Are transposition effects specific to letters?

Recent research has consistently shown that pseudowords created by transposing two letters are perceptually similar to their corresponding base words (e.g., jugde-judge). In the framework of the overlap model (Gomez, Ratcliff, & Perea, 2008), this effect is due to a noisy process in the localization of the "objects" (e.g., letters, kana syllables). In the present study, we examine whether this effect is specific to letter strings or whether it also occurs with other "objects" (namely, digits, symbols, and pseudoletters). To that end, we conducted a series of five masked priming experiments using the same-different task. Results showed robust effects of transposition for all objects, except for pseudoletters. This is consistent with the view that locations of familiar objects (i.e., letters, numbers, and symbols) can be best understood as distributions along a dimension rather than as precise points.