The loss of repetition priming and automaticity over time as a function of degree of initial learning

Semantic-to-autobiographical memory priming causes involuntary autobiographical memory production: The effects of single and multiple prime presentations

A number of studies (Mace et al., Memory & Cognition, 47, 299-312, 2019; Mace & Unlu, Memory & Cognition, 48, 931-941, 2020) have demonstrated that the activation of semantic memories leads to the activation of autobiographical memories on an involuntary memory task (the vigilance task; Schlagman & Kvavilashvili, Memory & Cognition, 36, 920-932, 2008), suggesting that this form of priming (semantic-to-autobiographical) plays a role in the production of involuntary autobiographical memories in everyday life. In the current study, we investigated the effects of prime repetition on involuntary memory production in the vigilance task. Primed participants were either treated to one priming session, where they judged the familiarity of words (e.g., parade), or three priming sessions, where they also judged the familiarity of words as well as decided whether sentences containing the words made sense (e.g., the parade dragged on for hours), and if their corresponding images were sensible (e.g., an image of a parade). The results showed that primed participants produced more involuntary memories with primed content on the vigilance task than control participants, and three-session primed participants produced more memories than one-session primed participants. Similar to other areas where prime repetition has been investigated (e.g., implicit memory, semantic priming), the results show that prime repetition enhances semantic-to-autobiographical memory priming. The results also further support the idea that semantic-to-autobiographical memory priming may play a significant role in the production of involuntary memories in everyday life, as concept repetition is a likely part of everyday experience. These implications, as well as others, are discussed.

The Outrage Effect of Personal Stake, Dread, and Moral Nature on Fine Dust Risk Perception Moderated by Media Use

Outrage factors are perceived characteristics of risk that provoke emotional responses and influence risk perception by individuals. We investigated outrage factors that are associated with risk perception regarding fine dust. A nationwide online survey (N = 1,000) measured the magnitude of 14 perceived outrage factors and media use in a South Korean population. As a result, the hypothetical three outrage factors of personal stake, dread, and moral nature were found to be influential. The risk perception increased when people perceived that the environmental hazard has personal implications or is associated with fearful images and irresponsible government/corporate actions. The risk perception was also heightened when fine dust was thought to cause large-scale damage to many people simultaneously. Those using news media frequently showed higher risk perception than those using it less frequently. However, heavy media users were affected to a lesser degree by the outrage effects voluntariness and effects on children. The implications of the direct and indirect outrage effect are discussed in light of risk perception studies.

Learning Habits: Does Overtraining Lead to Resistance to New Learning?

We explore the development of habitual responding within the colour-word contingency learning paradigm, in which participants respond to the colour of neutral words. Each word is most often presented in one colour. Learning is indicated by faster responses to the colour when the word is presented in the expected rather than in the unexpected colour. In Experiment 1, participants took part in two sessions, separated by one day. Critically, one set of words was trained across both days, and other new sets of words were introduced at various time points. Overall performance was faster on trials with overtrained words. Additionally, contingency effects were larger for overtrained words than for words introduced on Day 2. Removing the contingency had a similar impact on the learning effect for overtrained and new words. However, during a counterconditioning phase, where the words were made predictive of new colours, the previous contingency continued to influence performance for overtrained words but not for more recently introduced words. Relatedly, the new contingency was not acquired for the overtrained words. The reverse pattern was observed for recently-introduced words, with the newly-introduced contingency rapidly acquired and the influence of the old contingency quickly extinguished. In Experiments 2 and 3, however, both new and old learning effects were observed for both overtrained and recently-acquired contingencies. The net results suggest that while contingency learning effects are highly pliable during initial and subsequent learning, early-acquired contingency knowledge is maintained after removal of the contingency. Implications for models of learning are discussed.

