Semantic priming effects from single words in a lexical decision task

The present research examines the semantic priming effects of a centrally presented single prime word to which participants were instructed to either "attend and remember" or "ignore". The prime word was followed by a central probe target on which the participants made a lexical decision task. The main variables manipulated across experiments were prime duration (50 or 100 ms), the presence or absence of a mask following the prime, and the presence (or absence) and type of distractor stimulus (random set of consonants or pseudowords) on the probe display. There was a consistent interaction between the instructions and the semantic priming effects. Relative to the "attend and remember" instruction, an "ignore" instruction produced reduced positive priming from single primes presented for 100 ms, irrespective of the presence or absence of a prime mask, and regardless of whether the probe target was presented with or without distractors. Additionally, reliable negative priming was found from ignored primes presented for briefer durations (50 ms) and immediately followed by a mask. Methodological and theoretical implications of the present findings for the extant negative priming literature are discussed.     

Influence of prime-target relationship on semantic priming effects from words in a lexical-decision task

The present research examines the influence of prime-target relationship (associative and categorical versus categorical only) on priming effects from attended and ignored parafoveal words. Participants performed a lexical-decision task on a single central target, which was preceded by two parafoveal prime words, one of which (the attended prime) was spatially precued. The results showed reliable positive and negative priming effects from attended and ignored words, respectively. However, this priming pattern was observed only for the "associative and categorical", but not for the "categorical only" relationship condition. These results suggest that the lack of semantic priming effects from words in some prior studies may be attributed to the kind of material used (i.e. weakly-associated word pairs).     

Letter search does not affect semantic priming in a probe naming task

The normally robust semantic priming effect observed in lexical decision is usually reduced to the point of being absent, when a letter search has to be performed on the prime. It has been argued that semantic activation is thus not an automatic process but rather cognitively controlled and therefore adaptable to task demands. We examined the effects of letter search priming on pronunciation times and found a reliable semantic priming effect, following letter search that was not affected at all relative to a standard condition, where participants silently read the prime. Thus the nature of the prime task did not seem to affect the processing mode employed, semantic access occurred even though attention was focused on surface properties of the prime.     

The effects of response priming on the planning and execution of goal-directed movements in the presence of a distracting stimulus

Two models of selective reaching have been proposed to account for deviations in movement trajectories in cluttered environments. The response vector model predicts movement trajectories should deviate towards or away from the location a distractor of little or large salience, respectively. In contrast, the response activation model predicts that a distractor with large salience should cause movement deviations towards it whereas a distractor with little salience should not influence the movement. The precuing technique was combined with the distractor interference paradigm to test these predictions. Results indicate that when the target was presented at the precued (salient) location, movements were unaffected by a distractor. Conversely, when the distractor was presented at the precued location while the target was presented at an uncued (non-salient) location, participants demonstrated increased reaction times and trajectory deviations towards the location of the distractor. These findings are consistent with the model of response activation.     

Simple arithmetic processing: surface form effects in a priming task

Models of numerical processing vary on whether they assume common or separate processing pathways for problems represented in different surface forms. The present study employed a priming procedure, with target naming task, in an investigation of surface form effects in simple addition and multiplication operations. Participants were presented with Arabic digit and number word problems in one of three prime-target relationships, including congruent (e.g., '2+3' and '5'), incongruent (e.g., '9+7' and '5') and neutral (e.g., 'X+Y' and '5') conditions. The results revealed significant facilitatory effects in response to congruent digit stimuli at SOAs of 300 and 1000ms, in both operations. In contrast, inhibitory effects were observed in response to incongruent word stimuli in both the addition and multiplication operations at 300ms, and in the addition operation at 1000ms. The overall priming effects observed in the digit condition were significantly greater than in the word condition at 1000ms in the multiplication operation and at 300ms in the addition operation. The results provide support to separate pathway accounts of simple arithmetic processing for problems represented in different surface forms. An explanation for variation in processing due to differences in access to visual and phonological representations is provided.     

Negative priming in a gender decision task and in a semantic categorization task

In three experiments, we tested the hypothesis that negative priming (NP) can occur without prime or target selection, when conflicting properties are associated with the prime and the target, and when the experimental conditions allow the encoding of the target as a separate episode from the prime. These predictions were confirmed in Experiment 1, using a gender decision task. Responses were slower when prime and target had the same gender than when they had different genders, with an inter-stimulus interval (ISI) of 600 ms but not with an ISI of 25 ms. Experiment 2 eliminated a possible explanation of the NP obtained in Experiment 1, in terms of response inhibition during the prime processing. Finally, Experiment 3 demonstrated the replicability and the generality of our NP, in a semantic categorization task. Empirical and theoretical consequences of our results for studies using the priming paradigm are discussed.     

