Abstract:

Introduction
Inhibition of return (IOR) has been a major research focus in the field of attention since Posner and Cohen (1984) discovered this phenomenon. There are two main views on the generation of IOR. The first view is postulated by Posner and Cohen (1984), which claims that IOR is the withdrawal of attention from a location that leaves an inhibitory tag. The second view is that IOR has a close relation with oculomotor system (Rafal, et al, 1989), and that superior colliculus plays a very important role (Sapir & Soroker, 1999). Both views have obtained much support. However, all the previous research used the cue-target paradigm in the two dimension space, in which a cue was displayed first to indicate a peripheral location before the target appeared. In this paradigm, the cue would lead to attention shift as well as a saccade (or a saccade plan), so the previous research on IOR generation could not separate the attention factor from oculomotor factor effectively. To eliminate saccade’s contribution to IOR, we explored the generation of IOR by using random dot stereogram with slant information as material.
Method
Sixteen individuals participated in the study. Two experiments were conducted using a three dimension spatial cue-target paradigm. First, a random dot stereogram was displayed in the center of the screen as a cue, and the participants were asked to pay attention to the slant orientation of the plane. Then a target displayed in the center of screen with the same or different slant orientation as the cue, and the participants were required to respond to the target’s slant orientation. Thus, in this paradigm the participants did not need to make saccades or saccade plans to complete the task. We varied the consistency of orientation and angle between focused plane and tested plane in experiment 1 and 2. We also varied the consistency of orientation and angle between unattended plane and tested plane in experiment 2. . ANOVAs were performed in both experiments.
Results
The data analyses showed that the response to the plane having the same orientation with the cuing focused plane was much lower than that with different orientation. The response to the plane having the same orientation with cuing unattended plane was much slower than that with no cuing plane at all.
Conclusions
The results suggested that there was attention-related inhibition of return in three dimension space which was formed by disparity. Both the focused plane and the unattended plane led to IOR, but the former condition had a greater inhibition effect. The results support that inhibition of return is related to attention.

Key words: inhibition of return, slant plane, attention, saccade