More than just a problem with faces: altered body perception in a group of congenital prosopagnosics

ABSTRACT

It has been estimated that one out of 40 people in the general population suffer from congenital prosopagnosia (CP), a neurodevelopmental disorder characterized by difficulty identifying people by their faces. CP involves impairment in recognizing faces, although the perception of non-face stimuli may also be impaired. Given that social interaction depends not only on face processing, but also on the processing of bodies, it is of theoretical importance to ascertain whether CP is also characterized by body perception impairments. Here, we tested 11 CPs and 11 matched control participants on the Body Identity Recognition Task (BIRT), a forced-choice match-to-sample task, using stimuli that require processing of body-specific, not clothing-specific, features. Results indicated that the group of CPs were as accurate as controls on the BIRT, which is in line with the lack of body perception complaints by CPs. However, the CPs were slower than controls, and when accuracy and response times were combined into inverse efficiency scores (IESs), the group of CPs were impaired, suggesting that the CPs could be using more effortful cognitive mechanisms to be as accurate as controls. In conclusion, our findings demonstrate that CP may not generally be limited to face processing difficulties, but may also extend to body perception.

KEYWORDS:

• Developmental prosopagnosia
• Face processing
• Bodies
• Object processing

Acknowledgement

We thank Andrew J. Calder for suggesting that we use this task to examine non-face processing in people with congenital prosopagnosia. We also wish to thank Shahad Al-Janabi and Matthew Robson for their help in data collection.

ORCID

Davide Rivolta http://orcid.org/0000-0002-9969-9135

Romina Palermo http://orcid.org/0000-0002-8678-4592

Notes

¹Most previous group studies in CP reported data from 4–8 participants (Avidan et al., 2013; Righart & de Gelder, 2007; Rivolta et al., 2014).

² https://www.maccs.mq.edu.au/research/projects/prosopagnosia/register

³Non-parametric analysis (Mann–Whitney U test) showed that RTs in controls (M = 5030 ms, SD = 816) and CPs (M = 5582 ms, SD = 860) did not differ (p = .165).