Repetition priming mediated by task similarity in semantic classification

In the present study, the specificity of repetition priming between semantic classification tasks was examined using Osgood's (Osgood, Suci, & Tannenbaum, 1957) semantic space as a heuristic for determining the similarity between classifications. The classification tasks involved judging the meaning of words on semantic scales, such as pleasant/unpleasant. The amount of priming across classifications was hypothesized to decrease with increasing distance (decreasing similarity) between semantic scales in connotative semantic space. The results showed maximum repetition priming when the study and the test classifications were the same, intermediate degrees of priming when the study and the test classification scales shared loadings on semantic factors, and little priming when the study and the test classification scales loaded primarily on orthogonal semantic factors--that is, when the distance between scales was maximized. Consistent with the transfer-appropriate processing framework, repetition priming in semantic classifications was highly task specific, decreasing with increasing distance between classification scales.     

Negative priming between pictures and words in a selective attention task: Evidence for semantic processing of ignored stimuli

This study examined the processing of ignored pictures and words when attention was directed to a different picture or word. Previous work by Tipper (1985) demonstrated that the priming effect of an ignored picture on a subsequent categorically related picture is inhibitory. This effect was termednegative priming. Tipper concluded that ignored pictures achieved abstract categorical levels of internal representation, and that these representations were inhibited during selection of a simultaneously presented picture. This conclusion, however, was premature. Observation of the figures used by Tipper suggests that objects within a category have greater structural similarity than do objects in different categories. The negative priming effect could therefore be at a structural level of representation. The present study examined priming across symbolic domains (pictures and words) where there was no structural relationship between objects. Negative priming was again observed and was equivalent to the negative priming observed within symbolic domain. These data suggest that ignored drawings and words do achieve abstract categorical levels of representation, and that the mechanisms underlying negative priming operate at, or beyond, this level.     

Upper-left gaze bias reveals competing search strategies in a reverse Stroop task

Three experiments with a total of 87 human observers revealed an upper-left spatial bias in the initial movement of gaze during visual search. The bias was present whether or not the explicit control of gaze was required for the task. This bias may be part of a search strategy that competed with the fixed-gaze parallel search strategy hypothesized by Durgin [Durgin, F. H. (2003). Translation and competition among internal representations in a reverse Stroop effect. Perception &Psychophysics, 65, 367-378.] for this task. When the spatial probabilities of the search target were manipulated either in accord with or in opposition to the existing upper-left bias, two orthogonal factors of interference in the latency data were differentially affected. The two factors corresponded to two different forms of representation and search. Target probabilities consistent with the gaze bias encouraged opportunistic serial search (including gaze shifts), while symmetrically opposing target probabilities produced latency patterns more consistent with parallel search based on a sensory code.     

Excitatory and inhibitory priming by attended and ignored non-recycled words with monolinguals and bilinguals

Experiments examining identity priming from attended and ignored novel words (words that are used only once except when repetition is required due to experimental manipulation) in a lexical decision task are reported. Experiment 1 tested English monolinguals whereas Experiment 2 tested Twi (a native language of Ghana, Africa)-English bilinguals. Participants were presented with sequential pairs of stimuli composed of a prime followed by a probe, with each containing two items. The participants were required to name the target word in the prime display, and to make a lexical decision to the target item in the probe display. On attended repetition (AR) trials the probe target item was identical to the target word on the preceding attentional display. On ignored repetition (IR) trials the probe target item was the same as the distractor word in the preceding attentional display. The experiments produced facilitated (positive) priming in the AR trials and delayed (negative) priming in the IR trials. Significantly, the positive and negative priming effects also replicated across both monolingual and bilingual groups of participants, despite the fact that the bilinguals were responding to the task in their non-dominant language.     

