James H. Neely

Semantic Priming and Retrieval from Lexical Memory: Roles of Inhibitionless Spreading Activation and Limited-Capacity Attention.

Prior to each visually presented target letter string in a speeded word-nonword classification task, either BIRD, BODY, BUILDING, or xxx appeared as a priming event. When the target was a word, it was (a) a name of a type of bird on most BiRD-prime trials; (b) a name of part of a building on most BODY-prime trials; (c) a name of a part of the body on most BUiLDiNG-prime trials; (d) a name of a type of bird, part of a building, or part of the body equally often on xxx-prime trials. Thus, on BiRD-prime trials the subject expected the word target to be chosen from the same category as the category represented by the word prime itself (Nonshift), whereas on BODY-prime and BuiLDiNG-prime trials the subjects attention was to be shifted because he or she expected the word target to be chosen from a category other than the category represented by the word prime itself (Shift). The word target was an exemplar of either the category the subject expected (Expected) or a category the subject did not expect (Unexpected) and was either semantically related (Related) or semantically unrelated (Unrelated) to the word prime. Thus, there were five different types of word-prime-word-target trials: (a) BiRD-robin (Condition Nonshift-Expected-Related) ; (b) BiRD-arm (Condition Nonshift-Unexpected-Unrelated) ; (c) BODY-door (Condition Shift-Expected-Unrelated) ; (d) BODY-sparrow (Condition Shift-Unexpected-Unrelated); (e) BODYheart (Condition Shift-Unexpected-Related). The stimulus onset asynchrony (SOA) between the prime and the target letter string varied between 250 and 2,000 msec. At the 2,000-msec SOA, reaction times (RTs) on BiRD-robin type trials were faster than RTs on xxx-prime trials (a facilitation effect), whereas RTs on BIRDarm type trials were slower than RTs on xxx-prime trials (an inhibition effect). As SOA decreased, the facilitation effect on BiRD-robin trials remained constant, but the inhibition effect on BiRu-arm trials decreased until, at the 250-msec SOA, there was no inhibition. For the Shift conditions at the 2,000-msec SOA, facilitation was obtained on BODY-door type trials and inhibition was obtained on BODY-sparrow type trials. These two effects decreased in magnitude as the SOA decreased until, at the 250-msec SOA, there was no facilitation or inhibition. On BODY-heart type trials, there was an inhibition effect at the 2,000 msec SOA, which decreased as the SOA decreased until, at the 250-msec SOA, it became a facilitation effect. For the nonword targets, the facilitatory effects of the word primes decreased as SOA decreased. These results were regarded as supporting the theory of Posner and Snyder that postulates two distinct components of attention: a fast automatic inhibitionless spreading-activation process and a slow limited-capacity consciousattention mechanism.

The English Lexicon Project.

The English Lexicon Project is a multiuniversity effort to provide a standardized behavioral and descriptive data set for 40,481 words and 40,481 nonwords. It is available via the Internet at elexicon.wustl.edu. Data from 816 participants across six universities were collected in a lexical decision task (approximately 3400 responses per participant), and data from 444 participants were collected in a speeded naming task (approximately 2500 responses per participant). The present paper describes the motivation for this project, the methods used to collect the data, and the search engine that affords access to the behavioral measures and descriptive lexical statistics for these stimuli.

Semantic priming and retrieval from lexical memory: Evidence for facilitatory and inhibitory processes.

Immediately prior to each visually presented target letter string to which the subject made a speeded word-nonword classification response, a visually presented prime to which no overt response was required was shown for 360, 600, or 2,000 msec. For word (W) target trials, the priming event was either a semantically neutral warning signal (Condition NX), a word semantically related to the target word (Condition R), or a word semantically unrelated to the target word (Condition U); for nonword (N) target trials, the priming event was either the neutral warning signal (Condition NX) or a word prime (Condition WP). For the W target trials, reaction times (RTs) were slower in Condition U than in Condition NX and equally so for all three prime durations; RTs were faster in Condition R than in Condition NX and to a greater degree for the 600- and 2,000-msec prime durations than for the 360-msec prime duration. For the N targets, RTs were faster in Condition WP than in Condition NX and equally so for all prime durations. These results were interpreted within the framework of a two-factor theory of attention proposed by Posner and Snyder (1975a).

Semantic priming in the lexical decision task: Roles of prospective prime-generated expectancies and retrospective semantic matching.

In semantic priming paradigms for lexical decisions, the probability that a word target is semantically related to its prime (the relatedness proportion) has been confounded with the probability that a target is a nonword, given that it is unrelated to its prime (the nonword ratio). This study unconfounded these two probabilities in a lexical decision task with category names as primes and with high- and low-dominance exemplars as targets. Semantic priming for high-dominance exemplars was modulated by the relatedness proportion and, to a lesser degree, by the nonword ratio. However, the nonword ratio exerted a stronger influence than did the relatedness proportion on semantic priming for low-dominance exemplars and on the nonword facilitation effect (i.e., the superiority in performance for nonword targets that follow a category name rather than a neutral XXX prime). These results suggest that semantic priming for lexical decisions is affected by both a prospective prime-generated expectancy, modulated by the relatedness proportion, and a retrospective target/prime semantic matching process, modulated by the nonword ratio.

Interference and inhibition in memory retrieval.

