Studies of infant siblings of children with an Autism Spectrum Disorder (Autism Siblings) are concerned with early deficits relevant to autistic symptomatology. These deficits are typically subtle, suggesting the need for sensitive tools with strong face validity. Here we report on such a tool. The Continuous Measurement System allows non-experts to rate video records of behavior in time. The System can also be used for expert coding and is available for free download at http://measurement.psy.miami.edu/.
Examine the utility of continuous non-expert measurements in detecting differences in autism-related behavior.
In the current study, 181 students with no specialized training continuously rated negative-to-positive emotional valence using a joystick interface. They rated 20 Autism Siblings and 18 comparison siblings (six-month-olds) participating in the face-to-face/still-face protocol with their parents. Between 16 – 20 individuals rated each infant and each parent.
There was high concordance between mean ratings of affective valence and expert coding of infant and parent negative and positive facial expressions. During the still-face episode of the FFSF when parents are instructed to be non-responsive, Autism Siblings were rated significantly less positively that were comparison siblings, t(25.94) = 2.62, p = .01, Cohen’s d = .86 (Baker et al., in press). During the still-face, Autism Siblings also exhibited reduced group variance in positive affect but greater variance in negative affect than comparison infant siblings.
Time-series analyses were used to explore infant-parent influence and self-regulation (auto-regression) during interaction (Chow et al., in press). There were no group differences in interactive influence. Instead, individual Autism Siblings exhibited higher levels of self-regulation than comparison infants. The effect was only evident the still-face and reunion episodes, i.e., during and after the perturbation introduced by asking the parent to be non-responsive (ps < .05). In other words, Autism Siblings were, on average, less emotionally perturbed by the FFSF procedure than other infants.
Multiple, independent assessments by untrained raters can be used to efficiently measure key constructs relevant to autism risk. Findings replicated the well-established still-face effect and identified subtle risk associations consonant with results from previous investigations. Subtle differences including reduced mean levels of positive affective valence, and reduced variability of affective valence over time were evident among infants at risk for autism. These findings suggest that infant siblings of children with ASDs show relatively depressed but relatively invariant affect when they are not being engaged by their parents. The measurements have high face validity because they capitalize on the ability of human beings to respond to subtleties of behavior in a continuous fashion. The unique information offered by intuitive non-expert ratings is a potential alternative to complex and costly behavioral coding systems in studies of Autism siblings and, potentially, in studies of children and adults with ASDs.