Focus! Modeling Attentional Decay Over Time Through A Vigilant Attention Paradigm

Abstract

This thesis is an exploration of the time course of attentional decay using a task-related visual paradigm. Limits of attention have been observed at shorter timescales of 1-3 seconds (Gottsdanker, 1984) and longer timescales of up to an hour (Fisk and Schneider,1981). However, how attention varies as a function of task expectations is not well understood. As a part of this thesis, I conducted a study to test how the allocation of task-related attention varies as spatial and short-term temporal aspects of the task are manipulated. Participants (n=27) viewed two adjacent cartoon star stimuli and were directed to press a button when a transparency change occurred at a valid-cued or invalid-cued star. The opacity change occurred at a random time within one of four-time intervals from 1 second to 10 seconds. My analysis sought to investigate the differences in performance, quantified by reaction time, between the valid and invalid cues across the different time blocks. Additionally, I investigated whether a linear or nonlinear model could better fit the data using ML techniques, which may be indicative of nonlinear attentional decay over time. Through linear regression analysis, several effects were observed. I observed an effect of spatial cueing, such that performance was better for the valid stimuli location for all time blocks. This effect remained constant throughout each of the time blocks. Temporal attention effects included a general effect of vigilance, as across valid and invalid trials in each time block, reaction time decreased when the stimulus change occurred later in the trial. This effect of vigilance was most substantial for shorter time intervals. The differing slopes (effect) suggest that the subjects may be allocating attention throughout the paradigm. Supplementary analysis using machine learning techniques tested whether attention decay functioned in a linear or nonlinear manner, finding linear models to best represent attentional decay over time. Future research should explore whether this effect of vigilance on attention allocation is mediated as a conscious decision by the participant, as well as how allocation differs in those suffering from neurodevelopmental disorders, such as ADHD