Abstract
Many real-world visual search tasks involve interacting with dynamically changing displays of information. These must not only be searched but also monitored for change, demanding sustained attention and working memory resources. Display complexity may also entail high uncertainty regarding when and where targets will occur. Individual differences in working memory capacity (WMC), intolerance of uncertainty (IU) and target prediction may be important predictors of performance in such tasks. Participants completed a visual search for colour targets within dynamic displays while their eye movements were recorded. Trials contained arrays of 108 squares that changed between 16 colours at varying rates and responses were mouse-clicks on targets. Two experiments examined the limits of target prediction via manipulations of display dynamics, such that stimuli changed in ordered sequences through colour space, disordered sequences or randomly. To examine individual responses to uncertainty, a third experiment manipulated target prevalence and administered verbal/spatial 3-back WMC tasks and an IU questionnaire (IUS-12). As previously reported (Muhl-Richardson et al., 2015), under ordered dynamics, on average 49% of forthcoming targets were fixated pre-onset, but new data show this was significantly reduced when dynamics were randomised (24%) or disordered (7.97%). A significant effect of IU was observed upon false alarm rates (incorrect responses to non-targets) independently of target prevalence. Participants with greater IU made more false alarms and this relationship was moderated by WMC; those with higher WMC showed a reduced effect of IU. We conclude that: (1) predictive target detection is limited and requires the support of broad target templates that only operate when display dynamics incorporate order in colour space, rather than arising from learned probabilistic associations; (2) IU impedes target detection via a response bias towards target-similar stimuli to reduce uncertainty over forthcoming onsets; (3) high WMC moderates this effect through the availability of additional processing resources.
Meeting abstract presented at VSS 2016