Zoltan Dienes

Zoltan Dienes
University of Sussex · Sackler Centre for Consciousness Science (SCCS)

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80
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Introduction
Skills and Expertise

Publications

Publications (80)
Article
Full-text available
Research on implicit processes has revealed problems with awareness categorizations based on nonsignificant results. Moreover, post hoc categorizations result in regression to the mean (RTM), by which aware participants are wrongly categorized as unaware. Using Bayes factors to obtain sensitive evidence for participants’ lack of knowledge may deal...
Article
While several theories assume that responses to hypnotic suggestions can be implemented without executive intentions, the metacognitive class of theories postulate that the behaviors produced by hypnotic suggestions are intended and the accompanying feeling of involuntariness is only a consequence of strategically not being aware of the intention....
Preprint
Full-text available
Research on implicit processes has revealed problems with awareness categorizations based on non-significant results. Moreover, post-hoc categorizations result in regression to the mean (RTM), by which aware participants are wrongly categorized as unaware. Using Bayes factors to obtain sensitive evidence for participants’ lack of knowledge may deal...
Article
Full-text available
In hypnotic responding, expectancies arising from imaginative suggestion drive striking experiential changes (e.g., hallucinations) - which are experienced as involuntary - according to a normally distributed and stable trait ability (hypnotisability). Such experiences can be triggered by implicit suggestion and occur outside the hypnotic context....
Article
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Hypnosis and hypnotic suggestions are gradually gaining popularity within the consciousness community as established tools for the experimental manipulation of illusions of involuntariness, hallucinations and delusions. However, hypnosis is still far from being a widespread instrument; a crucial hindrance to taking it up is the amount of time neede...
Article
Full-text available
The ability to respond to hypnotic suggestibility (hypnotizability) is a stable trait which can be measured in a standardized procedure consisting of a hypnotic induction and a series of hypnotic suggestions. The SWASH is a 10-item adaptation of an established scale, the Waterloo-Stanford Group C Scale of Hypnotic Suggestibility (WSGC). Development...
Article
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We propose to change the default P-value threshold for statistical significance for claims of new discoveries from 0.05 to 0.005.
Article
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Aims: To illustrate how Bayes Factors are important for determining the effectiveness of interventions. Method: We consider a case where inappropriate conclusions were publicly drawn based on significance testing, namely the SIPS Project (Screening and Intervention Programme for Sensible drinking), a pragmatic, cluster-randomized controlled tria...
Article
Full-text available
Inference using significance testing and Bayes factors is compared and contrasted in five case studies based on real research. The first study illustrates that the methods will often agree, both in motivating researchers to conclude that H1 is supported better than H0, and the other way round, that H0 is better supported than H1. The next four, how...
Article
Full-text available
The sense of agency is the experience of initiating and controlling one’s voluntary actions and their outcomes. Intentional binding (i.e., when voluntary actions and their outcomes are perceived to occur closer together in time than involuntary actions and their outcomes) is increased in intentional action but requires no explicit reflection on age...
Article
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Volitional action and self-control—feelings of acting according to one’s own intentions and in being control of one’s own actions—are fundamental aspects of human conscious experience. However, it is unknown whether high-level cognitive control mechanisms are affected by socially salient but nonconscious emotional cues. In this study, we manipulate...
Article
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We investigate conditions in which more accurate metacognition may lead to greater susceptibility to illusion and thus conditions under which mindfulness meditation may lead to less accurate perceptions. Specifically, greater awareness of intentions may lead to an illusory compression of time between a voluntary action and its outcome (“intentional...
Article
Full-text available
Does sense of agency (SoA) arise merely from action-outcome associations, or does an additional real-time process track each step along the chain? Tracking control predicts that deviant intermediate steps between action and outcome should reduce SoA. In two experiments, participants learned mappings between two finger actions and two tones. In late...
Data
Figure A. Percentage of correct reproductions after each block type. The first learning block corresponds to the first block of the experiment. Rc-Tc represents blocks displayed after robot congruent-outcome congruent blocks. Rc-Ti represents blocks displayed after robot congruent-outcome incongruent blocks. Ri-Tc represents blocks displayed after...
Article
Background and aims: It has been proposed that more use should be made of Bayes Factors in hypothesis testing in addiction research. Bayes Factors are the ratios of the likelihood of a specified hypothesis (e.g. an intervention effect within a given range) to another hypothesis (e.g. no effect). They are particularly important for differentiating...
