Contextual interference effects in sequence learning for young and older adults

Practice of different tasks in a random order induces better retention than practicing them in a blocked order, a phenomenon known as the contextual interference (CI) effect. Our purpose was to investigate whether the CI effect exists in sequence learning, such that practicing different sequences in a random order will result in better learning of sequences than practicing them in blocks, and whether this effect is affected by aging. Subjects practiced a serial reaction time task where a set of three 4-element sequences were arranged in blocks or in a random order on 2 successive days. Subjects were divided into 4 groups based on a 2-GROUP (young or old) by 2-ORDER (random or blocked practice) between-subject design. Three days after practice (Day 5), subjects were tested with practiced and novel sequences to evaluate sequence-specific learning. The results replicate the CI effect in sequence learning in both young and older adults. Older adults retained sequences better when trained in a random condition than in a blocked condition, although the random condition incurs greater task switching costs in older adults during practice. Our study underscores the distinction between age-related effects on learning vs. performance, and offers practical implications for enhancing skill learning in older adults.     

Contextual interference in learning precision skills

This research studied the effect of different organisations of practice (blocked and random) on the learning of three different types of throwing. 35 male students practiced three precise throws for 3 wk. Initially the subjects were separated into two groups who trained under different conditions of practice (blocked and random). All subjects improved significantly from initial performance, with both blocked practice and random practice. At the end of acquisition no differences were found between the groups. No significant differences were found on retention tests carried out 48 hr., 4 wk., and 8 wk. after the training period.     

Contextual interference in implicit and explicit motor learning

The purposes of this study were to examine the contextual interference effect in implicit learning and to compare implicit and explicit learning. Thirty-two participants performed a pursuit-tracking task for 60 acquisition and ten retention trials. The middle segment of target pathways had only two patterns whereas other segments had random patterns. A combination of awareness and practice order for the middle segment created four acquisition conditions: implicit-blocked, implicit-serial, explicit-blocked and explicit-serial. A questionnaire and a recognition test revealed that implicit groups were unaware of the repetition. Results showed no contextual interference effect in either implicit or explicit learning. Acquisition and retention performances were better for the middle segment than the other segments regardless of awareness. No difference between the implicit and explicit groups was found, suggesting that the implicit learning condition led to learning equivalent to the explicit learning condition.     

Contextual interference effects on the acquisition and retention of fundamental motor skills

This study was designed to examine the effect of three practice models (repetitions, random, and combined) on the acquisition and retention of fundamental motor skills. 54 girls in Grade 4 were randomly assigned to the three different practice groups who practiced three skills of ball rolling, racket striking, and ball kicking. All subjects received pretests posttests, and a 3-wk, retention test. Performance was significantly improved during practice in the three groups for the three skills. The repetitions group performed better than the other two groups at the end of practice. The contextual interference effect in retention was only shown for the racket-striking skill, in which the random group was significantly better than the repetitions and the combined groups. An attempt was made to attribute that specific result to the special characteristics of the striking skill in this study as an open skill with which subjects had a previous experience.     

Time requirements of changes in program and parameter variables in rapid ongoing movements

Two experiments investigated the differences in processing time requirements of two types of modifications of a rapid ongoing movement. In response to a signal presented at either 0, 100, or 200 msec after initiation of a 400-msec horizontal arm movement, subjects attempted to either increase the speed of the movement or to reverse it. EMG modification latencies were shorter in the former condition than in the latter indicating a difference in processing-time requirement between modification types. The results support the generalized motor program hypothesis of Pew (1974) and Schmidt (1976) in that increasing the speed of an ongoing movement may require modification of a parameter variable while reversing movement direction requires the implementation of a new motor program.     

