The STEARC effect revisited: does time shape spatial attention and memory?

Numbers and time are closely linked to space. Two key effects illustrate this: the SNARC effect, associating smaller numbers with the left visual field and larger ones with the right, and the STEARC effect, linking the past to the left and the future to the right visual fields. This study examined whether time influences visual-spatial attention and memory by affecting attention shifts toward relevant visual fields and facilitating memory retrieval. To investigate this, we employed four experimental tasks: the SNARC task, the STEARC task, the visual-spatial attention task, and the visual-spatial memory task. In the SNARC task, participants pressed a key to determine whether the presented numbers were smaller or larger than 5. In the STEARC task, they assessed whether temporal words referred to the past or future. The SNARC and STEARC tasks confirmed number-space and time-space interactions, a necessary step before further investigation. During the visual-spatial attention task, participants responded to images presented in the left or right visual field following temporal reference words. We employed a single-key procedure for responses to eliminate any facilitation effects from response keys. In the visual-spatial memory task, participants indicated whether they had seen the images displayed previously. Our findings confirm the presence of the SNARC and STEARC effects. However, no detectable effect of temporal reference on visual-spatial attention was observed under the current task conditions. Similarly, no reliable effect was found in the visual-spatial memory task. Taken together, these findings suggest that temporal-spatial mappings may not be robustly observed in visual attention tasks that do not involve explicit left-right responses.