Motor imagery and ‘placebo-racket effects’ in tennis serve performance

ObjectivesThis study aimed at confirming whether Motor Imagery (MI) enhances tennis serve performance, and determining whether a placebo condition could affect the beneficial effects of MI.DesignThis study used a 3 × 2 factorial design. Three groups of tennis players were compared in service performance outcomes before and after a training session.MethodsTwenty-two tennis players were assigned into three groups: a control (C) and two experimental groups subjected to a similar MI intervention, one group using their regular own racket (MI group) while the other used a placebo racket (P group).ResultsAnalyses of Covariance revealed no significant group difference when comparing serve velocity after training session, but MI training improved serve accuracy and regularity. Combining placebo racket with MI further resulted in greater serve accuracy score as compared to MI alone. Players' perception of their serve quality improved after MI, and this effect was reinforced in the P group.ConclusionThese findings revealed that MI may be useful to achieve peak performance, and that the implement placebo effect might be a factor in sport performance, hence promoting the beneficial effects of alternative methods to improve tennis serve performance.     

Efficacy of stimulants for fatigue management: the effects of Provigil® and Dexedrine® on sleep-deprived aviators

The present report details the results of a quasi-experimental comparison between the alerting effects of modafinil (Provigil^®) and those of dextroamphetamine (Dexedrine^®) in sleep-deprived pilots. Data from two separate placebo-controlled studies (one on Dexedrine^® and one on Provigil^®) were merged and analyzed to determine whether one compound produced greater effects than the other relative to placebo. The results indicated there were differences between the two stimulants on only two of the 14 dependent measures. In one case (a flight performance measure), modafinil was more effective than dextroamphetamine, and in the other case (subjective fatigue ratings), dextroamphetamine was better than modafinil. The remaining measures indicated no statistically-significant differences between the two stimulants. However, in the majority of cases, it was clear that performance, subjective mood ratings, and physiological indices of alertness were substantially better under both drugs than under placebo. Thus, with the exception that modafinil produced more spontaneous reports of side effects than dextroamphetamine, the overall results indicated equivalent efficacy with the two compounds. Limitations of this study were that the two compounds were tested on different samples at different points in time, and there was no systematic measurement of side effects (instead, spontaneous reports were recorded). Future work should validate the present results in a controlled side-by-side comparison of dextroamphetamine and modafinil under conditions similar to the ones reported here.     

Autonomic and behavioral effects of dextroamphetamine and placebo in normal and hyperactive prepubertal boys

The hypothesis is tested that the response to dextroamphetamine in terms of activity, attention, impulsivity, and autonomic activity is similar in normal (N) and hyperactive (H) children. Fourteen N and 15 H boys had skin conductance (SC), heart rate (HR), and finger temperature (ST) recorded during rest, presentation of eight 75- dB tones, and a reaction time (RT) procedure on three occasions: off drug (Day 1) and after ingestion (double-blind) of placebo and of .5 mg/kg dextroamphetamine. Both N and H groups showed drug effects, compared to placebo, of reduced motor activity and impulsivity, improved attention (RT), increased HR and HR slowing during RT foreperiods, and decreased ST. Both groups also had decreases in SC responsivity but in different parts of the test. Placebo compared to Day 1 produced increased activity and autonomic arousal but no change in RT. Stimulant drugs thus have similar behavioral and autonomic effects in both N and H boys, but the beneficial effects on behavior do not depend critically on increases in arousal.     

Instrumental performance following reinforcer devaluation depends upon incentive learning

Conditioning an aversion to the reinforcer following instrumental training reduces performance in a subsequent extinction test. Three experiments examined whether this reinforcer-devaluation effect depends upon experience with the devalued reinforcer prior to the extinction test. In Experiments 1 and 2 thirsty rats were trained to press a lever for sucrose solution in a single session. All animals then received an injection of lithium chloride (LiCl) either immediately following the session or after a delay of 6 hr. On the next day either the sucrose solution or water was presented non-contingently either in the operant chamber without the lever present or in a separate drinking cage. In a subsequent extinction test only the animals that had received immediate LiCl and re-exposure to non-contingent sucrose pressed less than those in the delayed-LiCl control groups. Experiment 3 demonstrated that this difference depended, at least in part, on post-conditioning exposure to a contingent reinforcer. Lever pressing and chain pulling were reinforced concurrently with either a sucrose or a sodium chloride solution in a single session immediately before the administration of LiCl. All animals then received non-contingent presentations of one of the reinforcers in the absence of both manipulanda. Finally, performance of both actions was assessed in an extinction test. Re-exposure to a reinforcer produced a relative reduction in the performance of its associated action on test. These results are interpreted as evidence that the instrumental reinforcer devaluation effect depends upon a process of incentive learning.     

