What is developmental about developmental prosopagnosia?

Developmental prosopagnosia (DP) is characterised by difficulties recognising face identities and is associated with diverse co-occurring object recognition difficulties. The high co-occurrence rate and heterogeneity of associated difficulties in DP is an intrinsic feature of developmental conditions, where co-occurrence of difficulties is the rule, rather than the exception. However, despite its name, cognitive and neural theories of DP rarely consider the developmental context in which these difficulties occur. This leaves a large gap in our understanding of how DP emerges in light of the developmental trajectory of face recognition. Here, we argue that progress in the field requires re-considering the developmental origins of differences in face recognition abilities, rather than studying the end-state alone. In practice, considering development in DP necessitates a re-evaluation of current approaches in recruitment, design, and analyses.

Recognition of animal faces is impaired in developmental prosopagnosia.

An on-going debate in psychology and neuroscience concerns the way faces and objects are represented. Domain-specific theories suggest that faces are processed via a specialised mechanism, separate from objects. Developmental prosopagnosia (DP) is a neurodevelopmental disorder in which there is a deficit in the ability to recognize conspecific (human) faces. It is unclear, however, whether prosopagnosia also affects recognition of heterospecific (animal) faces. To address this question, we compared recognition performance with human and animal faces in neurotypical controls and participants with DP. We found that DPs showed deficits in the recognition of both human and animal faces compared to neurotypical controls. In contrast to, we found no group-level deficit in the recognition of animate or inanimate non-face objects in DPs. Using an individual-level approach, we demonstrate that in 60% of cases in which face recognition is impaired, there is a concurrent deficit with animal faces. Together, these results show that DPs have a general deficit in the recognition of faces that encompass a range of configural and morphological structures.

Recognition of pareidolic objects in developmental prosopagnosic and neurotypical individuals.

Developmental prosopagnosia (DP) is a neurodevelopmental disorder associated with difficulties in the perception and recognition of faces. However, the extent to which DP affects non-face object is an ongoing debate. In this study, we asked whether pareidolic objects (which give rise to the perception of a face) are also affected in DP. First, we compared performance in DPs (n = 30) and controls (n = 27) on a recognition task with faces, pareidolic objects and non-pareidolic objects (bottles). The pareidolic objects had either similar or dissimilar image statistics to faces. Consistent with our understanding of DP, we found that the pattern of recognition across items between DPs and controls was lowest for faces. Interestingly, there was also a low correlation between DPs and controls for pareidolic-similar objects that was similar to faces. In contrast, there were higher correlations between DPs and controls for pareidolic-dissimilar objects and bottles, which were both significantly different to faces. These findings suggest that the deficit in DP involves processing image properties that are common to faces. Next, using an individual differences approach across a large group of neurotypical adults (n = 94), we found that face recognition covaried with the recognition of pareidolic-similar objects, but not with pareidolic-dissimilar objects or non-pareidolic objects. Together, these findings support the idea that a representation based on image properties plays an important role in the perception and recognition of objects and faces and that the deficit in the perception of some object categories in DP could be explained by their similarity to the image properties found in faces.

Are adaptation aftereffects for facial emotional expressions affected by prior knowledge about the emotion?

Accurate perception of the emotional signals conveyed by others is crucial for successful social interaction. Such perception is influenced not only by sensory input, but also by knowledge we have about the others' emotions. This study addresses the issue of whether knowing that the other's emotional state is congruent or incongruent with their displayed emotional expression ("genuine" and "fake", respectively) affects the neural mechanisms underpinning the perception of their facial emotional expressions. We used a visual adaptation paradigm to investigate this question in three experiments employing increasing adaptation durations. The adapting stimuli consisted of photographs of emotional facial expressions of joy and anger, purported to reflect (in-)congruency between felt and expressed emotion, displayed by professional actors. A Validity checking procedure ensured participants had the correct knowledge about the (in-)congruency. Significantly smaller adaptation aftereffects were obtained when participants knew that the displayed expression was incongruent with the felt emotion, following all tested adaptation periods. This study shows that knowledge relating to the congruency between felt and expressed emotion modulates face expression aftereffects. We argue that this reflects that the neural substrate responsible for the perception of facial expressions of emotion incorporates the presumed felt emotion underpinning the expression.