Predictability and Immediate Memory for Consonant Sequences

Two measures which have been shown to predict the ease of learning trigrams, namely log letter frequency and sequential predictability, were applied to data from an experiment on short term memory. This involved the immediate recall of 120 six-letter consonant sequences which were presented visually one letter at a time. A significant correlation was found between the probability that a given sequence would be recalled correctly and both its mean log letter frequency (r = 0.308, p < 0.001), and its mean predictability (r = 0.393, p < 0.001). Partial correlation showed only a marginally significant effect of log letter frequency when predictability was partialled out (r = 0.161, 0.05 < p < 0.1). With log letter frequency partialled out, however, a reliable correlation between predictability and recall score remained (r = 0.300, p < 0.001).