Can hypnotic suggestibility be measured online?

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 needed to invest in identifying people high and low in responsiveness to suggestion. In this study, we introduced an online assessment of hypnotic response and estimated the extent to which the scores and psychometric properties of an online screening differ from an offline one. We propose that the online screening of hypnotic response is viable as it reduces the level of responsiveness only by a slight extent. The application of online screening may prompt researchers to run large-scale studies with more heterogeneous samples, which would help researchers to overcome some of the issues underlying the current replication crisis in psychology

Inference of selection gradients using performance measures as fitness proxies

O.D.F. is supported by the Natural Sciences and Engineering Research Council of Canada and the Madame Vigdís Finnbogadóttir Scholarship. M.B.M. is supported by a University Research Fellowship from the Royal Society (London).1.  Selection coefficients, i.e., selection differentials and gradients, are useful for quantifying selection and for making comparisons across traits and organisms, because they appear in known equations for relating selection and genetic variation to one another and to evolutionary change. However, selection coefficients can only be estimated in organisms where traits and fitness (components) can be measured. This is probably a major contributor to taxonomic biases of selection studies. Aspects of organismal performance, i.e., quantities that are likely to be positively related to fitness components, such as body size, are sometimes used as proxies for fitness, i.e., used in place of fitness components in regression-based selection analysis. To date, little theory exists to inform empirical studies about whether such procedures may yield selection coefficients with known relationships to genetic variation and evolution. 2.  We show that the conditions under which performance measures can be used as proxies for fitness are very limited. Such analyses require that the regression of fitness on the proxy is linear and goes through the origin. We illustrate how fitness proxies may be used in conjunction with information about the performance-fitness relationship, and clarify how this is different from substituting fitness proxies for fitness components in selection analyses. 3.  We apply proxy-based and fitness component-based selection analysis to a system where traits, a performance measure (size; similar to proxies that are commonly used in place of fitness), and a more proximate fitness measure, are all available on the same set of individuals. We find that proxy-based selection gradients are poorly reflective of selection gradients estimated using fitness components, even when proxy-fitness relationships are quite strong and reasonably linear. 4.  We discuss the implications for proxy-based selection analysis. We emphasise that measures of organismal performance, such as size, may in many cases provide useful information that can contribute to quantitative inferences about natural selection, and their use could allow quantitative inference about selection to be conducted in a wider range of taxa. However, such inferences require quantitative analysis of both trait-performance and performance-fitness relationships, rather than substitution of performance for measures of fitness or fitness components.PostprintPeer reviewe

Intentional binding as Bayesian cue combination: testing predictions with trait individual differences

We investigated differences in intentional binding in high and low hypnotizable groups to explore two questions relating to (a) trait differences in the availability of motor intentions to metacognitive processes and (b) a proposed cue combination model of binding. An experience of involuntariness is central to hypnotic responding and may arise from strategically being unaware of one’s intentions. Trait differences in the ability to respond to hypnotic suggestion may reflect differing levels of access to motor intentions. Intentional binding refers to the subjective compression of the time between an action and its outcome, indicated by a forward shift in the judged time of an action toward its outcome (action binding) and the backward shift of an outcome toward a causal action (outcome binding). Intentional binding is sensitive to intentional action without requiring explicit reflection upon agency. One way of explaining the sensitivity of intentional binding is to see it as a simple case of multisensory cue combination in which awareness of intentions increases knowledge of the timing of actions. Here we present results consistent with such a mechanism. In a contingent presentation of action and outcome events, low hypnotizable had more precise timing judgments of actions and also showed weaker action binding than highs. These results support the theory that trait hypnotizability is related to access to information related to motor intentions, and that intentional binding reflects the Bayesian combination of cross-modal cues

Concentration‐dependent optical‐absorption coefficient in n‐type GaAs

The doping-dependent, near-band-edge optical-absorption coefficient CY(h v) was deduced from optical transmission measurements in n-type GaAs thin films. The selenium-doped films were grown by metalorganic chemical-vapor deposition and do ed to produce room-temperature electron concentrations from 1.3 x 10” to 3.8X 1018 cm- P . The transmission measurements covered photon energies between 1.35 and 1.7 eV and were performed on double heterostructures with the substrate removed by selective etching. The results show good qualitative agreement with previous studies and good quantitative agreement, except for the heavily doped samples. For na=3.8 X 10” cme3, a( 1.42 eV\u3e is approximately four times that reported by previous workers. Secondary-ion-mass spectrometry measurements on flms grown under differing conditions demonstrate that a(hv) is sensitive to electrically inactive dopants and supports the hypothesis that precipitates or compensation influenced previous measurements. These comprehensive results on high-quality, uncompensated material should prove useful for fundamental studies of optical transitions in n-type GaAs as well as for modeling optoelectronic devices

Microsecond Lifetimes and Low Interface Recombination Velocities in Moderately Doped n-GaAs Thin Films

We have observed lifetimes greater than 1 ps in moderately doped, thin film, n-GaAs/A1a,Gae,As double heterostructure membranes formed by etching away the substrate. We attribute these ultralong lifetimes to enhanced photon recycling caused by the removal of the substrate. Nonradiative recombination in the bulk and at the interfaces is very low; the upper limit of the interface recombination velocity is 25 cm/S.-Such long lifetimes in GaAs doped at N,= 1.3 X 10” cme3 suggest that thin-film solar cells offer a potential option for achieving very high efficiencies

A study of minority carrier lifetime versus doping concentration in n‐type GaAs grown by metalorganic chemical vapor deposition

Time‐resolved photoluminescence decay measurements are used to explore minority carrier recombination in n‐type GaAs grown by metalorganic chemical vapor deposition, and doped with selenium to produce electron concentrations from 1.3×1017 cm−3 to 3.8×1018 cm−3. For electron densities n0\u3c1018 cm−3, the lifetime is found to be controlled by radiative recombination and photon recycling with no evidence of Shockley–Read–Hall recombination. For higher electron densities, samples show evidence of Shockley–Read–Hall recombination as reflected in the intensity dependence of the photoluminescence decay. Still, we find that radiative recombination and photon recycling are important for all electron concentrations studied, and no evidence for Auger recombination was observed

Computer vs live delivery of the Sussex Waterloo Scale of Hypnotisability (SWASH)

There exist reliable and stable trait differences in the ability to control phenomenology in response to imaginative suggestion. Hypnotisability scales measure response to imaginative suggestion within a hypnotic context. Because hypnotisability has recently been shown to predict measures of experiential change in psychological experiments (e.g., the rubber hand illusion), there is a need for easy to use screening tools which are accessible to researchers with little or no background in hypnosis or imaginative suggestion research. The SWASH is a time efficient group hypnotisability scale which can be administered to up to 50 participants simultaneously. Here we present norms from an undergraduate sample for a recorded version delivered by a computer program alongside norms for a live presentation. Reliability, validity and mean scores are similar across the two presentations. Computer delivery of a prerecorded script provides a simple tool to rapidly screen for hypnotisability in large groups for researchers with no prior experience of hypnosis research