Effect of mood states on the breadth of spatial attentional focus: an event-related potential study.

In order to determine the processing stage that is responsible for the effect of mood states on the breadth of attentional focus, we recorded event-related potentials from 18 students who performed a flanker task involving adjacent letters. To induce a specific mood state, positive, neutral, or negative affective pictures were presented repeatedly during the task. The participants' task was to respond to the central target letter by pressing a corresponding button. Spacing between each letter was manipulated so that it appeared either near or far. In 80% of the task trials, a probe stimulus was presented at one of four locations superimposed on the letter array: 0.5° left or right from the central letter or 1.5° left or right from the central letter. Reaction time data showed that the effect of spacing on the flanker compatibility effect was absent under positive mood state. The probe-evoked P1 amplitude was larger in the positive mood state than in the neutral and negative mood states. These results indicate that positive mood states may broaden the focus of attention during visual input stage.