What’s special about personally familiar faces? A ...bctill/papers/facerec/Herzmann2005.pdf ·...

What’s special about personally familiar faces?

A multimodal approach

GRIT HERZMANN,a STEFAN R. SCHWEINBERGER,b WERNER SOMMER,a and INESJENTZSCHc

aDepartment of Psychology, Humboldt-University at Berlin, Berlin, GermanybDepartment of Psychology,University of Glasgow, Glasgow, UKcSchool of Psychology,University of St. Andrews, St. Andrews, UK

Abstract

Dual-route models of face recognition suggest separate cognitive and affective routes. The predictions of these models

were assessed in recognition tasks with unfamiliar, famous, and personally familiar faces. Whereas larger autonomic

responses were only triggered for personally familiar faces, priming effects in reaction times to these faces, presumably

reflecting cognitive recognition processes, were equal to those of famous faces. Activation of stored structural rep-

resentations of familiar faces (face recognition units) was assessed by recording the N250r component in event-related

brain potentials. Face recognition unit activation increased from unfamiliar over famous to personally familiar faces,

suggesting that there are stronger representations for personally familiar than for famous faces. Because the topog-

raphies of theN250r for personally and famous faces were indistinguishable, a similar network of face recognition units

can be assumed for both types of faces.

Descriptors:Face recognitionmodels, Skin conductance responses, Event-related brain potentials, Priming, Personally

known faces

Human faces are outstandingly rich sources of information for

social interaction, providing detailed information about famil-

iarity, identity, mood, gender, age, or focus of attention. It is

therefore hardly surprising that the issues of how the cognitive

system accomplishes and how the brain implements these aspects

of face perception have enjoyed a great deal of scientific interest.

Traditional models of face recognition (Bruce & Young, 1986;

Hay&Young, 1982) have focusedmainly on cognitive processes.

However, more recent models (Breen, Caine, & Coltheart, 2000;

Ellis & Lewis, 2001) have included affective aspects of face rec-

ognition as well. These models suggest that a so-called cognitive

route analyzes the identity of faces and provides access to se-

mantic knowledge and name of familiar persons. In addition, a

second route is thought to be involved in the production of af-

fective responses to familiar faces. The assumption of these dis-

tinct routes in face processing was made in order to explain

impairments of face recognition in prosopagnosia and its sup-

posed counterpart, Capgras delusion.

Patients with prosopagnosia are unable to identify the faces of

familiar persons and to learn new faces. Typically, prosopagnosia

is a consequence of acquired brain damage, involving inferior

occipito-temporal lesions of the right or both hemispheres. These

patients often remain able to recognize familiar persons by voice

or gait, and may also show preserved semantic memory for peo-

ple, for example, when confronted with their names. Neverthe-

less, prosopagnosic patients may be unable to recognize faces of

even highly familiar people. However, such faces, even though

overtly unrecognized, may elicit signs of covert recognition, such

as skin conductance responses (SCR). For example, Bauer

(1984) presented the prosopagnosic patient LF with familiar

faces, paired with spoken names, which could or could not cor-

respond to the face. Although LF could not identify the correct

names, his SCRs were larger to correct than incorrect face/name

pairs. In other studies, prosopagnosic patients showed larger

SCRs to familiar as compared to unfamiliar faces in the absence

of overt recognition (Tranel & Damasio, 1985). In terms of dual-

route models, preserved differential SCRs may indicate that

some patients with prosopagnosia, although impaired in overt

recognition along the cognitive route of face recognition, still

have a relatively intact affective route.

Patients with Capgras delusion show a pattern of impairment

that appears to be almost the mirror image of prosopagnosia

(Ellis&Young, 1990). Capgras delusionmay occur in the context

This research was supported by a Socrates-Erasmus exchange stu-

dentship to G.H. while she was visiting Glasgow, by a grant by the

Deutsche Forschungsgemeinschaft (So 177/14-1) to W.S., and by grants

by the Biotechnology and Biological Sciences Research Council (17/

S14233) and the Royal Society to S.R.S.Address reprint requests to: Grit Herzmann, Department of Psy-

chology, Humboldt-University at Berlin, Rudower Chaussee 18, D-10099 Berlin, Germany. E-mail: [email protected], or toStefan R. Schweinberger, Department of Psychology, University ofGlasgow, Glasgow G12 8QQ, Scotland. E-mail: [email protected].

Psychophysiology, 41 (2004), 688–701. Blackwell Publishing Inc. Printed in the USA.Copyright r 2004 Society for Psychophysiological ResearchDOI: 10.1111/j.1469-8986.2004.00196.x

688

of psychiatric conditions or as a result of structural or toxic brain

damage. Although these patients are still able to identify familiar

faces, they lack a sense of familiarity to these faces and believe

that impostors, doubles, or aliens have replaced these people

(e.g., spouses or children). Ellis and Young proposed that Cap-

gras patients, though unimpaired in their cognitive route for face

recognition, might have a damaged affective route. Their pre-

diction that these patients would fail to produce a differential

SCR response to overtly recognized familiar faces was confirmed

by subsequent research (Ellis, Young, Quayle, & DePauw, 1997;

Hirstein & Ramachandran, 1997).

The dissociation of autonomic responses and overt face rec-

ognition in prosopagnosia and Capgras delusion was taken as

support for the existence of two routes to face recognition. Bauer

(1984) postulated two routes for face recognition in both neuro-

anatomical and functional terms. A ventral visual-limbic route in

inferior temporal cortex was suggested to mediate overt identi-

fication and to be impaired in prosopagnosia. A dorsal route

projecting from primary visual cortex to limbic structures via the

superior temporal sulcus and inferior parietal lobe was consid-

ered to be involved in the detection of emotional significance and

to mediate the preserved SCR responses in prosopagnosic pa-

tients. Ellis and Young (1990) adopted Bauer’s dual-route model

to accommodate Capgras delusion, which was considered to be

the consequence of damage in the affective route, as indicated by

the absence of SCRs to familiar faces (Ellis et al., 1997).

The theories of both Bauer (1984) and Ellis andYoung (1990)

claim that a face has to be identified to some degree before its

relevance for affective responses can be noticed. In terms of cur-

rent concepts about face recognition (e.g., Bruce &Young, 1986)

these models therefore make the implicit assumption of two in-

dependent sets of stored representations of familiar faces (face

recognition units) feeding into the affective and the cognitive

routes. Recently, Breen et al. (2000) pointed out that Bauer’s

model does not specify possible mechanisms for face recognition

in the dorsal route and noted that there is little evidence for object

or face recognition in this route (Ungerleider & Mishkin, 1982).

Therefore, Breen et al. made the more parsimonious suggestion

of one common pool of FRUs residing within the ventral visual

stream and feeding into both the cognitive and affective routes.

Breen et al. adapted the face recognition model of Bruce and

Young, which contains only a singleFcognitiveFroute, by

adding a module triggering affective responses to familiar faces.

In the modified model, face recognition units feed information

simultaneously and independently into both person identity

nodes and the affective module. Face recognition is thought to

take place along an anatomical route in ventral temporal lobe

structures, with the amygdala triggering affective responses to

familiar faces. Within this framework, Breen et al. explained the

dissociation between patients with prosopagnosia and Capgras

delusion. Prosopagnosia can be caused by an impaired connec-

tion between the face recognition units and the person identity

nodes, while the connection between the face recognition units

and the affective response module may be intact. In contrast, the

locus of impairment in Capgras delusion is either within the af-

fective module or in the connection between the face recognition

units and the affective module (see Figure 1). Subsequently, Ellis

and Lewis (2001) slightlymodified the dual-routemodel of Breen

et al. by adding an integrative device, which compares the out-

puts of the affective and cognitive routes. This was done to ex-

plain the delusion inCapgras patients when a familiar face fails to

elicit a corresponding affective response.

