Verbal and spatial acquisition as a function of distributed practice and code-specific interference.

Theories of memory must account for memory performance during both the acquisition (i.e., ongoing learning) and retention (i.e., following disuse) stages of training. One factor affecting both stages is whether repeated encounters with a set of material occur with no delay between blocks (massed) or alternating with another intervening task (spaced). Whereas the retention advantage for spaced over massed practice is well accounted for by some current theories of memory, theories of decay or general interference predict massed, rather than spaced, advantages during acquisition. In a series of 3 experiments, we show that the effects of spacing on acquisition depend on the relationship between primary and delay tasks. Specifically, massed acquisition advantages occur only in the presence of code-specific interference (the engagement in two alternating tasks both emphasizing the same processing code, such as verbal or spatial processing codes; e.g., learning letter-number pairs and reading text), whereas spaced acquisition advantages are observed only when code-specific interference is absent. These results present a challenge for major theories of memory. Furthermore, we argue that code-specific interference is important for researchers of the spacing and interleaving effects to take into consideration, as the relationship between the alternating tasks used has a substantial impact on acquisition performance.

Empirically valid principles for training in the real world.

Four sets of cognitive psychology experiments are aimed to identify and empirically support principles of training intended to increase training effectiveness. Each set supports a different training principle: strategic use of knowledge (learning and memory are facilitated whenever preexisting knowledge can be used as a mediator in the process of acquisition), training difficulty (conditions that cause desirable difficulties during learning might facilitate later retention and transfer), mental practice (mental practice can retard forgetting and promote transfer of training, sometimes to a larger extent than can physical practice), and cognitive antidote (adverse effects of prolonged work on routine tasks can be mitigated by adding cognitive complications). The first 2 principles are focused on knowledge acquisition and the last 2 on skill acquisition. Nevertheless, the principles converge on similar prescriptions: Contrary to intuition and common practice, the trainer is recommended to increase the complexity of the training situation rather than use the simplest methods available.

Intention to respond in a special way offers some protection against forgetting associations.

In a continuous memory-updating paradigm, subjects studied name-color associations and were tested later for the color associate given the name. The default color response was made in one location, but on predesignated trials the response was required to be made in a special location. Memory for the color associated with a given name was assessed after short and long retention intervals when both default and special responses were required. Separate measures were examined of memory for the intention to respond in a particular way (default or special) and of memory for the color associations paired with the names. Memory for color associates was better overall with short than with long retention intervals and was better when special (rather than default) responses were required, especially at the long retention interval. These results imply that the requirement to respond in a special way protects associations from loss due to forgetting.

Contextual memory and skill transfer in category search.

In three experiments, we examined transfer and contextual memory in a category search task. Each experiment included two phases (training and test), during which participants searched through category and exemplar menus for targets. In Experiment 1, the targets were from one of two domains during training (grocery store or department store); the domain was either the same or changed at test. Also, the categories were organized in one of two ways (alphabetically or semantically); the organization either remained the same or changed at test. In Experiments 2 and 3, domain and organization were held constant; however, categories or exemplars were the same, partially replaced, or entirely replaced across phases in order to simulate the dynamic nature of category search in everyday situations. Transfer occurred at test when the category organization or domain was maintained and when the categories or exemplars matched (partially or entirely) those at training. These results demonstrate that transfer is facilitated by overlap in training and testing contexts.

Terrorism after 9/11: reactions to simulated news reports.

Two experiments examined participants' responses to simulated news reports of terrorist attacks. Participants were told that a nondemocratic nation had sponsored strikes on military and cultural or educational sites in the United States. Participants in both experiments reacted more conflictually to terrorist attacks on military sites than to those on cultural or educational sites. Their conflictual responses on a thermometer scale escalated after repeated attacks. When tested in 2002 and 2004, 1 and 3 years after the real World Trade Center attacks, participants' reactions were more conflictual than those of participants examined before September 11, 2001. Furthermore, current participants' fear and anger increased, and forgiveness decreased, over repeated simulated attacks. Participants lower in masculinity showed more fear and less anger than did those higher in masculinity. This study shows that terrorist attacks produce more than simple terror.

A mental practice superiority effect: less retroactive interference and more transfer than physical practice.

Two experiments explored the benefits to retention and transfer conferred by mental practice. During familiarization, participants typed 4-digit numbers and took an immediate typing test on both old and new numbers. Participants then typed old 4-digit numbers, either physically or mentally, with either a different response configuration or the opposite hand from that used during familiarization. On a delayed test, participants physically typed both old and new numbers with the same response configuration and hand used during familiarization. Mental practice led to less retroactive interference and more transfer than did physical practice, supporting the hypothesis that mental practice strengthens an abstract representation that does not involve specific effectors.

