Location-Based IOR: A different Time Course for Detection and Discrimination task.

Juan Lupiáñez, Francisco Tornay y Pío Tudela.

Abstract: It has recently been argued that IOR is limited to detection and localization tasks (Neill et al., 1994). In this work we used a cue- target paradigm and compared detection vs discrimination tasks. Location-based IOR is shown with both detection and discrimination tasks, but at different SOAs.
Two boxes are displayed on the screen, one of them being flashed for 50 ms. After the flash, at different SOAs, a target is displayed for 33 ms either on the cued or the uncued box. Subjects were to respond to the target either detecting or discriminating it. Tasks and different SOAs were manipulated across experiments.
In the first experiment 100 and 600 ms cue- target SOA were used and subjects were to detect the target. Facilitation effect at the shorter and IOR at the longer SOA were obtained. The same SOAs were used in the second experiment but now subjects were required to discriminate the target. A facilitation effect was obtained at both short and long SOAs. Three SOAs (100, 600 and 1000 ms) were used in the third experiment, with discrimination task. In this case, results showed facilitation at short SOA, no effect at medium SOA and IOR at long SOA.
These results suggest that IOR is a robust effect, which shows a general principle of information processing. However, the time course of the effect is different depending on the experimental task. That could imply that inhibition take place at different representations (location-, environment-, object- based...) each one presenting different time courses.

IX Congress of the European Society for Cognitive Psychology (ESCOP).
Wurzburg, 1996.