The current study used event-related potentials (ERP) in combination with a variable viewing posi... more The current study used event-related potentials (ERP) in combination with a variable viewing position paradigm (VVPP) to direct fixations to specific face parts (eyes or mouths) in upright or inverted whole faces. The N170 elicited by the VVPP was greater to faces than to non-face objects (wristwatches), and was delayed and enhanced in response to face inversion. A larger N170 response was elicited when the participants׳ fixation was directed to the eyes than when directed to the mouths of both upright and inverted faces, an effect that was also modulated by the spatial location of the face in the visual field. The N170 face inversion effect (upright minus inverted) was greater when fixations were directed to the mouth than when directed to the eyes, suggesting that the point of fixation within a face modulates brain potentials due to contributions from the features themselves, as well as their relative location in the visual field.
In this review we examine how attention is involved in detecting faces, recognizing facial identi... more In this review we examine how attention is involved in detecting faces, recognizing facial identity and registering and discriminating between facial expressions of emotion. The first section examines whether these aspects of face perception are "automatic", in that they are especially rapid, non-conscious, mandatory and capacity-free. The second section discusses whether limited-capacity selective attention mechanisms are preferentially recruited by faces and facial expressions. Evidence from behavioral, neuropsychological, neuroimaging and psychophysiological studies from humans and single-unit recordings from primates is examined and the neural systems involved in processing faces, emotion and attention are highlighted. Avenues for further research are identified.
The ability to perceive, learn and recognise faces is a complex ability, which is key to successf... more The ability to perceive, learn and recognise faces is a complex ability, which is key to successful social interactions. This ability is proposed to be coordinated by neural regions in the occipital and temporal lobes, specialised for face perception and memory. While previous studies have suggested that memory for faces is compromised in some dementia syndromes, it remains unclear whether this simply reflects more generalised memory deficits. Here, we examined basic face perception (Identity-Matching), face recognition (Cambridge Face Memory Task) and object recognition (Cambridge Car Memory Task) in 11 semantic dementia (SD) patients (8 left-lateralised, 3 right-lateralised) and 13 behavioural-variant frontotemporal dementia (bvFTD) patients, compared with 11 controls. On the Identity-Matching task, bvFTD were impaired compared to controls, with a similar trend observed in the SD group. Importantly, both bvFTD and SD also demonstrated impaired face recognition. In contrast, only b...
As faces become familiar, recognition becomes easier but the style of processing also changes. He... more As faces become familiar, recognition becomes easier but the style of processing also changes. Here, twenty-one typically developing (TD) children and twenty-one children with autism spectrum disorder (ASD) were familiarised with 6 identities over 3 days. Next, they completed a 4-alternative forced-choice matching test in which targets were the 6 familiarised faces and 6 unfamiliar faces. The TD group showed a significant advantage for familiarised faces when matching whole faces and both internal and external facial regions. The ASD group showed similar familiarisation effects for whole and external faces, but not for internal regions. The ASD group was also impaired at matching eyes and mouths of familiarised faces. Results suggest the process of acquiring familiarity with faces differs from ASD and TD children.
We investigated the link between the ability to perceive facial expressions of emotion and the ab... more We investigated the link between the ability to perceive facial expressions of emotion and the ability to perceive visual form in Parkinson's disease (PD). We assessed in individuals with PD and healthy controls the ability to discriminate graded intensities of facial expressions of anger from neutral expressions and the ability to discriminate radial frequency (RF) patterns with modulations in amplitude from a perfect circle. Those with PD were, as a group, impaired relative to controls in discriminating graded intensities of angry from neutral expressions and discriminating modulated amplitudes of RF patterns from perfect circles; these two abilities correlated positively and moderately to highly, even after removing the variance that was shared with disease progression and general cognitive functioning. The results indicate that the impaired ability to perceive visual form is likely to contribute to the impaired ability to perceive facial expressions of emotion in PD, and that both are related to the progression of the disease.
People with congenital prosopagnosia (CP) report difficulty recognising faces in everyday life an... more People with congenital prosopagnosia (CP) report difficulty recognising faces in everyday life and perform poorly on face recognition tests. Here, we investigate whether impaired adaptive face space coding might contribute to poor face recognition in CP. To pinpoint how adaptation may affect face processing, a group of CPs and matched controls completed two complementary face adaptation tasks: the figural aftereffect, which reflects adaptation to general distortions of shape, and the identity aftereffect, which directly taps the mechanisms involved in the discrimination of different face identities. CPs displayed a typical figural aftereffect, consistent with evidence that they are able to process some shape-based information from faces, e.g., cues to discriminate sex. CPs also demonstrated a significant identity aftereffect. However, unlike controls, CPs impression of the identity of the neutral average face was not significantly shifted by adaptation, suggesting that adaptive coding of identity is abnormal in CP. In sum, CPs show reduced aftereffects but only when the task directly taps the use of face norms used to code individual identity. This finding of a reduced face identity aftereffect in individuals with severe face recognition problems is consistent with suggestions that adaptive coding may have a functional role in face recognition.
