Letter matching in word familiarity: Is slot overlap or relative position overlap a requirement?

Familiarity is the sense that something has been encountered before, either prior to or without being able to recall specifics of the previous encounter. Familiarity is thought to be driven by an overlap in features between stimuli recently activated in memory and the current stimulus. Research on word familiarity suggests that letters are a significant contributing feature. An unexplored question is the extent to which letter overlap needs to occur in the same positions between the initial encounter and the later encounter. Research on priming and lexical decision suggests that letters do not need to be in the exact correct locations for lexical activation to occur. Based on this research, two experiments are reported investigating how letter position matching might operate in word familiarity using a variant of recognition without cued recall. The results suggested that neither absolute nor relative position overlap were needed for some degree of letter matching to occur. Letters that were out of position that also did not maintain relative positions still contributed to word familiarity. Implications for the mechanism behind letter matching, as well as for other kinds of stimuli, are discussed.