Autistic teens' brains show lower responsiveness to unfamiliar voices

Adolescence is often characterized by a growing awareness of the social world and a desire to form new connections. However, a Stanford Medicine-led study has found that teenagers on the autism spectrum do not experience the same neurological shift toward unfamiliar voices that their neurotypical peers do.

Published July 13, 2026, in Proceedings of the National Academy of Sciences, the research reveals that the reward centers in the brains of autistic teens do not become increasingly responsive to the voices of strangers as they mature. This differs from typically developing teenagers, whose brains show an uptick in responsiveness to new vocal stimuli.

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Daniel Abrams, PhD, a clinical associate professor of psychiatry and behavioral sciences at Stanford Medicine, noted that while many teens with autism are eager to build friendships and romantic relationships, their brains may not be tuning into the vocal cues necessary to facilitate these bonds.

The Divergent Path of Adolescent Brains

The study, senior-authored by Vinod Menon, PhD, utilized functional magnetic resonance imaging (fMRI) to analyze the brain activity of 79 participants between 7 and 17 years old. The group consisted of 39 individuals with autism spectrum disorder and 40 typically developing participants matched for IQ, sex, and age. To prevent the brain from reacting to the meaning of words, researchers used recordings of nonsense words, such as keebudishawlt, spoken by the participant's mother, two unfamiliar women, and non-voice environmental sounds like a dishwasher.

The findings highlight a stark contrast in how "social" brain centers—specifically those focused on reward and salience (which directs attention)—behave over time:

• Neurotypical Teens: Reward and salience centers responded more strongly to voices as the participants grew older, with a strong pattern of tuning into unfamiliar voices more than their mother's voice.
• Autistic Teens: These brain regions did not become more responsive to voices with age. In some older participants, these regions were even less responsive than they had been in younger children.

Furthermore, the research found that teens with autism became increasingly attuned to their mother's voice during adolescence. This pattern was most pronounced in those with the most severe autism symptoms, representing the opposite trajectory of neurotypical development.

"In neurotypical kids, we found a strong pattern in adolescence to tune in more to unfamiliar voices than to Mom’s voice," said Abrams. "Instead of tuning into unfamiliar voices during adolescence, they were tuning in more to the sound of their mom than at younger ages. We think this pattern reflects the social communication challenges faced by many adolescents with autism."

Familiarity Across the Spectrum

The role of familiarity appears to be a consistent theme in autism research, extending beyond adolescence and vocal stimuli. According to reporting from PMC, previous studies of children aged two to five have shown that those with autism may exhibit normative pupillary reactions to fearful expressions when those expressions come from familiar people, such as childcare teachers. However, those same children showed a reduced response to fear expressed by unfamiliar people.

Implications for Treatment

Autism affects 1 in 31 children and is characterized by social difficulties, not just with interpreting voices but also with skills such as interpreting facial expressions and maintaining eye contact as well as restricted interests, repetitive behaviors and sensory aberrations. While early intervention for preschoolers is critical, Abrams argues that adolescents are often neglected in treatment planning.

Because the brain remains plastic throughout adolescence, researchers believe this phase represents a "golden opportunity" for targeted therapies. Understanding that autistic teens may be neurologically predisposed to favor familiar voices could lead to interventions that help them bridge the gap toward unfamiliar social partners.

Comparing Brain Responses by Age and Familiarity

Group	Response to Unfamiliar Voices (with age)	Response to Mother's Voice (with age)
Neurotypical Teens	Increases / More engaging	Remains rewarding but less dominant
Autistic Teens	Stagnant or decreases	Increases / Becomes more dominant

The research was supported by the National Institutes of Health, the Swiss National Science Foundation, the Brain and Behavior Research Foundation, and an anonymous donation, with contributions from ETH Zurich and the University of Zurich.