Fast trial pacing in a lexical decision task reveals a decay of automatic semantic activation

We report an experiment showing that reducing attentional resources by presenting trials with a short, 400 ms intertrial interval (ITI) (a) did not affect semantic priming at a 160 ms prime-to-target stimulus-onset asynchrony (SOA), relative to a 2500 ms ITI, and (b) eliminated the priming that occurred at a 1200 ms SOA when the ITI was 2500 ms. However, the elimination of priming at the 1200 ms SOA occurred only when the relatedness proportion (RP, proportion of related primes and targets) was .25 and not when it was .75. We interpret these results as showing that attentional/strategic priming occurs with an RP as low as .25, but only when sufficient attentional resources are available. Equally important, this is the first direct evidence that automatic semantic activation decays within 1200 ms in the standard semantic-priming/lexical-decision paradigm when attentional resources are not being used to maintain the goal of sustaining prime activation. We further argue that the frequent occurrences of related primes and targets with a high RP serve as reminders to maintain that goal such that cognitive load does not reduce long-SOA priming when the RP is high.     

Repetition priming within and between languages in semantic classification of concrete and abstract words

Although concrete nouns are generally agreed to have shared core conceptual representations across languages in bilinguals, it has been proposed that abstract nouns have separate representations or share fewer semantic components. Conceptual repetition priming methodology was used to evaluate whether translation equivalents of abstract nouns have shared conceptual representations and compare the degree of conceptual overlap for concrete and abstract nouns. Here 72 Spanish-English bilinguals made concrete-abstract decisions on English and Spanish nouns. Both concrete and abstract nouns elicited substantial between-language priming and these effects were of equivalent size, indicating that translation equivalents of both concrete and abstract nouns have shared conceptual representations and that abstract words do not share fewer components. The between-language priming effects and their attenuation relative to within-language priming indicate that the within-language effect is based on facilitation of both word comprehension and semantic decision processes.     

Effect of short and long exposure duration and dual-tasking on a global-local task

Past research has demonstrated a global advantage in responses to visually presented hierarchical stimuli such that, on incongruent trials, the global form interferes with responses to the local level [Kimchi, R. (1992). Primacy of wholistic processing and global/local paradigm: A critical review. Psychological Bulletin, 112, 24-38]. In Experiment 1, 32 adults performed alternating blocks of global or local identification of hierarchical letter stimuli in which the global and local letters were congruent, incongruent, or neutral, and were presented at either a short (17 ms) or long (100 ms) exposure duration. A global advantage was demonstrated at both durations. In the local-directed task, interference on incongruent, relative to neutral, trials was observed at both exposure durations, but facilitation on congruent trials, relative to neutral trials, was present only when stimuli were presented at the long exposure duration. In Experiment 2, global or local identification was performed by another group of 24 adults at either a long or short exposure duration, and also under conditions of full attention (FA) or dual-task (DT) conditions with a digit-monitoring task. Under FA, we again found significant interference at both exposure durations, but facilitation only at the long exposure duration. Under DT conditions, the pattern of facilitation and interference at the short duration remained unchanged. At the long duration, however, dual-tasking eliminated interference in the RT but not error data, while facilitation was present in both sets of data. Results are in line with a perceptual account of the global advantage, and suggest that facilitation requires consciously-mediated processes, whereas interference does not.     

Repetition priming within and between languages in semantic classification of concrete and abstract words

Although concrete nouns are generally agreed to have shared core conceptual representations across languages in bilinguals, it has been proposed that abstract nouns have separate representations or share fewer semantic components. Conceptual repetition priming methodology was used to evaluate whether translation equivalents of abstract nouns have shared conceptual representations and compare the degree of conceptual overlap for concrete and abstract nouns. Here 72 Spanish–English bilinguals made concrete–abstract decisions on English and Spanish nouns. Both concrete and abstract nouns elicited substantial between-language priming and these effects were of equivalent size, indicating that translation equivalents of both concrete and abstract nouns have shared conceptual representations and that abstract words do not share fewer components. The between-language priming effects and their attenuation relative to within-language priming indicate that the within-language effect is based on facilitation of both word comprehension and semantic decision processes.     

Masked priming effects in semantic categorization are independent of category size

The question whether subliminal primes can activate their semantic meaning or not is still of interest today. Three different competing theories have tried to account for the often inconsistent research results: The semantic categorization hypothesis, the direct motor specification hypothesis, and the category search model. The present study aimed to shed light on these different points of view by examining the role of category size in response congruency effects when novel primes are used. Three experiments were conducted and a transparent pattern of results emerged: Significant priming effects were obtained across different tasks, irrespective of category size and irrespective of stimulus set size. The findings are discussed in terms of the three theoretical frameworks. It becomes clear that the present results provide strong evidence in favor of the semantic categorization hypothesis, which assumes semantic processing of subliminal primes.     

