Mixture Distribution Analysis Reveals Interactions between Visual Perception and Object-based Attention
Mentor 1
Adam Greenberg
Location
Union Wisconsin Room
Start Date
5-4-2019 1:30 PM
End Date
5-4-2019 3:30 PM
Description
Object-based attention (OBA) allows for a preferential processing of information contained within object boundaries. Our previous research has shown that shifting attention within objects (while searching for a target) is impacted by the vertical and horizontal meridians of the visual field: horizontal shifts across the vertical meridian are more efficient than vertical shifts across the horizontal meridian (a shift direction anisotropy; SDA). Recently, we further tested these meridian effects by parametrically manipulating the visibility (i.e., contrast) of a line drawn on the horizontal meridian through four levels: 100% visible, 66%, 33%, and 0% (invisible). Results showed that the SDA (a) is statistically extinguished at 100% visibility, and (b) shows a stepwise numerical decrease (albeit, not statistically significant) from 0% to 33% to 66% visibility. We wondered whether this linear reduction in SDA could be explained by an increasingly larger number of participants perceiving the horizontal meridian as visibility increased. Using a mixture distribution analysis, we tested response times during the 33% and 66% visibility conditions to determine whether there is evidence for either a single, or dual, basis distributions. Evidence of dual distributions would support the hypothesis that two underlying groups of subjects experienced different percepts of the horizontal meridian; whereas evidence of a single distribution would argue against this account. These results will shed light on important sources of variability between subjects while engaged in object-based selective attention. Furthermore, this analysis will provide evidence for the influence of visual perception in guiding attention to objects.
Mixture Distribution Analysis Reveals Interactions between Visual Perception and Object-based Attention
Union Wisconsin Room
Object-based attention (OBA) allows for a preferential processing of information contained within object boundaries. Our previous research has shown that shifting attention within objects (while searching for a target) is impacted by the vertical and horizontal meridians of the visual field: horizontal shifts across the vertical meridian are more efficient than vertical shifts across the horizontal meridian (a shift direction anisotropy; SDA). Recently, we further tested these meridian effects by parametrically manipulating the visibility (i.e., contrast) of a line drawn on the horizontal meridian through four levels: 100% visible, 66%, 33%, and 0% (invisible). Results showed that the SDA (a) is statistically extinguished at 100% visibility, and (b) shows a stepwise numerical decrease (albeit, not statistically significant) from 0% to 33% to 66% visibility. We wondered whether this linear reduction in SDA could be explained by an increasingly larger number of participants perceiving the horizontal meridian as visibility increased. Using a mixture distribution analysis, we tested response times during the 33% and 66% visibility conditions to determine whether there is evidence for either a single, or dual, basis distributions. Evidence of dual distributions would support the hypothesis that two underlying groups of subjects experienced different percepts of the horizontal meridian; whereas evidence of a single distribution would argue against this account. These results will shed light on important sources of variability between subjects while engaged in object-based selective attention. Furthermore, this analysis will provide evidence for the influence of visual perception in guiding attention to objects.
