Feedback Trials Research Articles

Integrative model of dorsal anterior cingulate cortex supported by reward-based decision-making task and event-related FMRI

Anterior cingulate cortex (ACC) encompasses multiple subdivisions that subserve attentional, cognitive and emotional processing. but no single unifying model explains diverse results from neuroimaging and electrophysiological studies. Reviews of neuroinaging studies have shown that dorsal ACC (dACC) is vitally important to cognitive processing-but the mechanism(s) by which this region works have not been elucidated. In a single unit recording study of the homologous area in monkeys, Shima & Tanji (1998) reported that different populations of cells responded to target detection, motor response, reward, and reward reduction during a reward-based decision-making task. Critically, the proportion of each cell type varied, with more than five times as many cells showing selective responsivity to movement selection based on reduced reward (37%) versus constant reward (7%). The present event-related functional magnetic resonance imaging (fMRI) study in humans exploited these differential proportions to identify responses by different cell types intermixed within this region. Specifically, we predicted that during a reward-based motor decision task modeled after the Shima & Tanji task, fMRI signal within the dACC would be significantly higher following reduced reward feedback trials as compared to fixation baseline, constant reward trials and a non-specific switch command.

Adaptation to altered feedback in speech

This study focuses on how the control of fundamental frequency (F0) of the voice is influenced by modulations of auditory feedback. A methodology analogous to one used in visual perturbation studies of limb movements was used. In these studies, optical feedback is distorted and subjects adapt to the transformed conditions by relearning the spatial coordinates used in visuomotor control. It was investigated whether F0 control would exhibit an analogous adaptation response to altered auditory feedback conditions. Subjects were exposed to pitch-shifted auditory feedback through headphones while producing (a) sustained vowels and (b) sentence material. The F0 feedback was increased in 2 cent steps that were not noticed by the talkers. Both aural- and bone-conducted masking noise were used to minimize feedback from the true F0. During the transformed feedback condition, subjects decreased their pitch in response to the increasing pitch feedback. However, preliminary analyses did not reveal evidence of adaptation to the auditory transformations. This was examined by unexpectedly introducing normal feedback trials to test for ‘‘aftereffects.’’ Results will be discussed in terms of sensorimotor learning and the role of internal models of sensory feedback in speech motor control. [Work supported by NIH NIDCD Grant No. DC-00594 and NSERC.]

The Effects of Different Training Conditions on Transfer in Concept Formation

The effects of different practice conditions on transfer were investigated in two experiments involving concept-formation problems. In both experiments, the participants learned concepts by use of either the receptive or selective procedures. In the first experiment, participants were required to learn concepts, with delayed feedback, on the practice task; the concepts on the transfer tasks were from the same category. For the second experiment, participants received reduced feedback during training; the concepts on the transfer tasks were from a different category. Although the receptive procedure, in comparison with the selective method, slowed concept attainment, it facilitated transfer on all transfer tasks. In addition, delaying and lowering the percentage of feedback trials had the same effects. The results support other findings that conditions that make initial learning more difficult may increase positive transfer.

Effects of Frequency of Feedback on Transfer in Concept Identification

Two experiments were performed to investigate the effects of frequency of feedback on immediate- and delayed-transfer tasks in concept identification. In the first experiment, subjects were required to learn new concepts from the same category for the transfer tasks, whereas in the second experiment the transfer tasks involved concepts from a different category. Among the major findings was that although lowering the percentage of feedback trials slows concept attainment, it facilitated transfer on all transfer tasks. In general, the fewer the number of feedback trials subjects received, the greater the amount of transfer. The results are consistent with other studies that suggest that conditions that make it more difficult for subjects to initially learn a task may have positive benefits for transfer.

