When we smell a rose, we might take a deep breath to get the the sweet but subtle floral scent - and in a public bathroom we would wisely do just the opposte. Yet people with autism spectrum disorder (ASD) don't make this natural adjustment like other people do, autistic children go right on sniffing in the same way, no matter how pleasant or awful the scent.
Researchers writing in a new paper suggest that non-verbal tests related to smell might serve as useful early indicators of ASD. Earlier evidence had indicated that people with autism have impairments in "internal action models," the brain templates we rely on to seamlessly coordinate our senses and actions. It wasn't clear if this impairment would show up in a test of the sniff response, however.