A Field Trial of Attention and Search Conspicuity

Abstract

Conspicuity might be defined as the property of an object that causes it to attract attention or to be readily located by search. It is often regarded as an attribute of the target object, but the state of attention of the observer is a factor that cannot be ignored. In this paper we define two kinds of conspicuity, attention conspicuity and search conspicuity. Attention conspicuity refers to the capacity of the object to attract attention when it is unexpected. Search conspicuity is the property of the object that enables it to be quickly and reliably located by search. A field trial was conducted to provide measures of these two kinds of conspicuity. Two groups of subjects were required to drive along a defined route on which disc targets were placed; one group was simply asked to report what attracted attention and the other was to search for and report the disc targets. The frequency with which the discs were reported was taken as a measure of conspicuity. The two kinds of conspicuity were found to be related in a systematic way. It was found that conspicuity was not strongly dependent on either object reflectance or size. An important determinant was the angle at which the object was displaced away from the line of sight.