Investigating the independent effects of endogenous and exogenous attention on the capacity of audiovisual integration

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In our lives, we are constantly affected by information being processed by our sensory systems. While these inputs are initially processed separately (e.g. by our eyes and by our ears), they also interact at various stages in our brain, which makes the implicit decision about whether those sensory inputs came from the same source or not. To do this, our brain uses numerous cues, such as whether the information came from the same location in space, whether we sensed it at the same time, and whether the information seems to match between what we saw and what we heard. While this process occurs constantly and automatically through most of our daily existence, it can also be affected by information that occurs shortly before the stimuli in question. This process, known as attentional cueing, has been studied extensively in the visual and auditory modalities, but has not previously been studied in the context of audiovisual integration capacity. This proposal describes a program of research that will be conducted in the MMP Lab at the University of New Brunswick Saint John to examine these phenomena. The initial objective of the program will involve an investigation into exogenous cues (those which draw an individual's attention in the moment) and endogenous cues (those which direct an individual to shift their attention) in auditory, visual, and audiovisual conditions. The experiments under this first objective will look at how these different cueing conditions affect an individual's ability to integrate more than one visual stimulus with a sound. Two graduate students will be recruited in order to complete this investigation, which will provide them with an opportunity for training on psychophysical testing methodologies, and the opportunity to write and present at conferences. Once this first objective has been achieved, a third graduate student will be involved in a second project, working on creation of an attentional cueing test that involves auditory, visual, and audiovisual cues and targets. This builds on earlier versions of the task, and extends what is known about information presented in differing modalities. In addition to extending our understanding of modalities and attentional cueing, this research program will further knowledge about the phenomenology behind attention deficit disorders. Previous research has not always been in agreement in this regard, with some studies showing that attentional abilities are specifically and selectively reduced in individuals with attention disorders, while other studies suggest that the differences between affected individuals and non-affected individuals is actually at the sensory processing level. By reducing processing difficulty (through increasing the number of sensory cues available), we will be able to ascertain whether individuals' attention deficits are truly attentional, or whether they are sensory issues.