“…Healthy younger adults can maintain, on average, four visual representations accessible in VWM. This estimate, however, is subject to variation between individuals (Cowan, 2010;Luck & Vogel, 2013) and also within-individuals, reflecting trial-by-trial fluctuations due to changes in sustained attention (Adam et al, 2015;Adam & Vogel, 2017;deBettencourt et al, 2019deBettencourt et al, , 2020Fukuda et al, 2015;Mrazek et al, 2012;Rademaker et al, 2012). The contribution of attentional fluctuations to VWM performance has been examined, for example, by asking participants to rate their attentional levels towards the task (Adam & Vogel, 2017;Unsworth & Robison, 2016) or by interspersing memory probes in a sustained attention task at moments associated with high and low levels of sustained attention (deBettencourt et al, 2018(deBettencourt et al, , 2019.…”