You Turn Me Cold: Evidence for Temperature Contagion

Introduction

During social interactions, our own physiological responses influence those of others. Synchronization of physiological (and behavioural) responses can facilitate emotional understanding and group coherence through inter-subjectivity. Here we investigate if observing cues indicating a change in another''s body temperature results in a corresponding temperature change in the observer.

Methods

Thirty-six healthy participants (age; 22.9±3.1 yrs) each observed, then rated, eight purpose-made videos (3 min duration) that depicted actors with either their right or left hand in visibly warm (warm videos) or cold water (cold videos). Four control videos with the actors'' hand in front of the water were also shown. Temperature of participant observers'' right and left hands was concurrently measured using a thermistor within a Wheatstone bridge with a theoretical temperature sensitivity of <0.0001°C. Temperature data were analysed in a repeated measures ANOVA (temperature × actor''s hand × observer''s hand).

Results

Participants rated the videos showing hands immersed in cold water as being significantly cooler than hands immersed in warm water, F_(1,34) = 256.67, p<0.001. Participants'' own hands also showed a significant temperature-dependent effect: hands were significantly colder when observing cold vs. warm videos F_(1,34) = 13.83, p = 0.001 with post-hoc t-test demonstrating a significant reduction in participants'' own left (t₍₃₅₎ = −3.54, p = 0.001) and right (t₍₃₅₎ = −2.33, p = 0.026) hand temperature during observation of cold videos but no change to warm videos (p>0.1). There was however no evidence of left-right mirroring of these temperature effects p>0.1). Sensitivity to temperature contagion was also predicted by inter-individual differences in self-report empathy.

Conclusions

We illustrate physiological contagion of temperature in healthy individuals, suggesting that empathetic understanding for primary low-level physiological challenges (as well as more complex emotions) are grounded in somatic simulation.     

Eat Me If You Can: Cognitive Mechanisms Underlying the Distance Effect

Proximal objects provide affordances that activate the motor information involved in interacting with the objects. This effect has previously been shown for artifacts but not for natural objects, such as food. This study examined whether the sight of proximal food, compared to distant food activates eating-related information. In two experiments reaction times to verbal labels following the sight of proximal and distant objects (food and toys) were measured. Verbal labels included function words that were compatible with one object category (eating and playing) and observation words compatible with both object categories. The sight of food was expected to activate eating-related information when presented at proximity but not at distance, as reflected by faster reaction times to proximal than distant compatible eating words and no difference between reaction times to proximal and distant food for observation words (Experiment 1). Experiment 2 additionally compared the reaction times to wrapped and unwrapped food. The distance effect was expected to occur only for unwrapped food because only unwrapped food is readily edible. As expected, Experiment 1 and 2 revealed faster responses to compatible eating words at proximity than at distance. In Experiment 2 this distance effect occurred only for readily edible, unwrapped food but not for wrapped food. For observation words no difference in response times between the distances was found. These findings suggest that the sight of proximal food activates eating-related information, which could explain people’s differential behavioral responses to reachable versus distant food. The activation of eating-related information upon sight of accessible food could provide a cognition-based explanation for mindless eating.     

Mirroring Pain in the Brain: Emotional Expression versus Motor Imitation

Perception of pain in others via facial expressions has been shown to involve brain areas responsive to self-pain, biological motion, as well as both performed and observed motor actions. Here, we investigated the involvement of these different regions during emotional and motor mirroring of pain expressions using a two-task paradigm, and including both observation and execution of the expressions. BOLD responses were measured as subjects watched video clips showing different intensities of pain expression and, after a variable delay, either expressed the amount of pain they perceived in the clips (pain task), or imitated the facial movements (movement task). In the pain task condition, pain coding involved overlapping activation across observation and execution in the anterior cingulate cortex, supplementary motor area, inferior frontal gyrus/anterior insula, and the inferior parietal lobule, and a pain-related increase (pain vs. neutral) in the anterior cingulate cortex/supplementary motor area, the right inferior frontal gyrus, and the postcentral gyrus. The ‘mirroring’ response was stronger in the inferior frontal gyrus and middle temporal gyrus/superior temporal sulcus during the pain task, and stronger in the inferior parietal lobule in the movement task. These results strongly suggest that while motor mirroring may contribute to the perception of pain expressions in others, interpreting these expressions in terms of pain content draws more heavily on networks involved in the perception of affective meaning.     