Most developmental studies of face emotion processing show faces in isolation, in the absence of ... more Most developmental studies of face emotion processing show faces in isolation, in the absence of any broader context. Here we investigate two types of interactions between expression and threat contexts. First, in adults, following of another person's direction of social attention is increased when that person shows fear and the context requires vigilance for danger. We investigate whether this also occurs in children. Using a Posner-style eye-gaze cueing paradigm, we tested whether children would show greater gaze-cueing from fearful than happy expressions when the task was to be vigilant for possible dangerous animals. Testing across the 8-12-year-old age range, we found this fear priority effect was absent in the youngest children but developed to reach adult levels in the oldest children. However, even the oldest children were unable to sustain fear-prioritization when the onset of the target was delayed. Second, we addressed the development of 'threat bias' - namely faster identification of dangerous animals than safe animals - in the social context provided by expressive faces. In our non-anxious samples (i.e. with typical-population levels of anxiety), adults showed a threat bias regardless of the expression or looking direction of the just-seen cue face whereas 8-12-year-olds only showed a threat bias when the just-seen cue face displayed fear. Overall, the results argue that some, but not all, aspects of expression-context interactions are mature by 12 years of age.
The Quarterly Journal of Experimental Psychology, 2014
Individuals with autism have difficulty abstracting and updating average representations from the... more Individuals with autism have difficulty abstracting and updating average representations from their diet of faces. These averages function as perceptual norms for coding faces, and poorly calibrated norms may contribute to face recognition difficulties in autism. Another kind of average, known as an ensemble representation, can be abstracted from briefly glimpsed sets of faces. Here we show for the first time that children and adolescents with autism also have difficulty abstracting ensemble representations from sets of faces. On each trial, participants saw a study set of four identities and then indicated whether a test face was present. The test face could be a set average or a set identity, from either the study set or another set. Recognition of set averages was reduced in participants with autism, relative to age- and ability-matched typically developing participants. This difference, which actually represents more accurate responding, indicates weaker set averaging and thus weaker ensemble representations of face identity in autism. Our finding adds to the growing evidence for atypical abstraction of average face representations from experience in autism. Weak ensemble representations may have negative consequences for face processing in autism, given the importance of ensemble representations in dealing with processing capacity limitations.
To explore perception of facial expressions of emotion and its link with voluntary facial muscula... more To explore perception of facial expressions of emotion and its link with voluntary facial musculature control in Parkinson's disease (PD). We investigated in 2 sets of experiments in PD patients and healthy controls the perceptual ability to discriminate (a) graded intensities of emotional from neutral expressions, (b) graded intensities of the same emotional expressions, (c) full-blown discrepant emotional expressions from 2 similar expressions and the more complex recognition ability to label full-blown emotional expressions. We tested an embodied simulationist account of emotion perception in PD, which predicts a link between the ability to perceive emotional expressions and facial musculature control. We also explored the contribution of the ability to extract facial information (besides emotion) to emotion perception in PD. Those with PD were, as a group, impaired relative to controls (with large effect sizes) in all measures of discrimination and recognition of emotional expressions, although some patients performed as well as the best performing controls. In support of embodied simulation, discrimination and recognition of emotional expressions correlated positively with voluntary control of facial musculature (after partialing out disease severity and age). Patients were also impaired at extracting information other than emotion from faces, specifically discriminating and recognizing identity from faces (with large effect sizes); identity discrimination correlated positively with emotion discrimination and recognition but not with voluntary facial musculature control (after partialing out disease severity and age). The results indicate that impaired sensory and sensorimotor processes, which are a function of disease severity, affect emotion perception in PD.
