Theoretical and computational analysis of skill learning, repetition priming, and procedural memory.

This article analyzes the relationship between skill learning and repetition priming, 2 implicit memory phenomena. A number of reports have suggested that skill learning and repetition priming can be dissociated from each other and are therefore based on different mechanisms. The authors present a theoretical analysis showing that previous results cannot be regarded as evidence of a processing dissociation between skill learning and repetition priming. The authors also present a single-mechanism computational model that simulates a specific experimental task and exhibits both skill learning and repetition priming, as well as a number of apparent dissociations between these measures. These theoretical and computational analyses provide complementary evidence that skill learning and repetition priming are aspects of a single underlying mechanism that has the characteristics of procedural memory. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Long-term semantic memory versus contextual memory in unconscious number processing.

Subjects classified visible 2-digit numbers as larger or smaller than 55. Target numbers were preceded by masked 2-digit primes that were either congruent (same relation to 55) or incongruent. Experiments 1 and 2 showed prime congruency effects for stimuli never included in the set of classified visible targets, indicating subliminal priming based on long-term semantic memory. Experiments 2 and 3 went further to demonstrate paradoxical unconscious priming effects resulting from task context. For example, after repeated practice classifying 73 as larger than 55, the novel masked prime 37 paradoxically facilitated the "larger" response. In these experiments task context could induce subjects to unconsciously process only the leftmost masked prime digit, only the rightmost digit, or both independently. Across 3 experiments, subliminal priming was governed by both task context and long-term semantic memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory priming: Implicit and explicit memory for words and voices.

Five experiments explore priming effects on auditory identification and completion tasks as a function of semantic and nonsemantic encoding tasks and whether speaker's voice is same or different at study and test. Auditory priming was either unaffected by the study task manipulation (Exps 2, 4, and 5) or was less affected than was explicit memory (Exps 1 and 3). Study-to-test changes of speaker's voice had significant effects on priming when white noise masked target items on the identification test (Exps 1 and 2) or the stem-completion test (Exp 5). However, significant voice change effects were observed on priming of completion performance when stems were spoken clearly (Exps 3 and 4). Results are consistent with the idea that a presemantic auditory perceptual representation system plays an important role in the observed priming. Alternative explanations of the presence or absence of voice change effects under different task conditions are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intact perceptual memory in the absence of conscious memory.

Declarative memory enables conscious recollection of the past and has been proposed to be distinct from priming, a perceptual form of memory that operates nonconsciously and improves the ability to detect or identify recently presented stimuli. Yet, it has been difficult to obtain unambiguous evidence for the independence of declarative memory and priming. The authors report the first demonstration, using matched tests, of fully intact perceptual memory (priming) in a profoundly amnesic patient (E.P.), despite at-chance recognition memory. The priming and recognition tests included tests that were matched with respect to test materials, length of the study and test lists, and the kind of cues available at test. Priming appears to reflect neural changes within perceptual processing systems that occur before information reaches the brain systems that transform visual perception into conscious visual memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Generation and perceptual implicit memory: Different generation tasks produce different effects on perceptual priming.

The generation manipulation has been critical in delineating differences between implicit and explicit memory. In contrast to past research, the present experiments indicate that generating from a rhyme cue produces as much perceptual priming as does reading. This is demonstrated for 3 visual priming tasks: perceptual identification, word-fragment completion (WFC), and word-stem completion (WSC). This result occurred regardless of the mode of study response (written or spoken) or whether the generation condition was compared with reading words in or out of context. Rhyme generation did not produce priming on the letter height task (Masson & MacLeod, 2002), implying that the effect was not mediated by covert visualization. Nor was the effect due to the mere presence of the rhyme cue. Semantic generation (from definitions) produced a different pattern, exhibiting a reverse generation effect on WFC and WSC but full (read-level) priming on perceptual identification. The present results were not consistent with accounts based on the standard transfer-appropriate processing view, covert visualization, explicit contamination, or conceptual contributions to nominally perceptual tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual and nonperceptual components of implicit memory for pictures.