Publisher Summary This chapter discusses the causes of memory interference and the extent of situations in which these mechanisms operate. First, the chapter discusses some widely held assumptions about the situation of interference, focusing on the idea that such effects arise from competition for access via a shared retrieval cue. This notion is sufficiently general that it may be applied in a variety of interference settings, which is illustrated briefly. Then the classical interference paradigms from which these ideas emerged are reviewed. The chapter also reviews more recent phenomena that both support and challenge classical conceptions of interference. These phenomena provide compelling illustrations of the generality of interference and, consequently, of the importance of understanding its mechanisms. A recent perspective on interference is highlighted that builds upon insights from modern work, while validating intuitions underlying several of the classical interference mechanisms. According to this new perspective, forgetting derives not from acquiring new memories per se, but from the impact of later retrievals of the newly learned material. After discussing findings from several paradigms that support this retrieval-based view, the chapter illustrates how forgetting might be linked to inhibitory processes underlying selective attention.

Semantic Context Effects on Visual Word Processing: A Hybrid Prospective-Retrospective Processing Theory

Publisher Summary This chapter describes a hybrid prospective–retrospective theory of the way semantic context influences word recognition. This theory postulates the operation of two prospective priming mechanisms, expectancy and spreading activation, and one retrospective priming mechanism, a check for target-prime relatedness. There are four important ways in which hybrid prospective–retrospective theory of semantic priming promotes the understanding of the way semantic context influences the processes that mediate word recognition in lexical decision and pronunciation tasks. First, it uncovers the rather potent effects of a variable—the nonword ratio—that has heretofore been ignored in the analyses of semantic priming effects in the lexical decision task. Second, the theory suggests that an effect that has often been ignored and considered as a nuisance—the nonword facilitation effect—may actually be an important signature of the operation of a mechanism, the retrospective semantic matching mechanism, that can have a major influence on priming in the lexical decision task. Third, the hybrid prospective–retrospective theory of priming provides guidance as to whether a lexical decision or pronunciation task should be used to study the effects of semantic context. The fourth feature of the present theory is that it provides an integrative account of several diverse phenomena that have come to light in the heavily researched area of semantic context effects on word recognition.

Semantic priming in the pronunciation task: The role of prospective prime-generated expectancies

In the relatedness proportion effect, semantic priming increases with an increase in the probability that a word prime will be followed by a semantically related word target. This effect has frequently been obtained in the lexical decision task but not in a pronunciation task. In the present experiment, relatedness proportion was manipulated in two pronunciation tasks, one with and one without non word targets, using category names as primes. In both tasks, a relatedness proportion effect occurred for high-dominance category exemplars but not for low-dominance category exemplars. These results converge with recent lexical decision results in. suggesting that. semantic priming in pronunciation is affected by a prospective prime-generated expectancy that is modulated by the relatedness proportion.

Inhibition from semantically related primes: Evidence of a category-specific inhibition.

The phenomenon of inhibition from generating successive items within a category, reported by A. S. Brown (1981), was examined in two experiments. Subjects responded on target trials by either generating targets (e.g., generating BASS to B when it followed the category name FISH, Experiment 1) or reading them (reading BASS when it followed the category name FISH, Experiment 2). Prior to target trials, all subjects received priming trials consisting of either one or four exemplars from a single semantic category, which could be either the same category as the target’s category (related priming condition) or an unrelated category (unrelated priming condition). In both experiments, different groups of subjects either read or generated primes. When primes were read, target response times (RTs) were always facilitated in the related priming condition compared with in the unrelated priming condition. However, when primes were generated, this facilitation from related primes was eliminated, except in the one-prime condition, when targets were also generated. When primes and targets were both generated, RTs in the related priming condition were slower following four primes than following one prime. Thus, category-specific inhibition from multiple related primes is greatest when both primes and targets must be actively retrieved.

The Effects of Blocked Versus Random Presentation and Semantic Relatedness of Stimulus Words on Response to a Modified Stroop Task Among Social Phobics

Previous studies of the modified Stroop Color-Naming Task with social phobics have demonstrated increased latencies for the color-naming of social threat words in comparison to neutral or physical threat words. However, these effects could be partially due to differences in the semantic relatedness of the words in these various categories and/or the blocked format (i.e., all words of one type presented sequentially) in which words have been presented. To examine these issues, color-naming latencies of individuals with social phobia to social threat, semantically related neutral, and unrelated neutral words were examined in both blocked and randomly intermixed formats. Significant differences in color-naming were found for word stimuli presented in the blocked format only. In the blocked format, social phobics were significantly slower to color-name social threat words than related neutral words and significantly slower to color-name related neutral words than unrelated neutral words. Color-naming latencies also increased across trials regardless of word type. There were no effects of word type in the random format. Thus, both presentation format and semantic priming, as well as threat value, may have contributed to color-naming interference for the social threat words. Possible interpretations of our findings along with implications for future Stroop research in persons with social phobia are discussed.

Semantic priming modulates the N400, N300, and N400RP.

OBJECTIVE To determine whether ERP components can differentiate between the semantic priming mechanisms of automatic spreading activation, expectancy, and semantic matching. METHODS The present study manipulated two factors known to differentiate semantic priming mechanisms: associations between words (forward, backward, and symmetrical) and prime-target stimulus onset asynchrony (SOA). Twenty-six participants were tested in each SOA condition while high-density 128-channel data were collected. Principal components analysis was applied to separate the ERP components. RESULTS Priming was observed for all conditions. Three semantic components were present: (1) the standard N400 effect for symmetric and forward priming pairs at both short and long SOAs, (2) an N300 for the long SOA symmetric priming pairs, and (3) a right-lateralized posterior N400RP for long SOA backward priming pairs. CONCLUSIONS Results suggest that the N300 reflects expectancy, but only for categorical and/or semantic similarity priming. Results further suggest that the N400RP is a replicable ERP component that responds to semantic matching. There is also some evidence that the N400 indirectly responds to both ASA and expectancy, perhaps as part of a post-lexical updating process and that backward priming at short SOAs is different from that at long SOAs. SIGNIFICANCE Improved understanding of the semantic properties of the N400 and related ERP components may increase their utility for understanding language processes and for diagnostic purposes.