Dissociation of binding and learning processes

A single encounter of a stimulus together with a response can result in a short-lived association between the stimulus and the response [sometimes called an event file, see Hommel, Müsseler, Aschersleben, & Prinz, (2001) Behavioral and Brain Sciences, 24, 910-926]. The repetition of stimulus-response pairings typically results in longer lasting learning effects indicating stimulus-response associations (e.g., Logan & Etherton, (1994) Journal of Experimental Psychology: Learning, Memory, and Cognition, 20, 1022-1050]. An important question is whether or not what has been described as stimulus-response binding in action control research is actually identical with an early stage of incidental learning (e.g., binding might be seen as single-trial learning). Here, we present evidence that short-lived binding effects can be distinguished from learning of longer lasting stimulus-response associations. In two experiments, participants always responded to centrally presented target letters that were flanked by response irrelevant distractor letters. Experiment 1 varied whether distractors flanked targets on the horizontal or vertical axis. Binding effects were larger for a horizontal than for a vertical distractor-target configuration, while stimulus configuration did not influence incidental learning of longer lasting stimulus-response associations. In Experiment 2, the duration of the interval between response n - 1 and presentation of display n (500 ms vs. 2000 ms) had opposing influences on binding and learning effects. Both experiments indicate that modulating factors influence stimulus-response binding and incidental learning effects in different ways. We conclude that distinct underlying processes should be assumed for binding and incidental learning effects.

Repeated Repetition Priming in Face Recognition

Prior exposure to an item can facilitate subsequent recognition of that item. This effect, known as repetition priming, has been found for the recognition of many stimuli including faces (Bruce & Young, 1986). Three experiments are reported, which investigated whether repetition priming is limited to the first repetition or whether subsequent repetitions continually act to increase the speed of face processing. Experiment 1 demonstrated that repetition can reduce categorization time for faces after the first exposure, and this effect is independent of practice effects. Experiment 2 demonstrated that the relationship between reaction time and number of repetitions fits a negative power function. Experiment 3 investigated how delay affects this power function. Delay was found to decrease the negative gradient of the power curve. The effects of priming and delay are discussed in terms of the predictions made by Burton's (1994) interactive activation and competition with learning (IACL) model of face recognition and accounts of automaticity.

The role of allograph representations in font-invariant letter identification

The literate brain must contend with countless font variants for any given letter. How does the visual system handle such variability? One proposed solution posits stored structural descriptions of basic letter shapes that are abstract enough to deal with the many possible font variations of each letter. These font-invariant representations, referred to as allographs in this paper, while frequently posited, have seldom been empirically evaluated. The research reported here helps to address this gap with 2 experiments that examine the possible influence of allograph representations on visual letter processing. In these experiments, participants respond to pairs of letters presented in an atypical font in 2 tasks-visual similarity judgments (Experiment 1) and same/different decisions (Experiment 2). By using representational similarity analysis (RSA) in conjunction with linear mixed effect models (LMEM; RSA-LMEM) we show that the similarity structure of the responses to the atypical font is influenced by the predicted similarity structure of allograph representations even after accounting for font-specific visual shape similarity. Similarity due to symbolic (abstract) identity, name, and motor representations of letters are also taken into account providing compelling evidence for the unique influence of allograph representations in these tasks. These results provide support for the role of allograph representations in achieving font-invariant letter identification. (PsycINFO Database Record

Reading and lexicalization in opaque and transparent orthographies: Word naming and word learning in English and Spanish

Do skilled readers of opaque and transparent orthographies make differential use of lexical and sublexical processes when converting words from print to sound? Two experiments are reported, which address that question, using effects of letter length on naming latencies as an index of the involvement of sublexical letter-sound conversion. Adult native speakers of English (Experiment 1) and Spanish (Experiment 2) read aloud four- and seven-letter high-frequency words, low-frequency words, and nonwords in their native language. The stimuli were interleaved and presented 10 times in a first testing session and 10 more times in a second session 28 days later. Effects of lexicality were observed in both languages, indicating the deployment of lexical representations in word naming. Naming latencies to both words and nonwords reduced across repetitions on Day 1, with those savings being retained to Day 28. Length effects were, however, greater for Spanish than English word naming. Reaction times to long and short nonwords converged with repeated presentations in both languages, but less in Spanish than in English. The results support the hypothesis that reading in opaque orthographies favours the rapid creation and use of lexical representations, while reading in transparent orthographies makes more use of a combination of lexical and sublexical processing.

Do reading and spelling share a lexicon?