The transfer appropriate processing (TAP) framework posits that in data-driven tasks, such as picture naming (PN) or picture perceptual identification, repetition priming is greater when perceptual processes engaged at study are recapitulated at test. Thus, priming with pictures is greater after study-phase exposure to pictures than to words (picture names). A. S. Brown, D. R. Neblett, T. C. Jones, and D. B. Mitchell (see record 1991-26453-001) reported that a pure-list format eliminated perceptual priming: Participants who saw either pictures or words in a study phase showed equal priming in a PN task. In the present study, participants showed greater priming after exposure to pure lists of pictures than to pure lists of words in 3 PN and 1 picture perceptual identification experiments. Thus, perceptual priming occurred in 4 pure-list picture priming tasks, as predicted by the TAP framework. Priming also was found after exposure to words. In PN and picture perceptual identification tasks, implicit memory for pictures includes perceptual and nonperceptual components. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Midazolam amnesia and conceptual processing in implicit memory.

Prominent theories of implicit memory (D. Schacter, B. Church, & J. Treadwell, 1994) emphasize the dominant role of perceptual processing in mediating priming on perceptual implicit memory tests. Examinations of the effects of conceptual processing on perceptual implicit memory tests have produced ambiguous results. Although a number of investigations (e.g., J. Toth & R. Hunt, 1990) have demonstrated that variations in conceptual processing affect priming on perceptual implicit memory tests, these effects may arise because of the contaminating effects of explicit memory. The current experiment examined this controversy using midazolam, a benzodiazepine that produces a dense, albeit temporary, anterograde amnesia when injected prior to study. The experiment examined whether the effects of generation found on the implicit memory test of perceptual identification were affected by a midazolam injection prior to study. Results demonstrated that midazolam substantially diminished generation effects in free and cued recall, as well as overall performance on these tests, but had no detectable effect on the generation effect in perceptual identification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Component processes of conceptual priming and associative cued recall: The roles of preexisting representation and depth of processing.

The authors investigated depth-of-processing effects on conceptual priming by comparing incidental (implicit) and intentional (explicit) tests of word association. In Experiment 1, depth of processing at study influenced priming of weak and medium associates but not of strong associates. In Experiment 2, depth of processing influenced priming of weak associates but not of compound phrases (e.g., coathanger), whose preexperimental association strength matched that of weak associates. In Experiment 3, the same pattern persisted when study was auditory and test was visual, ensuring that priming was conceptual and not perceptual. In all experiments, in matched intentional tests, depth-of-processing effects occurred for all association strengths and for both phrases and associates, suggesting that the incidental tests were uncontaminated by voluntary retrieval, because they showed depth-of-processing effects only for some materials and not others, within the same participants and tests. Because depth-of-processing effects on involuntary free-association priming depend on the presence versus absence of a cohesive preexperimental representation, the memory-systems and conceptual/perceptual processing approaches to memory-test dissociations require modification to account for component processes of conceptual priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Available but unattended conceptual information in working memory: Temporarily active semantic content or persistent memory for prior operations?

In 2 experiments, the authors investigated available but unattended information following working memory task demands. The experimental task presented a memory set containing exemplars from 2 conceptual categories. Following instructions to focus attention on only 1 category, priming of both categories was assessed with category comparisons of exemplar pairs. Priming was greatest for the focused category and for exemplars from the memory set (direct priming). Priming also extended to new exemplars of both categories (indirect priming) and showed little decline over more than 1 min of intervening processes. Finally, changing between category exemplars and features across memory set and comparison phases eliminated the indirect priming. These results support a persistent, operation-specific, procedural account of available but unattended conceptual information in working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional sensitization of unconscious cognition: Task sets modulate subsequent masked semantic priming.

According to classical theories, automatic processes are autonomous and independent of higher level cognitive influence. In contrast, the authors propose that automatic processing depends on attentional sensitization of task-congruent processing pathways. In 3 experiments, the authors tested this hypothesis with a modified masked semantic priming paradigm during a lexical decision task by measuring event-related potentials (ERPs): Before masked prime presentation, participants attended an induction task either to semantic or perceptual stimulus features designed to activate a semantic or perceptual task set, respectively. Semantic priming effects on the N400 ERP component, an electrophysiological index of semantic processing, were obtained when a semantic task set was induced immediately before subliminal prime presentation, whereas a previously induced perceptual task set attenuated N400 priming. Across experiments, comparable results were obtained regardless of the difficulty level and the verbal or nonverbal nature of the induction tasks. In line with the proposed attentional sensitization model, unconscious semantic processing is enhanced by a semantic and attenuated by a perceptual task set. Hence, automatic processing of unconscious stimuli is susceptible to top-down control for optimizing goal-related information processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in explicit and implicit memory for pictures.