An Evaluation of the Effects of Diagnostic Composition on Individual Treatment Outcome Within Transdiagnostic Cognitive–Behavioral Group Therapy for Anxiety

Recently, studies have supported the efficacy of treating anxiety disorders utilizing a transdiagnostic, or non-diagnosis-specific, framework (Erickson, D. H. (2003). Group cognitive behavioural therapy for heterogeneous anxiety disorders. Cognitive Behaviour Therapy, 32, 179–186; Garcia, M. S. (2004). Effectiveness of cognitive-behavioural group therapy in patients with anxiety disorders. Psychology in Spain, 8, 89–97; Norton, P. J., & Hope, D. A. (2005). Preliminary evaluation of a broad-spectrum cognitive-behavioral group therapy for anxiety. Journal of Behavior Therapy and Experimental Psychiatry, 36, 79–97). Transdiagnostic group treatment packages focus on the common aspects inherent across the anxiety disorders such as behavioral and cognitive avoidance, and faulty cognitive appraisals of threat potential or meaning (Barlow, D. H., Allen, L. B., & Choate, M. L. (2004). Toward a unified treatment for emotional disorders. Behavior Therapy, 35, 205–230). Although research supports the overall efficacy of transdiagnostic cognitive behavior therapy (CBT) for anxiety disorders (Norton, P. J., & Philipp, L. M. (2008). Transdiagnostic approaches to the treatment of anxiety disorders: A quantitative review. Psychotherapy: Theory, Research, Practice and Training, 45, 214–226), the effect of diagnostically mixed group composition on individual outcomes is less clear. This study investigated the relationship between group composition and treatment outcome within diagnostically heterogeneous groups with the purpose of determining if diagnostic heterogeneity differentially impacted treatment outcome for 84 individuals during a 12-week transdiagnostic cognitive–behavioral group anxiety treatment program (Norton, P. J. (2012a). Group cognitive-behavioral therapy of anxiety: A transdiagnostic treatment manual. New York: Guilford). The diagnostic makeup of the treatment group was examined at the beginning of treatment and at the end of treatment, and the results indicated that the diagnostic makeup of the treatment group had no significant impact on individual treatment outcome. These findings have direct implications for the delivery of transdiagnostic treatments, and are discussed in terms of their global implications for the transdiagnostic approach to the treatment of anxiety disorders.     

Five weeks of immersive reminiscence therapy improves autobiographical memory in Alzheimer’s disease

ABSTRACT

We examined the effects of a new Immersive Reminiscence Therapy (IRT) programme on cognitive function, including autobiographical memory, in a sample Alzheimer’s disease (AD) patients. A total of 43 AD patients with mild to moderate disease severity were randomly assigned to either an intervention group (n?=?22, MMMSE?=?20.77), or a control group (n?=?21, MMMSE?=?19.24). The intervention group received one weekly group-based session of IRT for five weeks in an authentic 1950s style museum environment, matching the time of the participants’ youth. IRT included semi-structured conversations about the past. The control group received standard care. We assessed performance on cognitive function and autobiographical memory at baseline and post-intervention. Five weeks of IRT enhanced subsequent autobiographical memory performance, when participants were cued by concrete objects dated to their youth. Object-cued memories reported post intervention included a significantly higher degree of episodic details and higher word counts. The intervention showed no effect on the Autobiographical Memory Interview or word-cued recall. Global cognitive function and semantic autobiographical memory performance increased across time for both groups. Our findings demonstrate that immersion into a setting, rich on concrete cues dated to the participants’ youth can improve autobiographical remembering.     

Spatial learning of visual 'nonsense figures' during experimental ethanol intoxication

The interaction of alcohol and visuospatial learning was evaluated during two experimental sessions. During one session, participants were experimentally intoxicated to obtain a blood alcohol concentration of at least 0.10%. During another session, a nonalcohol placebo was administered. The learning task consisted of a paired-associate paradigm requiring participants to learn the distinct spatial positions of 6 visually presented "nonsense shapes." The visuospatial learning of participants in the placebo condition was generally superior to their learning while intoxicated. However, intercorrelations of performance measures indicated that the relation between alcohol ingestion and performance differences across conditions was not linear.     