Type A behaviour and aggression: Provocation, conflict and cardiovascular responsivity in the buss teacher—learner paradigm

This study investigated the effects of provocation and conflict on behavioural and physiological responses of male structured Interview-defined Type A and B college students. Subjetcs were assigned to one of the four conditions: (1) Provocation-conflict, (2) Provocation-no conflict, (3) No provocation-conflict, (4) No provocation-no conflict. The subjects were asked to teach concepts in the Buss teacher-learner paradigm using noise as negative feedback for incorrect responses and points as positive feedback for correct responses. The dependent variables were behavioural aggression (levels and duration of noise and amount of points), affect, blood pressure and heart rate. There was no evidence of more aggression with Type As. Type Bs showed a tendency to use higher levels of noise during the first five negative feedback trials. Results with the self-report measure of affect (MAACL) indicated that relative to Type Bs, Type As reported significantly more hostility and depression. Moreover, the conflict condition increased the systolic blood pressure of Type As but not of Type Bs. These results are discussed in the context of Glass' (1977) control hypothesis, suggesting that Type As may not only attempt to control their environment but their own reactions to stressors as well.

Factors affecting higher-order movement planning: a kinematic analysis of human prehension

Past studies of the kinematics of human prehension have shown that varying object size affects the maximum opening of the hand, while varying object distance affects the kinematic profile of the reaching limb. These data contributed to the formulation of a theory that the reaching and grasping components of human prehension reflect the output of two independent, though temporally coupled, motor programs (Jeannerod 1984). In the first experiment of the present study, subjects were required to reach out and grasp objects, with or without on-line, visual feedback. Object size and distance were covaried in a within-subjects design, and it was found that both grip formation and reach kinematics were affected by the manipulation of either variable. These data suggest that the control mechanisms underlying transport of the limb and grip formation are affected by similar task constraints. It was also observed that when visual feedback was unavailable after movement onset subjects showed an exaggerated opening of their hands, although grip size continued to be scaled for object size. The question remained as to whether the larger opening of the hand during no-feedback trials reflected the lack of opportunity to fine-tune the opening of the hand on-line, or the adoption of a strategy designed to increase tolerance for initial programming errors. To address this question, a second experiment was carried out in which we manipulated the predictability of visual feedback by presenting feedback and no-feedback trials in a random order. In contrast to the situation in which feedback and no-feedback trials were presented in separate blocks of trials (Exp. 1), in the randomly-ordered series of trials presented in Exp. 2, subjects always behaved as if they were reaching without vision, even on trials where visual feedback was continuously available. These findings suggest that subjects adopt different strategies on the basis of the predictability of visual feedback, although there is nothing to suggest that this takes place at a conscious, or voluntary, level. The results of both experiments are consistent with the notion of a hierarchically-organized motor control center, responsible for optimizing performance under a variety of conditions through the coordination of different effector systems and the anticipation of operating constraints.

Implicit acquisition of abstract knowledge about artificial grammar: Some methodological and conceptual issues.

Abstraction May be Postponed Until the Transfer Phase Throughout this discussion, we have tacitly assumed that the abstract knowledge revealed transfer tasks is elaborated during the study phase. Alternatively, however, subjects may simply encode specific items during the study phase, store them memory, and perform abstractive operations on their reminded representations the presence of new transfer items. For example, subjects asked for a grammaticality judg- ment about DJDMJJ the transfer phase may retrieve study items such as CVCPVV, SCPTVV, and so on, and then abstract a common feature: Repetitions of letters occur at the end of the items all cases. This alternative bears on the distinction between early and late computation models of categorization (Estes, 1986). Although early computation models, which full analysis of study exemplars takes place the encoding phase, are implicit traditional frameworks, there is a growing body of evidence for the late, or in line (Smith, 1989), computation model, which at least some processing occurs while subjects are dealing with new stimuli (e.g., Brooks, 1990; Medin & Ross, 1990). This alternative is obviously of crucial importance to the issue at hand. If researchers aim at eliciting implicit processing the study phase (although unsatisfactorily, as stressed above), they have never controlled the nature of the processing occurring the test phase. Typically, subjects at the beginning of the test phase are informed that the study strings were generated by a complex set of rules and that they should now assess the well-formedness of new items with regard to these rules. These instructions inevitably shift subjects to a rule discovery mental set. Mathews et al. (1989) did not mention the rule-based structure of items, but their test procedure remained explicit nature insofar as their subjects were instructed to make direct comparison between the study and test items. 2 Thus, clear evidence for a model which abstrac- tion is performed during the transfer task would be highly damaging to the claim that performance artificial grammar settings testifies to implicit abstraction. The recent Mathews et al. (1989) experiments were not designed to tackle this issue but nevertheless provided data suggesting that at least some rules are abstracted the transfer phase. For instance, above-chance grammaticality judgments for items made up of new letters did not appear immediately after letter change but rather after some feedback trials. This result is consonant with the idea that subjects do not generate ready-to-use abstract rules study phase but rather build them when given a problem that prompts rule elaboration. In the same vein, abstract verbalization was apparentlymthe Mathews et al. (1989) article is not entirely clear on this point--produced only on request the instructions.

