Abstract
Do category level expectations aid object detection? Perceptual expectation effects are typically demonstrated by establishing predictions regarding particular stimuli. Here we investigate whether predictions regarding the basic level (BL) category of an object facilitate its detection. In Experiment 1, participants viewed 90-ms exposures of displays divided into two equal-area regions by a central border. A familiar object in either its upright or inverted orientation was depicted on one side of the border. We take reports of the figure on the familiar side to assay the detection of that object. To generate expectations, we presented masked words either denoting the BL name of the familiar object or an unrelated object from a different superordinate category (natural/artificial). We predicted that expectation effects would be evident if BL primes facilitate object detection. For upright displays, participants were more likely to perceive the figure on the familiar side of the border when preceded by a BL prime versus an unrelated prime (p < .01). Critically, comparison to a no-prime condition revealed that this effect was driven by interference from the unrelated prime. We posit that predictions established by the unrelated primes are unconfirmed and hypotheses originating from the familiar side of the display are sent forward as error signals. This mismatch impedes object detection. In Experiment 2, display duration was longer (120ms), allowing more time to resolve the mismatch. Consistent with this interpretation, unrelated primes no longer reduced reports of the figure on the familiar side of the border (p = .87). Thus, activating the BL category of an object doesn't facilitate object detection, at least as measured by figure assignment, which we take to be an ideal assay of object detection. Instead, we show for the first time that the mismatch, at the superordinate level, of expectations and display-generated hypotheses impedes object detection.
Meeting abstract presented at VSS 2017