Taken together, all models of face recognition that attempt to

encompass both findings in prosopagnosia and Capgras delusion

and differences between overt and covert face recognition (Ba-

uer, 1984; Breen et al., 2000; Ellis & Lewis, 2001; Ellis & Young,

1990; Ellis et al., 1997) include two routes to face recognition,

termed affective and cognitive. As a result, dual-route models

provide a comprehensive framework for assumptions and inves-

tigations of face recognition. For intact processing systems, the

models postulate a similar relationship between facial familiarity

and response strength. For example, Breen et al. predict that the

affective response should increase with the degree of familiarity.

PreviousFmainly neuropsychologicalFresearch, which includ-

ed only one or two types of facial familiarity, confirmed this

relationship in the affective route. SCRs were more pronounced

for famous than for unfamiliar persons (Tranel & Damasio,

1985; Tranel, Fowles, & Damasio, 1985) or for personally famil-

iar than for famous faces (Tranel, Damasio, & Damasio, 1995).

From these observations and in line with dual-route models one

would expect SCRs to increase with facial familiarity when un-

familiar, famous, and personally familiar faces are compared.

Similarly, it can be thought that face familiarity should im-

prove cognitive processing. This has been demonstrated for the

comparison of famous with unfamiliar faces in several suggested

probes of processing within the cognitive route: priming, inter-

ference, matching effects, and the speed of face-name learning

(Bruce & Young 1986; Ellis, Lewis, Moselhy, & Young, 2000;

Pfutze, Sommer, & Schweinberger, 2002). Repetition priming

for faces reflects facilitation, for example, in reaction times to a

face that has been processed before, relative to initial encounter

(Bruce & Young, 1986). Current models of face recognition

(Burton, Bruce, & Hancock, 1999) assume that the decision

about facial familiarity is made at the person identity node level.

Whereas long-term repetition priming is thought to be mediated

mainly by the strengthening of links between face recognition

units and person identity nodes, immediate repetition priming

appears to involve facilitation at an earlier level of access to face

recognition units and/or structural encoding (Pfutze et al., 2002;

Schweinberger, Pfutze, & Sommer, 1995; Schweinberger, Picke-

ring, Jentzsch, Burton, & Kaufmann, 2002). Therefore, repeti-

tion priming in face identification may involve facilitation at

several loci along the cognitive route. Whereas previous studies

revealed stronger priming effects in RTs for famous than for

unfamiliar faces (Bruce & Valentine, 1985; Ellis et al., 2000;

Pfutze et al., 2002), personally familiar faces do not seem to have

been studied for priming effects. It is therefore an open question

whether there would also be an increase from famous to person-

ally familiar faces in RT priming.

Importantly, current research, mainly based on the model of

face recognition by Bruce and Young (1986), has identified at

least two consistent ERP correlates of face recognition within a

repetition priming task paradigm. First, a negativity for primed

relative to unprimed faces is seen over inferior temporal elec-

trodes at latencies of around 200–350 ms, an effect that has been

variously termed ‘‘N250r’’ or ‘‘early repetition effect’’ (ERE;

Pfutze et al., 2002; Schweinberger et al., 1995; Schweinberger,

Pickering, Jentzsch, et al., 2002). The N250r is typically larger

over the right than left hemisphere and is not present for asso-

ciative-semantic priming (Schweinberger, 1996). Moreover, the

N250r is reduced or even absent for unfamiliar as compared to

famous faces (Pfutze et al., 2002; Schweinberger et al., 1995),

suggesting that it depends on the contact with an existing mem-

ory representation. Although an N250r at similar latency as for

What’s special about personally familiar faces? 689

faces has been observed for written names, this effect is maximal

over the left hemisphere (Pfutze et al., 2002; Pickering &

Schweinberger, 2003). Thus, the N250r has a stimulus-depend-

ent topography, suggesting that it links to perceptual rather than

postperceptual representations. The face-elicited N250r has been

related to the transient activation of face recognition units, and is

therefore also of particular interest for dual-route models.

Another consistent ERP correlate of face priming is a late

ERP repetition effect (N400 or LRE), an increased centro-

parietal positivity (or reduced negativity) for repeated faces

at latencies around 300–600ms (Bentin & McCarthy, 1994;

Schweinberger et al., 1995; Schweinberger, Pickering, Burton, &

Kaufmann, 2002). This late repetition effect is likely related to

the N400, which was initially demonstrated to reflect the detec-

tion of semantic incongruency in sentences and was thought to

represent semantic integration (Kutas & Hillyard, 1980). An

N400-like pattern can also be elicited by faces, when these are

preceded by the same or by associated faces. The N400 may

reflect facilitation in assessing postperceptual or semantic mem-

ory codes for people (person identity node).

According to assumptions about cognitive networks for face

recognition (Burton et al., 1999; Mohr, Landgrebe, & Schwein-

berger, 2002), priming should especially facilitate recognition of

those faces for which there are stronger memory representations.

To the extent that a more frequent encounter of personally fa-

miliar as compared to famous faces might have induced stronger

neurocognitive networks, it might be expected that the N250r

increases from famous faces to personally familiar ones.

Importantly, the different versions of dual-route models dis-

agree with respect to the locus at which the two routes diverge.

Some models state that both routes diverge early in processing

and therefore imply two distinct sets of recognition mechanisms,

or face recognition units (Bauer, 1984; Ellis et al., 1997; Hirstein

& Ramachandran, 1997). Other models explicitly assert a com-

mon face recognition unit with the two routes diverging only

subsequently (Breen et al., 2000; Ellis & Lewis, 2001).

The N250r can provide functional evidence about face

processing, and the scalp topography of this component can,

to some extent, provide information about underlying sources. If

the N250r for two different types of facial familiarity showed

different scalp topographies, this would be evidence for the in-

volvement of at least partially different neural generators. To the

extent that N250r to personally familiar faces reflect the activa-

tion of a different set of face recognition units as compared to

famous faces, for example in a dorsal affective route (Bauer,

1984; Ellis et al., 1997; Hirstein & Ramachandran, 1997), it

690 G. Herzmann et al.

Figure 1. An adaptation of the dual-route models of face recognition proposed by Breen et al. (2000) and Ellis and Lewis (2001).

Face recognition is considered as matching a seen face to its stored representation at the level of the face recognition units. Face

recognition units activate simultaneously but independently the affective and the cognitive routes. The affective route leads to a

module triggering affective responses to familiar stimuli, of which skin conductance response is an indicator. The cognitive route

leads to person identity nodes, activates semantic information, and supports name retrieval. An abnormality at locationA will cause

a loss of overt face recognition and is therefore a possible explanation for prosopagnosia. An abnormality at location B will cause a

loss of differential SCR responses to familiar and unfamiliar stimuli. It will also cause a discrepancy in the integrative device and is

therefore a possible account for Capgras delusion. In the context of the present study, SCR responses are thought to be mainly

sensitive to activity along the affective route (B), RTpriming effects are thought to bemainly sensitive to activity along the cognitive

route (A), and the ERE should be sensitive to activity in the face recognition units.

should be reflected in distinguishable topographies of theN250r to

famous and personally familiar faces. In contrast, if affective and

cognitive routes of face recognition diverge only after the access to

a common pools of face recognition units (Breen et al., 2000; Ellis

& Lewis, 2001), the N250r topographies should not differ.

To our knowledge, the postulations of dual-route models for

both affective and cognitive aspects have not yet been tested for

more than two types of facial familiarity in the same healthy

population. For that reason itwas the first objective of the present

study to provide a more comprehensive test of the predictions of

dual-route models. We assessed several indices for affective and

cognitive aspects of face recognition, as a function of different

types of facial familiarity. More specifically, we investigated in

healthy participants how unfamiliar, famous, and personally fa-

miliar faces are processed at several levels of the face recognition

system. The affective route was assessed by recording skin con-

ductance responses, the cognitive route was investigated with a

short-term repetition priming task, and the N250r provided a

tool to investigate the effects of facial familiarity on the face

recognition units. Addressing the question of separate or com-

mon face recognition units was the second objective of the present

study. To answer this question we also used the N250r.

Because of the different methodological requirements for re-

cording SCRs and ERPs, the experiment was divided into two

parts where the same stimuli and the same participants were

employed. In Part 1 of the experiment, we explored the influence

of different types of facial familiarity on the affective route by

examining modulations in SCRs. In the second part of the ex-

periment, we investigated effects on the cognitive route as seen in

RT priming effects.

