Effects of horizontal displacement and inter-character spacing on transposed-character effects in same-different matching

On the distinction between position and order information when processing strings of characters

To probe the processing of gaze-dependent positional information and gaze-independent order information when matching strings of characters, we compared effects of visual similarity (hypothesized to affect gaze-centered position coding) with the effects of character transpositions (hypothesized to affect the processing of gaze-independent order information). In Experiment 1, we obtained empirical measures of visual similarity for pairs of characters, separately for uppercase consonants and keyboard symbols. These similarity values were then used in Experiment 2 to create pairs of four-character stimuli (four letters or four symbols) that could differ by substituting one character with a different character from the same category that was visually similar (e.g., FJDK-FJBK) or dissimilar (e.g., FJVK-FJBK). We also compared the effects of transposing two characters (e.g., FBJK-FJBK) with substituting two characters (e.g., FHSK-FJBK). "Different" responses were harder to make in the single substitution condition when the substituted character was visually similar, and this effect was not conditioned by character type. On the other hand, transposition costs (i.e., greater difficulty in detecting a difference with transpositions compared with double substitutions) were greater for letters compared with symbols. We conclude that visual similarity mainly affects the generic gaze-dependent processing of complex visual features, and that the encoding of letter order involves a mechanism that is specific to reading.

A Letter is a Letter and its Co-Occurrences: Cracking the Emergence of Position-Invariance Processing

Visual word recognition requires encoding letter identities and positions (orthographic processing). The present study focuses on the emergence of the mechanism responsible for encoding letter order in a word: position invariance. Reading experience leads to developing a flexible mechanism that encodes the information of the position of letters, explaining why jugde and judge are easily confused. Critically, orthographic regularities (e.g., frequent letter co-occurrences) modulate letter position encoding: the pseudoword mohter is extremely similar to mother because, in middle positions, the bigram TH is much more frequent than HT. Here, we tested whether position invariance emerges rapidly after the exposition to orthographic regularities-bigrams-in a novel script. To that end, we designed a study with two phases. In Phase 1, following Chetail (2017; Experiment 1b, Cognition, 163, 103-120), individuals were first exposed to a flow of artificial words for a few minutes, with four bigrams occurring frequently. Afterward, participants judged the strings with trained bigrams as more wordlike (i.e., readers quickly picked up subtle new orthographic regularities) than the strings with untrained bigrams, replicating Chetail (2017). In Phase 2, participants performed a same-different matching task in which they had to decide whether pairs of five-letter strings were the same or not. The critical comparison was between pairs with a transposition of letters in a frequent (trained) versus infrequent (untrained) bigram. Results showed that participants were more prone to make errors with frequent bigrams than with infrequent bigrams with a letter transposition. These findings reveal that position invariance emerges rapidly, after continuous exposure to orthographic regularities.

Reading about a RELO-VUTION

Pseudowords created by transposing two letters of words (e.g., MOHTER; CHOLOCATE) are highly confusable with their base word; this is known as the transposed-letter similarity effect. In this work, we examined whether transposed-letter effects occur when words span more than one line (e.g., CHOLO- in one line and CATE in another line; note that the transposed letters L and C are in different lines). While this type of presentation is not the canonical format for reading in alphabetic languages, it is widely used in advertising, billboards, and street signs. Transposed-letter pseudowords and their replacement-letter controls were written in the standard one-line format versus a two-line format (Experiments 1-2) or a syllable-per-line format (Experiment 3). While results showed some decrease in the transposed-letter effect in the two-line and syllabic formats, the transposed-letter effect was still substantial in the accuracy of responses. These findings demonstrate that even when the letters being transposed are relatively far apart in space, the transposed-letter effect is still robust. Thus, a major component of letter position coding occurs at an abstract level.