Article
Full-text available
In a famous series of experiments, Libet investigated the subjective timing of awareness of an intention to move, a task that can be considered a metacognitive judgement. The ability to strategically produce inaccurate metacognitions about intentions has been postulated to be central to the changes in judgements of agency common to all hypnotic res...
Article
Full-text available
Bayes factors provide a symmetrical measure of evidence for one model versus another (e.g. H1 versus H0) in order to relate theory to data. These properties help solve some (but not all) of the problems underlying the credibility crisis in psychology. The symmetry of the measure of evidence means that there can be evidence for H0 just as much as fo...
Article
Full-text available
No scientific conclusion follows automatically from a statistically non-significant result, yet people routinely use non-significant results to guide conclusions about the status of theories (or the effectiveness of practices). To know whether a non-significant result counts against a theory, or if it just indicates data insensitivity, researchers...
Article
Full-text available
Faces are one of the most important signals for reading people’s mental states. In sync with their apparent ‘chronic’ (cross-situational) relevance, faces have been argued to be processed independently of the task one is currently performing. Many of these demonstrations have involved ‘capture of attention’ or increased interference by faces functi...
Article
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Grapheme-color synesthesia is a perceptual experience where graphemes, letters or words evoke a specific color, which are experienced either as spatially coincident with the grapheme inducer (projector sub-type) or elsewhere, perhaps without a definite spatial location (associator sub-type). Here, we address the question of whether synesthesia can...
Article
Full-text available
Three experiments were run in an attempt to demonstrate the unconscious processing of active-versus-passive sentences. Using subjective measures to assess individual thresholds of subliminal perception, participants were presented with a prime sentence that denoted whether 1 of 2 characters was active or passive within the sentence (e.g., “A is inj...
Article
Full-text available
Electroencephalogram based Brain–Computer Interfaces (BCIs) enable stroke and motor neuron disease patients to communicate and control devices. Mindfulness meditation has been claimed to enhance metacognitive regulation. The current study explores whether mindfulness meditation training can thus improve the performance of BCI users. To eliminate th...
Article
Full-text available
Implicit learning research has focused on learning simple structures, such as chunks, even though such structures do not capture the richness of real-world human accomplishments. In particular, music and language exhibit certain recursive features that cannot be captured by regular grammars, let alone mechanisms that learn only chunks. We show in t...
Article
Full-text available
Analyzing metacognition, specifically knowledge of accuracy of internal perceptual, memorial, or other knowledge states, is vital for many strands of psychology, including determining the accuracy of feelings of knowing and discriminating conscious from unconscious cognition. Quantifying metacognitive sensitivity is however more challenging than qu...
Article
Full-text available
A series of five experiments investigated the extent of subliminal processing of negation. Participants were presented with a subliminal instruction to either pick or not pick an accompanying noun, followed by a choice of two nouns. By employing subjective measures to determine individual thresholds of subliminal priming, the results of these studi...
Data
Training items for concrete training domain. (DOC)
Data
Training items for abstract training domain. (DOC)
Article
Full-text available
The ability to enhance sensitivity to relevant (post)hypnotic suggestions has implications for creating clinically informed analogues of psychological and neuropsychological conditions and for the use of hypnotic interventions in psychological and medical conditions. The aim of this study was to test the effect of oxytocin inhalation on a post-hypn...
Article
Introduction: According to the cold control theory of hypnosis (Dienes and Perner, 2007), hypnotic response occurs because of inaccurate higher order thoughts of intending. The dorsolateral prefrontal cortex (DLPFC) is a region likely involved in constructing accurate higher order thoughts. Thus, disrupting DLPFC with low frequency repetitive tran...
Chapter
Full-text available
According to the 'cold control theory' of Dienes and Perner (2007) hypnotic responding is intimately linked to metacognition. Specifically, we proposed that what makes a hypnotic response hypnotic is the intentional performance of a (physical or mental) action while having inaccurate higher-order thoughts to the effect that one was not intending th...
Article
Full-text available
The present work investigated possible temporal constraints on the posthypnotic word blindness suggestion effect. In a completely within-subjects and counterbalanced design 19 highly suggestible individuals performed the Stroop task both with and without a posthypnotic suggestion that they would be unable to read the word dimension of the Stroop st...
Article
Full-text available
Unconscious Thought Theory posits that a period of distraction after information acquisition leads to unconscious processing which enhances decision making relative to conscious deliberation or immediate choice (Dijksterhuis, 2004). Support thus far has been mixed. In the present study, artificial grammar learning was used in order to produce measu...
