Lexical connectivity effects in immediate serial recall of words

In six experiments, we tested whether immediate serial recall is influenced by a word’s degree centrality, an index of lexical connectivity. Words of high degree centrality are associated with more words in free association norms than those of low degree centrality. Experiment 1 analyzed secondary data to explore the effect of degree centrality in wordlists containing a mixture of high- and low-degree words. High-degree words were advantaged across all serial positions, independently of other variables including word frequency. Experiment 2 replicated this finding using an expanded stimulus set. Experiment 3 used pure lists with each list containing high- or low-degree words only (e.g., HHHHHH vs. LLLLLL). Once again, high-degree words were better recalled across all serial positions. In Experiment 4, each wordlist alternated between high and low-degree words (e.g., HLHLHL and LHLHLH). Recall of lowdegree words was facilitated by the neighboring high-degree words, abolishing the overall high-degree advantage. Experiment 5 used a within-participant design and replicated the findings from Experiments 3 and 4 such that the high-degree advantage in pure lists disappeared in alternating lists. Experiment 6 compared high and low frequency words in pure lists while controlling for degree centrality between the item sets. A high-frequency advantage emerged, suggesting that the effects of frequency and degree centrality are separable. We conclude that degree centrality is a distinct psycholinguistic variable that affects serial recall as both (a) an item-level characteristic such that high (vs. low) degree words have greater accessibility in the lexicon and (b) an interitem property such that high-degree words facilitate the recall of neighboring words by enhancing the formation of associative links.