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PubMed2002

The influence of divided attention on holistic face perception.

There is evidence that upright, but not inverted, faces are encoded holistically. The holistic coding of faces was examined in four experiments by manipulating the attention allocated to target faces. In Experiment 1, participants in a divided attention condition were asked to match two upright flanker faces while encoding a centrally presented upright target face. Although holistic coding was evident in the full attention conditions, dividing attention disrupted holistic coding of target faces. In Experiment 2, we found that while matching upright flanker faces disrupted holistic coding, matching inverted flanker faces did not. Experiment 3 demonstrated that the differential effects of flanker orientation were not due to participants taking longer to match upright, than inverted, flanker faces. In Experiment 4, we found that matching fractured faces had an intermediate effect to that of matching upright and inverted flankers, on the holistic coding of the target faces. The findings emphasize the differences in processing of upright, fractured and inverted faces and suggest that there are limitations in the number of faces that can be holistically coded in a brief time.

Adolescent↗
PubMed2000

Neural substrates for the recognition of newly learned faces: a functional MRI study.

Face recognition is critical to the appreciation of our social and physical relations. Functional magnetic resonance imaging (fMRI) was used to identify brain regions involved in the recognition of newly learned faces. Two experiments were conducted. Experiment 1 contrasted a fixation control task with a face recognition task in which subjects were exposed solely to previously viewed faces (all-target). Experiment 2 compared a fixation control with another face recognition task in which subjects were presented with both novel and viewed faces (half-target). Compared to the fixation control, the all-target face recognition was associated with activation in the bilateral occipital and occipitotemporal regions, whereas the half-target face recognition produced activation in the right parietal and prefrontal regions, in addition to the occipital and occipitotemporal. The all-target minus half-target comparison revealed significant activation in the bilateral fusiform gyrus, suggesting stronger fusiform activity during the all-target than the half-target face recognition. The half-target minus all-target comparison showed significant activation in the superior and inferior parietal lobules and several regions in the right frontal lobe. These findings demonstrated that the bilateral fusiform gyrus is involved, not only in face perception, but in a certain aspect of face recognition memory and that this aspect is related to the actual recognition of previously viewed faces rather than the processing of novel ones, which results are consistent with previous lesion work. The right parietal and frontal regions, in contrast, are differentially more associated with the processes related to the detection of novel faces or retrieval effort.

Adult↗
PubMed2002

Face context interferes with local part processing in a prosopagnosic patient.

We investigated the role of local and global information on perceptual encoding of faces in patient HJA, who shows prosopagnosia and visual agnosia following occipito-temporal damage. HJA and an age-matched control were tested in a simultaneous matching task which focused on detection of local changes in faces: the inversion of central parts (eyes and mouth) relative to their context (as in the Thatcher illusion). Same-different judgements were made to normal, "that cherised" and mixed type face pairs. Whole faces (Experiment 1), or face parts (Experiment 2), were presented in upright and inverted orientations. Compared to the control, HJA was severely impaired at matching whole faces, but he improved dramatically when face parts were presented in isolation. This suggests an inhibitory influence of face context on HJAs processing of local parts and a relatively intact ability to process part-based information from a face (when context cannot interfere). Face inversion did not affect HJAs performance. A control experiment (Experiment 3) with non-face stimuli (houses) suggested that the inhibitory influence of context on HJAs performance was restricted to faces. These results indicate that contextual information in a face can have an adverse influence on the processing of local part-based information in prosopagnosia.

Aged↗
PubMed2003

Processing of normal, inverted, and scrambled faces in a patient with prosopagnosia: behavioural and eye tracking data.

In this study, we addressed the issue of a spared processing of faces in a patient (SB) with severe prosopagnosia. We designed an experiment comprising of two parts. In Part I, normal upright faces were entwined with scrambled faces, while in Part II normal upright faces were mixed with inverted faces, under unlimited time exposure. Performance, decision times, and eye movements were measured in both parts. The results indicated that SB categorised the normal faces better in the context of inverted faces than in the context of scrambled faces. Furthermore, SB's performance was better for the inverted faces than for the scrambled faces. Overall, SB performed better on the abnormal faces than on the normal faces, as did the control participants. Eye-tracking data showed that the pattern observed for the number of fixations and for exploration order was similar in SB and in controls. In the discussion, we propose that, despite his severe prosopagnosia, SB might have retained some kind of processing specific to face perception. Further investigations will be required, using limited time exposure, to determine the nature of this spared processing.

