D E) but with high accuracy on the second (which presented B, D, and F). Such a pattern indicates overselective responding to sample element B.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptEye Tracking Research and Understanding Stimulus OverselectivityAlthough the results of studies using matching-to-sample procedures may indicate that individuals with intellectual disabilities demonstrate stimulus overselectivity, these procedures do not illuminate the processes underlying overselectivity. Eye tracking research has provided new insights into this issue by direct measurements of observing behavior while individuals perform matching-to-sample tasks. This section describes two studies from the eye tracking laboratory at the University of Massachusetts Medical School’s Shriver Center for research in intellectual and developmental disabilities. These studies used matching-to-sample procedures to study visual stimulus overselectivity as it may occur with arrays of discrete forms. Although the tasks described in this section do not generally resemble the communication tasks faced by individuals who use AAC, the key take-away point to be made is that these studies can help in understanding the phenomenon of overselective attention itself. As we describe in the following section, such an understanding can in turn be used to help build interventions that do not require eye tracking research technology, but that can reduce the interference of overselectivity on behaviors that include learning and selecting symbols on an AAC display. Behavior and Eye Tracking Research: Measuring Overselectivity The first study, Dube et al. (2010), illustrates two primary points: First, overselectivity in individuals with intellectual disabilities need not indicate a deficit in the capacity for attention. Second, there is a useful distinction to be drawn between observing behavior (Dinsmoor, 1985) and the covert/internal process of attending. Although the terms are somewhat broader, the distinction between observing behavior and attending is largely parallel to the somewhat more specific distinction made within eye tracking research between “fixation” and “visual attention.” That is, as Wilkinson and Mitchell in this issueAugment Altern Commun. Author manuscript; available in PMC 2015 June 01.Dube and WilkinsonPage(2014) review, the presence of a fixation to a stimulus as recorded through eye tracking research apparatus is necessary but not sufficient to ensure that the stimulus has been attended to and order 5-BrdU forwarded for further cognitive processing. Thus, in some PNPP chemical information instances a stimulus receives a fixation, but the individual demonstrates no behavioral indication of having attended to it (e.g. they later report not having seen it, or fail to identify it). In behavioral psychology, the term “observing behavior” for visual stimuli includes not only the fixation itself, but also behavior such as changes in head and eye orientation that may accompany the fixation. The occurrence of observing behavior as reflected through fixations can be measured directly by an eye tracking research apparatus. In contrast to observing behavior, “attending” is measured indirectly, by some explicit behavioral response that verifies discrimination (processing) of the relevant stimuli. That is, there is a distinction between mere gaze fixation, and attention at the level of cognitive engagement. For example, if an eye-tracking research participant were asked to ident.D E) but with high accuracy on the second (which presented B, D, and F). Such a pattern indicates overselective responding to sample element B.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptEye Tracking Research and Understanding Stimulus OverselectivityAlthough the results of studies using matching-to-sample procedures may indicate that individuals with intellectual disabilities demonstrate stimulus overselectivity, these procedures do not illuminate the processes underlying overselectivity. Eye tracking research has provided new insights into this issue by direct measurements of observing behavior while individuals perform matching-to-sample tasks. This section describes two studies from the eye tracking laboratory at the University of Massachusetts Medical School’s Shriver Center for research in intellectual and developmental disabilities. These studies used matching-to-sample procedures to study visual stimulus overselectivity as it may occur with arrays of discrete forms. Although the tasks described in this section do not generally resemble the communication tasks faced by individuals who use AAC, the key take-away point to be made is that these studies can help in understanding the phenomenon of overselective attention itself. As we describe in the following section, such an understanding can in turn be used to help build interventions that do not require eye tracking research technology, but that can reduce the interference of overselectivity on behaviors that include learning and selecting symbols on an AAC display. Behavior and Eye Tracking Research: Measuring Overselectivity The first study, Dube et al. (2010), illustrates two primary points: First, overselectivity in individuals with intellectual disabilities need not indicate a deficit in the capacity for attention. Second, there is a useful distinction to be drawn between observing behavior (Dinsmoor, 1985) and the covert/internal process of attending. Although the terms are somewhat broader, the distinction between observing behavior and attending is largely parallel to the somewhat more specific distinction made within eye tracking research between “fixation” and “visual attention.” That is, as Wilkinson and Mitchell in this issueAugment Altern Commun. Author manuscript; available in PMC 2015 June 01.Dube and WilkinsonPage(2014) review, the presence of a fixation to a stimulus as recorded through eye tracking research apparatus is necessary but not sufficient to ensure that the stimulus has been attended to and forwarded for further cognitive processing. Thus, in some instances a stimulus receives a fixation, but the individual demonstrates no behavioral indication of having attended to it (e.g. they later report not having seen it, or fail to identify it). In behavioral psychology, the term “observing behavior” for visual stimuli includes not only the fixation itself, but also behavior such as changes in head and eye orientation that may accompany the fixation. The occurrence of observing behavior as reflected through fixations can be measured directly by an eye tracking research apparatus. In contrast to observing behavior, “attending” is measured indirectly, by some explicit behavioral response that verifies discrimination (processing) of the relevant stimuli. That is, there is a distinction between mere gaze fixation, and attention at the level of cognitive engagement. For example, if an eye-tracking research participant were asked to ident.
