Abstract
Spatial updating of self-to-object spatial relations could be performed either online or offline. According to the two-system theory of spatial updating, online updating is associated with transient representations and the presence of set size effects, whereas offline updating is associated with enduring representations and the absence of set size effects. However, this fixed updating-memory hypothesis is challenged in the present study. Meanwhile, a flexible updating-memory hypothesis is proposed, including two assumptions. First, updating strategy (online or offline) is independent of spatial representation (transient or enduring). Second, it is the type of spatial representation rather than updating strategy that determines whether set size effects may occur. Two experiments were conducted to verify these new assumptions. Experiment 1 replicated findings of previous research with a uniform updating task, indicating the difference in set size effects in the original studies was not simply due to the difference in their original tasks. Experiment 2 dissociated updating strategy from spatial representations. The updating strategy was manipulated via instructions, while the spatial representation was manipulated by whether varying the spatial layout in each set size trial by trial. The results of Experiment 2 suggested that updating strategy could be successfully manipulated and was flexibly associated with different spatial representations. In addition, the presence of set size effects depended on the spatial representation rather than updating strategy. These present findings undermined the two-system theory of spatial updating and supported the flexible updating-memory hypothesis.