In this review we examine how attention is involved in detecting faces, recognizing facial identi... more In this review we examine how attention is involved in detecting faces, recognizing facial identity and registering and discriminating between facial expressions of emotion. The first section examines whether these aspects of face perception are “automatic”, in that they are especially rapid, non-conscious, mandatory and capacity-free. The second section discusses whether limited-capacity selective attention mechanisms are preferentially recruited by faces
The current study used event-related potentials (ERP) in combination with a variable viewing posi... more The current study used event-related potentials (ERP) in combination with a variable viewing position paradigm (VVPP) to direct fixations to specific face parts (eyes or mouths) in upright or inverted whole faces. The N170 elicited by the VVPP was greater to faces than to non-face objects (wristwatches), and was delayed and enhanced in response to face inversion. A larger N170 response was elicited when the participants׳ fixation was directed to the eyes than when directed to the mouths of both upright and inverted faces, an effect that was also modulated by the spatial location of the face in the visual field. The N170 face inversion effect (upright minus inverted) was greater when fixations were directed to the mouth than when directed to the eyes, suggesting that the point of fixation within a face modulates brain potentials due to contributions from the features themselves, as well as their relative location in the visual field.
In this review we examine how attention is involved in detecting faces, recognizing facial identi... more In this review we examine how attention is involved in detecting faces, recognizing facial identity and registering and discriminating between facial expressions of emotion. The first section examines whether these aspects of face perception are "automatic", in that they are especially rapid, non-conscious, mandatory and capacity-free. The second section discusses whether limited-capacity selective attention mechanisms are preferentially recruited by faces and facial expressions. Evidence from behavioral, neuropsychological, neuroimaging and psychophysiological studies from humans and single-unit recordings from primates is examined and the neural systems involved in processing faces, emotion and attention are highlighted. Avenues for further research are identified.
The ability to perceive, learn and recognise faces is a complex ability, which is key to successf... more The ability to perceive, learn and recognise faces is a complex ability, which is key to successful social interactions. This ability is proposed to be coordinated by neural regions in the occipital and temporal lobes, specialised for face perception and memory. While previous studies have suggested that memory for faces is compromised in some dementia syndromes, it remains unclear whether this simply reflects more generalised memory deficits. Here, we examined basic face perception (Identity-Matching), face recognition (Cambridge Face Memory Task) and object recognition (Cambridge Car Memory Task) in 11 semantic dementia (SD) patients (8 left-lateralised, 3 right-lateralised) and 13 behavioural-variant frontotemporal dementia (bvFTD) patients, compared with 11 controls. On the Identity-Matching task, bvFTD were impaired compared to controls, with a similar trend observed in the SD group. Importantly, both bvFTD and SD also demonstrated impaired face recognition. In contrast, only b...
As faces become familiar, recognition becomes easier but the style of processing also changes. He... more As faces become familiar, recognition becomes easier but the style of processing also changes. Here, twenty-one typically developing (TD) children and twenty-one children with autism spectrum disorder (ASD) were familiarised with 6 identities over 3 days. Next, they completed a 4-alternative forced-choice matching test in which targets were the 6 familiarised faces and 6 unfamiliar faces. The TD group showed a significant advantage for familiarised faces when matching whole faces and both internal and external facial regions. The ASD group showed similar familiarisation effects for whole and external faces, but not for internal regions. The ASD group was also impaired at matching eyes and mouths of familiarised faces. Results suggest the process of acquiring familiarity with faces differs from ASD and TD children.
We investigated the link between the ability to perceive facial expressions of emotion and the ab... more We investigated the link between the ability to perceive facial expressions of emotion and the ability to perceive visual form in Parkinson's disease (PD). We assessed in individuals with PD and healthy controls the ability to discriminate graded intensities of facial expressions of anger from neutral expressions and the ability to discriminate radial frequency (RF) patterns with modulations in amplitude from a perfect circle. Those with PD were, as a group, impaired relative to controls in discriminating graded intensities of angry from neutral expressions and discriminating modulated amplitudes of RF patterns from perfect circles; these two abilities correlated positively and moderately to highly, even after removing the variance that was shared with disease progression and general cognitive functioning. The results indicate that the impaired ability to perceive visual form is likely to contribute to the impaired ability to perceive facial expressions of emotion in PD, and that both are related to the progression of the disease.
People with congenital prosopagnosia (CP) report difficulty recognising faces in everyday life an... more People with congenital prosopagnosia (CP) report difficulty recognising faces in everyday life and perform poorly on face recognition tests. Here, we investigate whether impaired adaptive face space coding might contribute to poor face recognition in CP. To pinpoint how adaptation may affect face processing, a group of CPs and matched controls completed two complementary face adaptation tasks: the figural aftereffect, which reflects adaptation to general distortions of shape, and the identity aftereffect, which directly taps the mechanisms involved in the discrimination of different face identities. CPs displayed a typical figural aftereffect, consistent with evidence that they are able to process some shape-based information from faces, e.g., cues to discriminate sex. CPs also demonstrated a significant identity aftereffect. However, unlike controls, CPs impression of the identity of the neutral average face was not significantly shifted by adaptation, suggesting that adaptive coding of identity is abnormal in CP. In sum, CPs show reduced aftereffects but only when the task directly taps the use of face norms used to code individual identity. This finding of a reduced face identity aftereffect in individuals with severe face recognition problems is consistent with suggestions that adaptive coding may have a functional role in face recognition.