EXPERIMENT: PART 1FSCR

In Part 1 of the experiment we investigated the affective aspects in

face recognition by means of recording SCRs as a function of

facial familiarity.

Method

Participants

Twenty-four participants (21 women, 3 men) with ages ranging

from 19 to 33 years (M5 21.9 years, SD5 3.2) were paid to

contribute data to the experiment. According to an adapted ver-

sion of the Edinburgh Handedness Inventory (Oldfield, 1971)

participants were strongly right-handed (M5186.2, range5

50–100). They reported normal or corrected-to-normal visual

acuity. All participants were psychology students at the Univer-

sity of Glasgow, and had been residents of the United Kingdom

or Ireland for a minimum of 5 years.

Stimuli

Sixty portraits were used, consisting of 15 personally familiar, 15

famous, and 30 unfamiliar faces. Photographs of famous and

unfamiliar persons were made available from earlier research.

The celebrities had been selected on the basis of previous high

ratings for ease of face recognition (Schweinberger, Pickering,

Burton, et al., 2002). Portraits of personally familiar persons

were taken from the lecturing staff in the Department of Psy-

chology at theUniversity ofGlasgow.All portraits were edited to

a unitary format. They were converted to gray scale, framed

within an area of 170 � 216 pixels, corresponding to 6.0 �7.6 cm, and all background was removed. An attempt was made

to homogenize the pictures with respect to contrast and average

luminance across the sets of famous, personally familiar, and

unfamiliar faces.

Prior to the experiment, the 15 best known personally familiar

persons and 15 best known celebrities were selected for each

participant out of two pools of pictures of 15 men and 7 women

each. To avoid any priming or habituation for the face stimuli,

these selections were based on the person’s names. Each person

was rated for ease of possible face recognition on a 5-point scale.

The selected unfamiliar faces were matched to familiar counter-

parts with respect to gender, approximate age, general portrait

style, and expression.

Procedure

After the rating participants were seated in a dimly lit, sound-

attenuated, and electrically shielded chamber. A fixed chin rest

was used tomaintain a constant viewing distance of 1m. A white

fixation cross in the center of the monitor changed into bold font

5 s before the onset of a face. The 60 faceswere presented once for

2,000ms in randomized order with interstimulus intervals be-

tween 12 and 18 s. The familiarity of each face was indicated by

key presses with the index and middle finger of the right hand.

Half the participants pressed the left key (index finger) for a

familiar face and the right key (middle finger) for an unfamiliar

face; this assignment of key to response category was reversed for

the other half. Responses were scored as correct if the appropri-

ate keywas pressedwithin a timewindowof 200 to 2,000ms after

face onset. Errors of omission (no key press) and commission

(wrong key) were recorded separately.MeanRTswere calculated

for correct responses only.

The experiment started with three practice trials, to be dis-

carded later. After completion of both parts of the experiment

participants rated the portraits shown, using the same rating

scale as in the beginning. As expected, the face sets differed, with

both personally familiar and famous faces being both rated as

well known (M5 3.8 and 3.9, respectively), and unfamiliar faces

as unknown (M5 0.2).

Recording

For SCR measurement, sintered Beckman Ag/AgCl electrodes,

1 cm in diameter, were affixed to the thenar and hypothenar

eminences of the left hand; a ground electrode was placed at the

left forearm. Isotonic electrolyte gel (K-Y Jelly, Johnson 1

Johnsont) was used. Skin conductance was recorded with a

Coulbournt Isolated Skin Conductance Coupler (Model V71-

23), and digitized at a sampling rate of 200Hz. Off-line, 10-s

epochs, starting 1 s before stimulus onset, were analyzed. A total

of 2.1% of all trials were excluded from analysis because of ar-

tefacts.

In addition to RTs and error rates, several response param-

eters were derived from the SCR (see below). Results were eval-

uated by means of Huynh–Feldt (Huynh & Feldt, 1976)

corrected repeated-measures ANOVAs; pairwise comparisons

between levels of familiarity were Bonferroni corrected. Within-

subject repeated measures are reported with (a) uncorrected de-

grees of freedom, (b) the corrected p value, and (c) the epsilon

value of the correction factor.


Results and Discussion

Performance

Means and standard deviations of RTs and error rates are shown

in Table 1. In RTs, a significant main effect of familiarity was

observed, F(2,46)5 18.5, po.001, e5 .57. Responses to unfa-

miliar faces were slower when compared to both personally fa-

miliar, F(1,23)5 18.1, po.001, and famous faces,

F(1,23)5 20.4, po.001, which did not differ from each other,

F(1,23)5 1.0. No effect of familiarity was observed in the error

rates, F(2,46)o1.

SCR

Trials without artefacts were analyzed by a computerized algo-

rithm. The criterion for a valid response was an increase in skin

conductance of at least 0.01mS between 1 and 7 s after stimulus

onset. In 55.1% of the trials these requirements were met. The

other trials were defined as nonvalid and amplitude was scored as

zero.

SCR magnitudewas quantified as mean peak amplitude with-

in the response window of all single trials including valid and

nonvalid (zero-amplitude) SCRs. SCR amplitude was calculated

in the same way but for valid responses only. SCR frequencies

were defined as the proportion of stimuli eliciting valid SCR

responses. The means and standard deviations of these param-

eters are shown in Table 2.

There were significant effects on SCR magnitude,

F(2,46)5 6.5, po.01, e5 .91, SCR frequency, F(2,46)5 4.1,

po.05, e5 .83, as well as a strong trend for SCR amplitude,

F(2,46)5 3.5, p5 .057, e5 .68. In response to personally famil-

iar faces, mean SCR magnitudes and frequencies were higher

when compared with famous faces, F(1,23)5 9.6, po.01 and

F(1,23)5 5.3, p5 .06 (uncorrected po.05), respectively, and al-

so when compared with unfamiliar faces, F(1,23)5 7.4, po.05

and F(1,23)5 7.7, po.05, respectively. Although only as a trend,

the effect on SCR amplitude tended to be the same as for the

other parameters (cf. Table 2). In contrast, unfamiliar and fa-

mous faces did not significantly differ in any of these measures,

Fs(1,23)o1.1.

Partly conformable to the predictions of dual-route models,

this experiment shows that autonomic responses to personally

familiar target faces were both more frequent and larger than

those to famous and unfamiliar target faces. Therefore, the fa-

miliarity-induced modulation of SCR magnitude and amplitude

suggests a stronger involvement of affective components of face

processing for personally familiar faces. Unexpectedly and in

contrast to previous findings (Tranel et al., 1985) as well as to

predictions of dual-route models, no significant differences in

SCRs were seen between famous and unfamiliar faces. One pos-

sible explanation for this discrepancy may be that the present

inclusion of an additional category with strong significance (i.e.,

personally familiar faces) may have dominated the smaller dif-

ferences between famous and unfamiliar faces. It is worth noting

that the results are not explainable simply by an orienting re-

sponse due to signal value (Ohmann, 1979). Because all faces

were targets, they bore the same relevance for the task. Further-

more, SCR differences occurred especially within the same re-

sponse category (familiar faces), which would be hard to explain

in terms of signal value with respect to the task.

Interestingly, RTs showed a different pattern from the SCR

findings, with similar RTs to personally familiar and famous

faces and slower responses to unfamiliar faces. Although this

pattern may be explained by the task, which placed both types of

familiar faces into the same category, the SCRs nevertheless dis-

criminated between these face classes.

EXPERIMENT: PART 2FPRIMING

In Part 2 of the experiment we investigated priming effects in

reaction times and aimed at exploring face recognition units with

repetition effects in event-related brain potentials as a function of

facial familiarity.

Method

Participants

Sixteen participants (15 women, 1 man), who had also taken part

in the first part of the experiment, contributed data to this study.1

All were strongly right-handed (M5185.9, range5 50–100);

ages ranged from 19 to 27 (M5 20.9) years.

Stimuli

The same stimuli as in Part 1 of the experiment were used.

Procedure

Directly following the SCR experiment, EEG electrodes were

applied and participants received written task instructions.

