Role of reading medium and audio distractors on visual search

Visual search is an active perceptual task influenced by objective factors and subjective factors such as task difficulty, distractors, attention and familiarity respectively. We studied the effect of different search directions, task medium and presence or absence of audio distractors on visual search time in young normal subjects METHODS: Twenty-four young (19-27 years) subjects with normal ocular health (except refractive error) participated in the study after obtaining informed consent. Subjects performed a word search task of ten 7-letter words of medium difficulty level. It was performed by each subject in Up-down, Down-Up, Left-Right, Right-Left, Diagonal and Random directions, with equal number of distractors. The task was performed in paper and digital medium, with or without audio distractors. The conditions were performed in random order by each subject and the time taken to accurately complete the word search was documented for each condition.

The visual search time (VST) was significantly different with different search directions (ANOVA p<0.0001, df=5), considering both digital and non-digital medium, with or without audio distractors. The average VST was the least for left-right search direction (100±7.2 s) and was highest for random search direction (291±19 s), on a digital medium (VST_digital: 183±77 s) and in presence of an audio distractor (VST_audio: 184±77 s). The VST scores were not correlated with the age (r=-0.14, p = 0.25).

The visual search time is significantly delayed for search direction other than left-right direction and in presence of an audio distractor on a digital medium. These factors could play a significant role in visual orientation and specific tasks such as reading.