In the reading and spelling literature, an ongoing debate concerns whether reading and spelling share a single orthographic lexicon or rely upon independent lexica. Available evidence tends to support a single lexicon account over an independent lexica account, but evidence is mixed and open to alternative explanation. In the current work, we propose another, largely ignored account--separate-but-shared lexica--according to which reading and spelling have separate orthographic lexica, but information can be shared between them. We report three experiments designed to competitively evaluate these three theoretical accounts. In each experiment, participants learned new words via reading training and/or spelling training. The key manipulation concerned the amount of reading versus spelling practice a given item received. Following training, we assessed both response time and accuracy on final outcome measures of reading and spelling. According to the independent lexica account, final performance in one modality will not be influenced by the level of practice in the other modality. According to the single lexicon account, final performance will depend on the overall amount of practice regardless of modality. According to the separate-but-shared account, final performance will be influenced by the level of practice in both modalities but will benefit more from same-modality practice. Results support the separate-but-shared account, indicating that reading and spelling rely upon separate lexica, but information can be shared between them.

The Interdependence of Long- and Short-Term Components in Unmasked Repetition Priming: An Indication of Shared Resources

It has been suggested that unmasked repetition priming is composed of distinct long-and short-term priming components. The current study sought to clarify the relationship between these components by examining the relationship between them. A total of 60 people (45 females, 15 males) participated in a computer-based lexical decision task designed to measure levels of short-term priming across different levels of long-term priming. The results revealed an interdependent relationship between the two components, whereby an increase in long-term priming prompted a decrease in short-term priming. Both long-term and short-term priming were accurately captured by a single power function over seven minutes post repetition, suggesting the two components may draw on the same resources. This interdependence between long- and short-term priming may serve to improve fluency in reading.

Greater priming for previously distracting information in young than older adults when suppression is ruled out

The use of previously distracting information on memory tests with indirect instructions is usually age-equivalent, while young adults typically show greater explicit memory for such information. This could reflect qualitatively distinct initial processing (encoding) of distracting information by younger and older adults, but could also be caused by greater suppression of such information by younger adults on tasks with indirect instructions. In Experiment 1, young and older adults read stories containing distracting words, which they ignored, before studying a list of words containing previously distracting items for a free recall task. Half the participants were informed of the presence of previously distracting items in the study list prior to recall (direct instruction), and half were not (indirect instruction). Recall of previously distracting words was age-equivalent in the indirect condition, but young adults recalled more distracting words in the direct condition. In Experiment 2, participants performed the continuous identification with recognition task, which captures a measure of perceptual priming and recognition on each trial, and is immune to suppression. Priming and recognition of previously distracting words was greater in younger than older adults, suggesting that the young engage in more successful suppression of previously distracting information on tasks in which its relevance is not overtly signaled.

Does distraction reduce the alcohol-aggression relation? A cognitive and behavioral test of the attention-allocation model

OBJECTIVE

This study provided the first direct test of the cognitive underpinnings of the attention-allocation model and attempted to replicate and extend past behavioral findings for this model as an explanation for alcohol-related aggression.

METHOD

A diverse community sample (55% African American) of men (N = 159) between 21 and 35 years of age (M = 25.80) were randomly assigned to 1 of 2 beverage conditions (i.e., alcohol, no-alcohol control) and 1 of 2 distraction conditions (i.e., distraction, no-distraction). Following beverage consumption, participants were provoked via reception of electric shocks and a verbal insult from a fictitious male opponent. Participants' attention allocation to aggression words (i.e., aggression bias) and physical aggression were measured using a dot probe task and a shock-based aggression task, respectively.

RESULTS

Intoxicated men whose attention was distracted displayed significantly lower levels of aggression bias and enacted significantly less physical aggression than intoxicated men whose attention was not distracted. However, aggression bias did not account for the lower levels of alcohol-related aggression in the distraction, relative to the no-distraction, condition.

CONCLUSIONS

These results replicated and extended past evidence that cognitive distraction is associated with lower levels of alcohol-related aggression in highly provoked males and provide the first known cognitive data to support the attentional processes posited by the attention-allocation model. Discussion focused on how these data inform intervention programming for alcohol-related aggression.

The influence of dopamine on automatic and controlled semantic activation in Parkinson's disease

Two semantic priming tasks, designed to isolate automatic and controlled semantic activation, were utilized to investigate the impact of dopamine depletion on semantic processing in Parkinson's disease (PD). Seven people with PD (tested whilst on and off levodopa medication) and seven healthy adults participated in the study. The healthy adult participants demonstrated intact automatic and controlled semantic activation. Aberrant controlled semantic activation was observed in the PD group on levodopa; however, automatic semantic activation was still evident. In contrast, automatic semantic activation was not evident in the PD group off levodopa. These results further clarify the impact of PD on semantic processing, demonstrating that dopamine depletion can cause disturbances in both automatic and controlled semantic activation.

