mean Movement Times (msec) ? 1 Standard Deviatoon

Fig. 5. Separation of RT and MT for the four feedback conditions when controlling both RT and MT. The mid points for each combination of feedback bands are marked as ideal performance.

controlled their movement time. and this control improved over trials. There was a significant effect of MT feedback band on movement time, (F(1.7) = 188.788, p c 0.001). The faster training band produced faster movement times. There was no effect of RT on mean movement time, (F(1,7) = 0.985, p > 0.05). There was no interaction between RT feedback band and MT feedback band, (F(1,7) = 0.705, p z 0.05). There was an interaction between MT training band and practice, (F(1,7) = 9.999, p -C 0.02). As may be seen in fig. 4, with practice there was a greater difference in movement time between the two feedback bands. Ss did not depend on the presence of augmented feedback for movement time. There was no effect of type of feedback on mean movement time, (F(1,7) = 0.233, p > 0.05).

Fig. 5 shows the degree of separation of RT and MT. As can be seen, the Ss’ mean performance for each condition was well within the feedback timebands. Ss ap- proached ideal performance, as indicated in fig. 5. The variability of performance was low for each condition and suggested that each condition was fairly distinct and independent from the others. Reaction time and movement time were independent.

Preprogramming may be examined as control of RT was made independent of movement times. Reaction time was varied, while movement times were controlled. If Ss preprogrammed, then a change in RT with no change in MT would produce no

222 J. Phdlrps, ll. Glencross / Indepmdence oJ RT and MT

change in movement accuracy. Absolute error was used as measure of positioning accuracy. This measure is of use on tasks in which constant error is low, for example, in tasks where the target is visible rather than in the dark or remembered (Newell 1976). Absolute error is easier to interpret than constant error in this positioning task. as error can occur in two dimensions. If there is constant error, it would act to inflate measures of absolute error and so more confidence might be placed in non-significant results.

Fast reaction times produced less accurate movements. The results do not show support for preprogramming. There was a significant effect of RT feedback band (F(1.7) = 6.329, p < 0.05) on absolute distance from the target. Faster reaction times produced less accurate movements. There was no effect of control of MT on movement accuracy, (F(1.7) = 0.266, p > 0.05). Speed of movement did not affect movement

RT , Feedback

,’ Presenl

\ MT Feedback PreSent

761

76

1

75

g74

E 1

6.6

1

RT , Feedback , Present \ I I \ \

i I \ \ \ I I I \ I I I \

150 200 200 250

MT Feedback Bands Block I

150 200 200 250

MT Feedback Bands BlOCh 2

Fig. 6. Absolute error Interaction of MT feedback band, presence of feedback and practice

J. Phillips, D. Glencro.w / Independence of RT and MT 223

accuracy. There was no interaction between control of RT and control of MT on movement accuracy, (F(1,7) = 0.350, p > 0.05). Ss had reached asymptotic perfor- mance as a group, as there was no effect of practice, (F(1.7) = 0.005, p > 0.05). There was a trend for movement time to effect accuracy. which was modified by reaction time and practice. The interaction of RT control and MT control and practice approached significance, (F(1.7) = 4.996, p -C 0.06). Control of reaction time had a greater effect on accuracy for fast movements in the penultimate block of trials, while control of reaction time had greater effects on accuracy for slow movements in the last block of trials. Augmented feedback improved movement accuracy. There was a significant effect of presence of feedback, ( F(1.7) = 5.503, p < 0.05). Movement feedback gave more accu- rate movements. There was also an effect of movement time that was modified by practice and feedback. (F(1.7) = 13.893, p > 0.01). As may be seen in fig. 6, speed of movement has little effect on accuracy, while in the last block of trials RT feedback caused an improvement in accuracy.

Discussion

This experiment examined whether the relationship between RT and MT could be modified. It was hypothesized that Ss could control RT and MT independently, and that Ss could preprogram, that is, that reaction time would be independent of movement accuracy. With a simple reaction time task and feedback, Ss separated RT and MT. Ss did not need to prepare their movement time during their reaction time. This separation may be influenced by practice and feedback to an extent. However, the complete separation of reaction time from movement time and accuracy did not occur. The results did not show complete preprogramming even in a simpler RT task. Ss showed less accurate movements with faster reaction times.

General discussion

The present findings suggest the results of previous experiments relating RT to MT were not due to structural limitations to performance. Subjects could separate RT and MT given practice. This was not dependent upon augmented feedback, as subjects reached a stable performance, where presence of feedback had little effect.

These experiments showed performance should not be dichotomised into programmed vs preprogrammed or controlled vs automatic processing. The first experiment suggested the relation of RT and MT was automatic, due to some bottom-up process, as performance was not controlled by the subject. The second experiment showed that an automatic relationship could be controlled. Performance was not either controlled or automatic, but depended upon the level of control. This

supports the level of control view of automaticity (Neumann 1984). Klapp’s (1980) suggestion that simpler RT was not a useful proce-

dure due to the possibility of preprogramming must be questioned. Klapp et al. (1974) suggested that preprogramming was indicated by the independence of RT and movement quality when using a simple RT task, with instructions to produce fast RT. Our first experiment showed that changes in reaction time tend to produce changes in movement time. The second experiment showed subjects did not need to prepare their MT during their reaction time. However, complete separation of RT and movement did not occur. If subjects changed their RT, there were changes in movement accuracy, suggesting some programming was occurring here. Preprogramming as a complete independence of RT and movement did not occur.

These experiments supported a model of the reaction process such as Rosenbaum’s (1980) where aspects of the response may be prepared in advance, but some aspects are left to be prepared during the reaction time. The degree of relationship of RT to movement can be controlled, but subjects still program parts of their movement. It was difficult to dissociate RT control from movement, suggesting that the movement latency has an important role in movement organisation. The reason that RT could not be completely separated from movement, is probably because some parts of a movement have to be left to the last moment before movement execution.

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