Adolescent↗
PubMed2003

Recognising the usual orientation of one's own face: the role of asymmetrically located details.

Our ability to recognise the usual horizontal orientation of our own face (mirror orientation) as compared with another very familiar face (normal orientation) was examined in experiment 1. Participants did not use the same kind of information in determining the orientation of their own face as in determining the orientation of the other familiar face. The proportion of participants who reported having based their judgment on the location of an asymmetric feature (eg a mole) was higher when determining the orientation of their own face than when determining that of the other familiar face. In experiment 2, participants were presented with pairs of manipulated images of their own face and of another familiar face showing conflicting asymmetric features and configural information. Each pair consisted of one picture showing asymmetric features of a given face in a mirror-reversed position, while the facial configuration was left unchanged; and one picture in which the location of the asymmetric features was left unchanged, while the facial configuration was mirror-reversed. As expected from the hypothesis that asymmetric local features are more frequently used for the judgment of one's own face, participants chose the picture showing mirror-reversed asymmetric features when determining the usual orientation of their own face significantly more often than they chose the picture showing normally oriented asymmetric features when determining the orientation of the other face. These results are explained in terms of competing forward and mirror-reversed representations of one's own face.

Adult↗
PubMed2004

Event-related brain potentials reveal anomalies in temporal processing of faces in autism spectrum disorder.

BACKGROUND: Individuals with autism exhibit impairments in face recognition, and neuroimaging studies have shown that individuals with autism exhibit abnormal patterns of brain activity during face processing. The current study examined the temporal characteristics of face processing in autism and their relation to behavior. METHOD: High-density event-related brain potentials (ERPs) were recorded to images of faces, inverted faces, and objects from 9 individuals with autism spectrum disorder (15-42 years old) and 14 typical individuals (16-37 years old). RESULTS: With respect to a face-sensitive ERP component (N170), individuals with autism exhibited longer N170 latencies to faces than typical individuals but comparable latencies to objects. Typical individuals exhibited longer N170 latencies to inverted as compared to upright faces, whereas individuals with autism did not show differences in N170 latency to upright versus inverted faces. Neural speed of face processing, as reflected in N170 latency, correlated with performance on a face recognition task for individuals with autism. CONCLUSIONS: These data provide evidence for slowed neural speed of face processing in autism and highlight the role of speed of processing in face processing impairments in autism.

Adolescent↗
PubMed2004

Exploring the Williams syndrome face-processing debate: the importance of building developmental trajectories.

BACKGROUND: Face processing in Williams syndrome (WS) has been a topic of heated debate over the past decade. Initial claims about a normally developing ('intact') face-processing module were challenged by data suggesting that individuals with WS used a different balance of cognitive processes from controls, even when their behavioural scores fell within the normal range. Measurement of evoked brain potentials also point to atypical processes. However, two recent studies have claimed that people with WS process faces exactly like normal controls. METHOD: In this paper, we examine the details of this continuing debate on the basis of three new face-processing experiments. In particular, for two of our experiments we built task-specific full developmental trajectories from childhood to adolescence/adulthood and plotted the WS data on these trajectories. RESULTS: The first experiment used photos of real faces. While it revealed broadly equivalent accuracy across groups, the WS participants were worse at configural processing when faces were upright and less sensitive than controls to face inversion. In Experiment 2, measuring face processing in a storybook context, the face inversion effect emerged clearly in controls but only weakly in the WS developmental trajectory. Unlike the controls, the Benton Face Recognition Test and the Pattern Construction results were not correlated in WS, highlighting the different developmental patterns in the two groups. Again in contrast to the controls, Experiment 3 with schematic faces and non-face stimuli revealed a configural-processing deficit in WS both with respect to their chronological age (CA) and to their level of performance on the Benton. CONCLUSION: These findings point to both delay and deviance in WS face processing and illustrate how vital it is to build developmental trajectories for each specific task.

Adolescent↗
PubMed2004

What's special about personally familiar faces? A multimodal approach.

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 representations 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 topographies of the N250r for personally and famous faces were indistinguishable, a similar network of face recognition units can be assumed for both types of faces.

Adult↗
PubMed2006

Basal testosterone moderates responses to anger faces in humans.