Figure 2 shows the trial sequence. At the beginning of each tri-

al, a white fixation cross appeared for 500ms, being replaced by a

prime face, presented for 500 ms and followed by a green fixation

circle. After 1,300 ms the circle was replaced by a target face,

presented for 2,000 ms. The interval between prime onsets was

6,300 ms.

Participants were asked to indicate by key presses with their

left and right index fingers whether the target face was familiar or

unfamiliar. No motor response was required to prime faces. For

a given participant, the assignment of stimulus category to the

left or right response key was the same as in Part 1 of the ex-

periment. Both speed and accuracy were emphasized. Two dif-

ferent feedback tones of 300 ms duration were presented after

incorrect (500Hz) or missing responses (650Hz). Responses

were scored as correct if the appropriate key was pressed between

200 and 2,000 ms after target onset. Mean reaction times were

calculated for correct responses only. Throughout the experi-

ment, short breaks were allowed after every 45 trials.

The prime for each of the 60 target faces (15 personally fa-

miliar, 15 famous, and 30 unfamiliar) could be either the same

face (primed condition) or a different face (unprimed condition).


Table 1. Mean Correct Reaction Times (RT, inMilliseconds) and

Percentage of Errors (PE) for Personally Familiar, Famous, and

Unfamiliar Faces in Part 1 of the Experiment

Familiarity type

RT PE

M SD M SD

Personally familiar 875.3 248.6 10.6 21.1Famous 855.5 270.4 6.9 20.0Unfamiliar 1163.0 299.8 6.6 11.8

1Although not all participants from the SCR study were available forthe ERP study, the results in Part 1 of the experiment were essentiallyunchanged even when only these 16 participants were considered.

In the unprimed condition, personally familiar and famous target

faces were preceded by unfamiliar primes, and unfamiliar target

faces were preceded by personally familiar or famous primes.

This allowed us to test repetition priming for both familiar and

unfamiliar targets without an impractically large amount of filler

trials and appeared appropriate because previous research

(Schweinberger et al., 1995) had indicated that responses to un-

primed target faces are independent of whether or not the pre-

ceding prime face is familiar.

The design involved the variables priming (primed vs. un-

primed) and familiarity (personally familiar, famous, and unfa-

miliar). Each of the 60 target faces appeared three times in the

primed condition and three times in the unprimed condition,

yielding a total of 360 experimental trials. In the unprimed con-

dition a given pair of faces was used only once in order to avoid

episodic priming. All trials were shown in randomized order.

Recording

The electroencephalogram (EEG) was recorded with sintered

Ag/AgCl electrodes mounted in an electrode cap (Easy-Capt) at

the scalp positions Fz, Cz, Pz, Iz, FP1, FP2, F3, F4, C3, C4, P3,

P4, O1, O2, F7, F8, T7, T8, P7, P8, FT9, FT10, P9, P10, PO9,

PO10, F90, F100, TP9, and TP10 (Pivik et al., 1993). The F90 andF100 electrodes were positioned 2 cm anterior to F9 and F10 at

the outer canthi of the left and right eyes, respectively. TP9 and

TP10 refer to inferior temporal locations over the left and right

mastoids, respectively. The TP10 electrode served as initial com-

mon reference and a forehead electrode (AFz) served as ground.

Impedances were typically kept below 5 kO. The horizontal

electrooculogram (EOG) was recorded from F90 and F100. Thevertical EOG was monitored from two additional electrodes

above and below the right eye. All signals were recorded with a

band-pass of 0.05Hz to 40Hz (� 6dB attenuation, 12 dB/oc-

tave), and a sampling rate of 200Hz.

Off-line, epochs of 1,700 ms starting 215 ms before target

onset were generated from the continuous record. Trials with

nonocular artefacts, saccades, and incorrect behavioral respons-

es were discarded. Trials with ocular blink contributions to the

EEG were corrected (Elbert, Lutzenberger, Rockstroh, &

Birbaumer, 1985) or excluded from data analysis if not enough

sample blinks could be obtained, as was the case in three par-

ticipants. ERPs were aligned to a 215-ms baseline before target

onset, averaged separately for each channel and experimental

condition, digitally low-pass filtered at 10Hz with zero phase

shift, and recalculated to average reference, excluding the vertical

EOG channel.

All dependent variables were analyzed bymeans of ANOVAs

with repeated measures on familiarity and priming, epsilon cor-

rected for heterogeneity of covariance, wherever appropriate.

Within-subject repeated measures are reported with (a) uncor-

rected degrees of freedom, (b) the corrected p value, and (c) the

epsilon value of the correction factor.

Results

Performance

Reaction times are shown in Table 3. Whereas RTs to unprimed

faces appear to be similar in the three familiarity conditions,

priming reduced RTs more for both types of familiar faces than

for unfamiliar faces. This pattern was confirmed by an interac-

tion between priming and familiarity, F(2,30)5 21.2, po.001,


Figure 2. Trial sequence for Part 2 of the experiment. Shown is an unprimed trial with a target face that was personally familiar to

the participants of this study, preceded by an unfamiliar prime face.

Table 2. Mean Magnitude (in Microsiemens), Amplitude (in Microsiemens), and Frequency

(in Percent) for Skin Conductance Responses to Personally Familiar, Famous, and Unfamiliar

Faces in Part 1 of the Experiment

Familiarity type

Magnitude Amplitude Frequency

M SD M SD M SD

Personally familiar 0.78 0.92 1.27 1.47 63 26Famous 0.54 0.62 0.88 1.06 58 25Unfamiliar 0.53 0.63 0.86 0.86 54 24

e5 .86, in addition to main effects of priming, F(1,15)5 67.6,

po.001, and familiarity, F(2,30)5 23.8, po.001, e5 .86. The

interaction is caused by the differential priming effects; there was

no familiarity effect in unprimed faces, F(2,30)o1.7, but a strong

effect of familiarity for primed faces, F(2,30)5 41.1, po.001,

e5 .72. Priming effects between personally familiar and famous

faces were indistinguishable, F(1,15)o1.7, p4.10, but priming

was smaller in unfamiliar faces relative to both personally fa-

miliar faces, F(1,15)5 35.1, po.001, and famous faces,

F(1,15)5 18.3, po.001, respectively. Although relatively small,

priming was still significant when tested for unfamiliar faces

alone, F(1,15)5 13.9, po.01.

Mean percentage of errors (Table 3) were generally low, ex-

cept that personally familiar faces were relatively often judged as

unfamiliar. This was reflected in a main effect of familiarity,

F(2,30)5 9.7, po.01, e5 .72, with higher error rates for per-

sonally familiar faces than for both famous, F(1,15)5 11.6,

po.01, and unfamiliar faces, F(1,15)5 9.4, po.05, which did

not differ from each other.2 However, effects of priming, Fo1,

and the interaction between priming and familiarity,

F(2,30)5 2.3, p4.10, e5 1.12, were not significant. Thus, error

rates do not suggest a speed–accuracy trade-off with respect to

the priming effects seen in RTs.

Event-Related Potentials

Figure 3 shows ERPs to personally familiar target faces as typical

examples of the observed waveforms. Figure 4 compares ERPs

to primed and unprimed faces for all three familiarities at the

most important electrode sites. ERPs were quantified with mean

amplitude measures, relative to a 215-ms prestimulus baseline, in

the time segments 120–140, 170–180, 230–270, 270–330, 330–

400, and 400–500 ms, relative to target onset. The first and sec-

ond segments correspond to the occipital P1 and the occipito-

temporal N170 peaks in the ERP waveforms, respectively. The

P1 is sensitive to variations in relatively early domain-general

visual processes, for example, those caused by differences in

contrast, brightness, or size (cf. Pfutze et al., 2002). TheN170 is a

face-specific component supposed to reflect structural encoding

(Bentin, Allison, Puce, Perez, & McCarthy, 1996; Eimer, 1998).

