Use-inspired basic research on individual differences in face identification: implications for criminal investigation and security.

This journal is dedicated to "use-inspired basic research" where a problem in the world shapes the hypotheses for study in the laboratory. This review considers the role of individual variation in face identification and the challenges and opportunities this presents in security and criminal investigations. We show how theoretical work conducted on individual variation in face identification has, in part, been stimulated by situations presented in the real world. In turn, we review the contribution of theoretical work on individual variation in face processing and how this may help shape the practical identification of faces in applied situations. We consider two cases in detail. The first case is that of security officers; gatekeepers who use facial ID to grant entry or deny access. One applied example, where much research has been conducted, is passport control officers who are asked to match a person in front of them to a photograph shown on their ID. What happens if they are poor at making such face matching decisions and can they be trained to improve their performance? Second, we outline the case of "super-recognisers", people who are excellent at face recognition. Here it is interesting to consider whether these individuals can be strategically allocated to security and criminal roles, to maximise the identification of suspects. We conclude that individual differences are one of the largest documented sources of error in face matching and face recognition but more work is needed to account for these differences within theoretical models of face processing.

The effect of arousal and eye gaze direction on trust evaluations of stranger's faces: A potential pathway to paranoid thinking.

BACKGROUND AND OBJECTIVES: When asked to evaluate faces of strangers, people with paranoia show a tendency to rate others as less trustworthy. The present study investigated the impact of arousal on this interpersonal bias, and whether this bias was specific to evaluations of trust or additionally affected other trait judgements. The study also examined the impact of eye gaze direction, as direct eye gaze has been shown to heighten arousal. METHODS: In two experiments, non-clinical participants completed face rating tasks before and after either an arousal manipulation or control manipulation. Experiment one examined the effects of heightened arousal on judgements of trustworthiness. Experiment two examined the specificity of the bias, and the impact of gaze direction. RESULTS: Experiment one indicated that the arousal manipulation led to lower trustworthiness ratings. Experiment two showed that heightened arousal reduced trust evaluations of trustworthy faces, particularly trustworthy faces with averted gaze. The control group rated trustworthy faces with direct gaze as more trustworthy post-manipulation. There was some evidence that attractiveness ratings were affected similarly to the trust judgements, whereas judgements of intelligence were not affected by higher arousal. LIMITATIONS: In both studies, participants reported low levels of arousal even after the manipulation and the use of a non-clinical sample limits the generalisability to clinical samples. CONCLUSIONS: There is a complex interplay between arousal, evaluations of trustworthiness and gaze direction. Heightened arousal influences judgements of trustworthiness, but within the context of face type and gaze direction.

Compensatory shifts in visual perception are associated with hallucinations in Lewy body disorders.

Visual hallucinations are a common, distressing, and disabling symptom of Lewy body and other diseases. Current models suggest that interactions in internal cognitive processes generate hallucinations. However, these neglect external factors. Pareidolic illusions are an experimental analogue of hallucinations. They are easily induced in Lewy body disease, have similar content to spontaneous hallucinations, and respond to cholinesterase inhibitors in the same way. We used a primed pareidolia task with hallucinating participants with Lewy body disorders (n = 16), non-hallucinating participants with Lewy body disorders (n = 19), and healthy controls (n = 20). Participants were presented with visual "noise" that sometimes contained degraded visual objects and were required to indicate what they saw. Some perceptions were cued in advance by a visual prime. Results showed that hallucinating participants were impaired in discerning visual signals from noise, with a relaxed criterion threshold for perception compared to both other groups. After the presentation of a visual prime, the criterion was comparable to the other groups. The results suggest that participants with hallucinations compensate for perceptual deficits by relaxing perceptual criteria, at a cost of seeing things that are not there, and that visual cues regularize perception. This latter finding may provide a mechanism for understanding the interaction between environments and hallucinations.

Visual Hallucinations in Older People: Appraisals but not Content or Phenomenology Influence Distress.

BACKGROUND: A previous study (Gauntlett-Gilbert and Kuipers, 2005) has suggested that distress associated with complex visual hallucinations (CVHs) in younger adults with psychosis may more strongly relate to appraisals of meaning than to the content of the hallucination. However, visual hallucinations are most commonly seen in the disorders of later life, where this relationship has not been investigated. AIM: To establish if there is a relationship between appraisals of CVHs and distress in older, non-psychotic people with CVHs. METHOD: All variables were measured using a semi-structured interview and were compared between a high distress group (n = 16) and a low distress group (n = 19). RESULTS: The high distress group rated their hallucinations as more malevolent and omnipotent, with greater negative implications for physical and mental health. There was no significant difference between groups on ratings of hallucination content (independently rated), frequency, awareness or control. CONCLUSION: Appraisals of CVHs are linked to distress.