A Device for Functional Residual Capacity Controlled Biofeedback of Respiratory Resistance - Ein Meßaufbau zur Rückmeldung des Atemwiderstandes unter Kontrolle der funktionellen Residualkapazität

A computer-aided procedure is presented providing subjects with analogous visual feedback of respiratory resistance, which is continuously measured using the forced oscillation method. Simultaneous pneumotachographical control of the breathing volume curve makes it possible to prevent reinforcement for decreases of respiratory resistance which are due to increases of functional residual capacity (FRC). Lung hyperinflation is an unsuitable way to reduce respiratory resistance; if it occurs, feedback is interrupted until the subject decreases his FRC to its initial level. Analysis of the data of 15 adult asthmatic subjects which underwent a 12-sessions feedback training showed that no substantial changes of FRC appeared within feedback trials. Advantages of this new biofeedback technique compared to other procedures are discussed with regard to volume control and feedback signal.

Self-report during feedback regulation of slow cortical potentials.

Subjects received exteroceptive feedback for bidirectional changes in slow cortical potentials or alpha power measured from the vertex. The slow potential group succeeded in shifting slow potentials toward negativity and positivity on feedback and transfer trials requiring these changes, after two sessions of training. Differentiation of negativity and positivity was accompanied by verbal reports of somatomotor activation that occurred on trials on which negative slow potentials were required (p less than .01). Vertical and lateral eye movements, chin and frontalis electromyogram, and heart rate did not differentiate between negativity and positivity trials in the slow potential negativity during feedback. Although the alpha power group did not succeed at controlling changes in alpha, evidence of a training effect appeared in verbal reports of emotional arousal (p less than .05) and focused vision (p less than .08) on alpha suppression trials in this group. We discuss the findings from the viewpoint that biofeedback tasks involving electrocortical responses are problems in the organization of action that subjects seek to solve.

The effect of feedback on young children's inappropriate word usage.

ABSTRACTThis study compared the effects of three types of adult feedback (acceptance, correction with joint labelling, and correction with explanation) on young children's inappropriate word usage. Four children were visited in their homes twice a week, from the time they were between 1;1 and 1;3 until they were approximately 1;7. Differential feedback was applied by the experimenter whenever the children extended a term to referents that were inappropriate, but similar to appropriate ones. Comprehension and production probes were administered prior to, during, and following the feedback trials to assess changes in word usage over time. Results indicated that the three types of feedback varied in their relative effectiveness in facilitating a positive change in word usage. Correction with explanation was more effective than correction with joint labelling, which in turn was more effective than simple acceptance.

Adolescents' performance on a sequence of proportional reasoning tasks

AbstractThis study was designed to investigate the understanding of proportion by a select group of college‐bound adolescents. Gender‐related differences and the influence of course experience were also studied in relation to first‐order direct proportional reasoning and multiple proportional reasoning. The 901 subjects were administered the Tall‐Short task as a test of first‐order direct proportional reasoning. From the 474 subjects classified as successful, a random subsample of 128 subjects was administered the Projection of Shadows task. Only 22 subjects succeeded on all four subtasks of this multiple proportion task. An analysis of the transcripts of responses showed that feedback and second trials were essential for success for most (68%) of these successful subjects. In addition, this select subsample generally used a multiplicative strategy and still could not overcome the inhibiting effect of focusing on direct proportions. There were significant gender differences, in favor of male subjects, in first‐order direct proportional reasoning but there were no gender differences in multiple proportional reasoning. Prior course experience in mathematics and science were each significantly related to first‐order direct proportional reasoning but there was no significant relationship between either of these variables and multiple proportional reasoning.

