Hypnotic Suggestions: Their Nature and Applicability in Studying Executive Functions

Exekutive Funktionen (EF) sind eine Gruppe von Top-Down-Prozessen, die in neuartigen Situationen eingesetzt werden, um neue Trigger-Response-Assoziationen herzustellen oder vorhandene Handlungsoptionen an neue Situationen anzupassen. Obwohl EF erschöpfend untersucht wurden, bleiben wichtige Fragen offen. Beispiele dafür sind (a) Sind Exekutivfunktionen vollständig trennbar oder beruhen sie auf einem gemeinsamen neurokognitiven System? (b) Was messen verschiedene Versionen der Stroop-Aufgabe, einer der meist-verwendeten Aufgaben zur Prüfung der Inhibitionsfunktion? (c) Muss Inhibition immer Ressourcen-fordernd sein, oder gibt es eine Form der Inhibition, die mühelos implementiert werden kann? Zur Beantwortung dieser Fragen, habe ich neurokognitive Korrelate von EF und ihrer Verbesserung mithilfe posthypnotischer Suggestionen (PHS) und Ereigniskorrelierter Hirnpotentiale (EKP) untersucht. Zusammenfassend ergaben sich folgende Antworten: (a) Psychometrische und EKP-Daten aus den Studien zur Gedächtnisaktualisierung und Inhibition sowie deren Verbesserung anhand PHS zeigten sowohl funktionsspezifische als auch gemeinsame neurokognitive Prozesse der Inhibition und Aktualisierung. (b) Obwohl sowohl die vokale als auch die manuelle Version der Stroop-Aufgabe Inhibitionsfunktionen erfordern, ist die vokale Version Ressourcen-fordernder, da sie mindestens einen zusätzlichen Lokus der Interferenz im Antwort-Produktionsprozess aufweist, der nicht mit PHS beeinflussbar ist und der in der manuellen Version fehlt. (c) Unter Verwendung PHS zur Erhöhung der Präferenzen für kalorienarme Lebensmittel untersuchte ich die Auflösung von Konflikten. Die EKP-Ergebnisse zeigten, dass auch Konflikt-Auflösung, ähnlich wie Inhibition, Ressourcen konsumiert. Insgesamt zeigt dieses Projekt, dass die Verwendung Aufgaben-bezogener PHS in Kombination mit Neuroimaging-Techniken einen fruchtbaren Ansatz für die Untersuchung ungeklärter Fragen über Exekutivfunktionen darstellt.Executive functions (EF) are a group of top-down processes used in novel situations to develop or adapt existing responses to the task at hand. Even though EFs are studied exhaustively, several important questions remain unanswered: (a) Are EFs entirely separated, or do they rely on a common system? (b) What do different versions of the Stroop task measure? (c) Does inhibition always need to be effortful? To address these questions, I investigated neurocognitive correlates of EFs and their enhancements by means of posthypnotic suggestions (PHS) and event-related potentials (ERP). However, before one can use PHSs, it must be elucidated whether and how they affect EFs. Although PHSs are used repeatedly for improving inhibition, it is unclear whether their effects are mediated by bottom-up or top-down processes. By using an updating task, I showed that effects of PHSs can be attributed to top-down processes. Accordingly, a new theory of hypnosis was proposed and empirically tested by modeling hypnotizability scores with structural equation modeling. In short, the simulation-adaption theory suggests that several top-down processes are employed for responding to suggestions. After elucidating the driving mechanism of PHSs is mentally practicing a novel strategy, PHSs were used for addressing the questions regarding EFs. Summarizing (a) the psychometric and ERP results from several studies indicated that different EFs rely on both function-specific and shared neurocognitive processes. (b) Even though different versions of the Stroop task are tapping into inhibition, the vocal compared to the manual version has at least an extra response-production-related locus of interference. (c) Using PHSs for increasing preferences for low-calorie food items, it is shown that resolve is effortful to implement, as indicated by increased P300 amplitudes. Together, this project shows how PHSs, along with neuroimaging techniques, can provide a novel approach for investigating EFs

Childhood trauma and violent behavior in adolescents are differentially related to cognitive-emotional deficits