Prior research [van Honk J, Tuiten A, Verbaten R, van den Hout M, Koppeschaar H, Thijssen J, de Haan E. Correlations among salivary testosterone, mood, and selective attention to threat in humans. Horm Behav 1999;36(1):17-24; van Honk J, Tuiten A, Hermans E, Putman P, Koppeschaar H, Thijssen J, Verbaten R, van Doornen L. A single administration of testosterone induces cardiac accelerative responses to angry faces in healthy young women. Behav Neurosci 2001;115(1):238-42.] showed relationships in humans between testosterone (T) and vigilance to facial expressions of anger, which are considered signals of an impending dominance challenge. In Study 1, we used a differential implicit learning task (DILT) (see [Schultheiss OC, Pang JS, Torges CM, Wirth MM, Treynor W. Perceived facial expressions of emotion as motivational incentives: evidence from a differential implicit learning paradigm. Emotion 2005;5(1):41-54.]) to investigate the degree to which subjects find anger faces reinforcing. In the DILT, separate sequences of actions were paired with presentations of anger faces, neutral faces or a blank screen. After training, performance on the three sequences was measured in the absence of face stimuli. Saliva was collected for T measurement. Higher T predicted better learning on sequences paired with sub-threshold (i.e., presented too fast for conscious awareness) anger faces, suggesting that T is related to reinforcing qualities of these faces. In Study 2, we examined whether morning or afternoon T better predicted attention and vigilance to anger faces. Participants were tested at 9:00 and 15:00. At each session, saliva was collected for T measurement, and participants completed a Stroop task and a dot-probe task [Mogg K, Bradley BP, Hallowell N. Attentional bias to threat: roles of trait anxiety, stressful events, and awareness. Q J Exp Psychol A 1994;47(4):841-64.] with facial expression stimuli. Morning (peak) T was a better predictor of responses to anger faces than afternoon T. Morning T predicted greater Stroop-like interference to sub-threshold anger faces, as well as attentional orienting away from sub-threshold anger faces. These effects were not present for joy faces or for supraliminal anger faces. T may generally decrease aversion to threatening stimuli, and/or may specifically facilitate approach towards signals of dominance challenge.

Adolescent↗
PubMed1998

An experimental evaluation of effects and side effects of asymmetric face-bows in the light of in vivo measurements of initial tooth movements.

By using a magnetic sensing system, the translational and rotational molar movements under the application of various asymmetric face-bows were measured two-dimensionally in human subjects to evaluate their primary effects and side effects. The asymmetric face-bow designs tested were three types of power arm face-bows, swivel offset face-bow, and internal hinge face-bow. Although all face-bow designs were considered to be effective in achieving asymmetric distalizations of the molars, they generated lateral displacements that may lead to an undesirable crossbite. The swivel offset face-bow may produce unexpected results and its fabrication is complicated. The internal hinge face-bow is remarkably effective for asymmetric molar distalizations. Unfortunately, it causes a strong crossbite tendency on the molar to be more distalized. Therefore the use of the power arm face-bow is thought to be relatively recommendable because it showed an acceptable asymmetric effect and is easily fabricated from a commercially available face-bow. It is concluded that all asymmetric face-bows generate lateral forces as side effects as long as the force delivery system with a combination of an asymmetric face-bow and a neck strap or head cap is applied. The current study suggests a method whereby the side effect of asymmetric face-bows can be eliminated.

Adult↗
PubMed2001

Face processing in schizophrenia: defining the deficit.

BACKGROUND: Abnormalities of face affect naming and face recognition occur in schizophrenia but it is not clear whether the deficits reflect wider underlying impairments of perception, memory, language or executive function. METHOD: Twenty-six patients with schizophrenia were compared with 23 healthy volunteers on neuropsychological tests and tests of face and affect processing. Face and non-face tests were compared at four levels of processing: visuo-spatial perception, recognition memory, language and naming, and executive function. We examined relationships with drug dose, duration of illness and pre-morbid and current IQ. RESULTS: Patients and controls did not differ in estimated pre-morbid IQ but current IQ was 12 points lower in patients. At each level of processing there were correlated deficits of face and non-face processing in the patients that were mostly independent of IQ decline. Impaired face and non-face visuo-spatial function and recognition performance were generally correlated with drug dose. Impairments in naming face emotions were correlated with other non-face naming tasks independently of drug dose. Patients performed less well than controls in classifying faces by emotion while ignoring identity and this was associated with poorer performance in Wisconsin Card Sorting. CONCLUSIONS: The pattern of results suggests that deficits in face processing reflect three wider neuropsychological impairments: a drug-related impairment of visual imagery, and disease-related impairments of semantic retrieval and executive function.

Adult↗
PubMed1993

Face recognition as a function of judgments of likability/unlikability.

