Sensory Deprivation
Encoding fear intensity in human sweat
Jasper de Groot, Peter Kirk & Jay Gottfried
Philosophical Transactions of the Royal Society: Biological Sciences, April 2020
Abstract:
Humans, like other animals, have an excellent sense of smell that can serve social communication. Although ample research has shown that body odours can convey transient emotions like fear, these studies have exclusively treated emotions as categorical, neglecting the question whether emotion quantity can be expressed chemically. Using a unique combination of methods and techniques, we explored a dose–response function: Can experienced fear intensity be encoded in fear sweat? Specifically, fear experience was quantified using multivariate pattern classification (combining physiological data and subjective feelings with partial least-squares-discriminant analysis), whereas a photo-ionization detector quantified volatile molecules in sweat. Thirty-six male participants donated sweat while watching scary film clips and control (calming) film clips. Both traditional univariate and novel multivariate analysis (100% classification accuracy; Q2: 0.76; R2: 0.79) underlined effective fear induction. Using their regression-weighted scores, participants were assigned significantly above chance (83% > 33%) to fear intensity categories (low–medium–high). Notably, the high fear group (n = 12) produced higher doses of armpit sweat, and greater doses of fear sweat emitted more volatile molecules (n = 3). This study brings new evidence to show that fear intensity is encoded in sweat (dose–response function), opening a field that examines intensity coding and decoding of other chemically communicable states/traits.
Chemosensory communication of aggression: Women's fine-tuned neural processing of male aggression signals
Bettina Pause, Dunja Storch & Katrin Lübke
Philosophical Transactions of the Royal Society: Biological Sciences, April 2020
Abstract:
The current study is the first to examine the central nervous processing of aggression chemosignals within men and women by means of chemosensory event-related potential (CSERP) analysis. Axillary sweat was collected from 17 men and 17 women participating in a competitive computer game (aggression condition) and playing a construction game (control condition). Sweat samples were pooled with reference to donor gender and condition, and presented to 23 men and 25 women via a constant flow olfactometer. Ongoing electroencephalogram was recorded from 61 scalp locations, CSERPs (P2, P3-1, P3-2) were analysed and neuronal sources calculated (low-resolution electromagnetic tomography, LORETA). Women, especially, showed larger P3-1 and P3-2 amplitudes in response to male as compared with female aggression signals (all p values < 0.01). The peak activation of this effect was related to activity within the dorsomedial prefrontal cortex (Brodmann area 8). As male aggression commonly targets physical harm, the competence of the human brain to sensitively detect male aggression signals is considered to be highly adaptive. The detection of male aggression signals seems to be of higher importance for women than for men. It is suggested that the processing of male aggression signals in women induces an immediate response selection.
Are We There Yet? An Anticipation Account of the Return Trip Effect
Zoey Chen, Ryan Hamilton & Derek Rucker
Social Psychological and Personality Science, forthcoming
Abstract:
Research has documented the psychological phenomenon in which the trip back from a destination is experienced as shorter than the trip to the destination. Deemed the “return trip effect” (RTE), prior work explained this phenomenon in terms of differential familiarity between home and outbound destination or an underestimation of initial travel time. The present article posits an anticipation account for the RTE: Outbound trips to a destination tend to foster higher levels of anticipation than return trips. Due to greater anticipation, people’s perception of time elongates. Importantly, the anticipation account makes novel predictions with regard to the occurrence of the RTE that cannot be accounted for by prior explanations. Multiple studies, with diverse methodologies, test and offer evidence in support of an anticipation account of the RTE.
Short-term Smartphone App-based Focused Attention Meditation Diminishes Cognitive Flexibility
Nicole Wolff & Christian Beste
Journal of Cognitive Neuroscience, forthcoming
Abstract:
Cognitive flexibility is an important aspect relevant to daily life situations, and there is an increasing public interest to optimize these functions, for example, using (brief ) meditation practices. However, the underlying neurophysiological mechanisms remain poorly understood. On the basis of theoretical considerations, both improvements and deteriorations of cognitive flexibility are possible through focused attention meditation (FAM). We investigated the effect of a brief “smartphone app”-based FAM on task switching using EEG methods, temporal signal decomposition, and source localization techniques (standardized low-resolution electromagnetic brain tomography). The study was conducted using a crossover study design. We show that even 15 min of FAM practicing modulates memory-based task switching, on a behavioral level and a neurophysiological level. More specifically, FAM hampers response selection and conflict resolution processes and seem to reduce cognitive resources, which are necessary to rapidly adapt to changing conditions. These effects are represented in the N2 and P3 time windows and associated with ACC. It seems that FAM increases the attention to one specific aspect, which may help to focus but carries also the risk that behavior becomes too rigid. FAM thus seems to modulate both the stimulus- and response-related aspects of conflict monitoring in ACC. Motor-related processes were not affected. The results can be explained using a “cognitive control dilemma framework,” suggesting that particularly alterations in “background monitoring” may be important to consider when explaining the effects of FAM during task switching.
Money does not stink: Using unpleasant odors as stimulus material changes risky decision making
Bettina von Helversen, Géraldine Coppin & Benjamin Scheibehenne
Journal of Behavioral Decision Making, forthcoming
Abstract:
Odors are strong elicitors of affect, and they play an important role in guiding human behavior, such as avoiding fire or spoiled food. However, little is known about how risky decision making changes when stimuli are olfactory. We investigated this question in an experimental study of risky decision making with unpleasant odors and monetary losses in a fully incentivized task with real outcomes. Odor and monetary decisions were matched so that monetary losses corresponded to the amount of money participants were willing to pay to avoid smelling an odor. Hierarchical Bayesian analyses using prospect theory show that participants were less sensitive to probabilities when gambling with odors than when gambling with money. These results highlight the importance of taking the sensory modality into account when studying risky decision making.
The Case of the Cognitive (Opti)miser: Electrophysiological Correlates of Working Memory Maintenance Predict Demand Avoidance
Jeffrey Nador et al.
Journal of Cognitive Neuroscience, forthcoming
Abstract:
People are often considered cognitive misers. When given a free choice between two tasks, people tend to choose tasks requiring less cognitive effort. Such demand avoidance (DA) is associated with cognitive control, but it is still not clear to what extent individual differences in cognitive control can account for variations in DA. We sought to elucidate the relation between cognitive control and cognitive effort preferences by investigating the extent to which sustained neural activity in a task requiring cognitive control is correlated with DA. We hypothesized that neural measures of efficient filtering will predict individual variations in demand preferences. To test this hypothesis, we had participants perform a delayed-match-to-sample paradigm with their ERPs recorded, as well as a separate behavioral demand-selection task. We focused on the ERP correlates of cognitive filtering efficiency (CFE) — the ability to ignore task-irrelevant distractors during working memory maintenance — as it manifests in a modulation of the contralateral delay activity, an ERP correlate of cognitive control. As predicted, we found a significant positive correlation between CFE and DA. Individuals with high CFE tended to be significantly more demand avoidant than their low-CFE counterparts. Low-CFE individuals, in comparison, did not form distinct cognitive effort preferences. Overall, our results suggest that cognitive control over the contents of visual working memory contribute to individual differences in the expression of cognitive effort preferences. This further implies that these observed preferences are the product of sensitivity to cognitive task demands.