Individual differences in motor skills ability affect the self-regulation of heart rate.

Twenty males who scored relatively high on the rotor-pursuit motor skills task (High performance group) were given seven 2-minute trials to increase heart rate and seven 2-minute trials to decrease heart rate, as were 20 males who scored relatively low on the rotor-pursuit task (Low performance group). Visual analogue feedback was not provided during the first and last acceleration and deceleration trials but was presented during all other trials. Both groups of subjects were able to decrease heart rate significantly with and without feedback. Subjects in the High performance group were able to increase heart rate significantly with feedback and could generalize this increase to a no-feedback trial following feedback trials. Subjects in the Low performance group could not increase heart rate with or without feedback. Changes in respiration rate paralleled those noted for heart rate, but changes in chin electromyographic activity generally did not parallel the heart rate results. The heart rate data are discussed in terms of motor skills theories of self-regulation of heart rate.

心拍率の随意制御におよぼす3拍の遅延フィードバックの効果

On a CRT display, analogue heart rate feedback of each beat was presented together with a target calculated from a subject's heart rate level. Twenty subjects received twenty-four 100-beat trials. All subjects were required to continue adjusting their heart rate around the target as close as possible under both immediate and 3-beat delayed feedback conditions. Half of the subjects received immediate feedback trials first, followed by delayed feedback trials, while the other half received trials in the reverse order. Results indicated that feedback delay disrupted the accuracy of heart rate control when subjects received delayed feedback after immediate feedback trials, and that feedback delay caused low-frequency oscillation in heart rate variability. Findings in this experiment suggest that voluntary control of heart rate can be understood from the viewpoint of motor skills learing.

Depression and negative processing of evaluative feedback

Beck's cognitive behavioral model of depression served to predict that depressed college students would negatively bias their processing of evaluative feedback relative to nondepressed college students. Depressed and nondepressed students performed a dot estimation task and received “good,” “average,” “poor,” or ambiguous feedback following each of 40 trials. Half of each subject group also received feedback under conditions of high or low task importance to assess the generality of depressive biasing tendencies. Analyses revealed significant negative processing biases among depressives relative to nondepressives in immediate perception and latencies of response to feedback stimuli during the latter 20 feedback presentations but not in response to earlier feedback trials. In addition, biases in the immediate perception of feedback stimuli were most pronounced under ambiguous feedback conditions. No differences were observed between depressives and nondepressives in the long-term recall of evaluative feedback, and measures of bias were not significantly affected by the perceived importance of the experimental task. Explanations are offered for the specificity of the findings obtained.

Heart rate biofeedback and cold pressor pain.

ABSTRACTThis study addressed the relative contributions of self‐regulated heart rate change and belief that heart rate is changing in an instructed direction to the perception of cold pressor pain. Forty male volunteers were each assigned to one of four combinations of increase or decrease heart rate instructions and increase or decrease feedback conditions. Subjects were given an initial 45‐sec cold pressor test, 25 feedback trials, and a final cold pressor in which they were told to change their heart rate in the instructed direction, but without the aid of feedback. Subjects were instructed specifically that increased heart rate was associated with increased pain and decreased heart rate with decreased pain. The veridical groups (consistent instructions and feedback) showed appropriate heart rate changes during biofeedback training and parallel changes in heart rate and pain perception during the final cold pressor. The non‐veridical (reverse) feedback groups showed no heart rate change during biofeedback training and no relationship between heart rate and pain perception changes during the final cold pressor test. EMG, respiration, and skin conductance data are presented, and several mechanisms are proposed to explain the physiological and subjective changes.

The effects of slow cortical potentials on response speed.

