Age differences in acquisition and retention of one-way avoidance learning in C57BL/6NNia and autoimmune mice

Acquisition and 48-h retention of a step-up active avoidance response were studied in separate age groups of C57BL/6NNia mice (aged 1.5, 3.5, 6, 12, or 26 months) and five strains of genetically autoimmune mice differing in life span. The C57BL/6NNia mice showed no change in ability to acquire the avoidance response between 1.5 and 3.5 months, but showed a steady decline in that ability thereafter. Mouse strains with early-onset autoimmune disorder (NZB/B1NJ, MRL/MpJ-lpr, and BXSB/MpJ) showed declines in acquisition capability between 1.5 and 3.5 months of age, whereas mouse strains with mild, late-onset autoimmune disorder (MRL/MpJ- + and NZBWF1/J) showed stable or improved acquisition during that period. Both the C57BL/6NNia and NZB/B1NJ mice showed age-dependent declines in 48-h retention performance by 12 months of age. These findings suggested that while 48-h retention performance deficits were most related to chronological age, avoidance acquisition deficits were related to development of autoimmunity.     

Antibody to amyloid beta protein alleviates impaired acquisition,retention, and memory processing in SAMP8 mice

SAMP8 (senescence-accelerated mouse, P8 strain) mice overproduce amyloid precursor protein and beta-amyloid and have learning and memory deficits. Preliminary data have indicated that overproduction of beta-amyloid plays a role in the pathogenesis of acquisition and retention deficits in SAMP8 mice. In the studies reported here, the authors examined the effects of polyclonal and monoclonal antibodies to beta-amyloid on acquisition and retention in an aversive T-maze testing paradigm when injected intracerebroventricularly (ICV) into 12-month SAMP8/TaJF mice. Both the polyclonal and monoclonal antibodies improved acquisition and retention when injected ICV 1 to 14 days prior to acquisition testing. Injection of all three antibodies intrahippocampally immediately following training improved retention on the T-maze when mice were tested 7 days later. The authors next studied the effect of monoclonal beta-amyloid antibody injected 48 h prior to training on the effect on retention in the T-maze of drugs modulating classical neurotransmitters. Arecoline and glutamate were injected directly into the hippocampus, and ketanserin, methiothepen, bicuculline, and OH-saclofen were injected into the septum. Previously, the authors have found that the doses of these drugs required to improve retention are markedly altered in 12-month SAMP8/TkJF mice compared to 4-month P8 mice. In these studies, it was demonstrated that antibody to beta-amyloid resulted in these drugs improving retention at doses that improved memory in 4-month SAMP8/TaJF mice. Based on these findings, we conclude that beta-amyloid overproduction is at least in part responsible for the acquisition and memory deficits in 12-month-old SAMP8/TaJF mice. Antibody to beta-amyloid restores the retention response to neurotransmitter manipulation to that seen in 4-month-old mice. beta-amyloid appears to play a key role in the loss of acquisition and retention seen in SAMP8/TaJF mice.     

Support for an explanation of the guidance effect in motor skill learning

The authors investigated whether the knowledge of results (KR) schedule influences the extent to which intrinsic feedback is noticed and used. Fifty-six participants received KR that was either delayed over 2 trials (Delay-2) or provided directly after each trial (Delay-0) during 160 trials of an unfamiliar aiming task. No-KR retention tests were given after 80 trials and 1 min and 24 hr after the end of acquisition. After retention, all participants were questioned about their use of intrinsic feedback during practice and whether those sources changed as a function of practice. The Delay-2 group performed significantly less accurately on the 1st and last blocks of acquisition trials but showed a significantly smaller performance decline from acquisition to retention. Moreover, the Delay-2 group noticed and used a greater variety of intrinsic feedback sources and its members were more likely to report that their usage changed with practice.     

