People with autism perceive sight, sound and touch in extremely unpredictable ways, new research suggests, a finding that may help explain behaviors associated with the developmental disorder.

In observing adults with and without autism as they experienced various sensory stimuli, researchers found that those with the disorder responded inconsistently even when they saw, heard or touched the exact same thing over and over again.

“This suggests that there is something very fundamental that is altered in the cortical responses in individuals with autism,” said Marlene Behrmann, professor of psychology at Carnegie Mellon University who worked on the study published this month in the journal Neuron. “It also begins to build a bridge between the kind of genetic changes that might have given rise to autism in the first place – and the kind of changes in the brain that are responsible for autistic behavioral patterns.”

For the study, researchers used functional magnetic resonance imaging, or fMRI, to observe brain activity in 14 adults with and 14 without autism as they experienced various sensory stimuli. To measure sight, participants watched a pattern of moving dots while their auditory responses were tested by listening to pure tones and short air puffs were used to assess reactions to touch.

While the typically developing adults in the study had fairly consistent reactions, those with autism displayed responses varying from strong to weak even when faced with the same stimuli repeatedly, researchers said. This unreliable view of the world may offer clues as to why people with autism exhibit certain behaviors, they said.

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