Question

describe how the visual search lab is completed and the data collected

Answer 1

In a visual search lab, the participants are typically asked to identify and respond to a selective stimulus in a visual field of similar stimuli within a limited time slot. The visual search lab thus designs problems to assess the nature of visual perception and the reaction time taken to respond to varied visual stimuli. These stimuli may pertain to feature, conjunction and/or spatial configuration.

In a typical search task, the participants may be asked to  look for say a black vertical rectangle among grey vertical rectangles. In the conjunction search task, subjects would look for a black vertical rectangle among grey vertical and black horizontal rectangles. For the spatial configuration search task, subjects would look for a digital '2' among digital '5's. These stimuli share the same features, but differ in their organization; the horizontal components of the 2s and the 5s remain the same, but the positions of the vertical features differ, resulting in a change in the locations of the lines.

The participants’ task would then be to press one key if the target is present and another key if the target is absent. Subjects are instructed to respond as quickly as possible while minimizing errors. The trials are labeled as HIT (target present correct trials), TNEG (True negative -trial absent correct trials), MISS (target present incorrect trials) and FA (False alarm - target absent incorrect trials).

Thus, the visual search lab allows for obtaining a large set of search responses on several hundreds of trials because of the relative speed and ease in the process of obtaining the response of the participants.