The relationship between face recognition and likability was investigated in three experiments. Subjects were asked to rate the likability of faces presented to them and then were tested on their ability to recognize the same faces. In Experiments 1 and 2, we used the subjects' individual ratings of likability to form idiocentric groups of faces (two groups, likable/unlikable, Experiment 1; three groups, likable/neutral/unlikable, Experiment 2). In Experiment 1, likable faces were found to be recognized more readily than were faces less likable. Experiment 2 revealed that the faces judged least likable were significantly less well remembered than neutral or more likable faces. In Experiment 3, a group mean for each face's likability was determined, and the faces were divided into quartiles according to the group mean scores. Again, the subjects' recognition responses for unlikable faces were at a lower level than for faces rated higher in likability. Experiments 2 and 3 found no difference in recognition memory between neutral and more likable faces. The results confirmed the notion that likability judgments (emotionality) play a mediating role in recognition.

Adult↗
PubMed2002

The impact of face shield use on concussions in ice hockey: a multivariate analysis.

OBJECTIVE: To identify specific risk factors for concussion severity among ice hockey players wearing full face shields compared with half face shields (visors). METHODS: A prospective cohort study was conducted during one varsity hockey season (1997-1998) with 642 male ice hockey players (median age 22 years) from 22 teams participating in the Canadian Inter-University Athletics Union. Half of the teams wore full face shields, and half wore half shields (visors) for every practice and game throughout the season. Team therapists and doctors recorded on structured forms daily injury, participation, and information on face shield use for each athlete. The main outcome measure was any traumatic brain injury requiring assessment or treatment by a team therapist or doctor, categorised by time lost from subsequent participation and compared by type of face shield worn. RESULTS: Players who wore half face shields missed significantly more practices and games per concussion (2.4 times) than players who wore full face shields (4.07 sessions (95% confidence interval (CI) 3.48 to 4.74) v 1.71 sessions (95% CI 1.32 to 2.18) respectively). Significantly more playing time was lost by players wearing half shields during practices and games, and did not depend on whether the athletes were forwards or defence, rookies or veterans, or whether the concussions were new or recurrent. In addition, players who wore half face shields and no mouthguards at the time of concussion missed significantly more playing time (5.57 sessions per concussion; 95% CI 4.40 to 6.95) than players who wore half shields and mouthguards (2.76 sessions per concussion; 95% CI 2.14 to 3.55). Players who wore full face shields and mouthguards at the time of concussion lost no playing time compared with 1.80 sessions lost per concussion (95% CI 1.38 to 2.34) for players wearing full face shields and no mouthguards. CONCLUSIONS: The use of a full face shield compared with half face shield by intercollegiate ice hockey players significantly reduced the playing time lost because of concussion, suggesting that concussion severity may be reduced by the use of a full face shield.

Adult↗
PubMed1985

Selectivity between faces in the responses of a population of neurons in the cortex in the superior temporal sulcus of the monkey.

There is a population of neurons in the cortex in the middle and anterior part of the superior temporal sulcus (STS) of the monkey with responses which are selective for faces. If, consistent with the effects of damage to the temporal lobe, these neurons are involved in face recognition or in making appropriate social responses to different individuals, then it might be expected that at least some of these neurons might respond differently to different faces. To investigate whether at least some of these neurons do respond differently to different faces, their responses were measured to a standard set of faces, presented in random sequence using a video framestore. It was found that a considerable proportion of the neurons with face-selective responses tested (34/44 or 77%) responded differently to different faces, as shown by analyses of variance. An index of the discriminability of the most and least effective face stimulus (d') ranged between 0.2 and 5.0 for the different neurons. Although these neurons often responded differently to different faces, they did not usually respond to only one of the faces in the set, so that information that a particular face had been shown was present across an ensemble of neurons, rather than in the responses of an individual neuron. These findings indicate that the responses of these neurons would be useful in providing information on which different behavioral responses made to different faces could be based. These neurons could thus be filters, the output of which could be used for recognition of different individuals and in emotional responses made to different individuals.

Animals↗
PubMed2006

Face processing stages: impact of difficulty and the separation of effects.

