A mixture distribution for visual foraging

Abstract

Visual foraging is investigated by examining the nature of statistical distributions underlying human search strategies. Eye movements uninfluenced by scene perception or higher level cognition tasks are used to generate a data set which can be analyzed to study 'pure' searches. Eye movements in the form of 'jump' length constituting the entire search process are studied to detect the presence of statistical distributions whose parameters can be estimated. Animal ecology studies have reported the presence of a Lèvy flight/power law model, which explains animal foraging patterns in few species. We consider a Lèvy flight model to explain visual foraging. Results from data analysis, while not ruling out the presence of a power law entirely, point strongly towards the presence of a mixture distribution which faithfully explains visual foraging. This mixture distribution is made up of gamma distributions.