ABSTRACTThe relationship between slow cortical potentials (SCPs) and response speed was investigated by training subjects to induce different cortical shifts by means of a biofeedback procedure. During two identical experimental sessions trials with visual feedback of the actual DC‐shifts alternated with reaction time trials without feedback. In reaction time trials only the signal for the required change in polarity was provided. At the end of the signal interval an immediate button‐press was required to stop a hissing noise. Two groups of 10 subjects each were investigated, one group receiving feed back from the left precentral recording(C3) and the other from the right precentral recording (C4). Results showed that subjects achieved control over their SCPs. At the end of the training period in the second session significant differences in SCPs between trials of the different required polarities were observed, during feedback trials as well as during reaction time trials without feedback. Subjects responded faster during trials in which a change toward more cortical negativity was required as compared to trials requiring less negativity.

Information and reward in voluntary heart rate control.

Two studies are reported which examined the relative effects of the pressence and absence of monetary incentives and instructions in a heart rate (HR) regulation task. Twelve male undergraduates were offered seven sessions of feedback assisted voluntary HR control training. In Experiment 1 six S s attempted to increase their HR with the aid of a "success," or positive binary visual signal. In Experiment 2 six S s were instructed to decrease their HR and were assisted by a "failure," or negative binary visual signal. In both studies the presence or absence of E's specific instructions to control HR was systematically varied from sessions 4 to 7. S s were paid on only half of the feedback trials of each session. These variables were thus systematically varied in a within-subject design. The main results suggest that (a) the instructions and monetary incentives significantly facilitated HR acceleration while showing no effects on HR deceleration; (b) in the no-instructions, no-incentive condition, HR control was minimal. The general hypothesis that Estes' interpretation of information and reward apply to human voluntary HR control received some support. It would appear that contrary to a traditional view, the exteroceptive feedback per se does not necessarily act as a reinforcer of the behavior, as witnessed for instance in the no-instructions, no-incentive conditions.

Biofeedback of slow cortical potentials. I

An experiment was performed to investigate the self-regulation of slow cortical potentials (SCP) found in a previous study (Elbert et al. 1979). Seventeen subjects received continuous visual feedback fo their actual cortical shift perceptible as a rocket moving across a TV-screen during intervals of 6 sec; subjects had to direct the rocket into one of two goals representing more or less cortical negativity, depending on the pitch of two signal tones. Within two identical experimental sessions feedback trials alternated with test trials without feedback. Highly significant differences of SCP between the two required polarities were demonstrated. The most pronounced differences were observed during test trials without feedback of the second session in which a positive shift below baseline level occurred when positivity (or less negativity) was required.

Instructed heart rate control in a high heart rate population

Forty college students were selected from a large number of introductory psychology students on the basis of high heart rate during an initial screening session. Subjects were then contacted and participated in two additional sessions during which heart rate, respiration rate, and skin conductance measures were obtained. Each session consisted of a baseline period followed by five trial periods during which subjects attempted to control their heart rate or performed a visual tracking task. Subjects were randomly assigned to one of four groups. One group served as a control and monitored a visual feedback display driven by their own heart rate but received no instructions to decrease their heart rate. In contrast, the three heart rate control groups were instructed to decrease heart rate during the trial periods by utilizing a relaxation procedure, proportional biofeedback, or proportional biofeedback plus criterion information. No group differences were present during the baseline periods. During feedback trials, however, all the training groups differed from the control in heart rate but did not differ from each other. It is suggested that feedback displays may not facilitate heart rate reduction beyond the level achieved by instructing subjects to use a general relaxation procedure.

A multivariate approach to the relationship between alpha waves and experience during feedback.

The variety of experiences associated with alpha enhancement have questioned the generality of early research and the reliability of the relationship. Participants were given eight alpha feedback trials and asked to complete a 40-scale semantic differential describing their experience. The eight principle components in the semantic differential were correlated with changes in alpha amplitude using canonical correlations, and two significant canonical variates were found. A procedure for estimating the influence of extraneous variables was illustrated by manipulating the instructional set and perceived locus of control. The influence of these variables varied in degree; some descriptive adjectives were strongly influenced by the manipulated variables, whereas other adjectives highly correlated with alpha activity were fairly independent of these influences. The most common strategy for alpha production was relaxation, which theoretically disconnected the interlocking of the sensory and motor systems. A cognitive strategy that bypasses the predictive processes used to guide the motor system was also in general accordance with some of the significant experiences isolated by canonical techniques.