Masked transposition effects for simple versus complex nonalphanumeric objects

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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.

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

In two same-different matching experiments we investigated whether transposed-character effects can be modulated by the horizontal displacement or inter-character spacing of target stimuli (strings of 6 consonants, digits, or symbols). Reference and target stimuli could be identical or differed either by transposing or substituting two characters. Transposition costs (greater difficulty in detecting a difference with transpositions compared with substitutions) were greater for letter stimuli compared to both digit and symbol stimuli in both experiments. In Experiment 1, half of the targets were displayed at the center of the screen and the other half were shifted by two character-positions to the left or to the right, whereas the reference was always presented at the center of the screen. Target displacement made the task harder and caused an increase in transposition costs whatever the type of stimulus. In Experiment 2, all stimuli were presented at the center of the screen and the inter-character spacing of target stimuli was increased by one character space on half of the trials. Increased spacing made the task harder and paradoxically caused an increase in transposition costs, but only significantly so for letter stimuli, and only in the discriminability (d') measure. These results suggest that target location and inter-character spacing manipulations caused an increase in positional uncertainty during the processing of location-specific complex features prior to activation of a location-invariant representation of character-in-string order. The hypothesized existence of a letter-specific order encoding mechanism accounts for the greater transposition costs seen with letter stimuli, as well as the greater modulation of these effects by an increase in inter-character spacing seen in discriminability (d').

Phonological priming effects with same-script primes and targets in the masked priming same-different task

Norris, Kinoshita and colleagues (Kinoshita & Norris, Journal of Experimental Psychology: Learning, Memory, and Cognition, 35(1), 1-18, 2009; Journal of Experimental Psychology: General, 137(3), 434-455, 2010; Norris & Kinoshita, Quarterly Journal of Experimental Psychology, 63(1), 194-204, 2008) have suggested that the masked priming same-different task (SDT) is an excellent tool for studying the orthographic coding process because, in most circumstances, performance in that task is driven entirely by orthographic codes. More specifically, although evidence of phonological influences (i.e., phonological priming effects in the SDT) have been reported, Kinoshita, Gayed, and Norris (Journal of Experimental Psychology: Human Perception and Performance, 44(11), 1661-1671, 2018) have claimed that phonological priming does not arise in the SDT when the prime and target are written in the same script and the targets are words, the most typical experimental situation. Indeed, it does appear that no-one has yet reported phonological priming effects in such situations. The question of whether it is possible to observe phonological priming in such situations was more fully examined in the present experiments. Experiment 1 involved a masked priming SDT using Japanese Kanji script in which the primes and targets were homophonic but shared no characters. Experiment 2 was a parallel experiment using Chinese stimuli. In both experiments, phonological priming effects were observed for both one- and two-character words. These experiments indicate that, although the priming effects in masked priming SDTs undoubtedly have a strong orthographic basis, phonological codes also play a role even when the prime and (word) target are written in the same script.

Orthographic and phonological priming effects in the same-different task

Masked priming tasks have been used widely to study early orthographic processes-the coding of letter position and letter identity. Recently, using masked priming in the same-different task Lupker, Nakayama, and Perea (2015a) reported finding a phonological priming effect with primes presented in Japanese Katakana, and English target words presented in the Roman alphabet, and based on this finding, suggested that previously reported effects in the same-different task in the literature could be based on phonology rather than orthography. In this article, the authors explain why the design of Lupker et al.'s experiment does not address this question; they then report 2 new experiments that do. The results indicate that the priming produced by orthographically similar primes in the same-different task for letter strings presented in the Roman alphabet is almost exclusively orthographic in origin, and phonology makes little contribution. The authors offer an explanation for why phonological priming was observed when the prime and target are presented in different scripts but not when they are presented in the same script. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Can letter position encoding be modified by visual perceptual elements?