Article
Full-text available
We introduce a method for quickly determining the rate of implicit learning. The task involves making a binary prediction for a probabilistic sequence over 10 minutes; from this it is possible to determine the influence of events of a different number of trials in the past on the current decision. This profile directly reflects the learning rate pa...
Article
Full-text available
This chapter explains the primary phenomenology of hypnosis with two new accounts of how hypnosis happens. First, it discusses in more detail the phenomena to be explained and the questions that have been addressed. Then, it briefly and selectively reviews previous generations of cognitive theories that have influenced and informed the answers to t...
Article
Full-text available
Meditation and hypnosis might be regarded as involving similar processes and skills. For example, both meditation and hypnosis are associated with high levels of absorption and imaginative capac-ity, and both can be used for self-regulation. Research has also shown that meditation improves attentional functioning, and that hypnotic response can inv...
Article
This chapter comments on the discussion in Chapter 16. It reviews a range of experimental studies on the implicit learning of complex musical structures and movement patterns. It shows that participants can learn specific complex musical structures, such as symmetries or inversions, without becoming aware of the knowledge they have acquired. Cognit...
Article
Full-text available
Researchers are often confused about what can be inferred from significance tests. One problem occurs when people apply Bayesian intuitions to significance testing-two approaches that must be firmly separated. This article presents some common situations in which the approaches come to different conclusions; you can see where your intuitions initia...
Article
Conscious awareness can be assessed by a number of behavioral and brain-based measures, each presupposing different theories of the nature of consciousness. Such measures can be used to indicate the effects of stimuli people are not conscious of; the effects of mental states people are not conscious of (in the domains of both perception and learnin...
Article
Full-text available
Alcohol impairs explicit memory, whilst leaving implicit memory relatively intact. Less is known about its effects on false memories. The present study examines the effects of alcohol on explicit and implicit false memories using study list repetition as a tool for modulating learning at encoding. Thirty-two participants were given either an alcoho...
Article
The dominant theory of what people can learn implicitly is that they learn chunks of adjacent elements in sequences. A type of musical grammar that goes beyond specifying allowable chunks is provided by serialist or 12-tone music. The rules constitute operations over variables and could not be appreciated as such by a system that can only chunk ele...
Article
Full-text available
This paper considers two subjective measures of the existence of unconscious mental states - the guessing criterion, and the zero correlation criterion - and considers the assumptions underlying their application in experimental paradigms. Using higher order thought theory (Rosenthal, e.g. 1986; 1995) the impact of different types of biases on the...
Article
Full-text available
Linear optic trajectory theory claims that people catch balls by running in a direction that keeps an optic trajectory of the ball linear. The authors show a range of ball trajectories for which departures of the optic trajectory from linearity do not predict which direction people will run, and the direction they choose does not correct these depa...
Article
In this chapter we establish what it is for something to be implicit or explicit. The approach to implicit knowledge is taken from Dienes and Perner (1999), which relates the implicit-explicit distinction to knowledge representations. What it is for a representation to represent something implicitly or explicitly is defined and those concepts are a...
Article
Full-text available
Explicit memory (EM) is the memory for events which occurs with full awareness of where and how the recalled events took place, whereas implicit memory (IM) is the memory which is unfolded without any awareness of these events and usually becomes apparent when performance is facilitated by its presence. These two types of memory can be understood a...
Article
Full-text available
Rationale: Explicit memory (EM) is the memory for events which occurs with full awareness of where and how the recalled events took place, whereas implicit memory (IM) is the memory which is unfolded without any awareness of these events and usually becomes apparent when performance is facilitated by its presence. These two types of memory can be u...
Article
Full-text available
This paper will offer a framework and a methodology for determining whether subjects have conscious or unconscious knowledge. The implicit-explicit distinction will be related to consciousness using the framework of Dienes & Perner (1999; 2001a,b,c) and the higher-order thought theory of Rosenthal (1986, 2000). Whether a mental state is conscious o...
Article
Full-text available
Nicotine administration has been found to enhance performance on tasks of selective attention. It has been proposed that efficient attentional filtering depends on the successful inhibition of distracting information. In the work reported here, a negative priming paradigm was adopted to test whether smoking enhanced the inhibition of irrelevant inf...
Article
Full-text available
The implicit-explicit distinction is applied to knowledge representations. Knowledge is taken to be an attitude towards a proposition which is true. The proposition itself predicates a property to some entity. A number of ways in which knowledge can be implicit or explicit emerge. If a higher aspect is known explicitly then each lower one must also...
