Background

How many times a word appear in a corpus constitutes its word frequency. Word frequency affects memory in robust but puzzling ways. In free recall paradigms high frequency (HF) words are easier to recall than low frequency (LF) words, in lists with homogenous word frequencies. If HF and LF words are mixed together in a list this affect recall of HF words negatively while recall of LF words is better than in homogenous lists. (Gregg, 1976; Ward, Woodward, Stevens & Stinson, 2003). HF words have more inter-item relations than LF words (Gregg, Montgomery & Castaño, 1980). Inter-item associations has been suggested by various researchers as an explanation for frequency effects or as a partial explanation (reviews in Gregg et al, 1980, and in Ward et al, 2003). The ERP (Event Related Potential) component N400,