Exploring a neural-network account of age-of-acquisition effects using repetition priming of faces

The question of whether age-of-acquisition (AoA), frequency, and repetition priming effects occur at a common stage or at different stages of processing is addressed. Two single-stage accounts (i.e., cumulative frequency and a neural-network simulation) are considered in regard to their predictions concerning the interactions between AoA and frequency with aging and priming effects. A repetition-priming face-classification task was conducted on both older and younger participants to test these predictions. Consistent with the predictions of the neural-network simulation, AoA had an effect on reaction times that could not be explained by cumulative frequency alone. Also, as predicted by the simulation, the size of the priming effect was determined by the cumulative frequency of the item. It is discussed how this evidence is supportive of the notion that AoA , frequency, and priming all have effects at a common and single stage during face processing.     

Dissociative prime-probe contextual similarity effects on negative priming and repetition priming: a challenge to episodic retrieval as a unified account of negative priming

This study examined the dependence of repetition priming (RP) and negative priming (NP) as a function of prime-probe contextual similarity in a paradigm in which participants were required to respond to a letter flanked by incompatible distractor letters (e.g., ABA). Experiment 1 used prime and probe displays containing a pair of "+" symbols that were presented horizontally or vertically. Experiments 2 and 3 manipulated whether the letter triplets contained the "!" symbol. In all experiments, regardless of whether the RP trials were intermixed with the NP trials (Experiment 2) or not (Experiment 3), RP was stronger in the prime-probe similar conditions than in the prime-probe dissimilar conditions, but NP was independent of prime-probe contextual similarity. These findings suggest that NP is not necessarily stronger in conditions in which episodic retrieval of the prime is more likely.     

Masked repetition priming using magnetoencephalography

Masked priming is used in psycholinguistic studies to assess questions about lexical access and representation. We present two masked priming experiments using MEG. If the MEG signal elicited by words reflects specific aspects of lexical retrieval, then one expects to identify specific neural correlates of retrieval that are sensitive to priming. To date, the electrophysiological evidence has been equivocal. We report findings from two experiments. Both employed identity priming, where the prime and target are the same lexical item but differ in case (NEWS-news). The first experiment used only forward masking, while the prime in the second experiment was both preceded and followed by a mask (backward masking). In both studies, we find a significant behavioral effect of priming. Using MEG, we identified a component peaking approximately 225 ms post-onset of the target, whose latency was sensitive to repetition. These findings support the notion that properties of the MEG response index specific lexical processes and demonstrate that masked priming can be effectively combined with MEG to investigate the nature of lexical processing.     

Associative processes in repetition priming

Three experiments that investigated alternative accounts of repetition priming are reported. All 3 experiments used semantic comparison tasks and included trials in which each of the 2 words being compared had previously occurred on separate trials. In the re-pair match condition, the response required matched that on the 2 previous trials in which the words had occured. In there-pair mismatch condition, the response required was opposite to that on the previous trials containing the words forming the critical pair. In all 3 experiments, responses were faster and more accurate in the re-pair match condition than in the re-pair mismatch condition. Possible accounts of this effect within the frameworks of instance theory and of transfer appropriate processing are considered.     

Cross-modal repetition priming of heterographic homophones

In two cross-modal priming experiments in French, we investigated the effects of auditorily presented heterographic homophones (an English example is /meId/) on the subsequent visual recognition of the dominant (MADE) and subordinate (MAID) printed forms. When only pronounceable, regular nonwords were used as distractor items in the lexical decision task, both dominant and subordinate forms were facilitated by the homophone prime relative to an unrelated word prime. When pseudohomophones were added among the nonword distractors, dominant targets continued to show facilitation while subordinate targets showed an inhibitory trend. These results provide evidence for inhibition-based selection in the processing of ambiguous words in the absence of any biasing context.     

Emotional arousal enhances word repetition priming

Three experiments were conducted to determine if emotional content increases repetition priming magnitude. In the study phase of Experiment 1, participants rated high-arousing negative (taboo) words and neutral words for concreteness. In the test phase, they made lexical decision judgements for the studied words intermixed with novel words (half taboo, half neutral) and pseudowords. In Experiment 2, low-arousing negative (LAN) words were substituted for the taboo words, and in Experiment 3 all three word types were used. Results showed significant priming in all experiments, as indicated by faster reaction times for studied words than for novel words. A priming × emotion interaction was found in Experiments 1 and 3, with greater priming for taboo relative to neutral words. The LAN words in Experiments 2 and 3 showed no difference in priming magnitude relative to the other word types. These results show selective enhancement of word repetition priming by emotional arousal.     

Modality-specific repetition priming of auditory word recognition

Subjects were pretrained on 30 experimental words by matching each to one of three definitions. The pretrained words were presented auditorily, or in their conventional spellings, or phonically misspelt (e.g., LORNE for lawn). The same words were later interleaved randomly with 70 new filler words and presented auditorily in a background of white noise. Only the auditory pretraining led to significantly improved recognition of the experimental words when compared with the recognition scores of a control group of subjects given no form of pretraining.     

