Reduced Face Inversion Effect Found in Individuals with Autism

Jason Griffin, PhD

Credit: Yale School of Medicine

A thorough analysis of previous studies on how individuals with autism spectrum disorder (ASD) process faces found that they exhibit a diminished face inversion effect. In these individuals, the face inversion effect is reduced, meaning that their ability to recognize faces is less affected by the orientation of the face (upright or inverted) compared with neurotypical individuals.¹

Face processing plays a fundamental role in human social cognition and significantly influences neural systems and social behavior. Since ASD is characterized by impairments in social interaction and communication, and studies have shown earlier intervention helps individuals adapt and overcome symptoms.²

The ability to recognize and interpret faces can be assessed through the face inversion effect, which refers to the decreased accuracy and altered neural response when faces are presented upside-down as compared with upright. Understanding the mechanisms underlying face processing differences in autism can enhance the overall comprehension of brain functioning in this population.¹

Investigators led by Jason Griffin, PhD, Yale Child Study Center, Yale University School of Medicine, conducted a systematic review and Bayesian meta-analysis to synthesize data from existing literature on face processing in ASD, specifically examining the face inversion effect across multiple mechanistic levels.

Searches were performed in various databases, including MEDLINE, Embase, Web of Science, and PubMed. The analysis included original research that reported performance-based measures of face recognition with upright and inverted faces in both ASD and neurotypical samples.

Out of 1768 articles screened, data from 38 empirical studies comprising 122 effect sizes, 899 ASD individuals, and 865 neurotypical individuals (total: 1764) were included in the meta-analysis.

The findings revealed that those with ASD exhibited a reduced face inversion effect size (Hedges g) which indicated a statistically significant reduction (g = −0.41; SE = 0.11; 95% credible interval [CrI], −0.63 to −0.18).

The data revealed significant heterogeneity among the effect sizes, indicating substantial variations across the included studies. In order to better understand the factors contributing to this heterogeneity, moderator analysis was conducted by the investigators.

Analysis results showed the differential impact of certain variables on the face inversion effect in individuals with ASD.

The attenuated face inversion effect in individuals with ASD was more prominent in the recognition of emotion compared with identity recognition. Investigators reported this effect was more evident in behavioral measures compared with electrophysiological measures.

Specifically, the attenuated face inversion effect in this population was found to be more pronounced in emotion recognition compared with identity recognition. Investigators noted the effect size (b = 0.46) supported the magnitude of this difference, with a larger positive value suggesting a more prominent effect.

The standard error (SE) associated with this effect size was 0.26, indicating the precision of the estimate. The 95% CrI for this effect size ranged from −0.08 to 0.95, capturing the plausible range of values for the effect size.

“This study found that on average, face recognition in autism is less impacted by inversion. These findings suggest less specialization or expertise of the face processing system in autism, particularly in recognizing emotion from faces as measured in behavioral paradigms.”

These findings highlight a difference in the way individuals with autism process faces, particularly in relation to emotional cues. The data suggest atypical face processing in autism may contribute to the social communication challenges experienced by individuals on the autism spectrum.

References:

1. Griffin JW, Azu MA, Cramer-Benjamin S, et al. Investigating the Face Inversion Effect in Autism Across Behavioral and Neural Measures of Face Processing: A Systematic Review and Bayesian Meta-Analysis. JAMA Psychiatry. Published online July 05, 2023. doi:10.1001/jamapsychiatry.2023.2105
2. Walter K. Preemptive Interventions Led to Reduction in Autism Spectrum Symptom Severity. HCPLive. September 21, 2021. https://www.hcplive.com/view/preemptive-interventions-reduction-autism-spectrum-symptom-severity