What is semantic diversity and why does it facilitate visual word recognition?

Previous research has speculated that semantic diversity and lexical ambiguity may be closely related constructs. This research sought to test this claim. We computed multidimensional contextual representations of words using Latent Semantic Analysis and from these derived semantic diversity values for 28,555 words. Using existing data resources, we demonstrated that greater semantic diversity is associated with more rapid word recognition, particularly for low-frequency words, but found no evidence that effects of lexical ambiguity on word recognition could be ascribed to semantic diversity. Further analysis of the LSA-based contextual representations revealed that they do not capture the distinct meanings of ambiguous words. Instead, these contextual representations appear to capture general information about the topics and types of written material in which words occur. These analyses suggest that the semantic diversity metric facilitates word recognition (particularly for low frequency words) because high diversity words are likely to have been encountered no matter what one has read, whereas many participants may not have encountered lower diversity words simply because the topics and types of written material in which they occur are more restricted.