The Influence of Spatial Attention and Decision Confidence on Location-Related Response Bias in Visual Comparison

The spatial congruency bias (SCB) is a phenomenon in visual attention in which objects are more likely to be judged as identical when they are presented in the same location. While this bias is robust and has been demonstrated on many types of displays, its underlying mechanisms are poorly understood. To investigate the SCB’s relationship with spatial attention and decision confidence, 30 undergraduate psychology students completed an object identity task on three-letter string stimuli that were successively presented in the same or different locations. Spatial attention was manipulated using valid, invalid, and neutral peripheral cues. Participants completed each trial by rating decision confidence. While we observed a robust SCB, we failed to detect a significant effect of spatial attention. Furthermore, we failed to detect a significant association between decision confidence and the SCB. This suggests that the mechanism underlying the SCB may not function as a heuristic operating in conditions of low decision confidence. Several methodological issues are discussed and suggestions for future research are proposed.