Spatial assimilation effects in sequential movements: effects of parameter value switching and practice organization

In Experiment 1, the author extended earlier work by investigating spatial assimilations in sequential aiming movements when participants were able to preplan only the 1st movement of a 2-movement sequence. Right-handed participants (N = 20) aged 18-22 years tried unimanual rapid lever reversals of 20 degrees and 60 degrees with an intermovement interval of 2.5 s. Following the 1st movement, participants made a same-distance movement, different-distance movement, or no movement in a randomly determined order. Participants overshot the short-distance target and undershot the long-distance target for both movements in the sequence, but the errors were greater when the 2nd movement differed from the 1st one. In Experiment 2, right-handed participants (N = 20) demonstrated greater assimilation effects after random practice than after blocked practice of both same-distances (20 degrees -20 degrees and 60 degrees -60 degrees ) and different-distances (20 degrees -60 degrees and 60 degrees -20 degrees ) sequences, although spatial errors were greater in different-distances conditions than in same-distances conditions. Overall, the experiments showed that parameter-value switching and practice organization are 2 major sources of spatial inaccuracy in sequential aiming movements.     

Rapid aimed limb movements: differential effects of practice on component submovements

Three experiments are reported in which subjects practiced rapid aimed limb movements (arm pointing and wrist rotation) toward a visible target region. Subjects were required to minimize their movement durations while still landing in the target. The movement trajectories were examined to assess the effects of practice on separate component submovements of the limb movements. The results revealed that practice improved primarily temporal, not spatial, aspects of performance. Practice reduced the overall movement durations, but had different effects on the individual submovements. Practice allowed subjects to reduce the amount of time spent performing final corrective submovements, but actually increased slightly the time needed to produce the initial ballistic submovement. The results suggest that practice in the present task primarily enhanced the ability to use feedback information, but there was also some evidence of changes in the ballistic, preprogrammed portion of the movements. The results demonstrate that analysis of submovements can reveal important details of the underlying motor control processes.     

Information processes in movement learning: capacity and structural interference effects

A series of experiments examined motor learning as an information processing activity occurring within a working short-term memory system and where response-produced feedback and knowledge of results (KR) are used to modify the action plan developed from previous attempts at the movement task. Use of interpolated activities in the KR delay interval allowed inferences to be made regarding the capacity and structural characteristics of these information processes. Results indicated no capacity limitations on the learning process but important structural effects were found. The results supported the idea that response-produced feedback is relatively unimportant as a feedback variable early in learning. Rather, the use of KR at a relatively high level of movement planning appears to be the important information processing activity underlying learning. Finally, the results supported the view that these information processes are related to cognitive problem solving activities.     

Contextual cueing under working memory load: Selective interference of visuospatial load with expression of learning

In a series of experiments, we investigated the dependence of contextual cueing on working memory resources. A visual search task with 50 % repeated displays was run in order to elicit the implicit learning of contextual cues. The search task was combined with a concurrent visual working memory task either during an initial learning phase or a later test phase. The visual working memory load was either spatial or nonspatial. Articulatory suppression was used to prevent verbalization. We found that nonspatial working memory load had no effect, independent of presentation in the learning or test phase. In contrast, visuospatial load diminished search facilitation in the test phase, but not during learning. We concluded that visuospatial working memory resources are needed for the expression of previously learned spatial contexts, whereas the learning of contextual cues does not depend on visuospatial working memory.     

Some effects of alcohol and eye movements on cross-race face learning

This study examines the impact of acute alcohol intoxication on visual scanning in cross-race face learning. The eye movements of a group of white British participants were recorded as they encoded a series of own-and different-race faces, under alcohol and placebo conditions. Intoxication reduced the rate and extent of visual scanning during face encoding, reorienting the focus of foveal attention away from the eyes and towards the nose. Differences in encoding eye movements also varied between own-and different-race face conditions as a function of alcohol. Fixations to both face types were less frequent and more lingering following intoxication, but in the placebo condition this was only the case for different-race faces. While reducing visual scanning, however, alcohol had no adverse effect on memory, only encoding restrictions associated with sober different-race face processing led to poorer recognition. These results support perceptual expertise accounts of own-race face processing, but suggest the adverse effects of alcohol on face learning published previously are not caused by foveal encoding restrictions. The implications of these findings for alcohol myopia theory are discussed.     

