Evaluating object recognition ability in developmental prosopagnosia using the Cambridge Car Memory Test

Individuals with developmental prosopagnosia (DP) sometimes experience object identification difficulties in addition to problems recognising faces. To better understand the distribution of non-face object recognition ability in this population, we administered the Cambridge Car Memory Test (CCMT) – a leading, standardised measure of object recognition ability – to a large sample of DPs (N = 46). When considered as a single group, the DPs scored lower than matched controls. This finding provides further evidence that developmental object agnosia (DOA) may be more common in DP than in the general population. Relative to the DPs’ face recognition deficits, however, car matching deficits were small and inconsistent. In fact, we observed a striking range of CCMT performance in our DP sample. While some DPs performed extremely poorly, many more achieved scores within one standard deviation of the typical mean, and several DP participants achieved excellent CCMT scores comparable with the best controls

The discrimination of facial sex in developmental prosopagnosia

Developmental prosopagnosia (DP) is a neurodevelopmental condition characterised by difficulties recognising and discriminating faces. It is currently unclear whether the perceptual impairments seen in DP are restricted to identity information, or also affect the perception of other facial characteristics. To address this question, we compared the performance of 17 DPs and matched controls on two sensitive sex categorisation tasks. First, in a morph categorisation task, participants made binary decisions about faces drawn from a morph continuum that blended incrementally an average male face and an average female face. We found that judgement precision was significantly lower in the DPs than in the typical controls. Second, we used a sex discrimination task, where female or male facial identities were blended with an androgynous average face. We manipulated the relative weighting of each facial identity and the androgynous average to create four levels of signal strength. We found that DPs were significantly less sensitive than controls at each level of difficulty. Together, these results suggest that the visual processing difficulties in DP extend beyond the extraction of facial identity and affects the extraction of other facial characteristics. Deficits of facial sex categorisation accord with an apperceptive characterisation of DP

Development and validation of the Interoceptive States Static Images (ISSI) database

Abstract Internal bodily signals provide an essential function for human survival. Accurate recognition of such signals in the self, known as interoception, supports the maintenance of homeostasis, and is closely related to emotional processing, learning and decision-making, and mental health. While numerous studies have investigated interoception in the self, the recognition of these states in others has not been examined despite its crucial importance for successful social relationships. This paper presents the development and validation of the Interoceptive States Static Images (ISSI), introducing a validated database of 423 visual stimuli for the study of non-affective internal state recognition in others, freely available to other researchers. Actors were photographed expressing various exemplars of both interoceptive states and control actions. The images went through a two-stage validation procedure, the first involving free-labelling and the second using multiple choice labelling and quality rating scales. Five scores were calculated for each stimulus, providing information about the quality and specificity of the depiction, as well as the extent to which labels matched the intended state/action. Results demonstrated that control action stimuli were more recognisable than internal state stimuli. Inter-category variability was found for the internal states, with some states being more recognisable than others. Recommendations for the utilisation of ISSI stimuli are discussed. The stimulus set is freely available to researchers, alongside data concerning recognisability

Typical integration of emotion cues from bodies and faces in Autism Spectrum Disorder

Contextual cues derived from body postures bias how typical observers categorize facial emotion; the same facial expression may be perceived as anger or disgust when aligned with angry and disgusted body postures. Individuals with Autism Spectrum Disorder (ASD) are thought to have difficulties integrating information from disparate visual regions to form unitary percepts, and may be less susceptible to visual illusions induced by context. The current study investigated whether individuals with ASD exhibit diminished integration of emotion cues extracted from faces and bodies. Individuals with and without ASD completed a binary expression classification task, categorizing facial emotion as ‘Disgust’ or ‘Anger’. Facial stimuli were drawn from a morph continuum blending facial disgust and anger, and presented in isolation, or accompanied by an angry or disgusted body posture. Participants were explicitly instructed to disregard the body context. Contextual modulation was inferred from a shift in the resulting psychometric functions. Contrary to prediction, observers with ASD showed typical integration of emotion cues from the face and body. Correlation analyses suggested a relationship between the ability to categorize emotion from isolated faces, and susceptibility to contextual influence within the ASD sample; individuals with imprecise facial emotion classification were influenced more by body posture cues