Pushing the limits of imagination: mental practice for learning sequences.

In 2 experiments, the efficacy of motor imagery for learning to type number sequences was examined. Adults practiced typing 4-digit numbers. Then, during subsequent training, they either typed in the same or a different location, imagined typing, merely looked at each number, or performed an irrelevant task. Repetition priming (faster responses for old relative to new numbers) was observed on an immediate test and after a 3-month delay for participants who imagined typing. Improvement across the delay in typing old and new numbers was found for the imagined and actual typing conditions but not for the other conditions. The findings suggest that imagery can be used to acquire and retain representations of sequences and to improve general typing skill.

Specificity effects in training and transfer of speeded responses.

In 3 experiments, participants, on signal, moved a cursor from a central position to 1 of 8 numerically labeled locations on the circumference of a clock face. Movements were controlled by a mouse in 1 of 4 conditions: vertical reversal, horizontal reversal, combined reversals, or normal (i.e., no reversals). Participants were trained in 1, 2, or 3 of these conditions and were tested 1 week later with either the same or a different condition. There were improvements across training and perfect retention across the delay. There was little or no transfer, however, even when training involved combined reversals or multiple conditions. These results illustrate severe specificity of training and are interpreted in terms of acquired inhibition of normal responses.

Verification of multiplication facts: an investigation using retrospective protocols.

Retrospective verbal protocols collected throughout participants' performance of a multiplication verification task (e.g., "7 x 3 = 28, true or false?") documented a number of different strategies and changes in strategy use across different problem categories used for this common experimental task. Correct answer retrieval and comparison to the candidate answer was the modal but not the only strategy reported. Experiment 1 results supported the use of a calculation algorithm on some trials and the use of the difference between the candidate and correct answers (i.e., split) on others. Experiment 2 clearly demonstrated that participants sometimes bypassed retrieval by relying on the split information. Implications for mental arithmetic theories and the general efficacy of retrospective protocols are discussed.

Brain processes associated with target finding.

The response execution stage of cognitive skill consists of several substages, including finding the proper response location among available alternatives and moving the effector to the target location. In order to unravel the brain dynamics associated with the finding process, the present experiments used two experimental conditions. In the number condition, which requires both finding and moving, subjects are presented on each trial with a digit, 0-9, are required to find that digit on a circular clock face, and then to move a cursor to that target's location. In the arrow condition, an arrow pointing to the location of the target on the clock face circumference appears simultaneously with the target digit; no target finding is required because subjects need only to move the cursor along the path marked by the arrow. A pilot and the main experiment revealed that response initiation times but not movement times were affected by these experimental manipulations. Analysis of magnetoencephalographic (MEG) activity revealed an early occipital activity which was not affected by experimental manipulations. Later activity with central-parietal and parieto-temporal loci presumably reflected changes in the dorsal and ventral pathways, respectively, and these were affected by experimental conditions. Finally, finding processes seem to be associated with a second late activation of the ventral pathway presumably reflecting ongoing recognition processes.

The influence of stimulus array on training of a speeded response.

We conducted two experiments to study the training of speeded responses to stimuli in a clock face array. Participants were trained on one clock face and later tested on either the same or a different clock face. The clock faces varied along 3 dimensions of change (left-right flip, up-down flip, and 180 degrees rotation). Skill acquisition was reflected in decreases in overall, initiation, and movement response times in the training and test phases except that movement time reached an asymptote during training and did not decrease further during test. Test performance was best when training and test used the same clock face and worst when the training to test change involved an up-down flip. The transition to different clock faces was consistent with an interpretation based on the violation of expectations about target positions acquired during training. Consistent trial-by-trial feedback led to better initiation time but not movement time during training than periodic feedback, but this effect did not persist into the test phase.

Effects of difficulty, specificity, and variability on training to follow navigation instructions.

To study the relative merits of three training principles - difficulty of training, specificity of training, and variability of training - subjects were trained to follow navigation instructions to move in a grid on a computer screen. Subjects repeated and then followed the instructions by mouse clicking on the grid. They were trained, given a short distractor task, and then tested. There were three groups, each receiving different message lengths during training: easy (short lengths), hard (long lengths), and mixed (all lengths), with all subjects given all lengths at test. At test, the mixed group was best on most lengths, the easy group was better than the hard group on short lengths, and the hard group was better than the easy group on long lengths. The results support the advantages of both specificity and variability of training but do not support the hypothesis that difficult training of the form used here would lead to overall best performance at test.

