Abstract
Recent evidence by Brady & Störmer (2020) suggests participants have better visual working memory (VWM) performance for real-world objects compared to simple features when using maximally dissimilar foils. The mechanisms underlying this benefit, however, remain unknown. One possible explanation for why memory performance is greater for real-world objects may be that objects are more memorable than simple features. Consequently, working memory for real-world objects may show a greater reliance on recollection processes. To test this question, we investigated whether increased working memory performance for real-world objects compared to simple features (e.g., colours) is due to a reliance on familiarity or recollection processes. Specifically, we predicted participants would depend more on recollection than familiarity for real-world objects. In our experiment, 50 participants responded to a change-detection task for real-world objects and colored circles using a 6-point confidence scale. Their performance data was modeled using receiver operating characteristic (ROCs) curves. Additionally, we used a dual-process signal detection model to determine the relative contributions of recollection vs familiarity. The results reveal that participants had greater overall memory performance (d-prime) for the real-world objects compared to the colored circles. Additionally, both real-world objects and colored features relied on familiarity, however, real-world objects relied on familiarity to a greater extent. Further, only real-word objects relied on recollection. That is, a one-sample t-test demonstrated that there was no significant recollection component used during the identification of simple features. Overall, our findings suggest that working memory performance for real-world objects is qualitatively different than that for simple color features. That is, only memory for real-world objects depended on recollection processes – perhaps due to the increased distinctiveness of real-world objects. These findings reveal that visual working memory may not rely on a singular mechanism, but instead may depend on the type of stimuli being remembered.