Coding categorical and coordinate spatial relations in visual–spatial short-term memory

Four experiments explored the coding of categorical and coordinate spatial relations in visual–spatial short-term memory (VSSTM). Participants judged whether two stimuli presented successively on a computer screen were the same or different. On positional change trials the two stimuli differed in the position of one element. Positional changes were of two types, coordinate and categorical. On coordinate trials the position of one element changed by a small amount, but retained the categorical relationships (above, below, left of, right of) to all other elements. On categorical trials one element moved by the same amount but additionally changed its categorical relationship to one of the other elements (e.g., changed from below to above). Participants detected categorical changes more accurately than coordinate changes when the elements were independent locations marked by squares, indicating that the categorical relationships amongst the squares were encoded in memory. Furthermore, this categorical advantage was unmodulated by either the suppression of articulation (Experiment 2) or by the requirement to retain either colour–position associations or positions only (Experiment 3). When the elements to be remembered were the vertices of simple outline polygons (Experiment 4) there was no categorical advantage, establishing the effect as spatial in nature. Contrary to predictions derived from Postma and De Haan (1996) Postma, A. and De Haan, E. H. 1996. What was where? Memory for object locations. Quarterly Journal of Experimental Psychology, 49A: 178–199. [Crossref], [Web of Science ®] , [Google Scholar], the employment of categorical relations appears not to be specifically linked to either verbal coding or to the requirement to associate objects with positions. The results suggest that the categorical relations are an intrinsic property of the representation of spatial configurations.     

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.     

Dissociative patterns of foreperiod effects in temporal discrimination and reaction time tasks

This study examined whether the process of temporal preparation for a target stimulus is the same regardless of the task required by the target stimulus. To this end, the same variable-foreperiod design was used in a temporal discrimination task (Experiment 1) and a reaction time task (Experiment 2). In Experiment 1, both temporal sensitivity and perceived duration increased as a function of foreperiod, whereas in Experiment 2, foreperiod did not influence reaction time. Furthermore, both temporal sensitivity and perceived duration revealed an asymmetric sequential effect of foreperiod, but the pattern of this effect was opposite to the pattern observed in the reaction time task. Together these dissociative patterns of foreperiod effects suggest that the mechanism of temporal preparation depends on the task required by the target stimulus.     

Homophonic context effects when naming Japanese kanji: evidence for processing costs?

The current study investigated the effects of phonologically related context pictures on the naming latencies of target words in Japanese and Chinese. Reading bare words in alphabetic languages has been shown to be rather immune to effects of context stimuli, even when these stimuli are presented in advance of the target word (e.g., Glaser & Düngelhoff, 1984 Glaser, W. R. and Düngelhoff, F. J. 1984. The time course of picture–word interference. Journal of Experimental Psychology: Human Perception and Performance, 10: 640–654. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Roelofs, 2003 Roelofs, A. 2003. Goal-referenced selection of verbal action: Modeling attentional control in the Stroop task. Psychological Review, 110: 88–125. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). However, recently, semantic context effects of distractor pictures on the naming latencies of Japanese kanji (but not Chinese hànzì) words have been observed (Verdonschot, La Heij, & Schiller, 2010 Verdonschot, R. G., La Heij, W. and Schiller, N. O. 2010. Semantic context effects when naming Japanese kanji, but not Chinese hànzì. Cognition, 115: 512–518. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). In the present study, we further investigated this issue using phonologically related (i.e., homophonic) context pictures when naming target words in either Chinese or Japanese. We found that pronouncing bare nouns in Japanese is sensitive to phonologically related context pictures, whereas this is not the case in Chinese. The difference between these two languages is attributed to processing costs caused by multiple pronunciations for Japanese kanji.     

Gummed-up memory: Chewing gum impairs short-term recall

Several studies have suggested that short-term memory is generally improved by chewing gum. However, we report the first studies to show that chewing gum impairs short-term memory for both item order and item identity. Experiment 1 showed that chewing gum reduces serial recall of letter lists. Experiment 2 indicated that chewing does not simply disrupt vocal–articulatory planning required for order retention: Chewing equally impairs a matched task that required retention of list item identity. Experiment 3 demonstrated that manual tapping produces a similar pattern of impairment to that of chewing gum. These results clearly qualify the assertion that chewing gum improves short-term memory. They also pose a problem for short-term memory theories asserting that forgetting is based on domain-specific interference given that chewing does not interfere with verbal memory any more than tapping. It is suggested that tapping and chewing reduce the general capacity to process sequences.     

