Components Or Flavors?

Inhibition of return(IOR) is discovered in the study of attentional orienting. The attention movement has not only an effect of early facilitation, but also an effect of later inhibition. When the interval between a spatially uninformative cue and a visual target calling for a simple detection response is short(<300ms), responses are faster for targets appearing at cued, relative to uncued locations. When the interval exceeds 300 ms, responses are slower when a target occurs at cued, relative to uncued locations. The latter effect is called inhibition of return by Posner in 1985. It is the core in the study of attention and its mechanism is a basic but important issue. Abram(1994) and Taylor(2000) interpreted this mechanism respectively and later named the theory of components and the theory of flavors. The two components theory holds that saccades to peripheral targets activate motor and attentional systems. According to the conditions of oculomotor system, the two flavors theory holds that motor system works when saccade is made to cue or target and attentional system works when key press is made. The two systems are working independently.Hilchey(2014) states that when the target occurs at the same location as the cue(<500ms), sensory adaptation and oculomotor facilitation are occurring in parallel, with the former effect larger than the latter so that the net effect is inhibitory. His opinion puts forward new sights to our study.The study explored the mechanism of IOR through three experiments, all of which were using spatial cueing paradigm. By making saccadic response, the first experiment compared peripheral targets and central targets at different SOAs and discovered that peripheral targets had larger IOR than central targets no matter the SOA was short or long. Thus we concluded that motor system(output decision)and attention system(input decision)contributed to the result. The central targets had an effect of facilitation at short SOAs and IOR effect at long SOAs, suggesting an output effect. But there was FOE in experiment, which referred to the disappearance of fixation when targets onset. This may increase the IOR effect. The second experiment explored the effect of FOE and target contrast to IOR. The target contrast was relative to the screen background, which had influence on attention system but not on motor system. It can be an indicator to test whether there was attention components in saccadic response. The result of Experiment 2 suggested that FOE can not make the IOR effect larger in Experiment 1. Meanwhile, low-contrast stimuli lead to larger IOR than high-contrast stimuli, which confirmed Experiment 1 that attention factor contributed to the robust IOR in peripheral targets. The results of Experiment 1 and Experiment 2 supported the two components theory. Experiment 3 explored whether there was saccadic preparation when manual response was made to peripheral targets. Generally speaking, FOE had an effect on saccade system and had no effect on attention system, so it can be used to test saccadic preparation. We did not find interactions between FOE and IOR effect. The result of Experiment 3 suggested there was only attention components in manual responses.