IntroductionConverging neurobiological and epidemiological evidence indicates that exposure to traumatic events in the early stages of development, that is, adverse childhood experiences (ACEs), negatively affects the likelihood of being involved in violent behavior later in life. These problems are hypothesized to be mediated by the disruption of executive functions, in particular, the ability to inhibit inappropriate actions. Here we aimed to distinguish the contribution of inhibition in non-emotional and emotional situations (i.e., emotion regulation) and assessed the modulating influence of stress, testing Nairobi county high school students in a two-experiment study.MethodsIn Experiment 1, neutral and emotional inhibition, working memory, and fluid intelligence were measured alongside questionnaires about ACE and violent behavior. Experiment 2 replicated these relations in an independent sample and assessed whether they would be aggravated after acute experimentally induced stress.ResultsExperiment 1 results showed that ACE was positively related to both non-emotional and emotional inhibition; in contrast, violent behavior was only associated with deficient emotional inhibition. Experiment 2 findings showed that stress did not significantly affect the relation of ACE to non-emotional inhibition and emotion regulation; however, it increased deficits of violent participants in their ability to down-regulate emotions.DiscussionTogether, results suggest that deficits in emotion regulation, especially under stressful conditions, are more critical than impairments in non-emotional inhibition in predicting violent behavior in victims of childhood trauma. These findings open perspectives toward more targeted research and interventions

Childhood trauma and violent behavior in adolescents are differentially related to cognitive-emotional deficits

Introduction Converging neurobiological and epidemiological evidence indicates that exposure to traumatic events in the early stages of development, that is, adverse childhood experiences (ACEs), negatively affects the likelihood of being involved in violent behavior later in life. These problems are hypothesized to be mediated by the disruption of executive functions, in particular, the ability to inhibit inappropriate actions. Here we aimed to distinguish the contribution of inhibition in non-emotional and emotional situations (i.e., emotion regulation) and assessed the modulating influence of stress, testing Nairobi county high school students in a two-experiment study. Methods In Experiment 1, neutral and emotional inhibition, working memory, and fluid intelligence were measured alongside questionnaires about ACE and violent behavior. Experiment 2 replicated these relations in an independent sample and assessed whether they would be aggravated after acute experimentally induced stress. Results Experiment 1 results showed that ACE was positively related to both non-emotional and emotional inhibition; in contrast, violent behavior was only associated with deficient emotional inhibition. Experiment 2 findings showed that stress did not significantly affect the relation of ACE to non-emotional inhibition and emotion regulation; however, it increased deficits of violent participants in their ability to down-regulate emotions. Discussion Together, results suggest that deficits in emotion regulation, especially under stressful conditions, are more critical than impairments in non-emotional inhibition in predicting violent behavior in victims of childhood trauma. These findings open perspectives toward more targeted research and interventions.Peer Reviewe

Cognitive simulation along with neural adaptation explain effects of suggestions: a novel theoretical framework

Hypnosis is an effective intervention with proven efficacy that is employed in clinical settings and for investigating various cognitive processes. Despite their practical success, no consensus exists regarding the mechanisms underlying well-established hypnotic phenomena. Here, we suggest a new framework called the Simulation-Adaptation Theory of Hypnosis (SATH). SATH expands the predictive coding framework by focusing on (a) redundancy elimination in generative models using intrinsically generated prediction errors, (b) adaptation due to amplified or prolonged neural activity, and (c) using internally generated predictions as a venue for learning new associations. The core of our treatise is that simulating proprioceptive, interoceptive, and exteroceptive signals, along with the top-down attenuation of the precision of sensory prediction errors due to neural adaptation, can explain objective and subjective hypnotic phenomena. Based on these postulations, we offer mechanistic explanations for critical categories of direct verbal suggestions, including (1) direct-ideomotor, (2) challenge-ideomotor, (3) perceptual, and (4) cognitive suggestions. Notably, we argue that besides explaining objective responses, SATH accounts for the subjective effects of suggestions, i.e., the change in the sense of agency and reality. Finally, we discuss individual differences in hypnotizability and how SATH accommodates them. We believe that SATH is exhaustive and parsimonious in its scope, can explain a wide range of hypnotic phenomena without contradiction, and provides a host of testable predictions for future research.Peer Reviewe

Cognitive simulation along with neural adaptation explain effects of suggestions: a novel theoretical framework