Memory seeding: representations underlying quantitative estimations.

N. R. Brown and R. S. Siegler (1996) found that training participants on a subset of country populations improved estimations for novel transfer country populations, an effect called seeding that remained intact over time. They attributed this effect to the abstraction by participants of a general metric framework for estimating populations not dependent on specific country anchors. In a series of 3 follow-up experiments, the authors found that training on seed populations produces both general metric information and durable specific country information. Moreover, minimal amounts of general (mean or range of populations) or specific (1 or 3 countries) information made available for inspection while estimating produced a significant seeding effect. Retention over long intervals was facilitated by both presenting 3 seed countries as opposed to 1 and providing names for the seed countries.

Effects of prolonged work on data entry speed and accuracy.

In 2 experiments, participants used a keyboard to enter 4-digit numbers presented on a computer monitor under conditions promoting fatigue. In Experiment 1, accuracy of data entry declined but response times improved over time, reflecting an increasing speed-accuracy trade-off. In Experiment 2, the (largely cognitive) time to enter the initial digit decreased in the 1st half but increased in the 2nd half of the session. Accuracy and time to enter the remaining digits decreased across though not within session halves. The (largely motoric) time to press a concluding keystroke decreased over the session. Thus, through a combination of facilitation and inhibition, prolonged work affects the component cognitive and motoric processes of data entry differentially and at different points in practice.

Specificity and transfer effects in time production skill: examining the role of attention.

Two experiments examined transfer of a prospective, time production skill under conditions involving changes in concurrent task requirements. Positive transfer of the time production skill might be expected only when the attentional demands of the concurrent task were held constant from training to test. However, some positive transfer was found even when the concurrent task at retraining was made either easier or more difficult than the concurrent task learned during training. The amount and direction of transfer depended more on the pacing of the stimuli in the secondary task than on the difficulty of the secondary task, even though difficulty affects attentional demands more. These findings are consistent with the procedural reinstatement principle of skill learning, by which transfer from one task to another depends on an overlap in procedures required by the two skills.

Conserving time in the classroom: the clicker technique.

Any technique that conserves classroom instructional time without sacrificing the amount learned is of great educational value. This research compared a laboratory analogue of the clicker technique to analogues of other classroom pedagogical methods that all involve repeated testing during teaching. The clicker analogue mimics the classroom practice of dropping material that is understood by the majority of the class, as revealed by testing with clicker questions, from further lecture. A fact learning and retrieval paradigm was used, in which college students learned facts about unfamiliar countries. Compressing instruction time based on group-level performance produced as much learning as no compression and as compression based on individual-level performance. Results suggest that the clicker technique is an efficient and cost-effective method of conserving instructional time without loss of amount learned.

Task integration in time production.

Two experiments examined training on a prospective time production task. Participants produced intervals, expressed in fixed arbitrary units, while performing a concurrent secondary task. After a 15-min filled delay, the participants were retrained on the same tasks. These experiments tested whether the primary and secondary tasks would be integrated into a single task. In Experiment 1, the secondary-task requirements were manipulated, but the time production task was fixed. In Experiment 2, the time production task requirements were manipulated, but the secondary task was fixed. The results suggest that participants integrate primary- and secondary-task requirements.

Strategy selection and use during classification skill acquisition.

Two experiments examined 3 variables affecting accuracy, response time, and reports of strategy use in a binary classification skill task. In Experiment 1, higher rule cue salience, allowing faster rule application, produced higher aggregate rule use than lower rule cue salience. After participants were pretrained on the relevant classification rule, rule reports were high but generally declined across training trials; after participants were pretrained on an irrelevant rule, reports of the relevant rule increased across training trials. In Experiment 2, no rule pretraining produced a pattern of results like that obtained with irrelevant rule pretraining in Experiment 1. Presenting novel stimuli during training in Experiment 2 elevated aggregate rule reports relative to conditions where they were absent. Two participant subgroups were identified: those persisting in rule reports and those transitioning from rule to memory reports during training. The proportion of persistent rule users was higher after rule discovery than after relevant rule pretraining. Overall, the results indicate that differences among prior experiments can be reconciled. Further, they raise questions about the inevitability of memory-based automaticity in binary classification, favoring instead strategy choice based on the costs and benefits of a particular strategy and of a shift from one strategy to another.