Most developmental studies of face emotion processing show faces in isolation, in the absence of ... more Most developmental studies of face emotion processing show faces in isolation, in the absence of any broader context. Here we investigate two types of interactions between expression and threat contexts. First, in adults, following of another person's direction of social attention is increased when that person shows fear and the context requires vigilance for danger. We investigate whether this also occurs in children. Using a Posner-style eye-gaze cueing paradigm, we tested whether children would show greater gaze-cueing from fearful than happy expressions when the task was to be vigilant for possible dangerous animals. Testing across the 8-12-year-old age range, we found this fear priority effect was absent in the youngest children but developed to reach adult levels in the oldest children. However, even the oldest children were unable to sustain fear-prioritization when the onset of the target was delayed. Second, we addressed the development of 'threat bias' - namely faster identification of dangerous animals than safe animals - in the social context provided by expressive faces. In our non-anxious samples (i.e. with typical-population levels of anxiety), adults showed a threat bias regardless of the expression or looking direction of the just-seen cue face whereas 8-12-year-olds only showed a threat bias when the just-seen cue face displayed fear. Overall, the results argue that some, but not all, aspects of expression-context interactions are mature by 12 years of age.
The Quarterly Journal of Experimental Psychology, 2014
Individuals with autism have difficulty abstracting and updating average representations from the... more Individuals with autism have difficulty abstracting and updating average representations from their diet of faces. These averages function as perceptual norms for coding faces, and poorly calibrated norms may contribute to face recognition difficulties in autism. Another kind of average, known as an ensemble representation, can be abstracted from briefly glimpsed sets of faces. Here we show for the first time that children and adolescents with autism also have difficulty abstracting ensemble representations from sets of faces. On each trial, participants saw a study set of four identities and then indicated whether a test face was present. The test face could be a set average or a set identity, from either the study set or another set. Recognition of set averages was reduced in participants with autism, relative to age- and ability-matched typically developing participants. This difference, which actually represents more accurate responding, indicates weaker set averaging and thus weaker ensemble representations of face identity in autism. Our finding adds to the growing evidence for atypical abstraction of average face representations from experience in autism. Weak ensemble representations may have negative consequences for face processing in autism, given the importance of ensemble representations in dealing with processing capacity limitations.
To explore perception of facial expressions of emotion and its link with voluntary facial muscula... more To explore perception of facial expressions of emotion and its link with voluntary facial musculature control in Parkinson's disease (PD). We investigated in 2 sets of experiments in PD patients and healthy controls the perceptual ability to discriminate (a) graded intensities of emotional from neutral expressions, (b) graded intensities of the same emotional expressions, (c) full-blown discrepant emotional expressions from 2 similar expressions and the more complex recognition ability to label full-blown emotional expressions. We tested an embodied simulationist account of emotion perception in PD, which predicts a link between the ability to perceive emotional expressions and facial musculature control. We also explored the contribution of the ability to extract facial information (besides emotion) to emotion perception in PD. Those with PD were, as a group, impaired relative to controls (with large effect sizes) in all measures of discrimination and recognition of emotional expressions, although some patients performed as well as the best performing controls. In support of embodied simulation, discrimination and recognition of emotional expressions correlated positively with voluntary control of facial musculature (after partialing out disease severity and age). Patients were also impaired at extracting information other than emotion from faces, specifically discriminating and recognizing identity from faces (with large effect sizes); identity discrimination correlated positively with emotion discrimination and recognition but not with voluntary facial musculature control (after partialing out disease severity and age). The results indicate that impaired sensory and sensorimotor processes, which are a function of disease severity, affect emotion perception in PD.
In this review we examine how attention is involved in detecting faces, recognizing facial identi... more In this review we examine how attention is involved in detecting faces, recognizing facial identity and registering and discriminating between facial expressions of emotion. The first section examines whether these aspects of face perception are “automatic”, in that they are especially rapid, non-conscious, mandatory and capacity-free. The second section discusses whether limited-capacity selective attention mechanisms are preferentially recruited by faces
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