Submission 682
The Impact of Grouping on Foraging for Change.
SymposiumTalk-01
Presented by: Ian Thornton
It is well known that explicitly searching for change is extremely demanding and requires the serial deployment of attention, as demonstrated by studies of “change blindness” (Rensink, O’Reagan & Clark 1997). Here, we examined what happens when participants are asked to “forage” for change. We combined the classic change blindness flicker paradigm with the human foraging task introduced by Kristjánsson, Jóhannesson & Thornton (2014). Displays consisted of 96 items, each having one of two colors (blue or yellow) and one of two orientations (45° tilt left or right), arranged in a 12 x 8 grid. At display onset, there were 24 items of each color/orientation combination, randomly distributed within the grid. The novel aspect was a flicker cycle that consisted of a 300 ms stimulus presentation followed by a 300 ms blank. Twenty randomly selected targets either changed color (10 items) or orientation (10 items) during the blank interval. Participants were given the goal of collecting 200 targets during the whole session, irrespective of the type of change. They could refresh the display at any time, allowing us to explore patch leaving behaviour as well as the typical selection speed and run patterns. In the current talk we explore what happens to foraging behaviour when an additional spatial structure is added. We show that simply adding grid lines, to divide the display into a series of 2 x 2 “bushes”, greatly improved performance on all measures and we discuss the implications of such grouping benefits for foraging more generally.