Catch Me If You Can: Diel Activity Patterns of Mammalian Prey and Predators

The activity patterns exhibited by animals are shaped by evolution, but additionally fine‐tuned by flexible responses to the environment. Predation risk and resource availability are environmental cues which influence the behavioural decisions that make both predators and prey engage in activity bursts, and depending on their local importance, can be strong enough to override the endogenous regulation of an animals’ circadian clock. In Southern Europe, wherever the European rabbit (Oryctolagus cuniculus) is abundant, it is the main prey of most mammalian mesopredators, and rodents are generally the alternative prey. We evaluated the bidirectional relation between the diel activity strategies of these mammalian mesopredators and prey coexisting in south‐western Europe. Results revealed that even though predation risk enforced by mammalian mesocarnivores during night‐time was approximately twice and five times higher than during twilight and daytime, respectively, murids consistently displayed unimodal nocturnal behaviour. Conversely, the European rabbits exhibited a bimodal pattern that peaked around sunrise and sunset. Despite the existence of some overlap between the diel rhythms of mesocarnivores and rabbits, their patterns were not synchronized. We suggest that the environmental stressors in our study areas are not severe enough to override the endogenous regulation of the circadian cycle in murids. European rabbits, however, are able to suppress their biological tendency for nocturnality by selecting a predominantly crepuscular pattern. In spite of the higher energetic input, mesocarnivores do not completely track rabbits’ activity pattern. They rather track rodents’ activity. We propose that these systems have probably evolved towards a situation where some degree of activity during high‐risk periods benefits the overall prey population survival, while the accessibility to sufficient prey prevents predators to completely track them.     

Automatic Imitation in Rhythmical Actions: Kinematic Fidelity and the Effects of Compatibility,Delay, and Visual Monitoring

We demonstrate that observation of everyday rhythmical actions biases subsequent motor execution of the same and of different actions, using a paradigm where the observed actions were irrelevant for action execution. The cycle time of the distractor actions was subtly manipulated across trials, and the cycle time of motor responses served as the main dependent measure. Although distractor frequencies reliably biased response cycle times, this imitation bias was only a small fraction of the modulations in distractor speed, as well as of the modulations produced when participants intentionally imitated the observed rhythms. Importantly, this bias was not only present for compatible actions, but was also found, though numerically reduced, when distractor and executed actions were different (e.g., tooth brushing vs. window wiping), or when the dominant plane of movement was different (horizontal vs. vertical). In addition, these effects were equally pronounced for execution at 0, 4, and 8 s after action observation, a finding that contrasts with the more short-lived effects reported in earlier studies. The imitation bias was also unaffected when vision of the hand was occluded during execution, indicating that this effect most likely resulted from visuomotor interactions during distractor observation, rather than from visual monitoring and guidance during execution. Finally, when the distractor was incompatible in both dimensions (action type and plane) the imitation bias was not reduced further, in an additive way, relative to the single-incompatible conditions. This points to a mechanism whereby the observed action’s impact on motor processing is generally reduced whenever this is not useful for motor planning. We interpret these findings in the framework of biased competition, where intended and distractor actions can be represented as competing and quasi-encapsulated sensorimotor streams.     

"You Have to Be Your Own Doctor": Sociocultural Influences on Alternative Therapy Use among Gay Men with AIDS in West Hollywood

This article considers the use of alternative therapies by gay men with AIDS in West Hollywood, California. In all, 89 different alternative therapies for HIV and AIDS treatment were uncovered during the course of the study. In addition to the high number of alternative therapies, a majority of the men in the study (69.2 percent) were currently using some type of alternative treatment. Sociocultural influences on the use of alternative therapies are explored, including AIDS activism. Because most of the men (92 percent) also use Western medicine as well, the interface of these two types of treatments is also explored, [alternative therapies, AIDS, gay men]