The subsequent segments were chosen in order to evaluate the

N250r (230–330 ms) and the N400 (330–500 ms). For each time

segment, ANOVAs were performed analogous to those for the

performance data, except for the inclusion of an additional re-

peated measurement factor electrode (30 levels). Note that, be-

cause the average reference sets the mean activity across all

electrodes to zero, condition effects in these ANOVAs are only

meaningful in interaction with electrode. Therefore, we report

only such interactions butFfor brevity’s sakeFwithout men-

tioning the electrode factor. If significant effects of priming, fa-

miliarity, or of their interaction showed up in the ANOVAs,

additional analyses were performed on specific regions of interest

(ROIs) in order further to locate these effects. These ROIs were

chosen at regions for which the components in question are most

clearly visible, and were, for N250r (a) frontal (Fz, F3, F4), (b)

temporal (T7, T8, P7, P8, TP9, TP10, P9, P10), and for N400 (c)

central-parietal (Cz, Pz, C3, C4, P3, P4).

P1. The P1 component can be seen at the occipital electrodes

around 125 ms after target onset. No significant effects of the

experimental variables on the P1 amplitude were observed,

Fso1.8, p4.10.

N170. The N170 is most pronounced at occipito-temporal

electrodes. TheANOVAof theN170 amplitude yielded effects of

priming, F(29,435)5 2.6, po.05, e5 .18, and familiarity,

F(58,870)5 3.1, po.01, e5 .13, but no interaction between

these factors, F(58,870)5 1.4, p4.10, e5 .16. The effects of

priming and familiarity onN170 amplitudewere rather weak and

inconsistent and will not be elaborated upon further.3

N250r (early repetition effect). The N250r is to be seen best

at inferior temporal electrodes (e.g., TP10). Moreover, a polarity

inversion of this effect is prominent at frontal electrodes (e.g.,

Fz). Figure 5 depicts the repetition effects by showing the dif-

ference waveforms between ERPs to primed and unprimed faces

for the three conditions; the topographies of the repetition effects

for the different time segments are shown in Figure 6. Inspection

of these figures not only shows that (a) the repetition effects

reflect an electrical negativity for primed faces over temporal

electrodes and a positivity over fronto-central electrodes, and but

also suggests that (b) the early repetition effect increased in am-

plitude from unfamiliar over famous to personally familiar faces.

From around 230 ms onward priming caused increased negativ-

ity at inferior temporal electrodes.

The amplitude measures in both the 230–270- and 270–330-

ms segments yielded strong effects of priming, Fs(29,435)5 12.4

and 26.4, respectively, pso.001, es5 .16. There were also effects


Table 3. Mean Correct Reaction Times (RT, inMilliseconds) and Percentages of Errors (PE)

for Personally Familiar, Famous, and Unfamiliar Target Faces in Part 2 of the Experiment

Familiarity type

Primed condition Unprimed condition

RT PE RT PE

M SD M SD M SD M SD

Personally familiar 530.2 102.6 6.0 5.2 663.6 81.9 6.3 6.6Famous 549.7 107.4 1.2 1.9 669.1 89.6 1.8 1.8Unfamiliar 642.7 108.6 3.1 3.6 685.5 102.1 1.7 2.2

2It is interesting that the observation of higher percentages of errors isin contrast with the finding of larger SCRs to personally familiar thanfamous faces. This would seem to exclude an explanation of the SCReffect in terms of overall better knowledge of personally familiar faces.

3Several studies (Bentin &Deouell, 2000; Eimer, 2000) have indicatedthat the N170 is insensitive to the familiarity of faces. Similarly, althoughthere are several studies that report face repetition effects for the N170 oreven earlier components (e.g., Braeutigam, Bailey, & Swithenby, 2001),one difficulty with these effects is that they appear to be rather incon-sistent across studies. Although we would not completely reject the pos-sibility that there may be small repetition effects on the N170, the presenteffects in this time range might also reflect temporal overlap with therising slope of the N250r, rather than differences in the N170 itself.

of familiarity, Fs(58,870)5 6.1 and 7.3, pso.001, es5 .20 and

.17, and significant interactions between priming and familiarity,

Fs(58,870)5 3.5 and 6.6, pso.001, es5 .16. Pairwise compari-

sons revealed significant priming effects at each level of famil-

iarity, all Fs(29,435)44.5, all ps o.01, all eso.19. Moreover,

priming effects in both time segments differed between personally

familiar and famous faces, Fs(29,435)5 5.0 and 4.3, po.001 and

po.01, es5 .28 and .18, respectively, and also between person-

ally familiar and unfamiliar faces, Fs(29,435)5 4.9 and 12.4,

pso.001, es5 .18 and .20, respectively. In contrast, priming ef-

fects differed between famous and unfamiliar faces in the 270–

330 ms segment, F(29,435)5 3.2, po.05, e5 .14, but not in the

preceding 230–270-ms segment, Fo1. It may be noted that in

both segments there were also significant familiarity-induced

modulations of amplitude for unprimed faces, Fs(29,435)5 5.2

and 4.0, pso.001, es5 .19 and .20. Bonferoni-corrected pairwise

comparison within the unprimed condition revealed significant

differences in amplitude between all familiarity conditions at the

230–270-ms segment, Fs(29,435)44.4, pso.01, eso.23. In the

270–330-ms time segment amplitudes differed significantly only

between personally familiar and unfamiliar, F(29,435)5 4.8,

po.001, eo.24, as well as between famous and unfamiliar faces,

F(29,435)5 5.8, po.001, eo.25, whereas personally familiar

faces did not differ from famous faces, Fo2.0.4

In the time segment between 230 and 270 ms the ROI analysis

at frontal electrodes revealed significant main effects of priming,

F(1,15)5 17.8, po.001, familiarity, F(2,30)5 6.7, po.01,

e5 1.13, and a trend for an interaction of priming and famili-

arity, F(2,30)5 2.6, p5 .10, e5 .81. This interaction was due to

priming effect differences between personally familiar and fa-

mous faces, F(1,15)5 7.5, po.05, but not for the other famil-

iarity comparisons, Fs(1,15)o1.7. In the same time segment,

temporal electrodes only revealed significant main effects of

priming, F(1,15)5 68.2, po.001, and familiarity, F(2,30)5

15.5, po.001, e5 .91, but no differences in priming effects

across familiarity conditions, F(2,30)5 1.6, p5 .22, e5 .95.

In the 270–330-ms segment the ROI analysis revealed similar

effects. At both frontal and temporal electrode sites the main

effects of priming and familiarity reached significance, pso.001.

Moreover, there was a significant interaction of familiarity and

priming at frontal electrodes, F(2,30)5 3.9, p5 .05, e5 .93, this

interaction again arising from priming effect differences between

personally familiar and famous faces, F(1,15)5 7.1, po.05.

Again, no significant interaction showed up at temporal elec-

trode sites, F(2,30)5 1.8, p5 .19, e5 .97.

To address the question of whether or not these data provide

evidence for separate face recognition units for the affective and

cognitive routes, the topographies of the N250r for each category

of facial familiarity were analyzed. If scalp topographies of the

N250r differ, one may conclude that at least some of the gen-

erator sources of this effect are different, lending support for the

idea of separate N250r. Interactions in ERP amplitudes of ex-

perimental variables with electrode site may derive from differ-

ences in the underlying neuronal source configuration only when

differences in source strength are ruled out. Therefore, ANOVAs

were calculated with factors familiarity and electrode site for the

N250r after scaling them to the same overall amplitude within

each condition with the average distance of the mean, derived

from the grand mean ERPs, as the divisor (McCarthy & Wood,


Figure 3. ERPs recorded for primed (solid lines) and unprimed (dashed lines) personally familiar target faces. Recordings are shown

for all 30 channels. Arrows indicate the P1, N170, the early repetition effect (N250r), and the late repetition effect (N400).

4The observed familiarity effects within the unprimed condition weresignificant but weaker than the N250r effect and showed a different to-pography. They appear to originate from a different source, and willtherefore not be analyzed any further.

