Autistic teens show diminished brain response to unfamiliar voices, potentially widening social gap

A recent study led by Stanford Medicine reveals that autistic teenagers demonstrate weaker brain reactions to unfamiliar voices compared to their typically developing peers, highlighting a potential challenge in social engagement during adolescence.

A Stanford Medicine-led study published in July found that autistic teenagers show a weaker brain response to unfamiliar voices than their typically developing peers, a difference researchers say may help explain why social interaction becomes harder for many adolescents on the spectrum. The findings suggest that, while most teenagers grow more responsive to new voices as they mature, autistic teens do not show the same shift. According to Stanford Medicine, that gap may shape how social communication develops over time.

The research, reported by Stanford Medicine and published in the Proceedings of the National Academy of Sciences, built on earlier work from the same team showing that younger autistic children already respond differently to their mothers’ voices. In the newer study, the scientists looked at about 80 children and teenagers aged 7 to 17, roughly half of whom had autism, and compared their brain activity while they listened to short recordings. The participants heard nonsense words spoken by their mothers, the same words spoken by unfamiliar women and non-human environmental sounds such as a dishwasher.

Using functional MRI, the researchers found that typically developing children showed stronger reward-related brain activity as they got older, particularly when listening to voices. That pattern was especially tied to a growing interest in unfamiliar voices during adolescence, a shift that appears to support wider social exploration and the formation of new relationships. Stanford Medicine said autistic adolescents showed the opposite trend, with lower reward responses to voices as they aged.

The study also found that autistic teenagers were more strongly drawn to their mothers’ voices than to unfamiliar voices, while the reverse was true for typically developing peers. Researchers said that pattern may contribute to a narrowing of social attention, reinforcing isolation and making it harder for autistic adolescents to engage with people outside the family circle. The team said the effect could deepen over time, creating a cycle in which weaker social engagement further limits exposure to new voices and social cues.

The researchers said the work is important because most behavioural interventions are aimed at younger children, leaving fewer options for teenagers. They argued that early intervention remains essential but should not come at the expense of adolescents, whose social needs are often overlooked. Stanford previously reported in 2019 that autistic children also show a reduced brain response to their mother’s voice, while another Stanford study in 2022 found that, in typically developing children, the brain usually begins shifting towards new voices around age 13.