Testing instance models of face repetition priming

Two experiments examining repetition priming in face recognition are reported. They employed eight rather than the more usual two presentation trials so that the prediction made by Logan's (1988) instance model of power function speedup of response time (RT) distributions could be examined. In Experiment 1, we presented the same photograph on each trial; in Experiment 2, we presented photographs of varying poses. Both experiments showed repetition priming effects for familiar and unfamiliar faces, power function speedup for both the mean and the standard deviation of RT and the power function speedup of the quanties of the RT distributions. We argue that our findings are consistent with the predictions made by the instance model and provide an explanatory challenge for alternative theoretical approaches.     

Strategic associative priming in the lexical decision task

Two experiments explore the nature of prelexical expectancy processes in the lexical decision task. The strength of the prime-target relationship and the size of the associative set defined by the prime were manipulated in both experiments. In Experiment 1, the proportion of strong relative to weak primes induced subjects to include strong and weak candidate words in their expectancy set, whereas in Experiment 2 that proportion attempted to induce subjects to include mainly strongly related words. Results showed that priming depended on whether the primes were included in the set. Thus, in Experiment 1 facilitation was obtained for both strong and weak primes, whereas in Experiment 2 the facilitation of weak primes depended on the size of the associative set defined by the prime. Results are discussed within a theoretical framework that includes prelexical expectancy processes in the lexical decision task.     

Object color affects identification and repetition priming

We investigated the influence of color on the identification of both non-studied and studied objects. Participants studied black and white and color photos of common objects and memory was assessed with an identification test. Consistent with our meta-analysis of prior research, we found that objects were easier to identify from color than from black and white photos. We also found substantial priming in all conditions, and study-to-test changes in an object's color reduced the magnitude of priming. Color-specific priming effects were large for color-complex objects, but minimal for color-simple objects. The pattern and magnitude of priming effects was not influenced either by the extent to which an object always appears in the same color (i.e., whether a color is symptomatic of an object) or by the object's origin (natural versus fabricated). We discuss the implications of our findings for theoretical accounts of object perception and repetition priming.     

An attention account of neural priming

Repetition priming of familiar stimuli (e.g., objects) produces a decrease in visual cortical activity for repeated versus novel items, which has been attributed to more fluent processing for repeated items. By contrast, priming of unfamiliar stimuli (e.g., abstract shapes) produces an increase in visual cortical activity. The mechanism for priming-related increases in activity for repeated unfamiliar stimuli is unknown. We hypothesised that such increases in activity may reflect attentional allocation to these items. We tested this hypothesis using a priming-spatial attention paradigm. During Phase 1 of Experiment 1, participants viewed unfamiliar abstract shapes and familiar objects. During Phase 2, participants identified target letters (S or H). Each target letter was preceded by a non-informative shape or object cue that was repeated (from Phase 1) or novel in the same (valid) or opposite (invalid) hemifield. In Experiment 2, we manipulated shape familiarity by presenting shapes once or six times during Phase 1. For both experiments, at valid locations, target identification accuracy was higher following repeated versus novel unfamiliar item cues and lower following repeated versus novel familiar item cues. These findings support our hypothesis that priming-related increases in visual cortical activity for repeated unfamiliar items may, in part, reflect attentional allocation.     

Testing an associative account of semantic satiation

How is the meaning of a word retrieved without interference from recently viewed words? The ROUSE theory of priming assumes a discounting process to reduce source confusion between subsequently presented words. As applied to semantic satiation, this theory predicted a loss of association between the lexical item and meaning. Four experiments tested this explanation in a speeded category-matching task. All experiments used lists of 20 trials that presented a cue word for 1 s followed by a target word. Randomly mixed across the list, 10 trials used cues drawn from the same category whereas the other 10 trials used cues from 10 other categories. In Experiments 1a and 1b, the cues were repeated category labels (FRUIT–APPLE) and responses gradually slowed for the repeated category. In Experiment 2, the cues were nonrepeated exemplars (PEAR–APPLE) and responses remained faster for the repeated category. In Experiment 3, the cues were repeated exemplars in a word matching task (APPLE–APPLE) and responses again remained faster for the repeated category.     

An associative account of the development of word learning

Word learning is a notoriously difficult induction problem because meaning is underdetermined by positive examples. How do children solve this problem? Some have argued that word learning is achieved by means of inference: young word learners rely on a number of assumptions that reduce the overall hypothesis space by favoring some meanings over others. However, these approaches have difficulty explaining how words are learned from conversations or text, without pointing or explicit instruction. In this research, we propose an associative mechanism that can account for such learning. In a series of experiments, 4-year-olds and adults were presented with sets of words that included a single nonsense word (e.g. dax). Some lists were taxonomic (i.,e., all items were members of a given category), some were associative (i.e., all items were associates of a given category, but not members), and some were mixed. Participants were asked to indicate whether the nonsense word was an animal or an artifact. Adults exhibited evidence of learning when lists consisted of either associatively or taxonomically related items. In contrast, children exhibited evidence of word learning only when lists consisted of associatively related items. These results present challenges to several extant models of word learning, and a new model based on the distinction between syntagmatic and paradigmatic associations is proposed.     