Category size effects revisited: frequency and masked priming effects in semantic categorization

Previous work indicates that semantic categorization decisions for nonexemplars (e.g., deciding that TURBAN is not an animal name) are faster for high-frequency words than low-frequency words. However, there is evidence that this result might depend on category size. When narrow categories are used (e.g., Months, Numbers), there is no frequency effect for nonexemplars. This result is confirmed, and is explained in terms of a category search model, which allows a "No" decision to be generated without access to the lexical entry for the target word. This explains the absence of a frequency effect, but not the presence of a strong masked repetition priming effect, which is assumed to have a lexical source. It is shown that this effect may not be lexical, since nonwords also show similar priming. Both of these priming effects disappear when a larger category is used. This pattern of results is explained on the assumption that category search is only possible with small categories, and that tentative category decisions are generated for the unconsciously perceived prime, which leads to a marked response congruence effect.     

Influence of prime-probe stimulus onset asynchrony and prime precuing manipulations on semantic priming effects with words in a lexical-decision task

The present research examines semantic priming from attended and unattended parafoveal words. Participants made a lexical decision in response to a single central target. The target was preceded by two parafoveal prime words, with one of them (the attended prime) being precued by a peripheral cue. The main variables manipulated across experiments were cue informativeness (valid vs. neutral cues) and stimulus onset asynchrony (SOA) between prime and probe (200, 300, 600, or 1,000 ms). The results showed (a) reliable semantic priming from both attended and ignored prime words and (b) that the ignored priming effects were either negative or positive, depending on both the prime-probe SOA and cue informativeness. The present findings are discussed in relation to inhibitory versus episodic retrieval models of negative priming.     

The sensory nature of knowledge: Sensory priming effects in semantic categorization

The aim of the present study was to show the perceptual nature of conceptual knowledge by using a priming paradigm that excluded an interpretation exclusively in terms of amodal representation. This paradigm was divided into two phases. The first phase consisted in learning a systematic association between a geometrical shape and a white noise. The second phase consisted of a short-term priming paradigm in which a primed shape (either associated or not with a sound in the first phase) preceded a picture of an object, which the participants had to categorize as representing a large or a small object. The objects were chosen in such a way that their principal function either was associated with the production of noise (“noisy” target) or was not typically associated the production of noise (“silent” target). The stimulus onset asynchrony (SOA) between the prime and the target was 100 ms or 500 ms. The results revealed an interference effect with a 100-ms SOA and a facilitatory effect with a 500-ms SOA for the noisy targets only. We interpreted the interference effect obtained at the 100-ms SOA as the result of an overlap between the components reactivated by the sound prime and those activated by the processing of the noisy target. At an SOA of 500 ms, there was no temporal overlap. The observed facilitatory effect was explained by the preactivation of auditory areas by the sound prime, thus facilitating the categorization of the noisy targets only.     

A challenging dissociation in masked identity priming with the lexical decision task

The masked priming technique has been used extensively to explore the early stages of visual-word recognition. One key phenomenon in masked priming lexical decision is that identity priming is robust for words, whereas it is small/unreliable for nonwords. This dissociation has usually been explained on the basis that masked priming effects are lexical in nature, and hence there should not be an identity prime facilitation for nonwords. We present two experiments whose results are at odds with the assumption made by models that postulate that identity priming is purely lexical, and also challenge the assumption that word and nonword responses are based on the same information. Our experiments revealed that for nonwords, but not for words, matched-case identity PRIME–TARGET pairs were responded to faster than mismatched-case identity prime–TARGET pairs, and this phenomenon was not modulated by the lowercase/uppercase feature similarity of the stimuli.     

Retroactive semantic priming in a lexical decision task

The present study reports two experiments that required subjects to name target items preceded by a masked prime. Additionally, and subsequent to the naming task, subjects were required to indicate whether or not the prime was a word, along with a confidence rating of their lexical decision. Experiment 1 demonstrates that the processing of masked primes is facilitated by related targets when such targets are presented either 100 or 200 msec after the onset of the prime. Experiment 2 extends the finding of “retroactive” priming to a 1000=msec separation in prime-target presentation (SOA). The extent of retroactive priming is not dependent on SOA between prime and target, nor is it affected by the prime-mask SOA, which varied from 10 to 180 msec. Priming of targets was also independent of prime-target and prime-mask SOA, providing that primes had been classified as words. For word primes classified as non-words there was no semantic priming on target naming reaction time. Implications of these findings with respect to the nature of retroactive priming and the current controversy concerning subliminal priming effects were discussed.