Visual Priming and Visual Hallucinations in Parkinson's Disease. Evidence for Normal Top-Down Processes.

BACKGROUND: Visual hallucinations (VH) are common in Parkinson's disease (PD) and are associated with increased morbidity and mortality. Current explanations for VH in PD suggest combined impairments in top-down attentional and bottom-up perceptual processes, which allow the passive "release" of stored images. Alternative models in other disorders have suggested that top-down factors may actively encourage hallucinations. In order to explore the interaction between top-down and bottom-up visual processing in PDVH, we developed novel experimental priming tasks in which top-down verbal cues were used to prime the bottom-up recognition of partial or ambiguous pictures. METHOD: Two groups of PD participants with (PD + VH, n = 16), and without VH (PD - VH, n = 20) were compared to a group of healthy older adults (NC, n = 20) on 3 novel measures of visual priming. RESULTS: All tasks showed significant priming effects. The PD + VH group was more impaired at accurately identifying silhouette and fragmented images compared to the PD - VH group. There were no differences in priming between the 2 PD groups. CONCLUSIONS: The study showed that VH in PD are not associated with relatively greater top-down activation, and that the interaction between top-down and bottom-up processes is intact.

A preliminary investigation into the existence of a hypervigilance subtype of auditory hallucination in people with psychosis.

BACKGROUND: The phenomenological heterogeneity of auditory hallucinations (AHs) means individual models struggle to account for all aspects of the experience. One alternative is that distinct subtypes of AHs exist, with each requiring their own unique explanatory model and tailored cognitive behavioural intervention strategies. AIMS: This exploratory study tested for the presence of one specific potential AH-subtype, hypervigilance hallucinations (HV-AHs). METHOD: Four specific aspects of the phenomenology of AHs (chosen on the basis of the predicted phenomenology of HV-AHs) were assessed using a semi-structured interview in 32 individual AHs taken from reports from 15 patients with psychosis. RESULTS: Cluster analysis (at the level of the individual AH-experience) offered support for the existence of a distinct HV-AH subtype, characterized by hearing threatening, externally-located voices when attention was externally-focused. Other clusters identified all shared the contrasting properties of occurring in quiet contexts when patients' attention was internally focused. CONCLUSIONS: The results offered tentative support for the existence of an HV-AH subcategorization and justifies future research in larger samples. Potential implications for models of AHs are also considered.

Recognising facial surfaces.

The extent to which faces depicted as surfaces devoid of pigmentation and with minimal texture cues ('head models') could be matched with photographs (when unfamiliar) and identified (when familiar) was examined in three experiments. The head models were obtained by scanning the three-dimensional surface of the face with a laser, and by displaying the surface measured in this way by using standard computer-aided design techniques. Performance in all tasks was above chance but far from ceiling. Experiment 1 showed that matching of unfamiliar head models with photographs was affected by the resolution with which the surface was displayed, suggesting that subjects based their decisions, at least in part, on three-dimensional surface structure. Matching accuracy was also affected by other factors to do with the viewpoints shown in the head models and test photographs, and the type of lighting used to portray the head model. In experiment 2 further evidence for the importance of the nature of the illumination used was obtained, and it was found that the addition of a hairstyle (not that of the target face) did not facilitate matching. In experiment 3 identification of the head models by colleagues of the people shown was compared with identification of photographs where the hair was concealed and eyes were closed. Head models were identified less well than these photographs, suggesting that the difficulties in their recognition are not solely due to the lack of hair. Women's heads were disproportionately difficult to recognise from the head models. The results are discussed in terms of their implications for the use of such three-dimensional head models in forensic and surgical applications.

Dynamic properties influence the perception of facial expressions.

Two experiments were conducted to investigate the role played by dynamic information in identifying facial expressions of emotion. Dynamic expression sequences were created by generating and displaying morph sequences which changed the face from neutral to a peak expression in different numbers of intervening intermediate stages, to create fast (6 frames), medium (26 frames), and slow (101 frames) sequences. In experiment 1, participants were asked to describe what the person shown in each sequence was feeling. Sadness was more accurately identified when slow sequences were shown. Happiness, and to some extent surprise, was better from faster sequences, while anger was most accurately detected from the sequences of medium pace. In experiment 2 we used an intensity-rating task and static images as well as dynamic ones to examine whether effects were due to total time of the displays or to the speed of sequence. Accuracies of expression judgments were derived from the rated intensities and the results were similar to those of experiment 1 for angry and sad expressions (surprised and happy were close to ceiling). Moreover, the effect of display time was found only for dynamic expressions and not for static ones, suggesting that it was speed, not time, which was responsible for these effects. These results suggest that representations of basic expressions of emotion encode information about dynamic as well as static properties.

