Meditation is becoming increasingly popular as a topic for scientific research and theories on meditation are becoming ever more specific. We distinguish between what is called focused Attention meditation, open Monitoring meditation, and loving kindness (or compassion) meditation. Research suggests that these meditations have differential, dissociable effects on a wide range of cognitive (control) processes, such as attentional selection, conflict monitoring, divergent, and convergent thinking. Although research on exactly how the various meditations operate on these processes is still missing, different kinds of meditations are associated with different neural structures and different patterns of electroencephalographic activity. In this review we discuss recent findings on meditation and suggest how the different meditations may affect cognitive processes, and we give suggestions for directions of future research.

IntroductionTaking microdoses (a mere fraction of normal doses) of psychedelic substances, such as truffles, recently gained popularity, as it allegedly has multiple beneficial effects including creativity and problem-solving performance, potentially through targeting serotonergic 5-HT2A receptors and promoting cognitive flexibility, crucial to creative thinking. Nevertheless, enhancing effects of microdosing remain anecdotal, and in the absence of quantitative research on microdosing psychedelics, it is impossible to draw definitive conclusions on that matter. Here, our main aim was to quantitatively explore the cognitive-enhancing potential of microdosing psychedelics in healthy adults.MethodsDuring a microdosing event organized by the Dutch Psychedelic Society, we examined the effects of psychedelic truffles (which were later analyzed to quantify active psychedelic alkaloids) on two creativity-related problem-solving tasks: the Picture Concept Task assessing convergent thinking and the Alternative Uses Task assessing divergent thinking. A short version of the Ravens Progressive Matrices task assessed potential changes in fluid intelligence. We tested once before taking a microdose and once while the effects were expected to be manifested.ResultsWe found that both convergent and divergent thinking performance was improved after a non-blinded microdose, whereas fluid intelligence was unaffected.ConclusionWhile this study provides quantitative support for the cognitive-enhancing properties of microdosing psychedelics, future research has to confirm these preliminary findings in more rigorous placebo-controlled study designs. Based on these preliminary results, we speculate that psychedelics might affect cognitive metacontrol policies by optimizing the balance between cognitive persistence and flexibility. We hope this study will motivate future microdosing studies with more controlled designs to test this hypothesis.Electronic supplementary materialThe online version of this article (10.1007/s00213-018-5049-7) contains supplementary material, which is available to authorized users.

Scientific interest in meditation has significantly grown in the past years; however, so far, science has neglected the idea that different types of meditations may drive specific cognitive-control states. It has been shown that focusedattention (FA) and open-monitoring (OM) meditation exert specific effect on creativity; OM meditation induces a control state that promotes divergent thinking, a style of thinking that allows many new ideas to be generated, while FA meditation tends to support convergent thinking, the process of generating one possible solution to a particular problem. In the present study, by using creativity tasks tapping into convergent (compound Remote Associates Task; cRAT) and divergent thinking (Alternate Uses Task; AUT), we investigated whether this effect was modulated by prior meditation experience, by comparing a group of practitioners (n=20) and a group of novices (n=20). The enhancing effect of OM meditation on divergent thinking was found to be robust irrespective of prior experience. However, while solving convergentthinking problems, practitioners used an insight strategy, as opposed to an analytical approach, significantly more often than the novices.

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Whereas ideomotor approaches to action control emphasize the importance of sensory action effects for action selection, motivational approaches emphasize the role of affective action effects. We used a game-like experimental setup to directly compare the roles of sensory and affective action effects in selecting and performing reaching actions in forced- and free-choice tasks. The two kinds of action effects did not interact. Action selection and execution in the forced-choice task were strongly impacted by the spatial compatibility between actions and the expected sensory action effects, whereas the free-choice task was hardly affected. In contrast, action execution, but not selection, in both tasks was strongly impacted by the spatial compatibility between actions and highly valued action effects. This pattern suggests that sensory and affective action effects serve different purposes: The former seem to dominate rule-based action selection, whereas the latter might serve to reduce any remaining action uncertainty.Electronic supplementary materialThe online version of this article (doi:10.3758/s13423-016-1139-x) contains supplementary material, which is available to authorized users.