What is this thing called frequency?

When researchers are interested in the influence of long-term knowledge on performance, printed word frequency is typically the variable of choice. Despite this preference, we know little about what frequency norms measure. They ostensibly index how often and how recently words are experienced, but words appear in context, so frequency potentially reflects an influence of connections with other words. This paper presents the results of a large free association study as well as the results of experiments designed to evaluate the hypothesis that common words have stronger connections to other words. The norms indicate that common words tend to be more concrete but they do not appear to have more associates, stronger associates, or more connections among their associates. Two extralist cued recall experiments showed that, with other attributes being equal, high- and low-frequency words were equally effective as test cues. These results suggest that frequency does not achieve its effects because of stronger or greater numbers of connections to other words, as implied in SAM. Other results indicated that common words have more connections from other words, including their associates, and that free association provides a valid index of associative strength.