Understanding person perception.

Bruce and Young's (1986) theoretical framework was actually a synthesis of ideas contributed by several people. Some of its insights have stood the test of time - especially the importance of using converging evidence from as wide a range of methods of enquiry as possible, and an emphasis on understanding the demands that are made by particular face perception tasks. But there were also areas where Bruce and Young failed to obey their own edicts (emotion recognition), and some topics they simply omitted (gaze perception). We discuss these, and then look at how the field has been transformed by computing developments, finishing with a few thoughts about where things may go over the next few (25?) years.

Attention to faces in Williams syndrome.

Williams syndrome (WS) is associated with distinct social behaviours. One component of the WS social phenotype is atypically prolonged face fixation. This behaviour co-exists with attention difficulties. Attention is multi-faceted and may impact on gaze behaviour in several ways. Four experiments assessed (i) attention capture by faces, (ii) interference from facial stimuli, (iii) face bias, and (iv) attention disengagement. Individuals with WS were compared to typically developing participants of comparable nonverbal ability and chronological age. The first three experiments revealed no atypicality of attention to faces in WS. However, in experiment 4 there was a suggestion that individuals with WS (compared to those developing typically) found it much more time consuming to disengage from faces than objects. The results are discussed in terms of attention abnormalities and possible face disengagement difficulties in WS.

The eyes or the mouth? Feature salience and unfamiliar face processing in Williams syndrome and autism.

Using traditional face perception paradigms the current study explores unfamiliar face processing in two neurodevelopmental disorders. Previous research indicates that autism and Williams syndrome (WS) are both associated with atypical face processing strategies. The current research involves these groups in an exploration of feature salience for processing the eye and mouth regions of unfamiliar faces. The tasks specifically probe unfamiliar face matching by using (a) upper or lower face features, (b) the Thatcher illusion, and (c) featural and configural face modifications to the eye and mouth regions. Across tasks, individuals with WS mirror the typical pattern of performance, with greater accuracy for matching faces using the upper than using the lower features, susceptibility to the Thatcher illusion, and greater detection of eye than mouth modifications. Participants with autism show a generalized performance decrement alongside atypicalities, deficits for utilizing the eye region, and configural face cues to match unfamiliar faces. The results are discussed in terms of feature salience, structural encoding, and the phenotypes typically associated with these neurodevelopmental disorders.

Improving the quality of facial composites using a holistic cognitive interview.

Witnesses to and victims of serious crime are normally asked to describe the appearance of a criminal suspect, using a Cognitive Interview (CI), and to construct a facial composite, a visual representation of the face. Research suggests that focusing on the global aspects of a face, as opposed to its facial features, facilitates recognition and improves composite quality; also, that the CI enables more effective use of a composite system. The current study evaluated a novel "holistic" Cognitive Interview (H-CI). This comprised a descriptive phase, using a CI, followed by a recognition-enhancing phase, involving the attribution of seven holistic properties. Participant-witnesses watched a video of a target, then 3 to 4 hours later received either a CI or an H-CI and constructed a single composite with a standard system, PRO-fit. Composites constructed after the H-CI were correctly named more than four times as often as those after the CI, attributable to an improvement in the quality of both the internal and external parts of the face. In police work, the H-CI offers the possibility of substantially improving the identification of criminal suspects.

Atypical unfamiliar face processing in Williams syndrome: what can it tell us about typical familiarity effects?

INTRODUCTION: Familiar and unfamiliar face perception is typically dissociated by the relative use of internal and external face features. The Williams syndrome (WS) social phenotype emphasises hypersociability, with an interest in interacting with people irrespective of familiarity. The aim is to explore whether unfamiliar face processing is characterised by the typical dissociation between internal and external features in WS, or whether the social stimulus drive towards strangers is linked to atypicalities of unfamiliar face processing. METHOD: The procedure replicates that previously used with typically developing children. Participants with WS (aged 10-18 years) and typically developing comparison participants determine whether two face parts are from the same person or different people, using the whole face, internal, and external features. RESULTS: Only participants with WS, and not typically developing participants, show greater accuracy matching unfamiliar faces from internal than external features. CONCLUSIONS: Evidence of atypical unfamiliar face processing in WS may inform models of typical face perception, revealing the origins of the relative advantage for internal features typically associated with familiar but not unfamiliar faces. The results also have implications for understanding more clearly the social phenotype associated with WS.

Exploring face perception in disorders of development: evidence from Williams syndrome and autism.