Normal composite face effects in developmental prosopagnosia

Upright face perception is thought to involve holistic processing, whereby local features are integrated into a unified whole. Consistent with this view, the top half of one face appears to fuse perceptually with the bottom half of another, when aligned spatially and presented upright. This ‘composite face effect’ reveals a tendency to integrate information from disparate regions when faces are presented canonically. In recent years, the relationship between susceptibility to the composite effect and face recognition ability has received extensive attention both in participants with normal face recognition and participants with developmental prosopagnosia. Previous results suggest that individuals with developmental prosopagnosia may show reduced susceptibility to the effect suggestive of diminished holistic face processing. Here we describe two studies that examine whether developmental prosopagnosia is associated with reduced composite face effects. Despite using independent samples of developmental prosopagnosics and different composite procedures, we find no evidence for reduced composite face effects. The experiments yielded similar results; highly significant composite effects in both prosopagnosic groups that were similar in magnitude to the effects found in participants with normal face processing. The composite face effects exhibited by both samples and the controls were greatly diminished when stimulus arrangements were inverted. Our finding that the whole-face binding process indexed by the composite effect is intact in developmental prosopagnosia indicates that other factors are responsible for developmental prosopagnosia. These results are also inconsistent with suggestions that susceptibility to the composite face effect and face recognition ability are tightly linked. While the holistic process revealed by the composite face effect may be necessary for typical face perception, it is not sufficient; individual differences in face recognition ability likely reflect variability in multiple sequential processes

Does developmental prosopagnosia impair identification of other-ethnicity faces?

Current approaches to the diagnosis of developmental prosopagnosia emphasise the perception and identification of same-ethnicity faces. This convention ensures that perceptual impairment arising from developmental prosopagnosia can be distinguished from problems arising from a lack of visual experience with particular facial ethnicities – the so-called ‘Other-Ethnicity Effect’. The present study sought to determine whether the perceptual difficulties seen in developmental prosopagnosia – diagnosed using same-ethnicity faces – extend to other-ethnicity faces. First, we sought to determine whether a group of Caucasian developmental prosopagnosics (N = 15) and typical Caucasian controls (N = 30) had similar experience with same- and other-ethnicity faces during development. All participants therefore completed a contact questionnaire that enquired about their experience of Caucasian, Black, and East Asian faces, at different developmental stages. Importantly, the two groups described very similar levels of visual experience with other-ethnicity faces. Second, we administered a sequential matching task to measure participants’ ability to discriminate same- (Caucasian) and other-ethnicity (Black, East Asian) faces. Relative to the experience-matched controls, the prosopagnosics were less accurate at discriminating both same- and other-ethnicity faces, and we found no evidence of disproportionate impairment for same-ethnicity faces. Given that the prosopagnosics and controls had similar opportunity to develop visual expertise for other-ethnicity faces, these results indicate that developmental prosopagnosia impairs recognition of both same- and other-ethnicity faces. The fact that developmental prosopagnosia affects the perception of both same- and other-ethnicity faces suggests that different facial ethnicities engage similar visual processing mechanisms. Our findings support the view that susceptibility to developmental prosopagnosia, and a lack of contact with other-ethnicity faces, contribute independently to the poor recognition of other-ethnicity faces

Is developmental prosopagnosia best characterised as an apperceptive or mnemonic condition?

Traditionally, developmental prosopagnosia (DP) has been thought of as an apperceptive condition that hinders individuals’ ability to encode face structure. However, several authors have recently raised the possibility that many DPs may be able to form accurate percepts, but be unable to maintain those percepts over time. The present study sought to distinguish these possibilities. In our first experiment 16 DPs and 22 typical controls completed a delayed match-to-sample task with face and car stimuli, with a retention interval of 1-second (low demand) or 6-seconds (high demand). As expected, the participants with DP were worse than the controls at face matching, and were disproportionately impaired at matching faces relative to cars. However, the relative degree of impairment seen in the DPs did not interact with retention interval; they exhibited similar levels of impairment when matching faces with 1- and 6-second delays. Next, we compared the performance of 72 DPs and 54 typical controls on the Cambridge Face Perception Test (CFPT), a task that measures face perception ability in a way that minimises the memory demands. As expected, we found that the DPs were impaired at the group level. This difference was not attributable to a few individuals with an apperceptive profile; rather we found evidence that the distribution of CFPT scores seen in the DP sample was shifted relative to that of typical controls. Some heterogeneity is likely in any neurodevelopmental population, and DP is no different. Generally, however, these findings suggest that selective STFM impairment may be relatively uncommon in this population. Instead, deficits of perceptual encoding may play a larger role in DP than currently acknowledged

DMTs and Covid-19 severity in MS: a pooled analysis from Italy and France

We evaluated the effect of DMTs on Covid-19 severity in patients with MS, with a pooled-analysis of two large cohorts from Italy and France. The association of baseline characteristics and DMTs with Covid-19 severity was assessed by multivariate ordinal-logistic models and pooled by a fixed-effect meta-analysis. 1066 patients with MS from Italy and 721 from France were included. In the multivariate model, anti-CD20 therapies were significantly associated (OR = 2.05, 95%CI = 1.39–3.02, p < 0.001) with Covid-19 severity, whereas interferon indicated a decreased risk (OR = 0.42, 95%CI = 0.18–0.99, p = 0.047). This pooled-analysis confirms an increased risk of severe Covid-19 in patients on anti-CD20 therapies and supports the protective role of interferon