scholarly journals Demand characteristics confound the rubber hand illusion

2020 ◽  
Author(s):  
Peter Lush
Keyword(s):  
Rubber Hand Illusion ◽  
Control Methods ◽  
Rubber Hand ◽  
Demand Characteristics ◽  
Psychological Science ◽  
Fit For Purpose ◽  
Procedure Text ◽  
And Control ◽  
Video Demonstration ◽  
Crucial Assumption

Reports of experiences of ownership over a fake hand following simple multisensory stimulation (the ‘rubber hand illusion’) have generated an expansive literature. Because such reports might reflect suggestion effects, demand characteristics are routinely controlled for by contrasting agreement ratings for ‘illusion’ and ‘control’ conditions. However, these methods have never been validated, and recent evidence that response to imaginative suggestion (‘phenomenological control’) predicts illusion report prompts reconsideration of their efficacy. A crucial assumption of the standard approach is that demand characteristics are matched across conditions. Here, a quasi-experiment design was employed to test demand characteristics in rubber hand illusion reports. Participants were provided with information about the rubber hand illusion procedure (text description and video demonstration) and recorded expectancies for standard ‘illusion’ and ‘control’ statements. Expectancies for control and illusion statements in synchronous and asynchronous conditions were found to differ similarly to published illusion reports. Therefore, rubber hand illusion control methods which have been in use for 22 years are not fit for purpose. Because demand characteristics have not been controlled in illusion report in existing studies, the illusion may be, partially or entirely, a suggestion effect. Methods to develop robust controls are proposed. That confounding demand characteristics have been overlooked for decades may be attributable to a lack of awareness that demand characteristics can drive experience in psychological science.

scholarly journals Demand Characteristics Confound the Rubber Hand Illusion

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Peter Lush
Keyword(s):  
Rubber Hand Illusion ◽  
Control Methods ◽  
Rubber Hand ◽  
Demand Characteristics ◽  
Psychological Science ◽  
Fit For Purpose ◽  
Procedure Text ◽  
And Control ◽  
Video Demonstration ◽  
Crucial Assumption

Reports of experiences of ownership over a fake hand following simple multisensory stimulation (the ‘rubber hand illusion’) have generated an expansive literature. Because such reports might reflect suggestion effects, demand characteristics are routinely controlled for by contrasting agreement ratings for ‘illusion’ and ‘control’ conditions. However, these methods have never been validated, and recent evidence that response to imaginative suggestion (‘phenomenological control’) predicts illusion report prompts reconsideration of their efficacy. A crucial assumption of the standard approach is that demand characteristics are matched across conditions. Here, a quasi-experiment design was employed to test demand characteristics in rubber hand illusion reports. Participants were provided with information about the rubber hand illusion procedure (text description and video demonstration) and recorded expectancies for standard ‘illusion’ and ‘control’ statements. Expectancies for ‘control’ and ‘illusion’ statements in synchronous and asynchronous conditions were found to differ similarly to published illusion reports. Therefore, rubber hand illusion control methods which have been in use for 22 years are not fit for purpose. Because demand characteristics have not been controlled in illusion report in existing studies, the illusion may be, partially or entirely, a suggestion effect. Methods to develop robust controls are proposed. That confounding demand characteristics have been overlooked for decades may be attributable to a lack of awareness that demand characteristics can drive experience in psychological science.

scholarly journals What do participants expect to experience in the rubber hand illusion?

2021 ◽  
Author(s):  
Arran T Reader
Keyword(s):  
Subjective Experience ◽  
The Body ◽  
Rubber Hand Illusion ◽  
Body Ownership ◽  
Rubber Hand ◽  
Demand Characteristics ◽  
Open Questions ◽  
Synchronous Condition ◽  
Subjective Reports