Individuals with Williams syndrome (WS) and autism are characterized by different social phenotypes but have been said to show similar atypicalities of face-processing style. Although the structural encoding of faces may be similarly atypical in these two developmental disorders, there are clear differences in overall face skills. The inclusion of both populations in the same study can address how the profile of face skills varies across disorders. The current paper explored the processing of identity, eye-gaze, lipreading, and expressions of emotion using the same participants across face domains. The tasks had previously been used to make claims of a modular structure to face perception in typical development. Participants with WS (N=15) and autism (N=20) could be dissociated from each other, and from individuals with general developmental delay, in the domains of eye-gaze and expression processing. Individuals with WS were stronger at these skills than individuals with autism. Even if the structural encoding of faces appears similarly atypical in these groups, the overall profile of face skills, as well as the underlying architecture of face perception, varies greatly. The research provides insights into typical and atypical models of face perception in WS and autism.

Parallel approaches to composite production: interfaces that behave contrary to expectation.

This paper examines two facial composite systems that present multiple faces during construction to more closely resemble natural face processing. A 'parallel' version of PRO-fit was evaluated, which presents facial features in sets of six or twelve, and EvoFIT, a system in development, which contains a holistic face model and an evolutionary interface. The PRO-fit parallel interface turned out not to be quite as good as the 'serial' version as it appeared to interfere with holistic face processing. Composites from EvoFIT were named almost three times better than PRO-fit, but a benefit emerged under feature encoding, suggesting that recall has a greater role for EvoFIT than was previously thought. In general, an advantage was found for feature encoding, replicating a previous finding in this area, and also for a novel 'holistic' interview.

The relative importance of external and internal features of facial composites.

Three experiments are reported that compare the quality of external with internal regions within a set of facial composites using two matching-type tasks. Composites are constructed with the aim of triggering recognition from people familiar with the targets, and past research suggests internal face features dominate representations of familiar faces in memory. However the experiments reported here show that the internal regions of composites are very poorly matched against the faces they purport to represent, while external feature regions alone were matched almost as well as complete composites. In Experiments 1 and 2 the composites used were constructed by participant-witnesses who were unfamiliar with the targets and therefore were predicted to demonstrate a bias towards the external parts of a face. In Experiment 3 we compared witnesses who were familiar or unfamiliar with the target items, but for both groups the external features were much better reproduced in the composites, suggesting it is the process of composite construction itself which is responsible for the poverty of the internal features. Practical implications of these results are discussed.

Repetition priming from moving faces.

Recent experiments have suggested that seeing a familiar face move provides additional dynamic information to the viewer, useful in the recognition of identity. In four experiments, repetition priming was used to investigate whether dynamic information is intrinsic to the underlying face representations. The results suggest that a moving image primes more effectively than a static image, even when the same static image is shown in the prime and the test phases (Experiment 1). Furthermore, when moving images are presented in the test phase (Experiment 2), there is an advantage for moving prime images. The most priming advantage is found with naturally moving faces, rather than with those shown in slow motion (Experiment 3). Finally, showing the same moving sequence at prime and test produced more priming than that found when different moving sequences were shown (Experiment 4). The results suggest that dynamic information is intrinsic to the face representations and that there is an advantage to viewing the same moving sequence at prime and test.

Four heads are better than one: combining face composites yields improvements in face likeness.

Four participants constructed face composites, of familiar and unfamiliar targets, using Pro-Fit, with reference images present or from memory. The "mean" of all 4 composites, created by morphing (4-morph) was rated as a better likeness than individual composites on average and was as good as the best individual likeness. When participants attempted to identify targets from line-ups, 4-morphs again performed as well as the best individual composite. In a second experiment, participants familiar with target women attempted to identify composites, and the trend showed better recognition from multiple composites, whether combined or shown together. In a line-up task with unfamiliar participants, 4-morphs produced most correct choices and fewest false positives from target-absent or target-present arrays. These results have practical implications for the way evidence from different witnesses is used in police investigations.

Evaluating the independence of sex and expression in judgments of faces.

Face recognition models suggest independent processing for functionally different types of information, such as identity, expression, sex, and facial speech. Interference between sex and expression information was tested using both a rating study and Garner's selective attention paradigm using speeded sex and expression decisions. When participants were asked to assess the masculinity of male and female angry and surprised faces, they found surprised faces to be more feminine than angry ones (Experiment 1). However, in a speeded-classification situation in the laboratory in which the sex decision was either "easy" relative to the expression decision (Experiment 2) or of more equivalent difficulty (Experiment 3), it was possible for participants to attend selectively to either dimension without interference from the other. Qualified support is offered for independent processing routes.