Abstract

Simon effects have been observed to arise from different modes of spatial information (e.g., physical loca- tion, arrow direction, and location word). The present study investigated whether different modes of spatial information elicit a unitary set of spatial codes when triggering a spatially corresponding response code. A pair of two different Simon tasks was presented in alternation: location- and arrow-based Simon tasks in Experiments 1 and 2, word- and location-based Simon tasks in Experiment 3, and arrow- and word- based Simon tasks in Experiment 4. Responses were collected using unimanual aimed-movement responses. Cross-task congruency sequence effects (CSEs) were found in Experiments 1 and 2, indicating a shared set of spatial codes between physical locations and arrow directions. Conversely, the absence of CSEs in Experiment 3 suggested that physical locations and location words elicited different sets of spatial codes. In Experiment 4, a CSE was evident in the arrow-based Simon task but not in the word-based one, implying an overlap in the spatial attributes of arrow directions with those of location words. Distributional analyses of the Simon effects revealed that different modes of spatial information yielded distinct temporal patterns of its activation and dissipation, implying quantitative differences in the Simon effects. The cross-comparisons of the CSE and delta function data indicated that the quantitative similarities in spatial modes did not corre- spond to the qualitative similarities, suggesting a crucial finding that each set of data reflects different aspects of the nature of the spatial codes.