Enhancing speech discrimination through stimulus repetition

PURPOSE

To evaluate the effects of sequential and alternating repetition on speech-sound discrimination.

METHOD

Typically hearing adults' discrimination of 3 pairs of speech-sound contrasts was assessed at 3 signal-to-noise ratios using the change/no-change procedure. On change trials, the standard and comparison stimuli differ; on no-change trials, they are identical. Listeners were presented with 5 repetition conditions: 2 and 4 sequential repetitions of the standard followed by sequential repetitions of the comparison; 2 and 4 alternating presentations of the standard and comparison; and 1 repetition of the standard and comparison.

RESULTS

Both sequential and alternating repetition improved discrimination of the fricative and liquid contrasts, but neither was clearly superior to the other across the conditions.

CONCLUSIONS

The results support previous findings that increasing the number of fricative and liquid stimulus presentations improves discriminability and extends the findings to natural speech stimuli. Further, the effect of repetition is robust: Both sequential and alternating repetitions improve speech-sound discrimination, and few differences emerge between the two types of stimulus repetitions. The results have implications for evaluating the strength of the internal representation of speech stimuli in clinical populations believed to have a core deficit in phonological encoding, such as children with hearing loss.

More is not always better: paradoxical effects of repetition on semantic accessibility

Repetition normally enhances memory. While in some cases the benefit of added repetition may be incremental, few would expect that massed repetition could actually reverse the benefits of brief repetition. Here we report two experiments that document a clear example of a paradoxical effect of massed repetition. Subjects first repeated words (e.g., "sheep") aloud one at a time for 0, 5, 10, 20, or 40 s. A free association phase followed in which cues could be completed with repeated words (e.g., "herd s___" for "sheep") or with semantically associated words (e.g., "fabric w___" for "wool"). Brief periods of repetition (5-10 s) resulted in priming, as would be expected based on research on repetition priming and spreading activation. Longer periods of repetition (20-40 s), however, abolished priming. Interestingly, this massed-repetition decrement was particularly robust for semantic associates of repeated words, and was evident after a 15-min delay. These findings document a paradoxical feature of the effects of rehearsal on memory: When ideas are repeated often enough, the benefits of rehearsal can actually be reversed.

Word-types, not word-tokens, facilitate extraction of phonotactic sequences by adults

Phonotactics-the permissibility of sound sequences within a word-correspond to lexical statistics, but controversy persists over which statistics are being tracked. In this study, lexical type and token counts were compared as they contributed to phonotactic extraction from an artificial lexicon. Young-adult participants were familiarized with a set of CVCCVC nonwords contextualized as a lexicon of Martian animal names. The type and token frequencies of word-medial consonant sequences within those names were varied systematically. Participants then rated new nonwords, containing the same medial sequences, on a 7-point scale for similarity to the Martian animal names. Higher ratings only followed high type frequency familiarization conditions, suggesting that word-types drove phonotactic extraction. Additionally, participants reversed the typical preference for high frequency English sequences, likely because they rated nonwords according to their membership to an unknown language. This finding suggests cognitively separable tracking of artificial language statistics and preexisting representations.

Effects of material emotional valence on the time course of massive repetition priming

Learning through repetition is a fundamental form and also an effective method of language learning critical for achieving proficient and automatic language use. Massive repetition priming as a common research paradigm taps into the dynamic processes involved in repetition learning. Research with this paradigm has so far used only emotionally neutral materials and ignored emotional factors, which seems inappropriate given the well-documented impact of emotion on cognitive processing. The present study used massive repetition priming to investigate whether the emotional valence of learning materials affects implicit language learning. Participants read a list of Chinese words and made speeded perceptual judgments about the spatial configuration of the two characters in a word. Each word was repeated 15 times in the whole learning session. There were three types of words, negative, positive, or neutral in their emotional valence, presented in separate blocks. Although similar levels of asymptotic performance were reached for different valence conditions showing comparable total effects of learning, learning of the positive words was found to be associated with fewer plateaus of shorter durations and to reach saturation earlier, compared with neutral and negative words. The results showed for the first time that the emotional valence of learning materials has significant effects on the time course of learning so that positive materials are learned faster and more efficiently, relative to negative and neutral materials. The study indicates the importance to explicitly consider the role of emotional factors in implicit language learning research.