The Effect of Placebo-Induced Changes in Expectancies on Maximal Force Production in College Students

This study used false information about a placebo (milk-sugar tablet) to induce expectancies regarding force production. Forty-two college students were assigned to a placebo/placebo (PP), placebo/no-placebo (PN), or control group, and underwent baseline testing and two trials assessing one-repetition maximum (1 RM) strength on a bench press and seated leg press. The PP and PN groups improved significantly compared to the control at Trial 1 for the bench press (p ≤ .01) and leg press (p ≤ .01). Disclosure of the true nature of the placebo resulted in force production declines in the PN group to levels approximating controls on the bench press (p > .05) and seated leg press (p > .05). The results suggest that placebo-associated expectancy effects played a significant part in the observed changes. Implications include information for coaches, teachers, and fitness enthusiasts about the importance of psychological factors in successful performance.     

Biased attention retraining in dysphoria: a failure to replicate

The present study replicated Wells and Beevers [(2010). Biased attention and dysphoria: Manipulating selective attention reduces subsequent depressive symptoms. Cognition &; Emotion, 24, 719–728] and examined the longitudinal effects of attentional retraining on symptoms of depression. Dysphoric undergraduate psychology students were randomly assigned into either a neutral or control training condition. Training was administered using a dot-probe task that presented participants with pairs of pictures (of sad and neutral content) that were followed by a probe that participants had to respond to. Training took place over four sessions during a two-week period, followed by a final follow-up session two weeks later. Mood was measured at baseline, post-training, and at follow-up. All participants showed a significant reduction in depressive symptoms throughout the study, F(1.7, 73.55)?=?21.19, p?Cognition &; Emotion, 24, 719–728]. Implications of the findings on research on attentional retraining in the context of depression are discussed.     

Success modulates consolidation of a visuomotor adaptation task

Consolidation is a time-dependent process that is responsible for the storage of information in long-term memory. As such, it plays a crucial role in motor learning. Prior research suggests that some consolidation processes are triggered only when the learner experiences some success during practice. In the present study, we tested whether consolidation processes depend on the objective performance of the learner or on the learner's subjective evaluation of his or her own performance (i.e., how successful the learner believes he or she is). Four groups of participants performed 2 sessions of a visuomotor adaptation task for which they had to learn a new internal model of limb kinematics; these sessions were either 5 min or 24 hr apart. The task was identical for all participants, but each group was given a difficult or an easy objective that affected the participants' evaluation of their own performance during the initial practice session. All groups adapted their movements similarly to the rotation of the visual feedback during the first session. However, when retested the following day, participants who had a 24-hr rest interval and had initially experienced success performed significantly better than those who did not feel successful or who were given a 5-min rest interval. Our results indicate that a certain level of subjective success must be experienced to trigger certain consolidation processes.     

Conditioned placebo responses

Following earlier animal research, we attempt to condition placebo effects in human subjects. Four groups of 8 voluntary subjects were told that the experimenters would test a powerful new analgesic cream over three sessions by assessing its ability to reduce experimentally induced pain. The analgesic cream was, in fact, a placebo. In the first session all subjects were tested with and without the cream to assess their placebo response. In the second session, to condition two groups (with differing stimulation levels) to experience pain relief in response to the placebo, we repeatedly paired a reduction in nocioceptive stimulation with placebo administration. (Subjects were unaware that stimulation levels were manipulated). To condition the other two groups (with different stimulation levels) to experience an exacerbation of the pain, we paired an increase in nocioceptive stimulation with placebo administration. In the third session, all subjects were again tested for placebo response. Results suggested that placebo responses are conditionable in the laboratory in both a positive and negative direction. The clinical implications of a learning theory of placebo behavior are discussed.     

Error reactivity in self-paced performance: Highly-accurate individuals exhibit largest post-error slowing

Reaction time is typically increased following an erroneous response. This post-error slowing is traditionally explained by a strategic adjustment of response threshold towards more conservative behaviour. A recently proposed orienting account provides an alternative explanation for post-error slowing. According to this account, committing an error evokes an orienting response (OR), which inhibits information processing in the subsequent trial, resulting in slow and inaccurate performance. We tested a straightforward prediction of the orienting account in the context of self-paced performance, adopting an individual-differences approach: Post-error slowing should be larger the less frequent an error is. To this end, participants were classified into three groups differing in overall performance accuracy. Larger post-error slowing and stronger post-error accuracy decrease were observed for the high-accuracy group than for the two other groups. Practice pronounced the post-error accuracy decline, especially for the high-accuracy group. The results are consistent with the orienting account of post-error slowing but are problematic for accounts based on strategic evaluation mechanisms.     