Effect of salespeople's acquisition–retention trade-off on performance

This research examines the impact of the acquisition–retention resource allocation at the individual salesperson level – that is, the proportion of their time dedicated to acquisition versus retention activities – on their sales performance. We extend prior research that investigates the acquisition–retention trade-off below (i.e., customer value approach) or above (i.e., firm portfolio approach) the salesperson's perspective by also incorporating many ‘within-firm’ factors that are critical to capturing the contingent nature of the allocation decision. The results suggest that firms can double their sales gains by implementing a trade-off strategy that customizes the acquisition allocation at the salesperson level. Using matched triadic data gathered from 227 salespersons, 106 supervisors and the seller's database, the authors find an inverted U-shaped linkage between the proportion of time allocated to acquisition activities and sales performance. Moderation analyses show that salespeople's optimal acquisition allocation depends on their knowledge breadth and job commitment, their supervisor's experience and job commitment and the quantity and quality of the prospects in their relationship portfolio.     

Psychoneurogenic stress influences upon retention of an inhibitory avoidance response in the rat

Hormones and peptides involved in the response of an organism to stress play a modulating role in learning and memory processes. We studied whether psychoneurogenic stressors such as sound stimulation or novelty influence retention of an inhibitory avoidance response. An impairing effect on retention was observed when these stressors were applied shortly after the acquisition trial, but not after a 3-h delay. However, sound stimulation and novelty applied shortly before the retention test may facilitate retention behavior. It is suggested that the effect of psychoneurogenic stressors on retention behavior may be linked to influences on consolidation and retrieval processes mediated through the neurohumoral response of the organism to stress.     

Cortical barrel lesions impair whisker-CS trace eyeblink conditioning

Whisker deflection is an effective conditioned stimulus (CS) for trace eyeblink conditioning that has been shown to induce a learning-specific expansion of whisker-related cortical barrels, suggesting that memory storage for an aspect of the trace association resides in barrel cortex. To examine the role of the barrel cortex in acquisition and retrieval of trace eyeblink associations, the barrel cortex was lesioned either prior to (acquisition group) or following (retention group) trace conditioning. The acquisition lesion group was unable to acquire the trace conditioned response, suggesting that the whisker barrel cortex is vital for learning trace eyeblink conditioning with whisker deflection as the CS. The retention lesion group exhibited a significant reduction in expression of the previously acquired conditioned response, suggesting that an aspect of the trace association may reside in barrel cortex. These results demonstrate that the barrel cortex is important for both acquisition and retention of whisker trace eyeblink conditioning. Furthermore, these results, along with prior anatomical whisker barrel analyses suggest that the barrel cortex is a site for long-term storage of whisker trace eyeblink associations.     

Knowledge of Results for Motor Learning: Relationship Between Error Estimation and Knowledge of Results Frequency

The authors of the present study investigated the apparent contradiction between early and more recent views of knowledge of results (KR), the idea that how one is engaged before receiving KR may not be independent of how one uses that KR. In a 2 × 2 factorial design, participants (N = 64) practiced a simple force-production task and (a) were required, or not required, to estimate error about their previous response and (b) were provided KR either after every response (100%) or after every 5th response (20%) during acquisition. A no-KR retention test revealed an interaction between acquisition error estimation and KR frequencies. The group that received 100% KR and was required to error estimate during acquisition performed the best during retention. The 2 groups that received 20% KR performed less well. Finally, the group that received 100% KR and was not required to error estimate during acquisition performed the poorest during retention. One general interpretation of that pattern of results is that motor learning is an increasing function of the degree to which participants use KR to test response hypotheses (J. A. Adams, 1971; R. A. Schmidt, 1975). Practicing simple responses coupled with error estimation may embody response hypotheses that can be tested with KR, thus benefiting motor learning most under a 100% KR condition. Practicing simple responses without error estimation is less likely to embody response hypothesis, however, which may increase the probability that participants will use KR to guide upcoming responses, thus attenuating motor learning under a 100% KR condition. The authors conclude, therefore, that how one is engaged before receiving KR may not be independent of how one uses KR.     