Hypnosis is an effective intervention with proven efficacy that is employed in clinical settings and for investigating various cognitive processes. Despite their practical success, no consensus exists regarding the mechanisms underlying well-established hypnotic phenomena. Here, we suggest a new framework called the Simulation-Adaptation Theory of Hypnosis (SATH). SATH expands the predictive coding framework by focusing on (a) redundancy elimination in generative models using intrinsically generated prediction errors, (b) adaptation due to amplified or prolonged neural activity, and (c) using internally generated predictions as a venue for learning new associations. The core of our treatise is that simulating proprioceptive, interoceptive, and exteroceptive signals, along with the top-down attenuation of the precision of sensory prediction errors due to neural adaptation, can explain objective and subjective hypnotic phenomena. Based on these postulations, we offer mechanistic explanations for critical categories of direct verbal suggestions, including (1) direct-ideomotor, (2) challenge-ideomotor, (3) perceptual, and (4) cognitive suggestions. Notably, we argue that besides explaining objective responses, SATH accounts for the subjective effects of suggestions, i.e., the change in the sense of agency and reality. Finally, we discuss individual differences in hypnotizability and how SATH accommodates them. We believe that SATH is exhaustive and parsimonious in its scope, can explain a wide range of hypnotic phenomena without contradiction, and provides a host of testable predictions for future research

How hypnotic suggestions work – A systematic review of prominent theories of hypnosis

In recent decades, hypnosis has increasingly moved into the mainstream of scientific inquiry. Hypnotic suggestions are frequently implemented in behavioral, neurocognitive, and clinical investigations and interventions. Despite abundant reports about the effectiveness of suggestions in altering behavior, perception, cognition, and agency, no consensus exists regarding the mechanisms driving these changes. This article reviews competing theoretical accounts that address the genesis of subjective, behavioral, and neurophysiological responses to hypnotic suggestions. We systematically analyze the broad landscape of hypnosis theories that best represent our estimation of the current status and future avenues of scientific thinking. We start with procedural descriptions of hypnosis, suggestions, and hypnotizability, followed by a comparative analysis of systematically selected theories. Considering that prominent theoretical perspectives emphasize different aspects of hypnosis, our review reveals that each perspective possesses salient strengths, limitations, and heuristic values. We highlight the necessity of revisiting extant theories and formulating novel evidence-based accounts of hypnosis.Peer Reviewe

The nature and persistence of the effects of posthypnotic suggestions on food preferences: The final report of an online study

The persistence of food preferences, which are crucial for diet-related decisions, is a significant obstacle to changing unhealthy eating behavior. To overcome this obstacle, the current study investigates whether posthypnotic suggestions (PHSs) can enhance food-related decisions by measuring food choices and subjective ratings. After assessing hypnotic susceptibility in Session 1, at the beginning of Session 2, a PHS was delivered aiming to increase the desirability of healthy food items (e.g., vegetables and fruit). After the termination of hypnosis, a set of two tasks was administrated twice, once when the PHS was activated and once deactivated in counterbalanced order. The task set consisted of rating 170 pictures of food items, followed by an online supermarket where participants were instructed to select enough food from the same item pool for a fictitious week of quarantine. After 1 week, Session 3 mimicked Session 2 without renewed hypnosis induction to assess the persistence of the PHS effects. The Bayesian hierarchical modeling results indicate that the PHS increased preferences and choices of healthy food items without altering the influence of preferences in choices. In contrast, for unhealthy food items, not only both preferences and choices were decreased due to the PHS, but also their relationship was modified. That is, although choices became negatively biased against unhealthy items, preferences played a more dominant role in unhealthy choices when the PHS was activated. Importantly, all effects persisted over 1 week, qualitatively and quantitatively. Our results indicate that although the PHS affected healthy choices through resolve, i.e., preferred more and chosen more, unhealthy items were probably chosen less impulsively through effortful suppression. Together, besides the translational importance of the current results for helping the obesity epidemic in modern societies, our results contribute theoretically to the understanding of hypnosis and food choices.Peer Reviewe

Repository: Can Posthypnotic Suggestions Boost Updating in Working Memory? Behavioral and ERP Evidence

