The impact of target frequency on vigilance decrement magnitude in dynamic visual environments

Vigilance decrements, where performance on monotonous tasks with rare targets worsens over time, have been well documented in the literature (Langner & Eickhoff, 2013). Recently, Karimi-Rouzbahani et al. (2021) replicated these findings with a dynamic multiple-object-monitoring (MOM) task that better captures elements of real-world environments and allows distinction of vigilance effects from the general effects of sustained attention. However, this study only compared very rare target frequencies (6%) to active responding (targets frequency of 50%). To more clearly understand how target frequency influences vigilance performance, examination of the intermediate target frequencies is necessary. Thus, the current study will use the MOM task (see Karimi-Rouzbahani et al., 2021 for more detail) and manipulate target frequency to: 1. Examine the effect of target frequency (TF) on the magnitude of the vigilance decrement. 2. Assess whether the findings of the original study (Karimi-Rouzbahani et al., 2021) can be replicated with a shorter task duration of 20 minutes. For this study, performance will be measured using the magnitude of the vigilance decrement. This decrement will be inferred from a) miss rate for targets; and b) reaction time (RT), defined as average RT on hits. A greater vigilance decrement will be demonstrated by an increase in miss rate and/or increase in RT over time on task (specifically, a comparison of the average performance in the first 3 blocks relative to the final 3 blocks).