Abstract
Spatial cuing usually improves response time in a detection task when the target location is cued a fraction of a second before stimulus onset. However, as cue and stimulus onset asynchrony increases, there is a range of SOAs where cuing worsens response time, a phenomenon called inhibition of return (IOR; Posner & Cohen, 1980, 1984). There is disagreement over whether IOR occurs for identification tasks as it does for simple response time tasks (e.g., Terry, Valdes, & Neill, 1994; Cheal, Chastain, & Lyon, 1998). Few researchers have studied IOR with an identification accuracy measure (e.g., Cheal & Chastain, 1999). Traditional spatial cuing effects on accuracy, with short cue-target SOAs, are more often found when targets are obscured by external noise, reflecting improved external noise filtering in attended conditions (e.g., Dosher & Lu, 2000). We hypothesized that IOR in identification tasks may be stronger in the presence of high external noise. We performed an identification task manipulating cue-target SOA (100-1200 ms) and contrast in the presence or absence of external noise, and measured both accuracy and response time. Observers each performed 9218 trials, and were analyzed individually. Attention filtering factors were estimated for each SOA. As in traditional cuing, larger cuing effects occurred in the high external noise condition. Two observers also showed evidence of IOR, with cuing effects on accuracy in low SOAs dissipating or reversing at higher SOAs; a third observer showed no consistent cuing effects on accuracy. We found little or no traditional cuing or IOR in low external noise, where IOR is usually tested. The cuing effect in response time was more variable, but generally consistent with accuracy results. Our results suggest that IOR in identification tasks is more likely to occur in the presence of high external noise, where attention may have stronger effects on accuracy.
Meeting abstract presented at VSS 2012