The role of intentional forgetting in reducing children's retroactive interference.

Preschool and kindergarten children's retention of stories was examined in the presence of interfering information and instructions to forget. Children learned 2 stories and, 24 hr later, were asked to recall the 1st or 2nd story learned. Some of the children were instructed, either following acquisition or just prior to the retention test, to forget the 2nd, or interfering, story. A model was used to isolate storage and retrieval effects, and the results showed that (a) retroactive interference affected both storage- and retrieval-based forgetting rates for the younger children but only storage-based forgetting rates for the older children, (b) intentional forgetting reduced retroactive interference primarily by attenuating storage-based forgetting regardless of age, (c) intentional forgetting instructions were effective only at acquisition for preschoolers but at both acquisition and retention for kindergarteners, and (d) all children recalled the to-be-forgotten story as well as they recalled the to-be-remembered story. These results are interpreted in terms of reorganization and distinctiveness effects in storage.     

Classical conditioning of beginning reading responses

The present study describes the first demonstration that laboratory-controlled experimental procedures can lead to the successful acquisition and subsequent retention of classically conditioned beginning reading responses (CCBRRs) in children of both sexes and mean age of 4 yr. Anticipatory instructions combined with higher-order classical conditioning temporally arranged into a trace conditioning paradigm presented for 10 trials for each response to be learned led to beginning reading responses being successfully acquired by 20 children during 95% of the 2,220 total acquisition learning trials and subsequently correctly recalled on 114 of the 222 retention test trials. Findings support the view that perhaps the relatively sudden and sustained acquisition learning curves for reading responses on the second-signalling-system level of behavior in the present study may be quite different from the relatively slow and incremental learning curves usually obtained in classical conditioning of the autonomic type which occur on the first-signalling-system level.     

Long-term memory in adulthood: An examination of the development of storage and retrieval processes at acquisition and retention

Although it is generally acknowledged that decrements in long-term memory play an important role in the decline of everyday cognitive functioning in adulthood, problems have arisen in localizing the source of these memory deficits. In this article we address three of the methodological and measurement issues that have led to difficulties in interpreting research on adulthood developmental differences in acquisition and long-term retention. Specifically, these issues are stages-of-learning confounds, failures to separate storage and retrieval processes, and failures to separate forgetting from other factors that influence long-term retention tests. A general framework is presented in which each of these problems is dealt with. This model is subsequently applied to an experiment that examined the acquisition and long-term retention of pictures and words in associative memory in both young and old adults. The major findings were that (a) the picture-word manipulation had asymmetrical effects on acquisition and retention, (b) these asymmetries were different for the young and old adults, and (c) the locus (storage/retrieval) of age differences was different at acquisition than at retention. These results strongly suggest that the rules governing acquisition and forgetting are different, not only within age groups, but also across developmental levels in adulthood. More importantly, because the locus of developmental differences was different for acquisition and forgetting, it may be that different mechanisms underly the processing deficits experienced by the elderly when acquiring information than when trying to retain that information over extended periods of time.     

Knowledge of results for motor learning: relationship between error estimation and knowledge of results frequency

The authors of the present study investigated the apparent contradiction between early and more recent views of knowledge of results (KR), the idea that how one is engaged before receiving KR may not be independent of how one uses that KR. In a 2 ×: 2 factorial design, participants (N = 64) practiced a simple force-production task and (a) were required, or not required, to estimate error about their previous response and (b) were provided KR either after every response (100%) or after every 5th response (20%) during acquisition. A no-KR retention test revealed an interaction between acquisition error estimation and KR frequencies. The group that received 100% KR and was required to error estimate during acquisition performed the best during retention. The 2 groups that received 20% KR performed less well. Finally, the group that received 100% KR and was not required to error estimate during acquisition performed the poorest during retention. One general interpretation of that pattern of results is that motor learning is an increasing function of the degree to which participants use KR to test response hypotheses (J. A. Adams, 1971; R. A. Schmidt, 1975). Practicing simple responses coupled with error estimation may embody response hypotheses that can be tested with KR, thus benefiting motor learning most under a 100% KR condition. Practicing simple responses without error estimation is less likely to embody response hypothesis, however, which may increase the probability that participants will use KR to guide upcoming responses, thus attenuating motor learning under a 100% KR condition. The authors conclude, therefore, that how one is engaged before receiving KR may not be independent of how one uses KR.     

