  A topological argument is presented concering the structure of semantic
space, based on the negative correlation between polysemy and word length. The
resulting graph structure is applied to the modeling of free-recall
experiments, resulting in predictions on the comparative values of recall
probabilities. Associative recall is found to favor longer words whereas
sequential recall is found to favor shorter words. Data from the PEERS
experiments of Lohnas et al. (2015) and Healey and Kahana (2016) confirm both
predictons, with correlation coefficients $r_{seq}= -0.17$ and $r_{ass}=
+0.17$. The argument is then applied to predicting global properties of list
recall, which leads to a novel explanation for the word-length effect based on
the optimization of retrieval strategies.
