title: Investigating task-dependent top-down effects on overt visual attention.
abstract: Different tasks can induce different viewing behavior, yet it is still an open question how or whether at all high-level task information interacts with the bottom-up processing of stimulus-related information. Two possible causal routes are considered in this paper. Firstly, the weak top-down hypothesis, according to which top-down effects are mediated by changes of feature weights in the bottom-up system. Secondly, the strong top-down hypothesis, which proposes that top-down information acts independently of the bottom-up process. To clarify the influences of these different routes, viewing behavior was recorded on web pages for three different tasks: free viewing, content awareness, and information search. The data reveal significant task-dependent differences in viewing behavior that are accompanied by minor changes in feature-fixation correlations. Extensive computational modeling shows that these small but significant changes are insufficient to explain the observed differences in viewing behavior. Collectively, the results show that task-dependent differences in the current setting are not mediated by a reweighting of features in the bottom-up hierarchy, ruling out the weak top-down hypothesis. Consequently, the strong top-down hypothesis is the most viable explanation for the observed data.
authors.affiliation: Institute of Cognitive Science, University of Osnabrück, Osnabrück, Germany. tbetz@uos.de
authors.forename: Torsten
authors.initials: T
authors.lastname: Betz
authors.forename: Tim C
authors.initials: TC
authors.lastname: Kietzmann
authors.forename: Niklas
authors.initials: N
authors.lastname: Wilming
authors.forename: Peter
authors.initials: P
authors.lastname: König
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D005133:Eye Movements / Q000502:physiology; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D006040:Goals; D006801:Humans; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011932:Reading; D055815:Young Adult