Cognitive models of face perception suggest parallel levels of processing yet there is little evidence of these levels in studies of brain function. Series of faces that engage different processes ((photographs, schematic and Mooney faces (incomplete two-tone faces)) were presented upright, inverted and scrambled; subjects performed a face/non-face discrimination while event-related potentials (ERPs) were recorded. Different patterns in N170 latency and amplitude provided evidence of multiple steps in face processing, which can be seen at the ERP level. We showed that first-order configural and holistic processing were evident at the N170. N170 latency indexed task difficulty for the upright faces, yet the face inversion effect was independent of difficulty. N170 amplitude inversion effect was unique to photographic faces. Separable ERP effects were found for the processing engaged by the three face types, although the P1 and N170 sources did not differ. Thus, it appears that common brain sources underlie the early processing stages for faces (reflected in the P1 and N170), whereas the P2 showed activation of primary visual areas for the non-photographic faces and reactivation of the same regions as the N170 for the photographic faces.

Adult↗
PubMed2006

Recognition memory of newly learned faces.

We used event-related fMRI to study recognition memory of newly learned faces. Caucasian subjects memorized unfamiliar, neutral and happy South Korean faces and 4 days later performed a memory retrieval task in the MR scanner. We predicted that previously seen faces would be recognized faster and more accurately and would elicit stronger neural activation than novel faces. Consistent with our hypothesis, novel faces were recognized more slowly and less accurately than previously seen faces. We found activation in a distributed cortical network that included face-responsive regions in the visual cortex, parietal and prefrontal regions, and the hippocampus. Within all regions, correctly recognized, previously seen faces evoked stronger activation than novel faces. Additionally, in parietal and prefrontal cortices, stronger activation was observed during correct than incorrect trials. Finally, in the hippocampus, false alarms to happy faces elicited stronger responses than false alarms to neutral faces. Our findings suggest that face recognition memory is mediated by stimulus-specific representations stored in extrastriate regions; parietal and prefrontal regions where old and new items are classified; and the hippocampus where veridical memory traces are recovered.

Adult↗
PubMed2005

Electrophysiological correlates of facial decision: insights from upright and upside-down Mooney-face perception.

We investigated the ERP correlates of the subjective perception of upright and upside-down ambiguous pictures as faces using two-tone Mooney stimuli in an explicit facial decision task (deciding whether a face is perceived or not in the display). The difficulty in perceiving upside-down Mooneys as faces was reflected by both lower rates of "Face" responses and delayed "Face" reaction times for upside-down relative to upright stimuli. The N170 was larger for the stimuli reported as "faces". It was also larger for the upright than the upside-down stimuli only when they were reported as faces. Furthermore, facial decision as well as stimulus orientation effects spread from 140-190 ms to 390-440 ms. The behavioural delay in 'Face' responses to upside-down stimuli was reflected in ERPs by later effect of facial decision for upside-down relative to upright Mooneys over occipito-temporal electrodes. Moreover, an orientation effect was observed only for the stimuli reported as faces; it yielded a marked hemispheric asymmetry, lasting from 140-190 ms to 390-440 ms post-stimulus onset in the left hemisphere and from 340-390 to 390-440 ms only in the right hemisphere. Taken together, the results supported a preferential involvement of the right hemisphere in the detection of faces, whatever their orientation. By contrast, the early orientation effect in the left hemisphere suggested that upside-down Mooney stimuli were processed as non face objects until facial decision was reached in this hemisphere. The present data show that face perception involves not only spatially but also temporally distributed activities in occipito-temporal regions.

Adult↗
PubMed2004

Effects of repetition learning on upright, inverted and contrast-reversed face processing using ERPs.

The effects of short-term learning on memory for inverted, contrast-reversed and upright faces were investigated using event-related potentials (ERPs) in a target/nontarget discrimination task following a learning phase of the target. Subjects were equally accurate for all three face types although responding more slowly to inverted and negative faces compared to upright faces. Face type affected both early ERP components P1 and N170, and long-latency components at frontal and parietal sites, reflecting the difficulty of processing inverted faces. Different effects of face type were found for P1 and N170 latencies and amplitudes, suggesting face processing could start around 100-120 ms and is sensitive to facial configuration. Repetition effects were also found on both early and long-latency components. Reduced N170 latency and amplitude for repeated targets are likely due to perceptual priming. Repetition effects on the N250 were delayed for inverted and negative faces, suggesting delayed access to stored facial representations for these formats. Increased frontopolar positivity at 250-300 ms and parietal positivity from 300 to 500 ms reflected familiarity 'old-new' repetition effects that were of similar magnitude for all three face types, indexing the accurate recognition of all faces. Thus, while structural encoding was disrupted by inversion and contrast-reversal, the learning phase was sufficient to abolish the effects of these configural manipulations behaviourally; all three face types were equally well recognised and this was reflected as equally large parietal old-new effects.

Adult↗