Deficits in eye contact have been a hallmark of autism1,2 since the condition’s initial description3. They are cited widely as a diagnostic feature4 and figure prominently in clinical instruments5; however, the early onset of these deficits has not been known. Here we show in a prospective longitudinal study that infants later diagnosed with autism spectrum disorders (ASDs) exhibit mean decline in eye fixation from 2 to 6 months of age, a pattern not observed in infants who do not develop ASD. These observations mark the earliest known indicators of social disability in infancy, but also falsify a prior hypothesis: in the first months of life, this basic mechanism of social adaptive action—eye looking—is not immediately diminished in infants later diagnosed with ASD; instead, eye looking appears to begin at normative levels prior to decline. The timing of decline highlights a narrow developmental window and reveals the early derailment of processes that would otherwise have a key role in canalizing typical social development. Finally, the observation of this decline in eye fixation—rather than outright absence—offers a promising opportunity for early intervention that could build on the apparent preservation of mechanisms subserving reflexive initial orientation towards the eyes.
This work was supported by grants from the Simons Foundation and the National Institute of Mental Health (R01 MH083727). Additional support was provided by the Marcus Foundation, the Whitehead Foundation, and the Georgia Research Alliance. We wish to thank the families and children for their time and participation. We also wish to thank S. Habayeb, S. Glazer, M. Ly, T. Tsang, J. Jones, A. Trubanova, J. Borjon, J. Moriuchi, K. Rice, J. Northrup, L. Edwards, J. Xu, S. Shultz, A. Krasno, C. Zampella, K. Knoch, D. Lin, K. Carr and A. Blank for their assistance in data collection and processing; P. Lewis, J. Paredes, P. Gorrindo and M. Ackerman for assistance in designing and building laboratory hardware and software; G. Ramsay and C. McCracken for discussions of data analysis and statistics; I. Zilber, A. Margolis, D. Blum, M. Dye, D. Simeone, A. Smith and K. O’Loughlin for project supervision, coordination, and data collection; T. Babitz for administrative support; and K. Chawarska, C. Saulnier, K. Bearss, S. Macari, R. Paul, A. Carney, T. Goldsmith, A. Steiner, G. Gengoux, D. Goudreau, E. Loring, J. McGrath and A. Gupta for their contributions to the clinical characterization of the samples.
Extended data figures
Extended data tables
This file contains Supplementary Text and Data and Supplementary References – see contents page in document for details.