1985). Recently, Urbach and Kutas (2002) criticized this proce-

dure as being potentially unreliable in its intended application of

identifying generator differences, particularly when overall base-

line differences exist between conditions, or whenmultiple sourc-

es are present simultaneously. In our experience, overall baseline

differences are not likely to be a strong concern in the present

study, which used average reference such that any overall dif-

ferences should be eliminated. In addition, dipole source local-

ization of theN250r to famous faces has suggested a single source

in the fusiform gyrus (Schweinberger, Pickering, Jentzsch, et al.,

2002). Nevertheless, when using scaling to investigate differences

in underlying neuronal source configuration, potential limita-

tions of this procedure should be kept in mind.

N250r topographies of priming effects differed significantly

across familiarity conditions in the 270–330-ms segment,

F(58,870)5 4.8, po.001, e5 .14. Figure 6 suggests that the pos-

itive aspect of the N250r peaked in midfrontal regions for un-

familiar faces, but for personally familiar and famous faces it was

more pronounced in more posterior central regions. Pairwise

comparisons confirmed differences in topography between un-

familiar and both personally familiar faces, F(29,435)5 9.0,

po.001, e5 .18, and famous faces, F(29,435)5 3.4, po.05,

e5 .17. However, N250r topographies for personally familiar

and famous faces were indistinguishable, F(29,435)5 2.5,

p4.10, e5 .14.

N400 (late repetition effect). In both the 330–400-ms and the

400–500-ms segment there were significant effects of priming,

Fs(29,435)5 22.6 and 5.0, po.001 and po.01, es5 .17 and .15,

of familiarity, Fs(58,870)5 4.1 and 2.6, pso.001, es5 .19 and

.17, and of their interactions, Fs(58,870)5 9.0 and 2.0, po.001

and po.05, es5 .18, respectively. These priming effects resemble

an N400-like modulation of the late positive complex, with more

negativity (or less positivity) for unprimed than primed faces at

central-parietal locations, and less negativity at prefrontal and

lateral frontal locations (see Figures 3–5). Furthermore, Figure 5

suggests that between 330 and 400 ms the N400 priming effect

(i.e., the difference between primed and unprimed faces) in-

creased in amplitude from unfamiliar over famous to personally

familiar faces. In the 330–400-ms segment, priming was signif-

icant at each level of familiarity, Fs(29,435)44.6, pso.001,

es5 .19. Post hoc comparisons showed differences in the N400


Figure 4. ERPs for personally familiar (first column), famous (second column), and unfamiliar target faces (third column)

comparing primed (solid lines) and unprimed conditions (dashed lines) at themost important electrode sites (Pz, Fz, TP10, and P10).

Vertical timelines indicate the areas of the early repetition effect, which were used in the ANOVA (230–270 ms and 270–330 ms).

priming effect between personally familiar and famous,

F(29,435)5 3.7, p5 .01, e5 .27, personally familiar and unfa-

miliar, F(29,435)5 15.3, p5 .001, e5 .21, and between famous

and unfamiliar faces, F(29,435)5 6.2, p5 .001, e5 .16. In the

400–500-ms segment, priming was significant for personally

familiar, F(29,435)5 4.9, po.001, e5 .20, and famous faces,

F(29,435)5 3.5, po.05, e5 .17, but was reduced to insignifi-

cance for unfamiliar faces,F(29,435)5 2.7, p4.10, e5 .10. ROIs

analysis of the 330–400-ms time segment revealed significant

main effects of priming, F(1,15)5 58.2, p5 .001, and familiarity,

F(2,30)5 8.8, p5 .001, e5 1.15, as well as an interaction be-

tween priming and familiarity at central-parietal electrodes,

F(2,30)5 23.9, p5 .001, e5 .93. Pairwise comparison showed

differences in priming effects between personally familiar and

famous, F(1,15)5 9.5, p5 .01, personally familiar and unfamil-

iar, F(1,15)5 48.4, p5 .001, and between famous and unfamiliar

faces, F(1,15)5 13.6, p5 .01. However, in the 400–500-ms

ROI analysis at central-parietal electrodes revealed only signif-

icant main effects of priming, F(1,15)5 9.6, p5 .01, and famil-

iarity, F(2,30)5 5.7, p5 .01, e5 .96, but no significant

interaction of both, Fo1.8. Finally, N400 topographies of prim-

ing effects (applying the scaling procedure described above)

did not differ significantly across familiarity, Fs(58,870)o2.9,

ps4.05.

Discussion

At the level of RTwe found least priming for unfamiliar faces and

larger but equivalent priming for personally familiar and famous

faces. There appears to be no advantage in the cognitive aspects

of face processing for personally familiar compared with famous

faces.

The ERP data revealed an early repetition effect (N250r)

around 230–330 ms that was negative at posterior temporal

electrodes but positive at mid-frontal sites, replicating previous

reports (Pfutze et al., 2002; Schweinberger et al., 1995;

Schweinberger, Pickering, Jentzsch, et al., 2002). Most impor-

tantly, N250r amplitude was significantly modulated by facial

familiarity. It was smallest for unfamiliar faces, increased to fa-

mous faces (see Pfutze et al., 2002 for similar results), and was

largest for personally familiar faces. The sensitivity of the N250r

to familiarity indicates that it is not simply a correlate of the

repetition of the stimulus but reflects the contact with memory

representations for faces. Furthermore affective dimensions,

such as likeability or attractiveness, could be thought to have

modulated the observed N250r amplitude effects, especially for

personally familiar faces. However, the present interstimulus in-

terval between prime and target of 1,300 ms was much too long

for possible affective priming, which would require an interstim-

ulus interval below 300ms (Greenwald, Klinger, & Schuh, 1995).

Decisions about the familiarity of a face are supposed to be

made at the person identity node level (Burton et al., 1999).

Repetition priming has been proposed to involve processing fa-

cilitation already during the access to face recognition units or

even structural encoding (Pfutze et al., 2002; Schweinberger et

al., 1995; Schweinberger, Pickering, Jentzsch, et al., 2002). In this

respect, the observed amplitude differences of the N250r for

personally familiar compared with famous or unfamiliar faces

could be a result of more widespread and stronger neural net-

works coding these faces. These network differences might result,

for example, from a more extensive range of visual experience

with personally familiar faces, compared with famous faces.

Stronger networks can be assumed to expedite information

processing by reducing the threshold for face recognition (Mohr

et al., 2002). In contrast to the quantitative differences in N250r

amplitudes, the topographies of N250r for personally familiar

and famous faces were indistinguishable. This is consistent with


Figure 5. ERP difference waves (primedminus unprimed) for personally

familiar (solid lines), famous (dashed lines), and unfamiliar target faces

(dotted lines) at the most important electrode sites (Pz, Fz, TP10, and

P10). Vertical timelines indicate the areas of the early repetition effect,

which were used in the ANOVA (230–270 ms and 270–330 ms).

the notion of similar underlying neural sources. The only top-

ographical difference found was between the N250r for unfamil-

iar faces and both personally familiar and famous faces, confirm-

ing earlier suggestions of qualitatively different underlyingmech-

anism for unfamiliar faces (Hancock, Bruce, & Burton, 2000).

The present N400 priming effect broadly replicates the N400-

like effect observed before (Bentin & McCarthy, 1994; Schwein-

berger et al., 1995; Schweinberger, Pickering, Burton, et al.,

2002). For the present data, this interpretation must be seen with

some restrictions because the N400 may have been partially in-

fluenced by a latency shift in a late positive ERP component (see

Figures 3 and 4) especially when RTs differed between condi-

tions. In the absence of such RT differences, in the 330–400-ms

segment the N400 priming effect was more pronounced for per-

sonally familiar than for famous faces, as can be seen in Figure 5.

According to network theories of face recognition (Burton et al.,

1999), this could reflect more elaborated semantic processing for

personally familiar than for famous people.

One must be aware that because of the small number of crit-

ical stimuli and of the preceding SCR experiment, each stimulus

was repeated four times across the two experiments. Multiple

repetitions could be assumed to have made the unfamiliar faces

familiar for the participants and consequently may have influ-

ences the RT and ERP results. However, multiple repetitions

were used in all conditions and therefore should not have caused

differences between conditions. In addition, although an influ-

ence of repetitions over longer time intervals is usually found for

N400, N250r reflects a more transient effect and seems to be

insensitive to repetitions over longer intervals (Schweinberger,

Pickering, Burton, et al., 2002).


