Similarity impacts all aspects of human behavior, from marital satisfaction to visual perception. Memory is no exception, with a large detrimental effect of similarity on order information recall for all studied features but the semantic ones. In fact, the insensitivity of short-term ordered recall performance to semantic similarity is challenging and a benchmark effect for evaluating memory models. Here, in five large-scale experiments, we revisited three key exceptions showing a detrimental effect of semantic similarity on short-term order recall and systematically tested if their findings were due to methodological issues. Despite the implementation of more stringent methodological controls, we consistently reproduced the detrimental effect of semantic similarity on order information across these five experiments. We then systematically reviewed the literature and found a substantial number of overlooked studies showing the presence of a detrimental effect of semantic similarity on order information recall. We identified task difficulty as a potential moderating variable accounting for previous inconsistencies. Across four additional experiments, we manipulated task difficulty by varying presentation speed and list length. As predicted, the detrimental effect of semantic similarity on order recall emerges under more difficult task conditions, and critically, when the task was easier, its effect on order recall vanished. The theoretical implications for contemporary models are reviewed. (PsycInfo Database Record (c) 2026 APA, all rights reserved).
Dauphinee et al. (Mon,) studied this question.