Contextual inference in learning and memory

Context is widely regarded as a major determinant of learning and memory across numerous domains, including classical and instrumental conditioning, episodic memory, economic decision-making, and motor learning. However, studies across these domains remain disconnected due to the lack of a unifying framework formalizing the concept of context and its role in learning. Here, we develop a unified vernacular allowing direct comparisons between different domains of contextual learning. This leads to a Bayesian model positing that context is unobserved and needs to be inferred. Contextual inference then controls the creation, expression, and updating of memories. This theoretical approach reveals two distinct components that underlie adaptation, proper and apparent learning, respectively referring to the creation and updating of memories versus time-varying adjustments in their expression. We review a number of extensions of the basic Bayesian model that allow it to account for increasingly complex forms of contextual learning.     

Training for the production of novel timing movements: Contextual considerations

Summary The present study represented an attempt to determine the extent to which transfer performance on a novel timing task is influenced by contextual similarity (i.e., similar instructions, task requirements, etc.) between training and transfer phases of performance. All subjects were given trials on a task which involved a linear ballistic arm movement. The length of the movement was defined as the distance between a start button and a hinged target, which was knocked over by the subject at the end of the response. During training subjects attempted to produce their movements in a time of 550 ms and were given knowledge of results regarding timing error after each trial. During transfer trials a 300 ms movement time was attempted and no knowledge of results was given. Context was defined by the number of different movement distances performed during training and transfer. Half of the subjects received training trials with a single distance (constant context) while the other half received an equal number of trials with each of three distances (varied context). During the transfer stage of the experiment, subjects either performed in the same movement distance context experienced during training (i.e., constant to constant; varied to varied) or in the opposite context (i.e., constant to varied; varied to constant). The results of the transfer analysis suggested that similariy of context between training and transfer phases of performance was not crucial to the accurate production of a novel closed-timing movement. Implications of the present results for recent theories of memory development are discussed.     

Dissociation of covert and overt spatial attention during prehension movements: Selective interference effects

In four experiments, the influence of distractor objects on the temporal evolution of the reach-tograsp movement toward a target object (an apple) was examined. In the first experiment, the distractor was another apple, which moved laterally behind the target and occasionally changed direction toward the target, thus becoming the to-be-grasped object. In the second and third experiments, the distractor was a stationary piece of fruit, which sometimes became the to-be-grasped object because of a change in illumination. The fourth experiment was a combination of the first two experiments. In all cases, selective interference effects on the transport and manipulation components were observed only when attention to the distractor was covert rather than overt. It is proposed that covert visuospatial attention selects information about distracting but potentially important stimuli, such that a registration of significance is accomplished without the need to process all available information.     

The effects of concurrent task interference on category learning: evidence for multiple category learning systems

Participants learned simple and complex category structures under typical single-task conditions and when performing a simultaneous numerical Stroop task. In the simple categorization tasks, each set of contrasting categories was separated by a unidimensional explicit rule, whereas the complex tasks required integrating information from three stimulus dimensions and resulted in implicit rules that were difficult to verbalize. The concurrent Stroop task dramatically impaired learning of the simple explicit rules, but did not significantly delay learning of the complex implicit rules. These results support the hypothesis that category learning is mediated by multiple learning systems.     

Contextual interference effect on acquisition and retention of pistol-shooting skills

The effects of contextual interference on learning pistol-shooting skills in a natural training environment were examined. The shooting skills consisted of three "stages" with different requirements for the skill variations commonly used in the field. 12 participants were randomly assigned into one of two practice conditions, blocked vs serial. Following a 20-min. safety and skill instructional session, Blocked group practiced 10 trials in a row at each stage, while Serial group performed 5 trials in a row for each of the three stages and then repeated the cycle. Both groups completed a total of 30 practice trials over the three stages. A 10-min. rest interval was provided prior to a retention test which included 9 trials (3 trials at each stage in a blocked format). Results based on the data of Stage III, the most complex skill among the three stages, showed a pattern consistent with previous findings that practicing in the serial schedule depressed performance during initial training but maintained the performance better at retention, relative to the blocked practice.     