Error reactivity in self-paced performance: Highly-accurate individuals exhibit largest post-error slowing

Reaction time is typically increased following an erroneous response. This post-error slowing is traditionally explained by a strategic adjustment of response threshold towards more conservative behaviour. A recently proposed orienting account provides an alternative explanation for post-error slowing. According to this account, committing an error evokes an orienting response (OR), which inhibits information processing in the subsequent trial, resulting in slow and inaccurate performance. We tested a straightforward prediction of the orienting account in the context of self-paced performance, adopting an individual-differences approach: Post-error slowing should be larger the less frequent an error is. To this end, participants were classified into three groups differing in overall performance accuracy. Larger post-error slowing and stronger post-error accuracy decrease were observed for the high-accuracy group than for the two other groups. Practice pronounced the post-error accuracy decline, especially for the high-accuracy group. The results are consistent with the orienting account of post-error slowing but are problematic for accounts based on strategic evaluation mechanisms.     

Trait predictors of placebo responses in itch

This study investigated trait predictors of placebo responses in the context of inflammatory skin reactions. This was a randomized, cross-over, experimental study using a deceptive placebo protocol. A healthy sample of volunteers (N = 48) completed online personality measures, then attended two laboratory sessions in which short-term inflammatory skin reactions were induced. One was a control session and the other the ‘treatment’ session in which a placebo cream was administered with the suggestion of a reduced skin reaction. A placebo response was defined as smaller skin reactions in control vs. treatment sessions. The traits ego resiliency and neuroticism were selected as possible predictors of placebo responses. Traits were selected in consideration of the two-faceted transactional model of placebo responsiveness and in light of empirical and psychometric considerations ego resiliency emerged as a consistent predictor of placebo responses in itch (p < .05). This is the first study to identify trait predictors of placebo responses in inflammatory skin reactions. Ego resiliency may typify greater placebo responsiveness; however, this may only be in certain contexts. Matching treatment approaches to bio-behavioural response tendencies may be useful clinically if the placebo component of traditional treatments can be enhanced.     

Practicing Elements Versus Practicing Coordination: Changes in the Structure of Variance

ABSTRACT

The authors explored effects of practice of a 2-finger accurate force production task on components of finger force variance quantified within the uncontrolled manifold (UCM) hypothesis, V_UCM, that had no effect on total force and V_ORT that affected total force. A variable task with graded instability was designed to encourage use of variable solutions. Two groups of subjects (n = 9 each) were tested prior to a 1.5-hr practice session, after the session, and 2 weeks later (retention test). Group 1 practiced 1 finger at a time, while Group 2 practiced the task with 2 fingers (index and middle) pressing together. Both groups showed comparable improvements in the performance indices. Both groups showed a decrease in V_ORT, while only Group 2 showed an increase in V_UCM. These effects persisted during the retention test. The results show that practicing elements and practicing redundant groups of elements may lead to similar changes in performance (i.e., in the variability of the total force produced by the set of fingers), accompanied by dramatically different changes in the structure of variance: A drop in V_UCM after the single-finger practice and an increase following the 2-finger practice. The strong retention effects promise applications of the method to rehabilitation.     

Do humans use episodic memory to solve a <Emphasis Type="Italic">What</Emphasis>-<Emphasis Type="Italic">Where</Emphasis>-<Emphasis Type="Italic">When</Emphasis> memory task?

What-Where-When (WWW) memory tasks have been used to study episodic(-like) memory in non-human animals. In this study, we investigate whether humans use episodic memory to solve such a WWW memory task. Participants are assigned to one of two treatments, in which they hide different coin types (what) in different locations (where) on two separate occasions (when). In the Active treatment, which mimics the animal situation as closely as possible, participants are instructed to memorize the WWW information; in the Passive treatment, participants are unaware of the fact that memory will be tested. In both groups, the majority of participants report using a mental time travel strategy to solve the task, and performance on a different episodic memory test significantly predicts performance on the WWW memory task. This suggests that the WWW memory task is a good test of episodic memory in humans. Participants remember locations and coins from the first hiding session better than they do those of the second hiding session, suggesting their memories may be reinforced during the second hiding session. We also investigated how well episodic memory performance predicted performance on the three aspects of the WWW memory task separately. In the Passive treatment, episodic memory performance predicts performance on all three aspects of the WWW memory task equally. However, in the Active treatment it only predicts performance on the what component. This could imply that during active encoding a different memory system is used for where and when information than during passive encoding. Encoding of what information seems to rely on episodic memory processing in both conditions.     

