Placebo effects in cognitive training

Foroughi, Cyrus K.; Monfort, Samuel S.; Paczynski, Martin; McKnight, Patrick E.; Greenwood, Pamela M.

doi:10.1073/pnas.1601243113

Cited by 218 publications

(193 citation statements)

References 39 publications

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“…To date, only a handful of studies have investigated the placebo effect in the cognitive domain245354, and even fewer studies deal with healthy persons55565758. Only one study investigated the possible biological systems involved in the generation of cognitive placebo effects by examining PD patients24.…”

Section: Discussionmentioning

confidence: 99%

Placebo Intervention Enhances Reward Learning in Healthy Individuals

Turi

Mittner

Paulus

et al. 2017

Sci Rep

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According to the placebo-reward hypothesis, placebo is a reward-anticipation process that increases midbrain dopamine (DA) levels. Reward-based learning processes, such as reinforcement learning, involves a large part of the DA-ergic network that is also activated by the placebo intervention. Given the neurochemical overlap between placebo and reward learning, we investigated whether verbal instructions in conjunction with a placebo intervention are capable of enhancing reward learning in healthy individuals by using a monetary reward-based reinforcement-learning task. Placebo intervention was performed with non-invasive brain stimulation techniques. In a randomized, triple-blind, cross-over study we investigated this cognitive placebo effect in healthy individuals by manipulating the participants' perceived uncertainty about the intervention's efficacy. Volunteers in the purportedly low-and high-uncertainty conditions earned more money, responded more quickly and had a higher learning rate from monetary rewards relative to baseline. Participants in the purportedly highuncertainty conditions showed enhanced reward learning, and a model-free computational analysis revealed a higher learning rate from monetary rewards compared to the purportedly low-uncertainty and baseline conditions. Our results indicate that the placebo response is able to enhance reward learning in healthy individuals, opening up exciting avenues for future research in placebo effects on other cognitive functions.Observational and interventional approaches are concomitantly used to study brain networks and their putative contributions to certain brain functions 1 . While the former approach is necessary to characterize the spatiotemporal patterns of neural activity, the interventional approach constitutes an important step towards facilitating causal inference 2 . Non-invasive brain stimulation (NIBS) interventions offer the possibility to induce transient perturbations in intact human brain networks by using electromagnetic induction or electrical current, while minimizing possible health risks, financial costs and ethical concerns [3][4][5] . Transcranial direct current stimulation (tDCS) is the most frequently employed research tool in studies that use electrical current as a NIBS technique 3 . It passes constant, low intensity current between two or more electrodes attached to the intact scalp. Depending on the polarity, the externally applied constant current can increase or decrease the spontaneous firing rate (i.e., cortical excitability) of the stimulated brain regions by depolarizing or hyperpolarizing resting membrane potentials 3 . Although most of the commercially available and certified tDCS devices are equipped with a double-blind operation mode, a large number of studies still use a single-blind study design, no blinding at all or inadequate blinding 6 . In these cases, the impact of intentional and unconscious preferences, bias and expectations of the participants as well as of the researchers can possibly lead to an overestima...

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Section: Discussionmentioning

confidence: 99%

Placebo Intervention Enhances Reward Learning in Healthy Individuals

Turi

Mittner

Paulus

et al. 2017

Sci Rep

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“…This creates an expectation of better performance following training, which is known to create positive cognitive outcomes. Indeed, participants who enrolled in a trial of CCT via a flyer suggesting CCT will improve working memory and fluid intelligence had greater post-training performance than participants who enrolled via a non-suggestive flyer, despite participating in the same program (Foroughi et al, 2016). Similarly, in a trial of healthy adults randomly assigned to a placebo pill or no-pill condition, those who took the placebo pill described as a “cognitive enhancer” had greater performance on tests of attention and delayed recall, though no effect was found in five secondary outcome measures (Oken et al, 2008).…”

Section: Expectancymentioning

confidence: 99%

Clinical Trials to Gain FDA Approval for Computerized Cognitive Training: What Is the Ideal Control Condition?

Motter

Devanand

Doraiswamy

et al. 2016

Front. Aging Neurosci.

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“…A recent study showed that simply telling participants on recruitment flyers that they will participate in a BBrain Training & Cognitive Enhancement^study is associated with stronger transfer effects and an increase in IQ of 5-10 points after just 1 h of cognitive training (Foroughi et al 2016). Therefore, participants in both groups may have performed better at posttest without an actual benefit to working memory capacity.…”

Section: Why Was There a Main Effect Of Time?mentioning

confidence: 99%

A More Rigorous Examination of the Effects of Mindfulness Meditation on Working Memory Capacity

Baranski

Was

2018

J Cogn Enhanc

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Working memory is a core cognitive system that is thought to support many forms of complex cognition. Mindfulness meditation has shown promise in improving the functioning of the working memory system, but no study has thoroughly tested its benefits by using a well-controlled study design (i.e., using multiple, valid outcome measures and an active, adaptive control group). The main goal of the current study was to more rigorously examine the effects of mindfulness meditation on working memory capacity. This was done by comparing 2 weeks of focused attention mindfulness meditation training to active, adaptive cognitive training regarding improvement on multiple, valid indicators of working memory capacity that were different from the tasks participants trained on. The results of the present experiment suggest that 2 weeks of focused attention mindfulness meditation training does not improve working memory capacity when controlling for non-specific effects. Future interventions using similar well-controlled study designs can consider using longer duration, more frequent, or alternative styles of mindfulness meditation training to potentially enhance working memory capacity.

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Placebo effects in cognitive training

Cited by 218 publications

References 39 publications

Placebo Intervention Enhances Reward Learning in Healthy Individuals

Placebo Intervention Enhances Reward Learning in Healthy Individuals

Clinical Trials to Gain FDA Approval for Computerized Cognitive Training: What Is the Ideal Control Condition?

A More Rigorous Examination of the Effects of Mindfulness Meditation on Working Memory Capacity

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