Updating is an essential executive function (EF), responsible for storing, retrieving, and substituting information in working memory (WM). Here we investigated whether posthypnotic suggestions (PHS) given to high-hypnotizable participants can enhance updating in WM and measured neural correlates of the observed effects by recording event-related brain potentials (ERP). In a tone-monitoring task different syllables were presented in random order, requiring a response to every fourth presentation of a given syllable. Experiment 1 (n = 19) established the relationship between performance and several ERP components across updating load (different numbers of syllables). In Experiment 2 (n = 18), a no-hypnosis (NH) and a hypnosis-plus-PHS session were administrated in counterbalanced order. Task instructions, presented at the beginning of the sessions, emphasized a cognitive strategy, demanding imagination of visual counters, a strategy that was also emphasized during PHS. PHS additionally contained suggestions stimulating cognitive simulation of the task, where participants were advised to apply the suggested strategy. Relative to the NH session, PHS enhanced WM performance with medium to large effect sizes. In ERPs, PHS increased the P2 and P3 components, indicating the proactive recruitment of control-related attention and updating-related cognitive control processes, respectively. PHS also reduced updating load effects in the posterior recognition component, suggesting diminished demands on WM buffers. These ERP findings suggest that PHS enhanced updating in WM by strengthening proactive control, which may have diminished the necessity for reactive control. Hence, the present results suggest that our PHS had worked like mental practice helping participants to develop an efficient and context-dependent trigger-action contingency. Consequentially, the present study provides a new framework for employing PHSs, which may be used as a basis for developing new training regimes for modifying WM or other EFs

Repository: Modification of Food Preferences by Posthypnotic Suggestions: An Eventrelated Brain Potential Study.

Unhealthy food choices are implicated in two worldwide issues, the burden of global disease and climate change. The preference for high- over low-calorie food and difficulties in inhibiting the desire for high-calorie food are important factors involved in unhealthy food choices. Here, we explored posthypnotic suggestions (PHS) as a possible new tool to increase the preference for low-calorie food. A food-face classification, measuring implicit food preferences, and a Go-NoGo task, measuring inhibition, were administrated with PHS being activated or deactivated in a counterbalanced design, while event-related brain potentials were recorded. In the food-face classification, without PHS the early visual P1 amplitude was larger in response to high than low-calorie pictures, possibly reflecting differential reward-associations. PHS eliminated this difference in P1 and yielded faster RTs and larger amplitudes of the late positive component in response to low- versus high-calorie items. Hence, positive bias toward low-calorie food due to PHS seems to have enhanced their effective processing by increasing motivated attention. In the Go-NoGo task, PHS decreased NoGo-N2 and increased P3 in both Go and NoGo conditions, possibly by turning low- and high-calorie items more pleasant and unpleasant, respectively, requiring more proactive control to inhibit task-irrelevant food-related emotions. In the Go condition, PHS quickened the rejection of salad-inappropriate high-calorie items and increased the amplitude of the late-P3 component, possibly indicating facilitated classification of high-calorie items and increased response monitoring. Together, PHS effectively increased the preference for low-calorie food and inhibition of impulses toward high-calorie food, therefore, PHS may be a promising tool to support healthy and sustainable food choices

How Hypnotic Suggestions Work – A Systematic Review of Prominent Theories of Hypnosis

In recent decades, hypnosis has increasingly moved into the mainstream of scientific inquiry and today is the subject of concerted study on an international basis. Hypnotic and posthypnotic suggestions are frequently and successfully implemented in behavioral, neurocognitive, and clinical investigations and interventions. Despite abundant reports about the effectiveness of suggestions in altering behavior, perception, cognition, and subjective sense of agency (SoA), no consensus exists regarding the mechanisms driving these changes. This article reviews competing theoretical accounts that address questions regarding the genesis of subjective, behavioral, and neurophysiological responses to hypnotic suggestions. We systematically analyze the broad landscape of influential and promising hypnosis theories that best represent our estimation of the current status and future avenues of scientific thinking about hypnosis. We start with procedural descriptions of hypnosis, suggestions, and hypnotizability, followed by a systematic analysis of selected theories of hypnosis. Considering that prominent theoretical perspectives emphasize different aspects of hypnosis, our review reveals that each perspective possesses salient strengths, limitations, and heuristic values. We highlight both the necessity of revisiting extant theories of hypnosis to refine and enhance their adequacy and fertility and the value of formulating novel evidence-based accounts of hypnosis