George Van Doorn

Colour-temperature correspondences: when reactions to thermal stimuli are influenced by colour.

In our daily lives, information concerning temperature is often provided by means of colour cues, with red typically being associated with warm/hot, and blue with cold. While such correspondences have been known about for many years, they have primarily been studied using subjective report measures. Here we examined this correspondence using two more objective response measures. First, we used the Implicit Association Test (IAT), a test designed to assess the strength of automatic associations between different concepts in a given individual. Second, we used a priming task that involved speeded target discrimination in order to assess whether priming colour or thermal information could invoke the crossmodal association. The results of the IAT confirmed that the association exists at the level of response selection, thus indicating that a participant’s responses to colour or thermal stimuli are influenced by the colour-temperature correspondence. The results of the priming experiment revealed that priming a colour affected thermal discrimination reaction times (RTs), but thermal cues did not influence colour discrimination responses. These results may therefore provide important clues as to the level of processing at which such colour-temperature correspondences are represented.

Does the colour of the mug influence the taste of the coffee

BackgroundWe investigated whether consumers’ perception of a café latte beverage would be influenced by the colour (transparent, white or blue) of the mug from which it was drunk.ResultsIn experiment 1, the white mug enhanced the rated “intensity” of the coffee flavour relative to the transparent mug. However, given slight physical differences in the mugs used, a second experiment was conducted using identical glass mugs with coloured sleeves. Once again, the colour of the mug was shown to influence participants’ rating of the coffee. In particular, the coffee was rated as less sweet in the white mug as compared to the transparent and blue mugs.ConclusionsBoth experiments demonstrate that the colour of the mug affects people’s ratings of a hot beverage. Given that ratings associated with the transparent glass mug were not significantly different from those associated with the blue mug in either experiment, an explanation in terms of simultaneous contrast can be ruled out. However, it is possible that colour contrast between the mug and the coffee may have affected the perceived intensity/sweetness of the coffee. That is, the white mug may have influenced the perceived brownness of the coffee and this, in turn, may have influenced the perceived intensity (and sweetness) of the coffee. These results support the view that the colour of the mug should be considered by those serving coffee as it can influence the consumer’s multisensory coffee drinking experience. These results add to a large and growing body of research highlighting the influence of product-extrinsic colour on the multisensory perception of food and drink.

Visual and haptic influence on perception of stimulus size

In six experiments, subjects judged the sizes of squares that were presented visually and/or haptically, in unimodal or bimodal conditions. We were interested in which mode most affected size judgments in the bimodal condition when the squares presented to each mode actually differed in size. Three factors varied: whether haptic exploration was passive or active, whether the choice set from which the subjects selected their responses was visual or haptic, and whether cutaneous information was provided in addition to kinesthetic information. To match the task for each mode, visual presentations consisted of a cursor that moved along a square pathway to correspond to the haptic experience of successive segments revealed during exploration. We found that the visual influence on size judgments was greater than the influence of haptics when the haptic experience involved only kinesthesis, passive movement, and a visual choice set. However, when cutaneous input was added to kinesthetic information, size judgments were most influenced by the haptic mode. The results support hypotheses of sensory integration, rather than capture of one sense by the other.

Attenuated self-tickle sensation even under trajectory perturbation

The efference copy account of the tickle effect (i.e., our inability to tickle ourselves) predicts no tickle effect (i.e., an ability to tickle ourselves) when the trajectory of a tactile stimulus is perturbed relative to the associated movement, and there is evidence in support of this. The active inference account, however, predicts the tickle effect should survive trajectory perturbation. We test these accounts of the tickle effect under the hypothesis that previous findings are due to attentional modulation, and that the tickle effect will be found in a paradigm with no conscious attention directed to the trajectory perturbation. We thus expected to find support for active inference. Our first experiment confirms this hypothesis, while our second seeks to explain previous findings in terms of the modulation of the tickle sensation when there is awareness of, and different degrees of attention to, the spatial tactile and kinesthetic trajectories.

Cutaneous inputs yield judgments of line length that are equal to, or better than, those based on kinesthetic inputs

An experiment was designed to investigate haptic perception of length depending on whether inputs were cutaneous or derived from passively-guided movements. Cutaneous inputs appeared to offer more accurate information than did those from kinesthesis. Our results are inconsistent with the view that, for identification of raised line drawings, kinesthetic inputs are more important than tactile inputs.

The more they move the less they know: Cutaneous capture of kinesthesis?