How preview space/time translates into preview cost/benefit for fixation durations during reading

Eye-movement control during reading depends on foveal and parafoveal information. If the parafoveal preview of the next word is suppressed, reading is less efficient. A linear mixed model (LMM) reanalysis of McDonald (2006) confirmed his observation that preview benefit may be limited to parafoveal words that have been selected as the saccade target. Going beyond the original analyses, in the same LMM, we examined how the preview effect (i.e., the difference in single-fixation duration, SFD, between random-letter and identical preview) depends on the gaze duration on the pretarget word and on the amplitude of the saccade moving the eye onto the target word. There were two key results: (a) The shorter the saccade amplitude (i.e., the larger preview space), the shorter a subsequent SFD with an identical preview; this association was not observed with a random-letter preview. (b) However, the longer the gaze duration on the pretarget word, the longer the subsequent SFD on the target, with the difference between random-letter string and identical previews increasing with preview time. A third pattern—increasing cost of a random-letter string in the parafovea associated with shorter saccade amplitudes—was observed for target gaze durations. Thus, LMMs revealed that preview effects, which are typically summarized under “preview benefit”, are a complex mixture of preview cost and preview benefit and vary with preview space and preview time. The consequence for reading is that parafoveal preview may not only facilitate, but also interfere with lexical access.     

Congruency effects in conceptualizing for speech

In naming a picture at the basic level, a semantically related distractor word induces interference in comparison to an unrelated word. When the task is changed from basic-level naming to categorization, however, this effect reverses to semantic facilitation. In previous studies, this semantic facilitation effect was attributed to “message congruency” at the conceptual level. The present study examines the nature of this message congruency effect: Is it due to competition between two activated category concepts in the incongruent condition or is it due to convergence of activity on a single category concept in the congruent condition? Two experiments show that neither the strength with which the context stimulus activates an incongruent category concept nor the semantic distance between the category concepts activated by target and distractor affect target categorization speed. We conclude that the message congruency effect is most likely due to convergence on a single category concept in the category-congruent condition.     

Identity-based inhibitory processing during focused attention

Recent data suggest that the operating principles governing inhibition of distractor-related activity may deviate from dominant models describing inhibitory processing during selective attention. Here we aimed to gain a better understanding of these data in order to determine whether they actually defy premises of current models. In addition to providing evidence against noninhibitory accounts of the data (see especially Experiment 6), the results support three main novel findings that challenge current theories. First, the data provide evidence that inhibition overpowered excitation from ongoing external input (Experiments 1–4), which suggests that inhibitory control processes are more powerful than current models indicate. Second, negative effects emerged even when targets appeared alone (Experiment 5), which suggests that selection does not play an essential role in triggering inhibitory processing. Third, relatively early distractor-related activity was affected, which supports a role for inhibition prior to action control (Experiment 3). These findings suggest a need to revise current models describing inhibition of distracting information during selective attention.     

Articulation effects in melody recognition memory

Various surface features—timbre, tempo, and pitch—influence melody recognition memory, but articulation format effects, if any, remain unknown. For the first time, these effects were examined. In Experiment 1, melodies that remained in the same, or appeared in a different but similar, articulation format from study to test were recognized better than were melodies that were presented in a distinct format at test. A similar articulation format adequately induced matching processes to enhance recognition. Experiment 2 revealed that melodies rated as perceptually dissimilar on the basis of the location of the articulation mismatch did not impair recognition performance, suggesting an important boundary condition for articulation format effects on memory recognition—the matching of the memory trace and recognition probe may depend more on the overall proportion, rather than the temporal location, of the mismatch. The present findings are discussed in terms of a global matching advantage hypothesis.     

No deficiency in left-to-right processing of words in dyslexia but evidence for enhanced visual crowding

Whitney and Cornelissen hypothesized that dyslexia may be the result of problems with the left-to-right processing of words, particularly in the part of the word between the word beginning and the reader's fixation position. To test this hypothesis, we tachistoscopically presented consonant trigrams in the left and the right visual field (LVF, RVF) to 20 undergraduate students with dyslexia and 20 matched controls. The trigrams were presented at different locations (from –2.5° to?+?2.5°) in both visual half fields. Participants were asked to identify the letters, and accuracy rates were compared. In line with the predictions of the SERIOL (sequential encoding regulated by inputs to oscillations within letter units) model of visual word recognition, a typical U-shaped pattern was found at all retinal locations. Accuracy also decreased the further away the stimulus was from the fixation location, with a steeper decrease in the LVF than in the RVF. Contrary to the hypothesis, the students with dyslexia showed the same pattern of results as did the control participants, also in the LVF, apart from a slightly lower accuracy rate, particularly for the central letter. The latter is in line with the possibility of enhanced crowding in dyslexia. In addition, in the dyslexia group but not in the control group the degree of crowding correlated significantly with the students’ word reading scores. These findings suggest that lateral inhibition between letters is associated with word reading performance in students with dyslexia.