Memory systems do not divide on consciousness: Reinterpreting memory in terms of activation and binding

There is a popular hypothesis that performance on implicit and explicit memory tasks reflects 2 distinct memory systems. Explicit memory is said to store those experiences that can be consciously recollected, and implicit memory is said to store experiences and affect subsequent behavior but to be unavailable to conscious awareness. Although this division based on awareness is a useful taxonomy for memory tasks, the authors review the evidence that the unconscious character of implicit memory does not necessitate that it be treated as a separate system of human memory. They also argue that some implicit and explicit memory tasks share the same memory representations and that the important distinction is whether the task (implicit or explicit) requires the formation of a new association. The authors review and critique dissociations from the behavioral, amnesia, and neuroimaging literatures that have been advanced in support of separate explicit and implicit memory systems by highlighting contradictory evidence and by illustrating how the data can be accounted for using a simple computational memory model that assumes the same memory representation for those disparate tasks.

The costs and benefits of cross-task priming

Two lines of research on cross-task priming yield opposite results. Research on repetition priming observed positive priming, whereas research on the role of priming in task-switching observed negative effects. We combined the two types of design. In the transfer phase of our paradigm, subjects performed task B either as a pure block (BBB) or as a switch block (ABAB). We presented items which were either unprimed or primed by prior presentation during a preceding priming phase performed on task A. Amongst others, the priming effect is determined by two factors: First, the more operation time the system needs during the probe event, the higher the likelihood to obtain priming. Protracting operation time by reducing stimulus quality favors positive priming, whereas providing more operation time by making subjects switch between tasks favors negative priming. Second, the strength of the memory trace of the prime event determines whether that trace can possibly yield negative priming, in that only strong traces can be retrieved together with the associated task/response.

Neural Response Suppression Predicts Repetition Priming of Spoken Words and Pseudowords

An important method for studying how the brain processes familiar stimuli is to present the same item on more than one occasion and measure how responses change with repetition. Here we use repetition priming in a sparse functional magnetic resonance imaging (fMRI) study to probe the neuroanatomical basis of spoken word recognition and the representations of spoken words that mediate repetition priming effects. Participants made lexical decisions to words and pseudowords spoken by a male or female voice that were presented twice, with half of the repetitions in a different voice. Behavioral and neural priming was observed for both words and pseudowords and was not affected by voice changes. The fMRI data revealed an elevated response to words compared to pseudowords in both posterior and anterior temporal regions, suggesting that both contribute to word recognition. Both reduced and elevated activation for second presentations (repetition suppression and enhancement) were observed in frontal and posterior regions. Correlations between behavioral priming and neural repetition suppression were observed in frontal regions, suggesting that repetition priming effects for spoken words reflect changes within systems involved in generating behavioral responses. Based on the current results, these processes are sufficiently abstract to display priming despite changes in the physical form of the stimulus and operate equivalently for words and pseudowords.

Exploring automaticity in text processing: syntactic ambiguity as a test case

A prevalent assumption in text comprehension research is that many aspects of text processing are automatic, with automaticity typically defined in terms of properties (e.g., speed and effort). The present research advocates conceptualization of automaticity in terms of underlying mechanisms and evaluates two such accounts, a computational-efficiency account (underlying computational processes become more efficient with practice) and a memory-based processing account (the underlying basis of processing shifts with practice, from computing interpretations to retrieving prior interpretations). In five experiments, short texts containing either an ambiguous or unambiguous syntactic structure were presented for multiple study trials. In both conditions, reading times in target regions decreased across trials, indicating automatization. Several findings supported the memory-based processing account (e.g., practice effects were largely item-specific, reading times were longer for ambiguous versus unambiguous sentences on early trials but converged on later trials) Some evidence was also found for a contribution of gains in computational efficiency (i.e., some item-general practice effects were observed). Implications for research on automaticity and text processing are discussed.