Selective lesions in the temporal-hippocampal region of the rat: effects on acquisition and retention of a visual discrimination task.

The first purpose of this study was to investigate whether lesions in the temporal region may affect acquisition or retention of a discrimination task. In Experiment 1, rats with lesions of the temporal cortex (TC), the lateral entorhinal cortex (LEC), or their interconnections were tested postoperatively in simultaneous brightness discrimination. The results show that neither TC lesions nor LEC lesions affected acquisition of the task, and only LEC lesions impaired retention. TC/LEC transections impaired both acquisition and retention. The second purpose was to investigate effects of hippocampal lesions and perforant path transections on the discrimination task (Experiment 2). Both hippocampal and perforant path lesions impaired acquisition of the task, whereas retention was unaffected. It is suggested that TC and LEC are primarily involved in information storing and that hippocampal function is primarily involved in information processing.     

Individualized Challenge Point Practice as a Method to Aid Motor Sequence Learning

We conducted two studies to investigate if and how: (1) the rate of skill acquisition was related to motor performance at retention of a serial RT task (Study 1); and (2) whether rate of skill acquisition and baseline performance could be used to design schedules of practice related to contextual interference (CI) to enhance motor learning (Study 2). In Study 1, a slower rate of skill acquisition of repeating sequences in practice was related to faster response times at retention. Based on performance in Study 1, three levels of individualized CI were created for Study 2. Compared to low and moderate levels of CI, the higher CI practice condition led to faster response times in retention. We conclude that an individualized ‘challenge point’, which generates high CI enhances motor learning by optimizing challenge.     

Variability of Practice and Contextual Interference in Motor Skill Learning

The purpose of this study was to investigate whether learning benefits in multiple-task learning situations are a result of contextual interference or of schema enhancement related to the amount of variability in the practice session. Two experiments were designed that replicated and extended the experiment reported by Wulf and Schmidt (1988). In a 2 (same vs. different relative time) x 2 (blocked vs. random practice schedule) design, 48 right-handed subjects were randomly assigned to one of four experimental conditions. A tapping task was employed that required a right-handed tap of three small brass plates arranged in a diamond pattern. Each segment had a specific time requirement. Target times and response times were provided on a computer screen directly in front of the subject. Each subject participated in two acquisition sessions (i.e., 198 practice trials) and was tested for learning on several different retention and transfer tests. In Experiment 2, a control group was added that received no acquisition phase. Results of both experiments showed a typical contextual interference effect, with depressed scores by the random groups during acquisition but significantly better scores than the blocked groups on several retention and transfer tests. Certain characteristics of the tests were found to influence the demonstration of the practice schedule effects. These results were consistent with predictions from Magill and Hall (1990) that the learning benefits of contextual interference are more likely to occur when skill variations are from different classes of movement and that the amount of variability in practice is more influential when the to-be-learned tasks are parameter modifications of the same generalized motor program.     

Repetition of cues in children's oddity learning and transfer

The hypothesis that repetition of specific cues interferes with oddity learning was directly tested by comparing two groups of preschool (3 to 5 years of age) children, one with repeated cues and the other with new cues on every trial. Repetition of cues retarded oddity learning confirming previous speculation based on error analyses. Performance on postsolution transfer trials with repeated cues was not affected by conditions of acquisition. Significant age effects were found in oddity acquisition, while there was only weak evidence for agerelated performance differences on transfer trials. Transfer performance on trials with repetition of cues was not related to whether or not the children were informed of such repetition. The results were related to theories of oddity acquisition and transfer.     

