LPP slopes index attention dynamics: Evidence from mindfulness inductions.

Substantial evidence suggests that the late positive potential (LPP) indexes motivated attention to salient stimuli. However, traditional measurement of the LPP via mean amplitude may not fully capture rapid attentional dynamics. A nascent line of work has sought to remediate this limitation by measuring the LPP slope (i.e., rate of amplitude change); yet its functional significance and sensitivity to direct experimental manipulation lacks validation. To address this gap, we re-analyzed data from a fully within-subject crossover experiment (N = 29), where attention was manipulated using focused attention (FA) and open monitoring (OM) mindfulness inductions, contrasted against an active control condition, during an affective picture viewing task involving negative and neutral images. As hypothesized, the FA induction produced flatter, more positive slopes across both negative and neutral images, suggesting enhanced attentional stability. Intriguingly, the OM induction selectively produced flatter slopes on negative but not neutral image trials, aligning with prior postulations that OM may reduce reactive disengagement from aversive stimuli. Collectively, these findings demonstrate that LPP slopes are sensitive to direct manipulations of attentional control, providing much needed experimental evidence for their utility as a neural marker of attention dynamics.