In the present study, the authors examined age effects in memory for nonverbal material. A picture fragment completion task was used to test explicit and implicit memory in a younger and an older group. Explicit memory was indexed by free recall of pictures, whereas implicit memory was indexed by perceptual learning (priming). Both free recall and perceptual learning performance were found to be impaired in the older group. A measure of executive functioning was found to be predictive of both explicit and implicit memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of repetition priming on recognition memory: Testing a perceptual fluency-disfluency model.

Five experiments explored the effects of immediate repetition priming on episodic recognition (the "Jacoby-Whitehouse effect") as measured with forced-choice testing. These experiments confirmed key predictions of a model adapted from D. E. Huber and R. C. O'Reilly's (2003) dynamic neural network of perception. In this model, short prime durations pre-activate primed items, enhancing perceptual fluency and familiarity, whereas long prime durations result in habituation, causing perceptual disfluency and less familiarity. Short duration primes produced a recognition preference for primed words (Experiments 1, 2, and 5), whereas long duration primes produced a preference against primed words (Experiments 3, 4, and 5). Experiment 2 found prime duration effects even when participants accurately identified short duration primes. A cued-recall task included in Experiments 3, 4, and 5 found priming effects only for recognition trials that were followed by cued-recall failure. These results suggest that priming can enhance as well as lower familiarity, without affecting recollection. Experiment 4 provided a manipulation check on this procedure through a delay manipulation that preferentially affected recognition followed by cued-recall success. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in the interface between perception and memory retrieval.

Four experiments examined how perception affects delayed recognition, visual pop out, and memory reactivation (priming) at 6 mo. Infants discriminated cues (Ls, Ts, and +s) differing in spatial arrangement or number of primitive perceptual units (textons) or both in a delayed recognition task and exhibited adultlike visual pop-out effects in a priming task. Performance at 6 mo resembled that at 3 mo and adult preattentive processing. Unlike at 3 mo, however, at 6 mo, an expectancy-based process overrode the perceptual characteristics of a novel pop-out stimulus in a delayed recognition test. Results indicate that delayed recognition memory becomes more "top down" over the 1st half-year, whereas memory priming remains age invariant and perceptually driven. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming effects in picture fragment completion: Support for the perceptual closure hypothesis.

The perceptual closure hypothesis says that priming will be optimum when just enough information is available in the prime to support closure. Across 5 experiments, a moderately complete fragmented image (Level 4) produced more priming than an almost complete (Level 7) or a very incomplete (Level 1) fragmented image. Only Level 4 priming was improved by increases in prime duration and by showing the prime again after Ss attempted to identify it. Explicit memory played little role in primed fragment completion except for Level 1 priming, in which specific fragment memory was responsible for the entire effect. In contrast, true perceptual learning was shown to be responsible for Level 4 and Level 7 priming. These priming effects cannot be accounted for by the transfer-appropriate procedures approach of H. L. Roediger and M. S. Weldon (1987) because Level 1 priming produced less transfer to Level 1 identification at test than Level 4 priming did. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuroanatomical and cognitive mediators of age-related differences in perceptual priming and learning.

Our objectives were to assess age differences in perceptual repetition priming and perceptual skill learning and to determine whether they are mediated by cognitive resources and regional cerebral volume differences. Fragmented picture identification paradigm allows the study of both priming and learning within the same task. The authors presented this task to 169 adults (ages 18–80), assessed working memory and fluid intelligence, and measured brain volumes of regions that were deemed relevant to those cognitive skills. The data were analyzed within a hierarchical path modeling framework. In addition to finding age-related decrease in both perceptual priming and learning, the authors observed several dissociations with regards to their neural and cognitive mediators. Larger visual cortex volume was associated with greater repetition priming, but not perceptual skill learning, and neither process depended upon hippocampal volume. In contrast, the volumes of the prefrontal gray and white matter were differentially related to both processes via direct and indirect effects of cognitive resources. The results indicate that age-related differences in perceptual priming and skill learning have dissociable cognitive and neural correlates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in implicit memory: Fragmented object identification and category exemplar generation.

