The contribution of morphological and semantic relatedness to repetition priming at short and long lags: Evidence from hebrew

The effect of morphological repetition at lag 0 and at lag 15 on lexical decision was investigated in Hebrew with three types of relation between prime and target. In the semantic-plus-morphological condition (SM), the prime and the target in each pair were two semantically related derivatives of the same root. In the “pure morphological” condition (M), the prime and the target derived from the same root, but their semantic association was very low, or nonexistent. In the semantic priming condition (S), primes and targets were semantically associated but were not morphologically related. The pure semantic relationship produced a significant facilitation at lag 0 that disappeared completely at lag 15. The pure morphological relation produced (smaller but) significant facilitation at lag 0 that was not attenuated at lag 15. When prime and target were semantically as well as morphologically related, the facilitation at lag 0 was similar to semantic priming, whereas at lag 15 it was similar to the pure morphological effect. Significant repetition effects at both lags were also found with non-words that shared the same (nonsensical) root and differed with respect to real derivational affixes. The differential time course for facilitation due to semantic and morphological relatedness suggests distinct underlying processes, although at lag 0 it is possible that semantic relatedness may augment the morphological repetition effect. Morphological repetition probably facilitates the retrieval of lexical information that, under certain circumstances, is necessary for lexical decision.     

Satiation effects in the perception of single letters’

When single letters were presented for five flashes, with S making a clarity judgment after each exposure, initial potentiation and subsequent satiation effects were found. A processing task and complete prior knowledge led to an increased probability of a “clear” response on the first exposure and to an earlier onset of the satiation effect. The results are discussed in terms of the neural network model underlying this research.     

Repetition priming reveals sustained facilitation and transient inhibition in reaction time

Reaction time (RT) in a detection or a location discrimination task increases when a target is repeatedly presented at the same location (inhibition), whereas RT decreases in feature (color or orientation) discrimination tasks (facilitation; Y. Tanaka & S. Shimojo, 1996a). Here, the time course of inhibition and facilitation was examined, using a repetition priming paradigm. Results indicate that inhibition occurred only in the immediately successive trial, whereas facilitation accumulated over several trials with location repetition. Moreover, inhibition and facilitation occurred in a task-relevant manner: Detection-location discrimination tasks produced transient RT increase, whereas feature discrimination tasks produced cumulative RT decrease. These results suggest a functional dissociation between spatial orienting and feature analysis, as well as top-down modulations by tasks leading to different types of visual memory.     

Priming of abstract letter representations may be universal: The case of Arabic

Recent research on the Roman alphabet has demonstrated that the magnitudes of masked repetition priming are equivalent for letter pairs that have similar visual features across cases (e.g., c-C) and for letter pairs with dissimilar features (e.g., g-G). Here, we examined whether priming of abstract letter representations occurs in an orthographic system, Arabic, in which the letters show an intricate number of contextual forms. Arabic does not have a lowercase/uppercase distinction, but the letters exhibit different forms that depend on their position (initial, medial, final, or isolated) and their connectivity. Importantly, some letters look quite different across positions (e.g., (symbol in text) and (symbol in text), which correspond to the letter 'ayn), whereas others look very similar (e.g. (symbol in text), and (symbol in text), which correspond to the letter fā'). We employed a masked priming same-different task, in which native speakers of Arabic decided whether a target letter was the same as or different from a reference letter presented in a different position (middle vs. isolated). The results showed masked repetition priming effects of the same magnitude for letter pairs with similar and with dissimilar visual features across letter positions. These data support the view that priming of abstract letter representations is a universal phenomenon.     

A study of relative-position priming with superset primes

Four lexical decision experiments are reported that use the masked priming paradigm to study the role of letter position information in orthographic processing. In Experiments 1 and 2, superset primes, formed by repetition of 1 or 2 letters of the target (e.g., jusstice-JUSTICE) or by insertion of 1 or 2 unrelated letters (e.g., juastice-JUSTICE), generated significant priming compared with unrelated primes and did not differ significantly from an identity priming condition. In Experiment 3, identity primes generated significantly faster responses than subset primes formed by removal of 2 letters from the target (e.g., jutie-JUSTICE), and subset primes generated faster responses than substitution primes formed by substitution of 2 letters of the target with unrelated letters (e.g., jumlice-JUSTICE). In Experiment 4, insertion of 3 unrelated letters continued to generate facilitation relative to unrelated primes but significantly less so than the identity prime condition. The authors discuss the implications of these results for letter-position coding schemes.     