Blindfolded participants felt pairs of “rivalrous” stimuli simultaneously, one with each index finger. The stimuli presented at each fingertip were 180° rotations of each other (e.g. <; and >;). Participants moved one index finger which caused a raised line to move underneath the other, stationary, index finger, in a yoked manner. Thus, when a <; was traced with the moving finger it caused a >; to be felt at the stationary finger. On all trials there was a raised line moving underneath the stationary finger. For the moving finger, a raised line was present on only one-third of the trials. When a raised line could be felt at the moving fingertip, the angle followed by this finger was invariably reported in conjunction with the angle present at the other (stationary) fingertip. However, when no line was present under the moving finger (i.e. when movement became the major cue for shape), participants almost always reported experiencing only the angle presented to the stationary fingertip - capturing the angle followed by the moving finger. Results are interpreted in light of optimal integration, bistable figures and inattentional blindness.

Down the rabbit hole: assessing the influence of schizotypy on the experience of the Barbie Doll Illusion

ABSTRACT Introduction: “Body swapping” illusions have been used to explore factors contributing to the experience of “owning” an artificial body. Preliminary research indicated that those people diagnosed with schizophrenia experience more vivid illusions of this kind than do “normal” individuals. Objectives: Here, we explored whether participants who rated themselves “high” on the cognitive-perceptual factor of the Schizotypal Personality Questionnaire (SPQ) experienced a more compelling sense of immersion in a variation of the body swapping illusion: The Barbie Doll Illusion. We also hypothesised that these individuals would experience a change in size perception when immersed in the illusion. Method: Forty-four participants wore a pair of Head-Mounted Display goggles connected to a video-camera, and thus a doll’s body replaced their own body in their visual field. In two conditions, touch was either applied synchronously or asynchronously to the doll’s and each participant’s leg. After each condition, participants filled out a questionnaire relating to their experience in the illusion. When both conditions were completed, they filled out the SPQ. Results: Our first hypothesis was confirmed, which suggested that people with higher cognitive-perceptual SPQ scores do indeed experience a more compelling Barbie Doll Illusion; however, our second hypothesis was not supported. Conclusion: Our study demonstrated, for the first time, that proneness to the positive and interpersonal factors of schizotypy in a normal population is sufficient to produce a compelling sense of swapping bodies.

The misperception of length in vision, haptics and audition

Participants felt, saw and heard stimuli travel over predetermined distances in three orientations --- gravitational-vertical, radial and horizontal. On all trials participants were required to judge the length of the distance travelled. Judgments based on visual information over-estimated length in the radial direction, while those based on haptic information overestimated length in the gravitational-vertical direction. Length estimates based on auditory information were similar across the three orientations. A combined modality condition using visual, haptic and auditory information mimicked the vision condition. Results are interpreted in light of the horizontal-vertical illusion.

A precision-of-information explanation of sensory dominance

Subjects identified letters or judged the sizes of squares presented visually and/or haptically. The stimuli were presented as spatiotemporal patterns (pre-recorded movement pathways) matched to avoid favouring either mode. Visual explorers were shown pathways as either a 1 cm line tracing out the shape (moving window condition) or as a line moving behind a stationary 1 cm window (stationary window condition). Haptic explorers| fingertips were guided along raised-line pathways (moving window condition) or felt the shapes, depicted in raised-line drawings, moving under their static fingertip (stationary window condition). Visual and haptic performance did not differ but the moving window conditions yielded lower latencies than stationary window conditions in both modes. When squares of different sizes were presented simultaneously to vision and kinesthesis, vision was dominant. The reverse was true when tactile (cutaneous) input was added to the kinesthetic information. These findings support the optimal integration hypothesis in that precision of information is critically related to dominance, and they challenge the concept of sensory capture as a modality-specific phenomenon.

Longitudinal association between social anxiety disorder and incident alcohol use disorder: results from two national samples of US adults

This study assessed the association between subclinical social fears and a 12-month diagnosis of Social Anxiety Disorder (SAD) at baseline and the risk of incident Alcohol Use Disorder (AUD) at follow-up, compared to those without subclinical social fears and a 12-month diagnosis of SAD. We performed an individual participant meta-analysis based on data from two national longitudinal surveys. Wave 1 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) was conducted in 2001–2002 in a sample of 43,093 adults and Wave 2 was conducted in 2004–2005 in 34,653 of the original respondents. Wave 1 of the National Comorbidity Survey was conducted in 1990–1992 in a sample of 8098 respondents and Wave 2 was conducted in 2001–2002 in 5001 of the original respondents. Binary logistic regression analyses were performed independently in each study and then the effect estimates were combined using random-effects meta-analysis. Neither subclinical social fears nor 12-month SAD at baseline were associated with incident AUD at follow-up. These findings conflict with reports of previous studies that a diagnosis of SAD is a risk factor for AUD in adults, and suggest that subclinical social fears are not associated with differential risk of incident AUD.