Cold Water and Decision-Making

Risk propensity, i.e., the ratio between risky and non-risky choices for each monetary value as measured in the risk decision-making task in the cold-water vs warm-water condition as described in Liu et al. (2021)

Participants will perform a computer-based reinforcement learning task described in Gueguen et al. (2024) to assess reward sensitivity in different monetary contexts. Behavioral range adaptation, which reflects value range-dependent, relative reward valuation, may be altered if reward processing itself is changed through a potent shift in the physiological state. To test whether reward processing is altered after cold vs warm water exposure, the extent to which range adaptation and reference-point centering occurs will be quantified using computational modeling methods.

Participants will be provided an ad libitum restaurant-like breakfast meal during which they can order various food items (e.g., bread, yogurts, cookies) in the desired amount. The ingested food type, nutritional value, and amount will be quantified to assess food preference after cold vs warm water exposure by linking the consumed food with a standardized food database (German Nutrient Database, Bundeslebensmittelschlüssel).

Task-based and resting-state heart-rate variability, measured with a three-point electrocardiogram (ECG)

Task-based and resting-state heart rate, measured with ECG

Task-based and resting-state respiration rate, measured via a respiration belt

Task-based and resting-state relative respiratory amplitude, measured via a respiratory belt

Phasic electrodermal activity, measured via electrodermal activity (EDA) electrodes

Tonic task-based and resting-state electrodermal activity, measured with EDA electrodes

Task-based and resting-state pupil dilation, measured via eye-tracking

Thermographic imaging of the face, full-body, supraclavicular, and scapular area using a thermal camera pre-, during, and post-immersion

Large neutral amino acid (LNAA) plasma concentration will be assessed via blood sampling at 4 time points (pre-immersion to 120 min post-immersion)

Catecholamines via blood sampling at 4 time points (pre-immersion to 120 min post-immersion)

Cortisol via blood sampling at 4 time points (pre-immersion to 120 min post-immersion)

Epigenetic markers (micro-RNA) via blood sampling at 4 time points (pre-immersion to 120 min post-immersion)

Psychological changes in perceived control, measured semi-continuously via self-reports throughout the experimental day. Measures range from 0% (not at all) to 100% (very much) with 100% indicating high perceived control.

Psychological changes in perceived freedom, measured semi-continuously via self-reports throughout the experimental day. Measures range from 0% (not at all) to 100% (very much) with 100% indicating high perceived freedom.

Psychological changes in perceived stress, measured semi-continuously via self-reports throughout the experimental day. Measures range from 0% (not at all) to 100% (very much) with 100% indicating high perceived stress.

Psychological changes in perceived state of flow, measured semi-continuously via self-reports throughout the experimental day. Measures range from 0% (not at all) to 100% (very much) with 100% indicating a high state of flow.

Psychological changes in self-efficacy, measured semi-continuously via self-reports throughout the experimental day. Measures range from 0% (not at all) to 100% (very much) with 100% indicating high self-efficacy.

Psychological changes in perceived pain, measured semi-continuously via self-reports throughout the experimental day. Measures range from 0% (not at all) to 100% (very much) with 100% indicating high perceived pain.

Psychological changes in emotions and their bodily origins, measured via self-reports pre- and post-immersion. Measures will be drawn on a virtual body using an adapted version of the Nummenmaa et al. (2014) emBODY tool with red color indicating increased perception and blue indicating decreased perception.

Psychological changes in affect, measured semi-continuously via the Positive Affect Negative Affect (PANAS) questionnaire to be filled out pre- and post-immersion. Measures for each item range from 1 (not at all) to 5 (very much) with 5 indicating the highest feeling perceived at the moment.

Trait autonomy is assessed via the Basic Psychological Need Satisfaction and Frustration Scale (BPNSFS). Measures range from 1 (not at all true) to 5 (totally true) with 5 indicating the highest score.

Emotion regulation, assessed via the Emotion Regulation Questionnaire (ERQ). Measures range from 1 (not at all true) to 7 (totally true) with 7 indicating the highest score.

Causality orientation, assessed via the General Causality Orientations Scale (GCOS). Measures range from 1 (very unlikely) to 6 (very likely) with 6 indicating the highest probability of responding as the item describes in the vignette scenario.

Delay discounting is assessed via the Delay Discounting Test by Kirby. Response options to each item are binary with one option corresponding to an immediate reward (e.g., 14 EUR today) and the second option corresponding to a higher but delayed reward (e.g., 19 EUR in 60 days).

Interoceptive awareness, assessed via the Multidimensional Assessment of Interoceptive Awareness (MAIA) questionnaire. Measures range from 0 (never) to 5 (always) with 5 indicating the highest response.

Generalized self-efficacy, assessed via the Self-Efficacy Scale (SWE). Measures range from "not at all true", "hardly true", "moderately true" and "exactly true". A higher score, indicated by a preference for "exactly true", indicated more self-efficacy.

Trait and state anxiety, assessed via the State-Trait Anxiety Inventory (STAI-S and STAI-T). State anxiety is assessed on a scale from 1 (not at all) to 8 (very much) with a higher score indicating high state anxiety. Trait anxiety is assessed on a scale from 0 (almost never) to 3 (almost always) with a higher score indicating high trait anxiety.

Psychological well-being is assessed via the short version of the Warwick-Edinburgh Mental Well-Being Scale (SWEMWBS). Responses range from "never" to "always" on a 5-point scale with a high score indicating higher mental well-being in the past two weeks.