Article
Full-text available
The relationship between implicit memory and implicit learning is explored. Dienes and Fahey (1995) showed that learning to control a dynamic system was mediated by a look-up table consisting of previously successful responses to specific situations. The experiment reported in this paper showed that facilitated performance on old situations was ind...
Article
The relationship between implicit memory and implicit learning is explored. Dienes and Fahey (1995) showed that learning to control a dynamic system was mediated by a look-up table consisting of previously successful responses to specific situations. The experiment reported in this paper showed that facilitated performance on old situations was ind...
Article
Full-text available
In this reply to Neal and Hesketh and to the commentators, we argue that implicit knowledge is partly abstract and can be usefully defined by the criteria of both metaknowledge and intentional control. We suggest that the pattern of dissociations supports a claim of separate implicit and explicit learning modes. According to our characterization, i...
Article
Full-text available
In this review, we consider three possible criteria by which knowledge might be regarded as implicit or inaccessible: It might be implicit only in the sense that it is difficult to articulate freely, or it might be implicit according to either an objective threshold or a subjective threshold. We evaluate evidence for these criteria in relation to a...
Article
This article examines the claim that the learning of a dynamic control task is mediated by a lookup table consisting of previously successful trials on the task. Consistent with the predictions of a lookup table, in 2 experiments participants tended to give the same response to situations in which they had previously been successful rather than uns...
Article
A cricket or baseball fielder can run so as to arrive at just the right place at just the right time to catch a ball. It is shown that if the fielder runs so that d2(tan alpha)/dt2 = 0, where alpha is the angle of elevation of gaze from fielder to ball, then the ball will generally be intercepted before it hits the ground. This is true whatever the...
Article
Volpe et al. (Nature 282, 722, 1979 [19]) described an experimental study of four patients with parietal tumours who were able to judge whether two simultaneous stimuli were identical or different, even when they were unable to name the stimulus contralateral to their brain injury. We report the case of another patient, E.M., in whom we have invest...
Article
Subjects exposed to strings of letters generated by a finite state grammar can later classify grammatical and nongrammatical test strings, even though they cannot adequately say what the rules of the grammar are (e.g., Reber, 1989). The MINERVA 2 (Hintzman, 1986) and Medin and Schaffer (1978) memory-array models and a number of connectionist outoas...
Article
Three visual search experiments examined whether motion is coded as two separate features, speed and direction. Increasing the heterogeneity of the directions in which stimuli moved disrupted detection of a target defined by speed (fast among medium and slow nontargets), suggesting that speed is coded integrally with direction. However, heterogenei...
Article
Feature integration theory has recently been revised with two proposals that visual conjunction search can be parallel under some circumstances--either because items with nontarget features are inhibited, or because items with target features are excited. We examined whether excitatory or inhibitory guidance controlled conjunction search for an X o...
Article
Two experiments examined the claim for distinct implicit and explicit learning modes in the artificial grammar-learning task (Reber, 1967, 1989). Subjects initially attempted to memorize strings of letters generated by a finite-state grammar and then classified new grammatical and nongrammatical strings. Experiment 1 showed that subjects' assessmen...
Article
Two distinctions in the human learning literature are becoming increasingly influential; implicit versus explicit memory, and implicit versus explicit learning, respectively. To date, these distinctions have been used to refer to apparently different phenomena. Recent research suggests, however, that the same processes may be underlying performance...
Article
Search for a target defined by a conjunction of movement and form (e.g., an X moving up in a display of intermingled Os moving up and stationary Xs) is parallel. This result is also found if (a) the moving Os and target X move in unpredictable directions so that the moving stimuli do not form a clear perceptual group or (b) the nontarget Xs also mo...
Article
Rationale: Explicit memory (EM) is the mem- ory for events which occurs with full awareness of where and how the recalled events took place, whereas implicit memory (IM) is the memory which is unfolded without any awareness of these events and usually becomes ap- parent when performance is facilitated by its presence. These two types of memory can...
Article
Full-text available
First off, we would like to thank Terhune for his careful (and kind) consideration of cold control theory. In his comment on our paper, Terhune queries some of the evidence for cold control theory and asks what specific predictions could be made to distinguish cold control from dissociated control theory. We agree with the thought that while cold c...

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Projects

Project (1)
Project
To understand how and why people respond to suggestions. To understand the efficacy of suggestions in clinical and medical se