Figure 6. Topographical voltage maps of ERP differences between primed and unprimed conditions showing priming effects for

personally familiar (left column), famous (middle), and unfamiliar faces (right column) at different latencies after target

presentation. All maps were obtained by using spherical spline interpolation. Equipotential lines are separated by 1 mV/line;negativity is shaded.

General Discussion

Within the framework of dual-route models (Breen et al., 2000;

Ellis & Lewis, 2001), the present study had two main objectives.

Objective 1

In the present study we explored the effects of three different

types of facial familiarity on affective as well as cognitive aspects

of face recognition, and on the face recognition units, using

SCRs, priming effects, and the N250r.

We found that face familiarity caused different effects in SCRs

and RT priming. Whereas stronger cognitive effects (RT prim-

ing) were elicited by famous than unfamiliar faces, this was not

the case for the autonomic responses (SCR). Strong autonomic

responses were only triggered for personally known faces for

which, however, cognitive activation did not exceed the level

attained for famous faces.

According to dual-route models, the SCR is assumed to rep-

resent the activation within an affective route. However, these

models are not very specific about what is meant with affect: Is it

an emotional response to the familiar face or is it a reflection of

the significance of the displayed person for the observer? It

should also be kept in mind that, although SCRs are a result of

activation of the sympathetic autonomic nervous system, they

are rather unspecific responses, which can be caused by a number

of affective as well as cognitive processes. Therefore, cognitive

components of face processing could, in principle, have contrib-

uted to the observed SCR results.

Electrodermal responses have been suggested to be triggered

by processes such as novelty, emotion, or significance of the

stimulus (e.g., Dawson, Schell, & Filion, 2000). In the setting of

the present study, it is unlikely that novelty has triggered the

obtained results of larger SCRs to personally familiar faces. It

can be assumed that the participants have seen their lecturers as

frequently as or even more often than the shown celebrities and,

of course, also more often than the unfamiliar faces. Because

personally familiar and famous faces were both used as targets

and placed into the same category, they had the same significance

with respect to the task, yet they differed in SCRs. Therefore the

‘‘affective’’ response reflected in the SCRs to personally familiar

faces might relate to emotional responses or to the ‘‘personal

significance’’ for the observer. In principle, it may be possible

that the participants experienced a specific emotional response to

their lecturers as their portraits were shown such as joy, fear, and

so forth. However, to us it seems to be more plausible that the

observed SCRs may reflect the importance or significance of the

portrayed lecturers for our participantsFtheir students. There-

fore, the SCRs may represent the significance of the stimuli as

defined by the personal background of the observer rather than

by the experimental task.

The amplitude of the N250r exhibited reliable quantitative

differences in the face recognition units between all three types of

familiarity. Showing a continuous increase from unfamiliar over

famous to personally known faces, this result could point to the

assumptions of increasing face recognition units strength with

facial familiarity.

It may be argued that lecturers may not be typical instances

for personally familiar people, as might be family members or

friends. Although it would be desirable to replicate the present

findings with these kinds of stimuli, the pictures employed here

did elicit significant effects, especially in the N250r amplitudes,

which are thought to be a sign of stored facial structures. In SCRs

and the N250r, personally familiar faces were found to cause the

largest effects. This can additionally be caused by their high (so-

cial) importance, which lecturers as authorities bear for their

students. These results confirm the notion that personally famil-

iar compared with famous faces encompass especially an advan-

tage in affective aspects of face processing and may have a

stronger network of face recognition units.

Objective 2

We also addressed the question of whether there are unitary or

multiple face recognition mechanisms, or face recognition units,

feeding into the affective and cognitive routes of face processing,

using both functional and neural information of the early rep-

etition effect (N250r).

We found that the N250r, taken to reflect face recognition

unit activation, did not differ in its neural underpinnings between

personally familiar and famous faces. Although a quantitatively

larger N250r was seen for personally familiar faces, the scalp

topographies of the N250r to personally familiar and famous

faces were indistinguishable. Recent brain electric source anal-

yses of the N250r are consistent with a generator in fusiform

gyrus (Schweinberger, Pickering, Jentzsch, et al., 2002), an area

that is strongly implicated in face recognition (Kanwisher,

McDermott, & Chun, 1997) and face repetition priming (Hen-

son, Shallice, & Dolan, 2000).

Before taking this result as evidence for a common face

recognition unit, one needs to be aware of certain limitations of

ERP research. In particular, whereas topographical differences

between two ERPs or ERP effects indicate that these were gen-

erated by at least partially different sources, there might beFat

least in principleFa number of reasons for the absence of such

differences. For an ERP to be recordable at the scalp, simulta-

neous activity of a vast number of suitably aligned neurons is

required. Although this is often the case for cortical sources, it

may not hold true in many subcortical sources (Wood & Allison,

1981). We believe that this problem is unlikely to have biased the

present interpretation, as scalp-recorded ERPs can likely be re-

corded from key structures in the dorsal route, specifically the

superior temporal sulcus (Puce, Smith, & Allison, 2000) and

cingulate gyrus (Badgaiyan & Posner, 1998). However, respons-

es to personally familiar faces along the affective route would

include activity in ventral limbic structures (and amygdala in

particular), and it is well possible that such activitymight bemore

difficult to pick up. Despite these caveats, we would like to em-

phasize that the present ERP data did show topographical dif-

ferences in N250r between unfamiliar faces and both famous and

personally familiar faces. This not only lends support to the idea

that the recognition of familiar and unfamiliar faces is governed

by a qualitatively different mechanism (Hancock et al., 2000), it

also suggests that the equivalence of the topographies for per-

sonally and famous faces is unlikely to be a result of insufficient

power to find such topographical differences in the present ex-

periment.

Using the framework of dual-route models to test the influ-

ence of facial familiarity on face processing reinforced the sug-

gestion that face recognition is the result of the interaction of

several components in the information processing system. In

addition, the results of the study strengthen the notion of one

single set of face recognition units, feeding into both the affective

and cognitive route. The current findings are consistent with the

views of Breen et al. (2000) and Ellis and Lewis (2001) that the


initial parts of face recognition take place along a single ana-

tomical routeFthe ventral route.

Finally, with the present study we provide insight into the class

of familiar faces by adding findings about personally familiar faces

to the existing results of familiarity-induced effects on SCR, RT

priming, and the N250r. For personally familiar faces, more

widespread and elaborative networks may be assumed for (a)

stored representations of facial structures (face recognition unit),

as indicated by larger effects of the N250r amplitude; and (b)

stored semantic codes, as indicated by a higher amplitude of the

N400. Additionally, these faces are associated with a stronger af-

fective response, as seen in larger SCRs. However, as the topog-

raphies of the N250r to personally familiar and famous faces did

not differ, recognition of both types of familiar faces can be

thought to be triggered essentially by the same neural generator,

most likely the fusiform gyrus (Schweinberger, Pickering,

Jentzsch, et al., 2002).

To conclude, by using a multidimensional methodological

approach we have been able to give a comprehensive insight into

modulations of face recognition by facial familiarity. In partic-

ular, we have provided new evidence that face recognition units

may serve as common modules feeding into both affective and

cognitive routes. The strength of the networks representing face

recognition units appears to increase as a function of the degree

of facial familiarity.

REFERENCES

Badgaiyan, R. D., & Posner, M. I. (1998). Mapping the cingulate cortexin response selection and monitoring. NeuroImage, 7, 255–260.

Bauer, R. M. (1984). Autonomic recognition of names and faces inprosopagnosics: a neuropsychological application of the GuiltyKnowledge Test. Neuropsychologia, 22, 457–469.

Bentin, S., Allison, T., Puce, A., Perez, E., & McCarthy, G. (1996).Electrophysiological studies of face perception in humans. Journal ofCognitive Neuroscience, 8, 551–565.

Bentin, S., & Deouell, L. Y. (2000). Structural encoding and identifica-tion in face processing: ERP evidence for separate mechanisms. Cog-nitive Neuropsychology, 17, 35–54.