The sense of body ownership (the feeling that the body belongs to the self) is commonly believed to arise through multisensory integration. This is famously shown in the rubber hand illusion (RHI), where touches applied synchronously to a false hand and to the participant’s real hand (which is hidden from view) can induce a sensation of ownership over the fake one. Asynchronous touches weaken the illusion, and are typically used as a control condition. Subjective experience during the illusion is measured using a questionnaire, with some statements designed to capture illusory sensation and others designed as controls. However, recent work by Lush (2020, Collabra: Psychology) claimed that participants may have different levels of expectation for questionnaire items in the synchronous condition compared to the asynchronous condition, and for the illusion-related items compared to the control items. This may mean that the classic RHI questionnaire is poorly controlled for demand characteristics. As such, Lush (2020) suggested that subjective reports in the RHI may reflect compliance or even the generation of experience to meet expectations (‘phenomenological control’), rather than multisensory processes underlying the sense of body ownership. In the current work a conceptual replication of Lush (2020) was performed with an improved experimental design. Participants were presented with a video of the RHI procedure and reported the sensations they would expect to experience, both in open questions and by rating questionnaire items. In keeping with Lush (2020), participants had greater expectations for illusion statements in the synchronous condition compared to the asynchronous condition, and for illusion statements compared to control statements. However, there was also evidence that some expectations may be driven by exposure to the questionnaire items rather than exposure to the illusion procedure. The role of pre-illusion expectations and expectations driven by questionnaire exposure in the RHI require further examination.

scholarly journals Phenomenological control: response to imaginative suggestion predicts measures of mirror touch synaesthesia, vicarious pain and the rubber hand illusion

2019 ◽  
Author(s):  
Peter Lush ◽  
Vanessa Botan ◽  
Ryan Bradley Scott ◽  
Anil Seth ◽  
Jamie Ward ◽  
...  
Keyword(s):  
Rubber Hand Illusion ◽  
Top Down ◽  
Rubber Hand ◽  
Large Sample ◽  
Psychological Science ◽  
Task Requirements ◽  
Control Response ◽  
Psychological Experiments ◽  
Psychological Studies ◽  
Normally Distributed

[Published in Nature Communications as Trait phenomenological control predicts experience of mirror synaesthesia and the rubber hand illusion] The control of top down processes to generate experience has been studied within the context of hypnosis since the birth of psychological science. 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. The possibility that they account for experiential change in psychological studies has been overlooked. In large sample studies (of 156, 404 and 353 participants) we report substantial relationships between hypnotisability and experimental measures of experiential change (mirror-sensory synaesthesia and the rubber hand illusion) comparable to relationships between hypnotisability and individual hypnosis scale items. The control of phenomenology to meet expectancies arising from perceived task requirements can account for experiential change in psychological experiments.

scholarly journals Hypothesis awareness confounds asynchronous control conditions in indirect measures of the rubber hand illusion

2021 ◽  
Vol 8 (11) ◽  
Author(s):  
P. Lush ◽  
A. K. Seth ◽  
Z. Dienes
Keyword(s):  
Multisensory Integration ◽  
Visual Stimulation ◽  
Control Measures ◽  
Rubber Hand ◽  
Subjective Report ◽  
Demand Characteristics ◽  
Asynchronous Control ◽  
Indirect Measures ◽  
Body Location ◽  
And Control

Reports of changes in experiences of body location and ownership following synchronous tactile and visual stimulation of fake and real hands (rubber hand (RH) effects) are widely attributed to multisensory integration mechanisms. However, existing control methods for subjective report measures (asynchronous stroking and control statements) are confounded by participant hypothesis awareness; the report may reflect response to demand characteristics. Subjective report is often accompanied by indirect (also called ‘objective’ or ‘implicit’) measures. Here, we report tests of expectancies for synchronous ‘illusion’ and asynchronous ‘control’ conditions across two pre-registered studies ( n = 140 and n = 45) for two indirect measures: proprioceptive drift (a change in perceived hand location) and skin conductance response (a measure of physiological arousal). Expectancies for synchronous condition measures were greater than for asynchronous conditions in both studies. Differences between synchronous and asynchronous control condition measures are therefore confounded by hypothesis awareness. This means indirect measures of RH effects may reflect compliance, bias and phenomenological control in response to demand characteristics, just as for subjective measures. Valid control measures are required to support claims of a role of multisensory integration for both direct and indirect measures of RH effects.

scholarly journals Order effects in the rubber hand illusion

2021 ◽  
Author(s):  
Peter Lush
Keyword(s):  
Multisensory Integration ◽  
Rubber Hand Illusion ◽  
Order Effects ◽  
Rubber Hand ◽  
Demand Characteristics ◽  
Test Order ◽  
Integration Mechanisms ◽  
Synchronous Condition ◽  
The Difference ◽  
Proprioceptive Drift

