Walk, stop, search : the effect of simulated motion on visual attention

Abstract

Responses in covert orienting of visual attention tasks (COVAT) produce a biphasic pattern of results. When the stimulus onset asynchrony (SOA) is less than 300 ms, reaction times (RTs) to cued targets are faster than uncued targets, whereas when the SOA is greater than 300 ms RTs to uncued targets are faster than cued targets. This latter phenomenon is termed inhibition of return (lOR). lOR is believed to be a mechanism that promotes efficient search by biasing attention to new locations or objects. To date, most research on lOR has been restricted to situations in which participants are seated while viewing stimuli presented on a monitor; however, many real life searches take place while the searcher is in motion. One way to look at the effect of motion on the orienting of attention is to stimulate the otoliths of the vestibular system by having people lie prone with their neck in a flexed position (known as head down neck flexion or HDNF). We had participants complete a COVAT (with SO As of 100 and 800 ms) while in three different positions: seated, lying prone, and in HDNF. When in HDNF there was a significant decrease in the magnitude of responses compared to the other two positions; both less facilitation and less inhibition were observed. The results are discussed in terms of the relationship between vestibular activation (i.e., HDNF) and the orienting of visual attention.