The effect of repetition on the perception of single letters)

Single letters were presented for from one to five flashes, with S required to report what he saw after each f1ash. The clarity of the letter increased sharply with repetition. Since the letters were no larger than one-third of a degree in size, clarity could not have .been increased by S making different fixations from f1ash to f1ash and combining them into a total percept. Nor was S guessing, since this could be ruled out by other indicators. Thus, it was concluded that repetition of the stimulus can have a direct effect on the clarity of a S’s percept of that stimulus.     

The effect of repetition on the perception of single letters

Single letters were presented for from one to five flashes, with S required to report what he saw after each flash. The clarity of the letter increased sharply with repetition. Since the letters were no larger than one-third of a degree in size, clarity could not have been increased by S making different fixations from flash to flash and combining them into a total percept. Nor was S guessing, since this could be ruled out by other indicators. Thus, it was concluded that repetition of the stimulus can have a direct effect on the clarity of a S’s percept of that stimulus.     

Repetition priming is not purely episodic in origin

The sufficiency of similarity among surface attributes of prime-target pairs to account for the pattern of facilitation obtained in the repetition priming paradigm was evaluated. In Experiment 1, morphological primes were singular, inflected case forms of Serbo-Croatian words and visual similarity of prime and target was manipulated by alternating the two alphabets in which the Serbo-Croatian language is written. Results indicated that the magnitude of facilitation in the alphabetically alternating condition was not reduced relative to the nonalternating condition (RUPI-RUPI vs. RUPI-RUPI) which suggested that visual similarity is not a necessary condition for facilitation in the present task. In Experiment 2, related pairs included (a) base forms with diminutives, a class of highly productive and semantically predictable derivations marked in Serbo-Croatian by suffixes and (b) base words with morphologically unrelated monomorphemic words whose orthographic pattern encompassed the target in initial position and a sequence of letters in final position that elsewhere functions as a diminutive suffix. No facilitation of word targets by orthographically similar but morphologically unrelated primes was observed although there was a tendency toward facilitation among structurally similar pseudowords. Collectively, the experiments suggested that structural similarity of prime and target is not a sufficient condition for facilitation in the repetition priming paradigm.     

Effects of noise letters upon the identification of a target letter in a nonsearch task

During a 1-sec tachistoscopic exposure, Ss responded with a right or left leverpress to a single target letter from the sets H and K or S and C. The target always appeared directly above the fixation cross. Experimentally varied were the types of noise letters (response compatible or incompatible) flanking the target and the spacing between the letters in the display. In all noise conditions, reaction time (RT) decreased as between-letter spacing increased. However, noise letters of the opposite response set were found to impair RT significantly more than same response set noise, while mixed noise letters belonging to neither set but having set-related features produced intermediate impairment. Differences between two target-alone control conditions, one presented intermixed with noise-condition trials and one presented separately in blocks, gave evidence of a preparatory set on the part of Ss to inhibit responses to the noise letters. It was concluded that S cannot prevent processing of noise letters occurring within about 1 deg of the target due to the nature of processing channel capacity and must inhibit his response until he is able to discriminate exactly which letter is in the target position. This discrimination is more difficult and time consuming at closer spacings, and inhibition is more difficult when noise letters indicate the opposite response from the targe     

VERY LONG-LASTING PRIMING IN PICTURE NAMING

Abstract— A form of long-lasting repetition priming has been demonstrated by faster naming of pictures repeated from a prior exposure than new pictures. This facilitation is independent of explicit memory in both normal subjects (Mitchell & Brown, 1988) and amnesic patients (Cave & Squire. 1992). Using picture naming, the current study demonstrated that priming could be detected with delays of between 6 and 48 weeks between the initial exposure and the priming test. Recognition memory was also above chance at these delays, but performance on the two tests appeared independent. These results show that a single stimulus exposure can have very long-lasting effects. Accounts of repetition priming as a form of implicit memory will have to accommodate long-lasting changes in stimulus processing based on a single exposure.     