A plethora of studies has revealed that letter position coding is relatively flexible during word recognition (e.g., the transposed-letter [TL] pseudoword CHOLOCATE is frequently misread as CHOCOLATE). A plausible explanation of this phenomenon is that letter identity and location are not perfectly bound as a consequence of the limitations of the visual system. Thus, a complete characterization of letter position coding requires an examination of how letter position coding can be modulated by visual perceptual elements. Here we conducted three lexical decision experiments with TL and replacement-letter pseudowords that manipulated the visual characteristics of the stimuli. In Experiment 1, each syllable was presented either in a different colour or monochromatically (e.g., vs. ) with the transposition occurring across syllables. In Experiment 2, the critical letters had a consistent contrast or not (e.g., vs. ). In Experiment 3, the stimuli were presented either simultaneously or serially, letter by letter (i.e., as occurs in braille reading). Results showed that whereas colouring differently each syllable only produced a small nonsignificant reduction of the TL effect, the other two manipulations-presenting the two critical letters with an altered contrast and presenting the letters one at a time-reduced, but did not eliminate, the magnitude of the TL effect relative to the regular format. Although these findings are consistent with models that postulate an early perceptual locus of the TL effect, the robustness of the TL effect suggests that letter position coding also has an orthographic abstract component.

Evidence for letter-specific position coding mechanisms

The perceptual matching (same-different judgment) paradigm was used to investigate precision in position coding for strings of letters, digits, and symbols. Reference and target stimuli were 6 characters long and could be identical or differ either by transposing two characters or substituting two characters. The distance separating the two characters was manipulated such that they could either be contiguous, separated by one intervening character, or separated by two intervening characters. Effects of type of character and distance were measured in terms of the difference between the transposition and substitution conditions (transposition cost). Error rates revealed that transposition costs were greater for letters than for digits, which in turn were greater than for symbols. Furthermore, letter stimuli showed a gradual decrease in transposition cost as the distance between the letters increased, whereas the only significant difference for digit and symbol stimuli arose between contiguous and non-contiguous changes, with no effect of distance on the non-contiguous changes. The results are taken as further evidence for letter-specific position coding mechanisms.

Position coding effects in a 2D scenario: the case of musical notation

How does the cognitive system encode the location of objects in a visual scene? In the past decade, this question has attracted much attention in the field of visual-word recognition (e.g., "jugde" is perceptually very close to "judge"). Letter transposition effects have been explained in terms of perceptual uncertainty or shared "open bigrams". In the present study, we focus on note position coding in music reading (i.e., a 2D scenario). The usual way to display music is the staff (i.e., a set of 5 horizontal lines and their resultant 4 spaces). When reading musical notation, it is critical to identify not only each note (temporal duration), but also its pitch (y-axis) and its temporal sequence (x-axis). To examine note position coding, we employed a same-different task in which two briefly and consecutively presented staves contained four notes. The experiment was conducted with experts (musicians) and non-experts (non-musicians). For the "different" trials, the critical conditions involved staves in which two internal notes that were switched vertically, horizontally, or fully transposed--as well as the appropriate control conditions. Results revealed that note position coding was only approximate at the early stages of processing and that this encoding process was modulated by expertise. We examine the implications of these findings for models of object position encoding.

Electrophysiological signatures of masked transposition priming in a same-different task: evidence with strings of letters vs. pseudoletters

Research on masked transposed-letter priming (i.e., jugde-JUDGE triggers a faster response than jupte-JUDGE) has become a key phenomenon to reveal how the brain encodes letter position. Recent behavioural evidence suggests that the mechanism responsible for position coding in a masked priming procedure works with familiar "object" identities (e.g., letters, digits, symbols) but not with unfamiliar object identities (e.g., pseudoletters). Here we used event-related potentials (ERPs) to explore the time course of masked transposition priming of letters vs. pseudoletters in a cue-target same-different matching task. Target stimuli were preceded by a masked prime that could be: (i) identical to the target; (ii) identical to the target except for the transposition of two internal letters/pseudoletters; or (iii) identical to the target except for the substitution of two internal letters/pseudoletters. Only cue-target 'same' trials were analyzed. The priming manipulation affected the "same" trials of the letter strings between 250 ms and 450 ms: identity and transposition conditions produced less negative amplitudes than the substitution condition. Because of the onset latency of this priming effect, we suggest that masked primes affected mainly the cognitive processes related to the categorization of the trials (match versus mismatch), rather than to the initial stages of orthographic processing.