Trial-to-trial carryover effects on spatial attentional bias.

Visual Probe Tasks (VPTs) have been extensively used to measure spatial attentional biases, but as usually analysed, VPTs do not consider trial-to-trial carryover effects of probe location: Does responding to a probe on, e.g., the location of a threat cue affect the bias on the subsequent trial? The aim of the current study was to confirm whether this kind of carryover exists, using a novel task version, the diagonalized VPT, designed to focus on such trial-to-trial interactions. Two versions of the task were performed by a sample of college students. In one version cues were coloured squares; in the other, cues were threat-related and neutral images. Both versions included partially random positive or negative response feedback and varying Cue-Probe Intervals (200 or 600 ms). Carryover effects were found in both versions. Responding to a probe at the location of a cue of a given colour induced an attentional bias on the subsequent trial in the direction of that colour. Responding to a threat-related cue induced an attentional bias towards threat on the subsequent trial. The results provide evidence that trial-to-trial carryover effects on spatial attentional bias indeed exist. A methodological implication is that previous probe location could be considered in analyses or re-analyses of spatial visual attention tasks.