Attention, rehearsal, and memory for serial order

In three experiments, subjects attended to one of two simultaneous nine-digit sequences, presented binaurally in different voices (one male, one female). Substantial repetition effects (defined as gains in immediate memory performance for previously presented sequences relative to novel ones) were found for two exposure conditions: (a) one that required reproduction of the full sequence on each exposure (Experiment 1), and (b) one that required recall of a different two-digit subsequence on each exposure (Experiment 2). In Experiment 3, the following conditions produced no repetition effects, even though tests had substantial power to detect small effects: 10 consecutive presentations in the unattended voice; 4 prior presentations in a task that required attention to each digit as it was presented (but not to digit order); and 4 prior presentations in a task that required attention to digit order during their presentations. These results, together with those of previous studies, support the conclusion that repetition effects on immediate memory occur only with procedures that encourage covert rehearsal of full-sequence order on each exposure. These findings also limit the generality of others' conclusions that event order is automatically encoded for attended events, and extend previous findings showing unattended exposures to be without effect on recall measures.     

Morphological analysis of disrupted morphemes: Evidence from Hebrew

In concatenative languages such as English, the morphemes of a word are linked linearly so that words formed from the same base morpheme also resemble each other along orthographic dimensions. In Hebrew, by contrast, the morphemes of a word can be but are not generally concatenated. Instead, a pattern of vowels is infixed between the consonants of the root morpheme. Consequently, the shared portion of morphologically-related words in Hebrew is not always an orthographic unit. In a series of three experiments using the repetition priming task with visually presented Hebrew materials, primes that were formed from the same base morpheme and were morphologically-related to a target facilitated target recognition. Moreover, morphologically-related prime and target pairs that contained a disruption to the shared orthographic pattern showed the same pattern of facilitation as did nondisrupted pairs. That is, there was no effect over successive prime and target presentations, of disrupting the sequence of letters that constitutes the base morpheme or root. In addition, facilitation was similar across derivational, inflectional and identical primes. The conclusion of the present study is that morphological effects in word recognition are distinct from the effects of shared structure.     

Effects of orthography are independent of phonology in masked form priming

Briefly presented forward-masked primes that share letters with a word target have been shown to facilitate performance in different word recognition tasks. However, in all the experiments that have previously reported these facilitatory effects, related primes not only shared more letters with the target than did unrelated primes (orthographic priming), but they also shared more phonemes (phonological priming). The stimuli used in the present experiments allow us to separate out the effects of orthographic priming from phonological priming. Varying prime exposure duration from 14 to 57 msec, it is shown that effects of orthography follow a distinct time-course from the effects of phonology, and that orthographic facilitation does not result from a confound with phonological prime-target overlap.     

Cross-trial priming in visual search for singleton conjunction targets: role of repeated target and distractor features

Kristjánsson, Wang, and Nakayama (2002) demonstrated that visual search for conjunctively defined targets can be substantially expedited ("primed") when target and distractor features are repeated on consecutive trials. Two experiments were conducted to examine whether the search response time (RT) facilitation on target-present trials results from repetition of target-defining features, distractor features, or both. The experiments used a multiple conjunctive search paradigm (adapted from Kristjánsson et al., 2002), in which the target and distractor features were varied (i.e., repeated) independently of each other across successive trials. The RT facilitation was numerically largest when both target and distractor features were repeated, but not significantly larger than that when only distractor features were repeated. This indicates that cross-trial priming effects in conjunctive visual search result mainly from the repetition of distractor, rather than target, features.     

Access to concrete word meanings in the cerebral hemispheres: facilitation and inhibition effects

In 2002 Shibahara and Lucero-Wagoner, using a priming paradigm, reported a larger facilitation for concrete noun pairs in the right than left hemisphere when the stimulus onset asynchrony was 250 msec. Their related prime-target pairs were similar not only in meaning but also perceptual attributes, such as shape. They had reported such perceptual information to be available only in the right hemisphere early in target processing. Thus, we predicted that, when the stimulus onset asynchrony is long, there would be no effect of perceptual information on target processing in the right hemisphere, resulting in no hemispheric differences in the amount of facilitation. We also predicted that target processing would be inhibited by prior presentation of unrelated primes only in the left hemisphere because inhibition seems to be produced by the attention system in the left hemisphere. The present experiment was designed to test these predictions, using the stimulus onset asynchrony of 550 msec. and the same prime-target pairs. Analysis showed no hemispheric differences in the amount of facilitation, and inhibition effects for unrelated pairs were produced in both hemispheres. It is suggested that the inhibition effects in each hemisphere might be produced by different mechanisms.     

