|
Scientific Understanding of Consciousness |
Autism Behavioral Indication in Infants
Nature 459, 257-261 (14 May 2009) Two-year-olds with autism orient to non-social contingencies rather than biological motion Ami Klin, David J. Lin, Phillip Gorrindo, Gordon Ramsay & Warren Jones Yale Child Study Center, Yale University School of Medicine, New Haven, Connecticut 06519-1124, USA Haskins Laboratories, New Haven, Connecticut 06511, USA Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, Connecticut 06520-8074, USA Typically developing human infants preferentially attend to biological motion within the first days of life. This ability is highly conserved across species and is believed to be critical for filial attachment and for detection of predators. The neural underpinnings of biological motion perception are overlapping with brain regions involved in perception of basic social signals such as facial expression and gaze direction, and preferential attention to biological motion is seen as a precursor to the capacity for attributing intentions to others. Perception of biological motion may be altered in children with autism from a very early age, with cascading consequences for both social development and the lifelong impairments in social interaction that are a hallmark of autism spectrum disorders. Here we show that two-year-olds with autism fail to orient towards point-light displays of biological motion, and their viewing behaviour when watching these point-light displays can be explained instead as a response to non-social, physical contingencies—physical contingencies that are disregarded by control children. This observation has far-reaching implications for understanding the altered neurodevelopmental trajectory of brain specialization in autism. Ready benefits for adaptive interaction with other living beings: following the movements of a conspecific, looking at others to entreat or avoid interaction, learning by imitation, or directing preferential attention to cues that build on biological motion (such as facial expression and gaze direction). Notably, many of the same behaviours have also been shown as deficits in children with autism: deficits in social interaction, diminished eye contact and reduced looking at others, problems with imitation, deficits in recognizing facial expressions, and difficulties following another's gaze. Autism is a lifelong, highly prevalent, and strongly genetic disorder defined by impairments in social and communicative functioning and by pronounced behavioural rigidities. Although the preponderance of evidence points to prenatal factors instantiated in infancy, knowledge of the first two years of life in autism remains largely limited to retrospective data and indirect observations: because autism is rarely diagnosed before 18 months, relatively little is known about autism during the first two years of development. In later life, much more is known about the consequences—cognitive, social and behavioural—of having autism. Altered visual scanning, of both faces and social scenes, as well as altered neural processing of social information, have been documented. In school-age children with autism, perception of biological motion is impaired, but the manner in which very young children with autism relate to biological motion in early life, during periods critical for brain development and before compensatory coping strategies are established, has not, to our knowledge, been previously studied. In the current study, we sought to address whether preferential attention to biological motion is altered in children with autism by two years of age, and what other factors might guide the visual attention of children with autism if they do fail to orient towards biological motion.
Return to — Abnormal Function of Brain |