Effect of Trait Anger on Cognitive Processing of Emotional Stimuli

In the present experiment, the authors examined whether trait anger was associated with cognitive biases for anger-related semantic stimuli. Fifty-two undergraduate students completed the Trait Anger Scale (TAS; C. D. Spielberger, G. Jacobs, S. Russell, & R. Crane, 1983), and those reporting TAS scores in the upper (n = 17) or lower (n = 13) quartiles of the sample were assigned to high- and low-anger groups, respectively. The 30 participants then engaged in a lexical decision task that presented various emotion words, neutral words, and nonwords. Results indicated that individuals who reported high levels of trait anger displayed facilitative biases in the processing of semantic anger-related stimuli. This predisposition to more readily process anger-related information may underlie their propensity to experience intense feelings of anger when provoked.

Task-switching and long-term priming: role of episodic stimulus-task bindings in task-shift costs

When subjects switch between two tasks, performance is slower after a task switch than after a task repetition. We report five experiments showing that a large part of these "task-shift-costs" cannot be attributed to a control operation, needed to configure the cognitive system for the upcoming task (e.g., ). In all experiments subjects switched between picture-naming and word-reading. We presented different stimuli either in just one of the two tasks, or in both of them. Shift-costs were larger for stimuli presented in both tasks than for those presented in only one task, even after more than 100 intervening trials between prime and probe events. We suggest (as proposed by ) that stimuli acquire associations with the tasks in which they occur. When the current task activation is weak, as on a switch of tasks, stimuli can trigger retrieval of the associated, competing task, provoking larger time costs.

From primed to learn: the saturation of repetition priming and the induction of long-term memory

Although practice can make perfect, it is not clear how much practice is needed to trigger long-lasting performance gains on a given task. Here, using a letter enumeration task, we show that the transition of experience dependent performance gains to a relatively stable form, as well as the triggering of delayed, long-lasting, between session gains (both effects are considered manifestations of consolidation processes) is amount-of-practice dependent. We then show (a) that consolidation processes, once triggered, can proceed without further practice as a function of time and (b) that the triggering of consolidation processes is related to repetition priming effects--performance gains in processing a previously experienced item. However, we show that repetition priming effects saturate after a limited number of consecutive repetitions and reflect an initial, but potentially reversible, response to the repeated experience. Moreover, we show that one critical parameter determining the occurrence of repetition priming (but not skill learning) is the presence of interference (by a somewhat different set of items) prior to the primer presentation. Thus, our results suggest that the saturation of repetition priming effects, rather than priming per se, may be critical to the induction of slow learning processes and consolidation.

Task demands and representation in long-term repetition priming

The effects of task demands on the representation of letter strings in long-term repetition priming (LTRP) were explored in two lexical decision experiments. The stimuli in both experiments were words and nonwords, some presented horizontally and some vertically. The only difference between the two experiments was the response required by the participant. In Experiment 1, the participants pressed one of two buttons, indicating whether or not a given stimulus was a word. In Experiment 2, the participants pressed one of four buttons, indicating both the lexical status and the orientation of a given stimulus. The results were that in Experiment 1, LTRP was not disrupted by a change in stimulus orientation, whereas in Experiment 2 it was, suggesting that the nature of the stimulus representation utilized in LTRP is partially dependent on the demands of the task.

Age of acquisition in face categorisation: is there an instance-based account?

An instance-based model of the effects of age of acquisition (AoA) is offered and derived predictions are considered. A face-categorisation experiment is reported which tested these predictions. Nine participants made speeded-categorisation judgements of 185 faces from two TV shows. Ratings were given for the faces' frequency of occurrence in the shows and, for each face, the length of time the character was in the show and the time since they had left was found. Regression analyses were used to find how the factors affected the speed of categorisation. Speed of categorisation was found to follow a negative power function of the frequency and time on the show and a positive power function of the time since they had left. This was supportive of the instance-based account and suggests that effects of AoA with words and objects can be explained in terms of cumulative frequency.

Single and multiple test repetition priming in implicit memory

Using a picture naming task, we compared the magnitude of repetition priming after one prior study episode (single test priming) versus multiple prior study presentations (multiple test priming). Pictures were repeated either one, two, or three times, and the interval between tests was either several minutes (blocked test) or one week (spaced test). Priming increased with additional prior presentations (beyond one) in the multiple test format. In addition, single test priming decreased within one hour after initial exposure, with little change from one hour to two weeks. Priming was unaffected by a simultaneous recognition task, suggesting that picture naming is an implicit task relatively immune from explicit memory contamination.