Group process in short-term outpatient therapy groups for schizophrenics

The short form of the group climate questionnaire (GCQ-S) was used to evaluate process in three 12-session therapy groups for outpatient schizophrenics. Results showed no difference on the Engaged dimension between the short-term schizophrenic groups and either a normative sample of outpatient neurotic groups or the first 26 sessions of a long-term outpatient schizophrenic group. However, the short-term groups scored significantly lower (p<.001) on the Avoiding and Conflict dimensions as compared with either long-term sample. The session-to-session GCQ-S dimension pattern did not support the presence of sequential group stages, but there was a tendency for the Engaged scores to increase and the Avoiding and Conflict scores to decrease as time went on.The authors gratefully acknowledge K. Roy MacKenzie, M.D., and Don Brown, M.D., for their helpful comments regarding this paper. Parts of this paper were presented in a poster session at the American Group Psychotherapy Association Annual Meeting in New York, February 8–12, 1988.     

Instructed versus pharmacological effects of alcohol in alcoholics and social drinkers

Twelve alcoholics and 12 social drinkers were studied in an experiment where instructions about alcohol or placebo were orthogonally crossed with administration of alcohol or placebo in a Balanced Placebo Design. Three subjects were simultaneously observed while watching soccer games on the TV together and having free access to a mixed drink, which in the alcohol conditions contained 150ml of 80% proof vodka. The assessment procedure included several aspects of drinking behavior, behavioral observations during the session, psychiatric ratings and nurse observations before and after each session, ratings for craving, self-reported state anxiety and physiological changes (heart rate and blood pressure). In general, the results showed the alcoholic's behavior to be controlled by instruction-induced expectancies rather than by the actual beverage given, whereas the social drinkers showed tendencies in the opposite direction. The implications of these results for the traditional disease conception of alcoholism and for learning theory approaches are discussed.     

Adherence,expectations and the placebo response: Why is good adherence to an inert treatment beneficial?

Objective: The current study sought to better understand why good adherence to a placebo treatment has been reliably associated with health benefits. We proposed a model where initial expectations shape adherence, which then influences subsequent expectations that affect placebo response. Design: Seventy-two participants were told that they were enrolling in a study of physical activity and memory, and were asked to increase their physical activity by 35% for two weeks (placebo treatment). Main outcome measures: Adherence to this physical activity target was measured by pedometer. Expectations and short-term memory (free recall) were assessed before and after physical activity. Results: Initial expectations predicted adherence to physical activity (r = .27, p < .03), but adherence did not predict subsequent expectations (r = .06, p = .60). Testing a multi-step meditational model revealed that initial expectations predicted better memory even after controlling for adherence, subsequent expectations, baseline memory and gender (c’ = 1.10, 95% CI = .46–1.74). Stronger expectations for memory improvement predicted better memory performance, but adherence and later expectations did not mediate this association. Conclusions: Good adherence to a placebo may reflect strong treatment expectations which may convey benefits by enhancing the non-specific effects of treatment.     

Effects of reinforcement and response-cost history on instructional control

The present study compared the effects of reinforcement or punishment versus no additional consequences for instruction following on instructional control and subsequent rule-governed insensitivity. In two experiments, adult participants were presented with repeated choices between a short progressive-time schedule and either a fixed time-schedule or a longer progressive-time schedule. In Experiment 1, three groups were given an initially accurate instruction relative to the direct contingency. A control group experienced no additional consequences for compliance with instructions, whereas compliance resulted in additional points for a second group, and noncompliance led to the subtraction of points for a third group. In a subsequent phase, instructions became inaccurate and there were no additional consequences for compliance or noncompliance for any group. Consistent with previous results, rule-governed insensitivity was observed in all participants. Experiment 2 employed the same procedure, except instructions were inaccurate throughout all sessions, and compliance in the subsequent phase resulted in diminishing points per session. Reinforcement for following instructions increased instructional control and subsequent rule-governed insensitivity. This increase was maintained even after the termination of additional consequences, a result that supports theoretical suggestions that a history of reinforcement for complying with instructions and rules is an important factor in rule-governed insensitivity.