The identity model and factors controlling the superiority of the study-test method over the anticipation method

Short-term memory (STM) and long-term memory (LTM) components are assumed to overlap in such a way that the response reflects predominantly STM components in short retention intervals but LTM ones in long retention intervals. Based on the STM and LTM overlap hypothesis, the identity model postulates that basic processes per study, test, and intervening study and test events as well as intercycle intervals, respectively, are the same for both anticipation and study-test methods in cued (paired-associate) recall and recognition (verbal discrimination learning). A crucial difference between the two methods is the differential retention interval distribution (containing an overlap area). Amounts of STM components in the short-term store (STS), that is, critical items, seem to control the varied superiority of the study-test method over the anticipation method. This is directly linked to the learning difficulty dimension, which in turn is determined by such variables as list length, learning materials, exposure durations (presentation rates), acquisition stages, learning ability, developmental stages (ages), and others.     

Six- and Ten-Year-Olds' Attribution of Punitiveness and Nurturance to Parents and other Adults

The effects of modeling and corrective feedback on conceptual rule acquisition and retention was studied with three- and four-year-old children. Brief observation of a model was effective in creating significant acquisition and retention of conceptual rule judgments and explanations. Corrective feedback improved the child's ability to explain the conceptual rule but did not assist nonverbal performance. The facilitative influence of corrective feedback was largely confined to the four-year-old age group. In general, four-year-old children were more successful than three-year-olds in learning to provide viable reasons for conceptual judgments. The pedagogical significance of these findings are discussed.     

Effect of intermittent reinforcement on acquisition and retention in delayed matching-to-sample in pigeons

Experiments 1 and 2 involved independent groups that received primary reinforcement after a correct match with a probability of 1.0, .50 or .25. Correct matches that did not produce primary reinforcement produced a conditioned reinforcer. Both experiments revealed little evidence that acquisition or retention was adversely affected by use of intermittent reinforcement. Experiment 3 involved a group that received 100% reinforcement and two others that received 25% reinforcement, one of which received conditioned reinforcement and the other did not. Following acquisition and retention testing, birds in group 100% and group 25% with conditioned reinforcement were exposed to 25% reinforcement and no conditioned reinforcement. Results revealed that conditioned reinforcement was important in promoting acquisition but was irrelevant in maintaining performance. It was concluded that intermittent reinforcement, especially when combined with conditioned reinforcement during acquisition, supports levels of acquisition and retention comparable to that of continuous reinforcement. Theoretically, the findings are consistent with an extension of Blough's instance-based theory of discrimination performance and, practically, they suggest that use of intermittent reinforcement could result in increased efficiency and economy in labs using delayed matching.     

Delay-induced attenuation of latent inhibition with a conditioned emotional response depends on CS–US strength

Latent Inhibition (LI) attenuation when a long delay is introduced between acquisition and test phases has been repeatedly observed using aversive conditioning procedures (e.g., Aguado, Symonds, & Hall, 1994). This effect has been used as evidence to support those theories that consider LI to be the result of a retrieval failure. We designed three experiments intended to control for a possible effect of incubation of fear as a possible source of delay-induced attenuated LI. Specifically, we examined the effects of a retention interval between conditioning and testing stages on LI using a 3-stage conditioned emotional response procedure (preexposure, conditioning, and testing). Experiment 1 showed that the LI effect was completely abolished in the delayed testing condition. Experiment 2 evaluated whether a process of fear incubation, developed during the retention interval but obscured by a ceiling effect, produced the attenuation of LI. To this end, we reduced magnitude of conditioning by decreasing US intensity and number of acquisition trials. Experiment 3 directly assessed the relationship between CS–US strength and fear incubation. Experiments 2 and 3 revealed that the apparent reduction of LI after the delay was, at least partially, the result of an incubation effect that is a function of the strength of the CS–US association. The results are discussed with respect to their implications for the different theories of LI.