Stimuli

The stimuli were 16 videos (duration 10 s each; see Fig. 1) of a female model seated behind a table, with four objects in front of her. We increased the number of target objects from our previous study of younger low functioning children with ASD (Falck-Ytter et al. 2015) in order to better match the current sample, that was older and had higher IQ. For the first 1.5 s. of the video, the model’s face was covered by an animated attention grabber. A female voice said “hello!” and the attention grabber then disappeared, revealing the model looking straight ahead, smiling slightly. The model then started turning her head toward one of the four objects. The duration of each head turn was 0.5 s. The model kept looking at the object for another 5 s, before turning her head back (0.5 s.) and looking straight ahead for the remaining 2.5 s. The high interest condition included two sets of objects, one with model trains and one with toy vehicles. Both trains and vehicles are documented common interest areas in ASD, and have previously been used in studies measuring attention to objects related to circumscribed interests (Sasson et al. 2008, 2011; Sasson and Touchstone 2013). The baseline condition also included two sets of objects, one with flowering house plants and one with house plants with green leaves. The plants were roughly the same size as the trains/vehicles, and we aimed for the different object types to be somewhat equivalent in terms of perceptual detail. Plants were chosen to represent ordinary objects, regularly seen by most children and uncommon as circumscribed interests. Eight videos included trains/vehicles and eight videos included plants. Each of the four objects comprising a stimulus set was attended to once by the model.

Screen shots of the stimulus video, showing the attention grabber covering the model’s face, the model engaging in direct gaze, the model attending to one of the objects and then engaging in direct gaze again. Areas of interest (AOIs) are highlighted. Upper row depicts one of two stimuli sets in the high interest condition; lower row depicts one of two stimuli sets in the baseline condition