Acquisition and extinction of signaled avoidance as a function of intermittent reinforcement

Signaled, shuttle-box avoidance responding in female rats of the Fischer₃₄₄ strain was examined as a function of four separate contingencies of intermittent reinforcement. In Experiment 1, when avoidance responses during acquisition were reinforced 25% of the time with prompt CS termination, animals responded equally often during acquisition and significantly more often during extinction than animals who received such reinforcement on a 100% schedule. Similar results were found under a trace procedure in Experiment 2 when avoidance responses were reinforced 25% of the time with informational feedback stimuli. In contrast, during Experiment 3, when animals were shocked on only 25% of the trials on which they failed to respond, the level of avoidance responding during both acquisition and extinction was significantly less than it was when animals were shocked on a 100% schedule. Comparable results were found in Experiment 4 when avoidance responses during acquisition averted shock on only 25% of the trials. Thus, intermittent reinforcement contingencies involving response-contingent feedback stimuli and shock have differential effects on avoidance responding during both acquisition and extinction trials under the signaled avoidance procedure.     

Long-term retention of a motor skill: Implicit sequence knowledge is not retained after a one-year delay

Experimental work shows that some motor skills are retained well over a long delay and others are not. It is possible that motor tasks that are primarily implicit are retained over long intervals, whereas those with an explicit component are subject to more rapid forgetting. To test whether implicit motor skills are retained, 24 (experienced) participants were retested after a one-year delay for their retention of an implicit motor sequence. They had been trained on the sequence in a button-pushing task. Although the experienced participants responded faster than they had a year earlier, they showed no retention of the sequence compared to 24 participants who had received no training a year earlier, and no savings in relearning the sequence. The overall speed effect may indicate that the amount of training is crucial to the degree of retention of a skill. The results indicate that it is not the case that implicit motor skills are well retained whereas those with an explicit component are not.     

Resolving a conflict between sensory feedback and knowledge of results, while learning a motor skill

In a recent study, Buekers, Magill, and Hall (1992) showed that even when verbal knowledge of results (KR) was redundant with sensory feedback, erroneous KR influenced the learning of motor skills. To determine why this occurred, we conducted two experiments. In Experiment 1, subjects performed 50 practice trials on a complex anticipation task and then performed three non-KR retention tests of 25 trials each. The results indicated that when correct KR and erroneous KR were provided alternately, subjects ignored the erroneous KR and performed according to the correct KR. Experiment 2 compared different ratios of no KR to erroneous KR. The results showed that, for low ratios (1:1 and 4:1), learning experience was similar to a condition in which erroneous KR was presented on all trials. For a higher ratio (9:1), however, learning performance was similar to performance when KR was correct on all trials or was not presented. These results are interpreted as support for the hypothesis that when two conflicting sources of information are available, the subject's degree of uncertainty about the valid source of information influences his selection of the information to guide performance.     

Effects of reducing frequency of intrinsic knowledge of results on the learning of a motor skill

The guidance hypothesis suggests too much knowledge of results during skill acquisition can be detrimental to long-term performance. Possibly, the learner becomes dependent on augmented KR and is unable to use intrinsic feedback. This study examined this hypothesis with three groups performing a golf putting task. One group received continuous KR about ball path and final location; the other groups were deprived of specific KR on 50% or 100% of the acquisition trials. As expected, the continuous KR group performed better during acquisition, but the KR-deprived groups performed better on delayed retention trials, especially when KR was absent.     

The automaticity of complex motor skill learning as a function of attentional focus

The present experiment was designed to test the predictions of the constrained-action hypothesis. This hypothesis proposes that when performers utilize an internal focus of attention (focus on their movements) they may actually constrain or interfere with automatic control processes that would normally regulate the movement, whereas an external focus of attention (focus on the movement effect) allows the motor system to more naturally self-organize. To test this hypothesis, a dynamic balance task (stabilometer) was used with participants instructed to adopt either an internal or external focus of attention. Consistent with earlier experiments, the external focus group produced generally smaller balance errors than did the internal focus group and responded at a higher frequency indicating higher confluence between voluntary and reflexive mechanisms. In addition, probe reaction times (RTs) were taken as a measure of the attention demands required under the two attentional focus conditions. Consistent with the hypothesis, the external focus participants demonstrated lower probe RTs than did the internal focus participants, indicating a higher degree of automaticity and less conscious interference in the control processes associated with the balance task.     

Recall and recognition processes in motor memory: effects of feedback and knowledge of results delay

In linear movement tasks of 200 msec (Experiment 1 -ballistic movement) and 500 msec (Experiment 2 - nonballistic movement), motor recall strength was assessed by absolute, constant, and variable error; recognition strength was assessed by Z'-transformed actual-estimate correlations and absolute actual-estimate difference scores. Contrary to predictions, neither increased KR delay (45 vs. 5 sec) nor limited visual-auditory-tactile feedback caused decrements in recognition processes over KR-training or KR-withdrawal trial blocks for the 200-msec task. In the 500-msec task, the independent variables impaired recognition through training and transfer trials but impaired recall only in the training trials. Results generally did not support the hypothesized independence between recall and recognition processes. Several methodological issues related to recall, and recognition research were discussed.     

Synchronization and knowledge of results in a ventilatory motor task

The ability of healthy subjects to adopt a given value of inspiratory duration (TI) was examined in two different conditions: a knowledge condition in which subjects were informed of their performance on TI and synchronization of subjects' breathing rate to a periodic visual signal. The target value of TI was computed individually, by the same formula for all subjects in both procedures. 40 subjects were tested in a double-transfer design; each subject participated in two sessions 24 hr. apart. In addition to previous results showing better retention of the ventilatory task in subjects following the knowledge procedure after 24 hr., this study also shows better performance in this condition. No transfer could be evidenced, suggesting low similarity between the two tasks in spite of the fact that the resulting breathing patterns were nearly identical. The influence of the magnitude of the target on performance was also investigated.