Bentin, S., & McCarthy, G. (1994). The effects of immediate stimulusrepetition on reaction time and event-related potentials in tasks ofdifferent complexity. Journal of Experimental Psychology: Learning,Memory, and Cognition, 20, 130–149.

Braeutigam, S., Bailey, A. J., & Swithenby, S. J. (2001). Task-dependentearly latency (30–60 ms) visual processing of human faces and otherobjects. NeuroReport, 12, 1531–1536.

Breen, N., Caine, D., & Coltheart, M. (2000).Models of face recognitionand delusional misidentification: A critical review. Cognitive Neuro-psychology, 17, 55–71.

Bruce, V., & Valentine, T. (1985). Identity priming in the recognition offamiliar faces. British Journal of Psychology, 76, 373–383.

Bruce, V., & Young, A. (1986). Understanding face recognition. BritishJournal of Psychology, 77, 305–327.

Burton, A. M., Bruce, V., & Hancock, P. J. B. (1999). From pixels topeople: Amodel of familiar face recognition.Cognitive Science, 23, 1–31.

Dawson, A. E., Schell, A. M., & Filion, D. L. (2000). The electrodermalsystem. In J. T. Cacioppo, L. G. Tassinary, & G. G. Berntson (Eds.),Handbook of psychophysiology (2nd ed, pp. 200–223). Cambridge,UK: Cambridge University Press.

Eimer, M. (1998). Does the face-specific N170 component reflect theactivity of a specialized eye processor? NeuroReport, 9, 2945–2948.

Eimer, M. (2000). Event-related brain potentials distinguish processingstages involved in face perception and recognition. Clinical Neuro-physiology, 111, 694–705.

Elbert, T., Lutzenberger, W., Rockstroh, B., & Birbaumer, N. (1985).Removal of ocular artifacts from the EEGFA biophysical approachto the EOG. Electroencephalography and Clinical Neurophysiology,60, 455–463.

Ellis, H. D., & Lewis, M. B. (2001). Capgras delusion: A window on facerecognition. Trends in Cognitive Sciences, 5, 149–156.

Ellis, H. D., Lewis, M. B., Moselhy, H. F., & Young, A. W. (2000).Automatic without autonomic responses to familiar faces: Differen-tial components of implicit face recognition in a case of Capgrasdelusion. Cognitive Neuropsychiatry, 5, 255–269.

Ellis, H. D., & Young, A. W. (1990). Accounting for delusional mis-identifications. British Journal Of Psychiatry, 157, 239–248.

Ellis, H. D., Young, A. W., Quayle, A. H., & DePauw, K. W. (1997).Reduced autonomic responses to faces in Capgras delusion. Proceed-ings of the Royal Society of London B, 264, 1085–1092.

Greenwald, A. G., Klinger, M. R., & Schuh, E. (1995). Activation bymarginally perceptible (‘‘subliminal’’) stimuli: Dissociation of uncon-scious from conscious cognition. Journal of Experimental Psychology:General, 124, 22–42.

Hancock, P. J. B., Bruce, V., & Burton, A. M. (2000). Recognition ofunfamiliar faces. Trends in Cognitive Sciences, 4, 330–337.

Hay, D. C., & Young, A. W. (1982). The human face. In H. D. Ellis(Ed.), Normality and pathology in cognitive functions (pp. 173–202).London, New York: Academic Press.

Henson, R., Shallice, T., &Dolan, R. (2000). Neuroimaging evidence fordissociable forms of repetition priming. Science, 287, 1269–1272.

Hirstein, W., & Ramachandran, V. S. (1997). Capgras syndrome: Anovel probe for understanding the neural representation of the iden-tity and familiarity of persons. Proceedings of the Royal Society ofLondon B, 264, 437–444.

Huynh, H., & Feldt, L. S. (1976). Estimation of the Box correction fordegrees of freedom from sample data in randomized block and split-plot designs. Journal of Educational Statistics, 1, 69–82.

Kanwisher, N., McDermott, J., & Chun, M. M. (1997). The fusiformface area: A module in human extrastriate cortex specialized for faceperception. The Journal of Neuroscience, 17, 4302–4311.

Kutas, M., & Hillyard, S. A. (1980). Reading senseless sentences: Brainpotentials reflect samantic incongruity. Science, 207, 203–205.

McCarthy, G., & Wood, C. C. (1985). Scalp distributions of event-re-lated potentials: An ambiguity associated with analysis of variancemodels. Electroencephalography and Clinical Neurophysiology, 62,203–208.

Mohr, B., Landgrebe, A., & Schweinberger, S. R. (2002). Interhemi-spheric cooperation for familiar but not unfamiliar face perception.Neuropsychologia, 40, 1841–1848.

Ohmann, A. (1979). The orienting response, attention, and learning: Aninformation processing perspective. In H. D. Kimmel, E. H. vanOlst,& J. F. Orlebeke (Eds.), The orienting reflex in humans (pp. 443–472).Hillsdale, NJ: Erlbaum.

Oldfield, R. C. (1971). The assessment and analysis of handedness: TheEdinburgh inventory. Neuropsychologia, 9, 97–113.

Pfutze, E.-M., Sommer, W., & Schweinberger, S. R. (2002). Age-relatedslowing in face and name recognition: Evidence from event-relatedbrain potentials. Psychology and Aging, 17, 140–160.

Pickering, E. C., & Schweinberger, S. R. (2003). N200, N250r and N400event-related brain potentials reveal three loci of repetition primingfor familiar names. Journal of Experimental Psychology: Learning,Memory, and Cognition, 29, 1298–1311.

Pivik, R. T., Broughton, R. J., Coppola, R., Davidson, R. J., Fox, N., &Nuwer, M. R. (1993). Guidelines for the recording and quantitativeanalysis of electroencephalographic activity in research contexts.Psychophysiology, 30, 547–558.

Puce, A., Smith, A., & Allison, T. (2000). ERPs evoked by viewing facialmovements. Cognitive Neuropsychology, 17, 221–239.

Schweinberger, S. R. (1996). How Gorbachev primed Yeltsin: Analysesof associative priming in person recognition by means of reactiontimes and event-related brain potentials. Journal of ExperimentalPsychology: Learning, Memory, and Cognition, 22, 1383–1407.

Schweinberger, S. R., Pfutze, E.-M., & Sommer, W. (1995). Repetitionpriming and associative priming of face recognition: Evidence fromevent-related potentials. Journal of Experimental Psychology: Learn-ing, Memory, and Cognition, 21, 722–736.

Schweinberger, S. R., Pickering, E. C., Burton, A. M., & Kaufmann, J.M. (2002). Human brain potential correlates of repetition priming inface and name recognition. Neuropsychologia, 40, 2057–2073.


Schweinberger, S. R., Pickering, E. C., Jentzsch, I., Burton, A. M., &Kaufmann, J. M. (2002). Event-related brain potential evidence for aresponse of inferior temporal cortex to familiar face repetitions. Cog-nitive Brain Research, 14, 398–409.

Tranel, D., &Damasio, A. R. (1985). Knowledge without awareness: Anautonomic index of facial recognition by prosopagnosics. Science,228, 1453–1454.

Tranel, D., Damasio, H., & Damasio, A. R. (1995). Double dissociationbetween overt and covert face recognition. Journal of CognitiveNeuroscience, 7, 425–432.

Tranel, D., Fowles, D. C., & Damasio, A. R. (1985). Electrodermaldiscrimination of familiar and unfamiliar faces: A methodology. Psy-chophysiology, 22, 403–408.

Ungerleider, L., &Mishkin,M. (1982). Two cortical visual systems. InD.J. Ingle, M. A. Goodale, & R. J. W. Mansfield (Eds.), Analysis ofvisual behavior (pp. 549–586). Cambridge, MA: MIT Press.

Urbach, T. P., & Kutas, M. (2002). The intractability of scaling scalpdistributions to infer neuroelectric sources. Psychophysiology, 39,791–808.

Wood, C. C., & Allison, T. (1981). Interpretation of evoked potentials: Aneurophysiological perspective. Canadian Journal of Psychology, 35,113–135.

(Received July 31, 2003; Accepted January 5, 2004)


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