What happens during the stimulus onset asynchrony in the dot-probe task? Exploring the role of eye movements in the assessment of attentional biases.

The dot-probe paradigm is one of the most often used paradigms to investigate attentional biases towards emotional information. However, a large number of the dot-probe studies so far used a long stimulus onset asynchrony allowing for eye movements to occur, which might increase the error variance. This study aimed at addressing this methodological issue by varying the instructions with regard to the gaze behavior and calculating the reaction time (RT) bias score (i.e., RTs for targets presented at the location of the emotional compared to the neutral stimulus) separately for trials with eye movements and trials without eye movements. Results of Experiment 1 (using typical instructions, i.e., instructions that are lenient with regard to eye movements) showed an RT bias, but only in the trials without eye movements The overall RT bias (calculated "blind" for eye movements) was non-significant. In Experiment 2, stricter instructions and small changes in the procedure led to a sharp decrease in the number of eye movements, such that both the RT bias in the trials without eye movements as well as the RT bias across all trials was significant.

Cultural influences on oculomotor inhibition of remote distractors: evidence from saccade trajectories.

This study investigated whether low-level attentional processes as indicated by saccade trajectories are modulated by higher-order factors as indicated by participants' cultural background. We hypothesized that if the East Asian participants engage in context-dependent attentional processing to a greater extent than the Western participants, then the magnitude of the distractor effect on saccade trajectories (Doyle & Walker, 2001) should be larger with the East Asian participants than with the Western participants. Participants executed vertical saccades towards targets presented on the vertical meridian above or below fixation. Simultaneously with the target, a distractor appeared in one of the screen quadrants. Consistently with our hypothesis, we found evidence that the saccades of the Chinese participants tended to curve away from the distractors more strongly than the saccades of the German participants. However, this effect was restricted to the upper distractors and the lower targets. The findings are discussed in terms of cross-cultural differences in distractor-related activation and inhibition and functional specialization of hemifields.

Upper-lower visual field asymmetries in oculomotor inhibition of emotional distractors.

The present study investigated oculomotor inhibition of emotional faces as indicated by saccade curvatures. In Experiment 1, participants saccaded towards a target that appeared above or below fixation while single facial distractors depicting neutral, happy, and angry expressions appeared in one of the four quadrants of the screen. In Experiment 2, participants selected between two objects on the screen by saccading towards a predefined target, while again single facial emotional distractors were presented in one of the four screen quadrants. In both experiments, saccade trajectories curved most strongly away from angry distractors indicating enhanced attentional capture by angry faces. This effect occurred with upright faces but not with inverted faces. The emotion effect was restricted to targets at the lower vertical meridian. The lower visual field has been argued to be specialized for action in peripersonal space and near vision. The modulation by target location might be attributed to activation of near space representation by saccades toward a lower target, inducing increased vigilance for stimuli of action relevance to protect the peripersonal space from interference.