Strategies and Pseudoneglect on Luminance Judgments: An Eye-Tracking Investigation

Four experiments were conducted to examine competing hypotheses relevant to the strategies believed to underlie pseudoneglect. The 4 experiments implemented manipulations relevant to eye-movement monitoring to evaluate the potential role of a comparison versus a global strategy in producing a left bias in a task involving a judgment of luminosity. Experiment 1 required task completion under free viewing while eye movements were monitored. The link between the observed behavioral bias and the strategy inferred from the pattern of eye movements was then examined. In Experiment 2, the eye-movement manipulation promoted reliance on a comparison strategy. Experiment 3 forced participants to use a global strategy. Finally, Experiment 4 also forced participants to use a global strategy, but it minimized the influence of memory in the task. Results from all 4 experiments supported the preponderance of the global strategy as driving the left bias. In Experiment 1, the magnitude of the bias decreased as the number of comparison increased. In Experiment 2, the left bias disappeared. Finally, in Experiments 3 and 4, the bias was the largest in the present series of experiments. These findings are discussed in the context of existing explanations of pseudoneglect.