Semantic inhibition of return is the exception rather than the rule

Inhibition of return (IOR) has recently been reported for lexical/semantic categories (see, e.g., Fuentes, Vivas, & Humphreys, 1999). The present research examines the impact on semantic IOR of three components: item repetition, item heterogeneity, and spatial variability. Experiments 1 and 2 indicate that lexical/semantic IOR occurs only after extensive repetition. Experiment 2 also shows that semantic IOR is independent of spatial variability. Experiments 3 through 5 show facilitatory rather than inhibitory effects when the item pool is heterogeneous. The results support an episodic account of semantic IOR, according to which inhibitory effects accumulate with massive repetition of homogeneous items.