Dissociation of Stimulus Representation and Response Selection in Conflict Processing of Multiple Frames of Reference.

Humans use multiple frames of reference (FORs) to represent spatial information, for example, one egocentric FOR (anchored on the observer) and various intrinsic FORs (anchored on the objects in the environment). Previous studies have shown that the cognitive resource competition of FORs will lead to FOR-based conflicts (e.g., egocentric-intrinsic, intrinsic-intrinsic) and their interactions. However, it remains unclear whether these conflicts and their interactions occur during the cognitive process stage of stimulus-representation, response-selection, or both. In our study, on the basis of a modified two-cannon task, the spatial congruency and response congruency of two cannons (intrinsic FORs anchored) were manipulated to localize the two process stages of intrinsic-intrinsic conflict. The results revealed that intrinsic-intrinsic conflict was affected by both factors, indicating that response time (RT) in the spatially incongruent condition was longer than that in the spatially congruent condition and that RT in the response incongruent condition was longer than that in the response congruent condition. Furthermore, an interaction between egocentric-intrinsic and intrinsic-intrinsic conflicts was observed, showing that the egocentric-intrinsic conflict did not change between the spatially congruent and incongruent conditions but increased from the response congruent condition to the response incongruent condition. These findings suggest that intrinsic-intrinsic conflict occurs in both the stimulus-representation and response-selection stages, whereas egocentric-intrinsic conflict occurs only in the response-selection stage. The two conflicts share a common conflict processing mechanism in the response-selection stage.