In a cross-sectional study of 164 participants aged 21 to 91, the authors examined age differences on two implicit tests, fragmented object identification (FOI) and category exemplar generation (CEG), and on tests of explicit memory, attention, and verbal fluency. FOI results revealed impaired perceptual skill learning in those over 60 and a decrease in perceptual priming across young, middle-aged, and older groups. CEG priming was impaired in those over 80. Regression analysis revealed explicit contamination of priming on both the FOI and CEG tests. Across the three implicit measures, age accounted for 4 to 13% of the variance when explicit memory was controlled. Semantic fluency predicted CEG priming, suggesting possible frontal lobe involvement on the test. Altogether, results indicate that age has a small but reliable influence on implicit memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Long-term repetition priming of briefly identified objects.

The authors provide evidence that long-term memory encoding can occur for briefly viewed objects in a rapid serial visual presentation list, contrary to claims that the brief presentation and quick succession of objects prevent encoding by disrupting a memory consolidation process that requires hundreds of milliseconds of uninterrupted processing. Subjects performed a search task in which each item was presented for only 75 ms. Nontargets from the search task generated priming on 2 subsequent indirect memory tests: a search task and a task requiring identification of visually masked objects. Additional experiments revealed that information encoded into memory for these nontargets included perceptual and conceptual components, and that these results were not due to subjects maintaining items in working memory during list presentation. These results are consistent with recent neurophysiological evidence showing that stimulus processing can occur at later stages in the cognitive system even when a subsequent new stimulus is presented that initiates processing at earlier stages. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Playing chess unconsciously.

Expertise in a certain stimulus domain enhances perceptual capabilities. In the present article, the authors investigate whether expertise improves perceptual processing to an extent that allows complex visual stimuli to bias behavior unconsciously. Expert chess players judged whether a target chess configuration entailed a checking configuration. These displays were preceded by masked prime configurations that either represented a checking or a nonchecking configuration. Chess experts, but not novice chess players, revealed a subliminal response priming effect, that is, faster responding when prime and target displays were congruent (both checking or both nonchecking) rather than incongruent. Priming generalized to displays that were not used as targets, ruling out simple repetition priming effects. Thus, chess experts were able to judge unconsciously presented chess configurations as checking or nonchecking. A 2nd experiment demonstrated that experts' priming does not occur for simpler but uncommon chess configurations. The authors conclude that long-term practice prompts the acquisition of visual memories of chess configurations with integrated form-location conjunctions. These perceptual chunks enable complex visual processing outside of conscious awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Latent inhibition, habituation, and sensory preconditioning: A test of priming in short-term memory.

Four experiments, with 136 male Long-Evans hooded rats, tested priming in short-term memory as a model for latent inhibition and habituation. The model postulates that the 2 phenomena result from reduced processing when a representation of the target stimulus is already active (primed) in short-term memory at the time of its presentation. Priming is assumed to depend on the integrity of an association formed between the contextual stimuli and the conditioned stimulus/stimuli (CS) during exposure. Using a procedure that should have overshadowed the context, Exp I found that latent inhibition and habituation were nevertheless maintained when a 2nd CS of either equal or shorter duration overlapped with the target during exposure. In Exps II–IV, sensory preconditioning as well as habituation and latent inhibition were obtained with compound exposure, providing reasonable evidence that the added CS was processed along with the target during exposure. Results are interpreted as being inconsistent with the priming model. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spreading activation versus compound cue accounts of priming: Mediated priming revisited.

Spreading activation theories and compound cue theories have both been proposed as accounts of priming phenomena. According to spreading activation theories, the amount of activation that spreads between a prime and a target should be a function of the number of mediating links between the prime and target in a semantic network and the strengths of those links. The amount of activation should determine the amount of facilitation given by a prime to a target in lexical decision. To predict the amount of facilitation, it is necessary to measure the associative links between prime and target in memory. Free-association production probability has been the variable chosen in previous research for this measurement. However, in 3 experiments, the authors show priming effects that free-association production probabilities cannot easily predict. Instead, they argue that the amount of priming depends on the familiarity of the prime and target as a compound, where the compound is formed by the simultaneous presence of the prime and target in short-term memory as a test item. (PsycINFO Database Record (c) 2010 APA, all rights reserved)