Semantic priming of person recognition: Categorial priming may be a weaker form of the associative priming effect

An interactive activation and competition account (Burton, Bruce, & Johnston, 1990) of the semantic priming effect in person recognition studies relies on the fact that primes and targets (people) have semantic information in common. However, recent investigations into the type of relationship needed to mediate the semantic priming effect have suggested that the prime and target must be close associates (e.g., Barry, Johnston, & Scanlan, 1998; Young, Flude, Hellawell, & Ellis, 1994). A review of these and similar papers suggests the possibility of a small but non-reliable effect based purely on categorial relationships. Experiment 1 provided evidence that when participants were asked to make a name familiarity decision it was possible to boost this small categorial effect when multiple (four) primes were presented prior to the target name. Results from Experiment 2 indicated that the categorial effect was not due to the particular presentation times of the primes. This boosted categorial effect was shown to cross domains (names to faces) in Experiment 3 and persist in Experiment 4 when the task involved naming the target face. The similarity of the pattern of results produced by the associative priming effect and this boosted categorial effect suggests that the two may be due to the same underlying mechanism in semantic memory.     

Attention and repetition priming in the verb generation task

Transfer-appropriate processing (TAP) and identification–production frameworks predict that repetition priming will be reduced by encoding-phase divided attention (DA) in implicit memory tasks that involve conceptual analysis of test stimuli and require responses that go beyond the identification of the test cue. This prediction was tested using the verb generation task. Verb generation priming was weakly affected by a number classification distracting task at encoding that impacted recognition, was affected more by a more demanding mental arithmetic task, and was abolished entirely by a selective attention manipulation. Priming originating largely from a process unique to the verb generation task was also found to be attention-sensitive. DA affected priming equivalently for high-competition and low-competition items, against the identification–production framework which predicts greater DA effects on priming in high-competition conditions. The results fit comfortably within the TAP framework.     

Understanding the relationship between repetition priming and mere exposure

Over the last two decades interest in implicit memory, most notably repetition priming, has grown considerably. During the same period, research has also focused on the mere exposure effect. Although the two areas have developed relatively independently, a number of studies has described the mere exposure effect as an example of implicit memory. Tacit in their comparisons is the assumption that the effect is more specifically a demonstration of repetition priming. Having noted that this assumption has attracted relatively little attention, this paper reviews current evidence and shows that it is by no means conclusive. Although some evidence is suggestive of a common underlying mechanism, even a modified repetition priming (perceptual fluency/attribution) framework cannot accommodate all of the differences between the two phenomena. Notwithstanding this, it seems likely that a version of this theoretical framework still offers the best hope of a comprehensive explanation for the mere exposure effect and its relationship to repetition priming. As such, the paper finishes by offering some initial guidance as to ways in which the perceptual fluency/attribution framework might be extended, as well as outlining important areas for future research.     

Influence of stimulus repetition on negative priming.

Potential age-related differences in the influence of stimulus repetition on negative and positive priming were investigated in a same-different picture comparison task. Forty-eight young adults and 48 old adults compared a target picture of a familiar object with a standard picture of a familiar object to determine if they were the same or different, while ignoring an overlapping distractor picture presented in a different color. Negative priming effects increased in magnitude with the repetition of the experimental stimuli in a similar fashion for both young and old adults. Conversely, positive priming effects decreased in magnitude with increases in stimulus repetition for both young and old adults. These data suggest that identity-based inhibition develops in a similar fashion from young adulthood to old age. Furthermore, these data add to the growing body of studies that suggest age invariance in the ability to inhibit task-irrelevant information in the environment on the basis of stimulus identity.     

Semantic and associative priming in picture naming

We report four picture-naming experiments in which the pictures were preceded by visually presented word primes. The primes could either be semantically related to the picture (e.g., "boat" - TRAIN: co-ordinate pairs) or associatively related (e.g., "nest" - BIRD: associated pairs). Performance under these conditions was always compared to performance under unrelated conditions (e.g., "flower" - CAT). In order to distinguish clearly the first two kinds of prime, we chose our materials so that (a) the words in the co-ordinate pairs were not verbally associated, and (b) the associate pairs were not co-ordinates. Results show that the two related conditions behaved in different ways depending on the stimulus-onset asynchrony (SOA) separating word and picture appearance, but not on how long the primes were presented. When presented with a brief SOA (114 ms, Experiment 1), the co-ordinate primes produced an interference effect, but the associated primes did not differ significantly from the unrelated primes. Conversely , with a longer SOA (234 ms, Experiment 2) the co-ordinate primes produced no effect, whereas a significant facilitation effect was observed for associated primes, independent of the duration of presentation of the primes. This difference is interpreted in the context of current models of speech production as an argument for the existence, at an automatic processing level, of two distinguishable kinds of meaning relatedness.