Seeing a fake hand brushed in synchrony with brushstrokes to a participant’s hand (the rubber hand illusion; RHI) prompts reports of referred touch, illusory ownership and that the real hand has drifted toward the fake hand (proprioceptive drift). According to one theory, RHI effects are attributable to multisensory integration mechanisms, but they may alternatively (or additionally) reflect the generation of experience to meet expectancies arising from demand characteristics (phenomenological control). Multisensory integration accounts are supported by contrasting synchronous and asynchronous brush stroking conditions, typically presented in counter-balanced order. This contrast is known to be confounded by demand characteristics, but to date there has been no exploration of the role of demand characteristics relating to condition-order. In an exploratory study, existing data from a rubber hand study (n = 124) were analysed to test order effects. Synchronous condition illusion report and the difference between synchronous and asynchronous conditions in both report and proprioceptive drift were greater when the asynchronous condition was performed first (and therefore participants were exposed to the questionnaire materials). These order effects have implications for interpretation of reports of ownership experience: in particular, there was no mean ownership agreement in the synchronous-first group. These data support the theory that reports of ownership of a rubber hand are at least partially attributable to phenomenological control in response to demand characteristics.

scholarly journals Rubber hand illusion report is confounded by demand characteristics and may entirely reflect compliance, bias and implicit imaginative suggestion effects

2021 ◽  
Author(s):  
Peter Lush ◽  
Zoltan Dienes ◽  
Anil Seth
Keyword(s):  
Rubber Hand Illusion ◽  
Rubber Hand ◽  
Demand Characteristics ◽  
Adequate Control

In a previous paper, we reported substantial relationships between phenomenological control (trait response to imaginative suggestion) and responses to the rubber hand illusion, vicarious pain, and mirror synaesthesia. We argued that these responses may reflect phenomenological control rather than, or in addition to, other mechanisms. Ehrsson et al disagree with our claims regarding the rubber hand illusion. They provide analyses which replicate and extend our results, but which they argue undermine our claims. Here, we explain why our claims remain justified, drawing attention to the fact that comparing synchronous and asynchronous stroking in the rubber hand illusion is confounded by demand characteristics. Altogether, reported experience of ownership in the rubber hand illusion may be entirely attributable to phenomenological control, compliance and bias effects. Future experiments, with adequate control conditions, are needed to establish whether other mechanisms are involved.

scholarly journals Demand characteristics confound asynchronous control conditions in indirect measures of the rubber hand illusion.

2021 ◽  
Author(s):  
Peter Lush ◽  
Anil Seth ◽  
Zoltan Dienes
Keyword(s):  
Subjective Experience ◽  
Visual Stimulation ◽  
Control Measures ◽  
Rubber Hand Illusion ◽  
Rubber Hand ◽  
Subjective Report ◽  
Demand Characteristics ◽  
Asynchronous Control ◽  
Indirect Measures ◽  
Body Location

Reports of experiences of ownership of a fake hand following synchronous tactile and visual stimulation of fake and real hands have been attributed to multisensory integration mechanisms (the rubber hand ‘illusion’). However, it has been shown that the subjective reports expected, namely stronger experiences in the synchronous than asynchronous condition, and for ‘illusion’ rather than ‘control’ statements, are clear to subjects; thus, the reports may reflect response to demand characteristics. Subjective report is often accompanied by so-called ‘objective’ or ‘implicit’ measures. Like subjective report, an asynchronous control condition is typically employed for these measures. Here we report tests of expectancies for synchronous ‘illusion’ and asynchronous ‘control’ conditions for two indirect measures of rubber hand effects across two pre-registered studies (n = 140 and n = 45): proprioceptive drift (a change in perceived hand location) and skin conductance response (SCR; a measure of physiological arousal). Participants expectancies for the synchronous condition measures were greater than for asynchronous ‘control’ condition in both studies. Previous work has shown that subjects can voluntarily produce alterations in both subjective experience of body location and in SCR. Thus, indirect measures of rubber hand effects may reflect compliance, bias and phenomenological control in response to demand characteristics, just as for subjective measures, and the asynchronous control condition is in general invalid for controlling demand characteristics in rubber hand procedures. Valid control measures are required to support claims of a role of multi-sensory integration for both direct and indirect measures of rubber hand effects.

Auditory cues influence the rubber-hand illusion.

2018 ◽  
Vol 44 (7) ◽  
pp. 1012-1021 ◽  
Author(s):  
Dominika Radziun ◽  
H. Henrik Ehrsson
Keyword(s):  
Rubber Hand Illusion ◽  
Rubber Hand ◽  
Auditory Cues
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