The Brain Behind The Mask: How Autistic People "Pass As Non-Autistic"
- Lidi Garcia
- Aug 5
- 5 min read
A new study shows that many autistic adolescents manage to appear "non-autistic" in certain settings, such as school or home, even after having a clinically confirmed diagnosis. This is called PAN (Passing as Non-Autistic). Scientists have found that these young people's brains process faces more quickly but react less emotionally to them. This may help explain why they adapt better in social settings, even while maintaining their autistic characteristics.
While autism is generally characterized by difficulties in social interaction, recent research shows that this can vary greatly depending on the context. In other words, many autistic young people behave differently at home, at school, or in clinics.
A phenomenon called "Passing as Non-Autistic" (PAN) describes precisely this: situations in which an autistic person appears not to be autistic, or does not clearly demonstrate their autistic characteristics, especially in social settings. This does not mean the person is faking or trying to deceive; often, this behavior occurs automatically and unconsciously.
Studies show that PAN is more common than previously thought. Some young people demonstrate clear signs of autism when evaluated by professionals (in clinical settings), but appear neurotypical, that is, non-autistic, when observed by parents or teachers in everyday life.
This behavioral variation has led researchers to seek deeper explanations, especially regarding what happens in the brains of these individuals.
What might cause this change in behavior?
There are several theories to explain PAN. One is that these young people use compensatory cognitive strategies to appear more socially "adjusted." They may, for example, copy facial expressions, imitate gestures, or try to control their emotions consciously or automatically.
Other theories suggest that PAN may be related to greater emotional regulation, meaning these young people are better able to control how their emotions appear externally. It's also possible that they have strengths in specific areas, such as memory or logical reasoning, that help them "navigate" social interactions.
Whatever the explanation, these strategies depend on how these people's brains process social information, such as faces and expressions. Therefore, scientists have been investigating the neural mechanisms behind PAN—that is, what happens in these people's brains when they see or interact with other people.
One of the most common ways to study the brain in real time is using EEG (electroencephalography), which records the brain's electrical activity. With EEG, scientists can observe event-related potentials (ERPs), which are brain signals triggered by specific stimuli, such as seeing a face.
Two ERPs are especially important in the study of autism:
N170: A signal that appears quickly (about 170 milliseconds) after seeing a face. It is an indicator of how the brain recognizes faces. In autistic people, this signal tends to emerge more slowly, which may indicate slower facial processing.
Late Positive Potential (LPP): A signal that appears later (after 300 milliseconds) and shows how the brain reacts emotionally to stimuli. It is usually stronger when the person sees something emotionally striking, such as a face with a sad or happy expression. In autistic people, the LPP can be weaker, suggesting a less intense emotional response, but this varies depending on the type of emotion and the context.
These signals help scientists understand not only what a person sees, but also how they feel and react to what they see.
This study, conducted by researchers at Stony Brook University, USA, investigated how autistic adolescents with and without PAN process faces and emotions. To do so, the researchers analyzed the N170 and LPP signals while the adolescents performed a facial expression recognition task (while wearing EEG).
The sample consisted of 44 adolescents (average age 13), assessed by different individuals in different contexts: parents (at home), teachers (at school), and clinical professionals. The scientists compared these assessments using well-recognized scales in the field of autism: the SRS-2 (Social Responsiveness Report, administered by parents and teachers) and the ADOS-2 (a clinical assessment administered by experts).
This made it possible to identify those who consistently displayed autistic characteristics across contexts and those who exhibited discrepancies, appearing more or less autistic depending on the environment. This discrepancy is what defines PAN.
About 44% of the adolescents studied exhibited signs of PAN, meaning they displayed autistic characteristics in clinical settings but not at home or school. When scientists analyzed the brain signals of these young people, they found two main results:
- The N170 was faster in young people with PAN, indicating more efficient or automatic facial processing.
- The LPP was weaker, especially when faces displayed more subtle emotions, suggesting a reduced emotional response.
These findings indicate that young people with PAN process faces more quickly but react less emotionally to them. This may explain why they are able to adapt or appear less autistic in certain environments: their brains are responding differently to the social context, both in perception and emotion.
This is the first study to identify possible brain mechanisms linked to PAN. It shows that PAN is not just a matter of visible behavior, but is related to real differences in brain function.
These young people are not just "trying" to fit in; their brains are, in fact, reacting to the social world in a specific way.
This discovery is important for improving how autism is assessed and understood. It can also help develop more appropriate interventions, respecting the complexity of the autistic experience and avoiding misjudgments based solely on behavioral appearance in a single context.
READ MORE:
Automatic and affective processing of faces as mechanisms of passing as non-autistic in adolescence
Abigail P. Houck, Jared K. Richards, Talena C. Day, Janelle J. Goodwill, Kathryn M. Hauschild, Isha Malik, and Matthew D. Lerner
Scientific Reports, volume 15, Article number: 22850 (2025)
Abstract:
Passing as non-autistic (PAN) is the phenomenon by which an autistic person does not present as autistic in certain contexts. Despite a proliferation of research on the construct on PAN, no study has yet examined the neurocognitive processes implicated in PAN. This study examined two well-characterized event-related potentials (ERPs) often associated with autism - the N170 and the Late Positive Potential (LPP) - in response to faces as putative mechanisms of PAN. Participants were 44 community-recruited youth (Mage = 13.36, Nmale = 30) who completed a facial emotion recognition task during EEG recording. PAN was operationalized using best practices (moderation) for calculating the discrepancy between community informant (parent and teacher) and clinician-reported autism symptoms. Results reveal a substantial proportion (approximately 44%) of the community-recruited adolescent sample met criteria for PAN. This status was associated with faster N170 latency to faces, and attenuated LPP amplitude to facial emotions, particularly subtle facial emotions. Findings suggest autistic adolescents who PAN may have more efficient automatic process of, and reduced reactivity to, social stimuli. This study provides the first direct test of a potential neurocognitive mechanism of PAN, supporting emotion regulation-mediated PAN models.
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