Incidental psychomotor learning: the effects of number of movements, practice, and rehearsal

Three experiments were conducted to investigate the effects of the number of movements, practice, and rehearsal on incidental and intentional psychomotor learning. incidental learners received no formal instructions to learn the central task to which they were exposed in a choice reaction-time task. The movements to the targets in this task comprised a movement sequence. Intentional learners also performed the choice reaction-time task but were additionally instructed to remember the order of the movements. Intentional learning was superior to incidental learning, unless rehearsal was disrupted; all three independent variables demonstrated similar functional effects under both learning conditions. It was concluded that incidental and intentional learning are not distinct types of learning; and that "intent to learn" per se is a significant factor in psychomotor learning only when it elicits beneficial cognitive processes such as rehearsal.     

Contextual override of pragmatic anomalies: evidence from eye movements

Readers typically experience processing difficulty when they encounter a word that is anomalous within the local context, such as 'The mouse picked up the dynamite...'. The research reported here demonstrates that by placing a sentence in a fictional scenario that is already well known to the reader (e.g., a Tom and Jerry cartoon, as a context for the example sentence above), the difficulty usually associated with these pragmatic anomalies can be immediately eliminated, as reflected in participants' eye movement behaviour. This finding suggests that readers can rapidly integrate information from their common ground, specifically, their cultural knowledge, whilst interpreting incoming text, and provides further evidence that incoming words are immediately integrated within the global discourse.     

Searching for interference effects in learning new face-name associations

In three experiments we attempted to increase interference using experimental manipulations in a face-name learning paradigm. All experiments included young and older adult participants because ageing is associated with increases in both susceptibility to interference and difficulty in learning face-name associations. None of the experiments produced interference for either age group: The inclusion of confusable (i.e., ambiguous) names and occupations, having to learn an additional piece of information in association with each face, and requiring participants to guess when uncertain all failed to negatively impact name learning. Interference does not appear to be the critical mechanism underlying the difficulty of learning proper names, and it cannot account for older adults' disproportionate decline in name-learning ability.     

Drug-preexposure effects in flavor-aversion learning: associative interference by conditioned environmental stimuli

Previous research has documented that exposure to a drug reduces the ability of the drug to support subsequent flavor-aversion learning. The four experiments reported here examined the hypothesis that this drug-preexposure effect is due to associative interference from environmental stimuli associated with the drug effects during preexposure. When distinctive environmental stimuli (confinement in a black compartment) were present during drug preexposure, these stimuli significantly disrupted subsequent flavor-aversion learning. Furthermore, flavor conditioning was not significantly disrupted when drug preexposure occurred in the absence of salient environmental stimuli or when the previously conditioned environmental stimuli were extinguished prior to flavor conditioning. It is significant, and in contrast to other published research, that flavor conditioning was not disrupted when the distinctive cues paired with the drug during preexposure were absent at the time of the flavor-drug pairing. These results are thus consistent with results from conventional studies of stimulus blocking and suggest that associative processes can play a major role in the drug-preexposure effect.     

Children's susceptibility to retroactive interference: the effects of age and degree of learning.

The effects of age and degree of learning on children's susceptibility to retroactive interference were examined. Children (4- and 7-year-olds) participated in a target game either once or three times. Each time, they learned the target stimuli to criterion. Two days later, the children either rested or participated in a second game containing inconsistent information. Retrieval tests were administered 3 weeks later. Children who participated in the target game repeatedly recognized more information from that game, both accurately and as intrusions, than did children who participated only once. Both age groups were susceptible to retroactive interference; degree of susceptibility was affected by neither age nor degree of learning. Nevertheless, the 7-year-olds were more accurate at test. These findings suggest that differences in the forgetting rate between 4- and 7-year-olds are not caused by differential susceptibility to retroactive interference.