Comparing Response Times and Error Rates in a Simultaneous Masking Paradigm

Abstract

In simultaneous masking, performance on a foveally presented target is impaired by one or more flanking elements. Previous studies have demonstrated strong effects of the grouping of the target and the flankers on the strength of masking (e.g., Malania, Herzog & Westheimer, 2007). These studies have predominantly examined performance by measuring offset discrimination thresholds as a measure of performance, and it is therefore unclear whether other measures of performance provide similar outcomes. A recent study, which examined the role of grouping on error rates and response times in a speeded vernier offset discrimination task, similar to that used by Malania et al. (2007), suggested a possible dissociation between the two measures, with error rates mimicking threshold performance, but response times showing differential results (Panis & Hermens, 2014). We here report the outcomes of three experiments examining this possible dissociation, and demonstrate an overall similar pattern of results for error rates and response times across a broad range of mask layouts. Moreover, the pattern of results in our experiments strongly correlates with threshold performance reported earlier (Malania et al., 2007). Our results suggest that outcomes in a simultaneous masking paradigm do not critically depend on the outcome measure used, and therefore provide evidence for a common underlying mechanism.