Searching for many targets: An analysis of speed and accuracy

Three Ss scanned matrices of letters for 40 sessions in a test of Neisser’s claim that feature tests in high-speed searches operate independently and in parallel. In the multiple-target condition (MTC), the matrix contained any one of four target letters, while in the four single-target conditions (STC), the S knew which particular target was embedded in the list. In contrast to previous studies, the error rates for individual target letters in the MTC were analyzed separately rather than being pooled. Two Ss made more errors on the hardest target when searched for in the MTC than in the STC. This difference would be masked by pooling error rates. The third S’s scanning rate in the MTC was not as rapid as in the STC. Neither a sequential nor a strictly parallel feature processing model can account for these data.     

Inhibition and anticipation in visual search: evidence from effects of color foreknowledge on preview search

We present four experiments in which we examined the effects of color mixing and prior target color knowledge on preview search (Watson & Humphreys, 1997). The task was to detect a target letter (an N or a Z) that appeared along with other new letters, when old distractors remained in the visual field. In some conditions, participants were told the target's color, in others, they were not. Foreknowledge of the target's color produced large improvements in search for both baseline and preview presentations (Experiment 1). For preview presentations, the magnitude of this effect was reduced if the target shared its color with a single colored set of previewed letters (Experiment 2). Removing this similarity across the displays greatly improved search efficiency (Experiment 3). In Experiment 4, we assessed and rejected the proposal that the effects reflected the probability that the target was carried by a particular color. We discuss the results in terms of separate effects of (1) inhibitory carryover from a preview color group and (2) an anticipatory set for a known target color.     

Target position and practice in the identification of letters in varying contexts: A word superiority effect

A forced-choice detection paradigm controlling for postperceptual inference was used to investigate letter identification in three-position displays. Letters from a predesignated set of four targets appeared singly, in strings of noise characters, in unpronounceable nonsense strings, and in words. Subjects knew which context would occur, but did not know which of the three display positions would contain the target. Correct detection data were collected at constant exposure duration over five testing sessions. Overall identification accuracy was higher in words than in all other contexts, the first word superiority effect to be found with targets specified in advance since Reicher’s (1969). This effect remained constant over sessions. An interaction between context type and target position showed enhanced accuracy for initial and terminal letters in words, but depressed accuracy at initial and terminal positions in other contexts. This was interpreted to mean that prior knowledge of context is used to alter the dynamics of perceptual analysis.     

Proofreading familiar text: Constraints on visual processing

Recent emphasis on the interactive nature of processing during reading has focused attention on how higher level syntactic-semantic processes might constrain or alter the processing of letters and words during reading. The present studies addressed this question by examining the effect of prior knowledge about a passage on the subsequent ability to see visual errors when rereading the same text. Experiment 1 demonstrated that prior knowledge of a passage leads to better proofreading of that passage. Experiment 2 showed that this facilitation is at the level of visual letter and word analyses, not through higher level constraints on rereading. The data are discussed in terms of skilled visual pattern analyses and in terms of the redistribution of processing resources.     

The role of letter identity and letter position in orthographic priming

Four experiments are reported investigating orthographic priming effects in French by varying the number and the position of letters shared by prime and target stimuli. Using both standard masked priming and the novel incremental priming technique (Jacobs, Grainger, & Ferrand, 1995), it is shown that net priming effects are affected not only by the number of letters shared by prime and target stimuli but also by the number of letters in the prime not present in the target. Several null results are thus explained as a tradeoff between the facilitation generated by common letters and the inhibition generated by different letters. Inhibition was significantly reduced when different letters were replaced by nonalphabetic symbols. Facilitation effects disappeared when the common letters did not have the same relative position in the prime and target strings, thus supporting a relative-position coding scheme for letters in words.