The study, published on the journal Molecular Autism by researchers from the Department of Psychology of Sapienza University of Rome, the Institute of Science and Technology of Cognition of the National Research Council of Italy (CNR-ISTC), the Santa Lucia IRCCS Foundation, Harvard University and the University of Cambridge, is an important piece in the reconstruction of the genetic background of autism
More than a third of autistic adults with no intellectual disabilities are prosopagnosic, i.e. they have a clinical difficulty in recognising and memorising other people from their face, according to a study published on the journal Molecular Autism.
Researchers at Sapienza University of Rome, the Institute of Cognition Sciences and Technologies of the National Research Council of Italy (CNR-ISTC), IRCCS Santa Lucia Foundation, Harvard University and the University of Cambridge, estimated the prevalence of prosopagnosia and its characteristics in a group of 80 autistic participants from Italy, the United States and the United Kingdom and a related control group of neurotypical participants.
The study investigated the characteristics of prosopagnosia in autism and its associations with symptomatological severity, personality traits and social skills, proposing the recognition of identity as a potential endophenotype in autism.
“While developmental prosopagnosia regards 2-3% of the general population, we found the first evidence that 36% of autistic adults with no intellectual disability are prosopagnosic”, say Ilaria Minio-Paluello and Giuseppina Porciello, main authors of the study. “We also saw that the two groups of prosopagnosic and non-prosopagnosic autistic individuals did not differ in their symptomatological severity, number of autistic traits, general intelligence, memory, empathic traits and alexithymia. This leads us to hypothesise that difficulties in individual face recognition might not constitute a causal link between genes and autism but might rather contribute to the genetic background of autism.”
Further analysis revealed that only in the group of prosopagnosic autistic people was the recognition of identity from the face connected with the ability to recognise another person’s mental states from the look, both of which are essential skills for orientation in the social world. “It is unlikely that this association is due to a reduced ability to recognise faces, as non-autistic people with developmental prosopagnosia have no difficulty in deciphering other people’s mental states when looking at their eyes”, adds Minio-Paluello. “We think instead that reduced attention to the eyes could affect both the recognition of identity and mental states. The probability that facial identity and recognition of mental states have an underlying common neurobiological mechanism increases the potential relevance of memory for faces as an endophenotype in autism.”
Several previous studies had shown that similarly to neurotypical people, autistic people have more difficulty processing faces shown upside down (inversion effect). “In our work, on the other hand, we have shown that prosopagnosic autistics do not have the typical reversal effect when they have to memorise faces, whereas this happens when faces remain visible – Porciello points out. This, together with the relationship between memory for faces and understanding other people’s mental states, is another example of autistic prosopagnosics differing from non-autistic developmental prosopagnosics.”
“Autistic people are very different from one another in their clinical, etiological and genetic characteristics, and this makes it difficult to identify both causes and effective interventions”, concludes Minio-Paluello. “We believe that the differences in the ability to recognise individual identity from faces, given its heritability and independence from general intelligence, will be useful in addressing the high heterogeneity of autism, allowing us to identify significant subgroups.”
Further studies – the authors point out – will be necessary to verify whether the results obtained on the sample involved can also be extended to the types of autistic people not represented, such as children, women and people with intellectual disabilities.
Ilaria Minio-Paluello, Giuseppina Porciello, Alvaro Pascual-Leone, Simon Baron-Cohen.
Face individual identity recognition: a potential endophenotype in autism. Molecular Autism September 2020. DOI 10.1186/s13229-020-00371-0 DOI https://doi.org/10.1186/s13229-020-00371-0
Department of Psychology
Department of Psychology
Source: Sapienza University of Rome