Maren Hawighorst

Chemosensory signals of competition increase the skin conductance response in humans

In vertebrates, chemosensory signals of competition are communicated between conspecifics, eliciting behavioral and physiological adaptations in the perceiving animal. The current study investigates, whether chemosensory signals of competition are also communicated between humans, and whether they elicit physiological changes in the perceiver. It is further investigated whether personality traits alter this physiological responding. Axillary sweat was collected from six male donors during a competition (badminton match) and a sport control condition (running). The donors testosterone rose stronger during the competition as compared to the sport control condition. The chemosensory stimuli were presented to 18 (9 male) participants through a constant-flow olfactometer, while the skin conductance response (SCR) was measured. Results reveal that the SCR was larger in response to chemosensory signals collected during the competition condition as compared to those collected during the sport control condition. Furthermore, regression analyses showed, that higher scores on trait social anxiety were related to larger SCRs towards the chemosensory signals of competition. The current result suggests that chemosensory signals of competition can be communicated between humans, and that they elicit orienting in the perceiving individual. These data are consistent with current research, suggesting that high socially anxious individuals process threatening social information preferentially. The current results add to the growing body of research into human chemosensory communication of social information, and extend previous research on the chemosensory communication of anxiety.

Challenging the assumptions for thermal sensation scales

ABSTRACT Scales are widely used to assess the personal experience of thermal conditions in built environments. Most commonly, thermal sensation is assessed, mainly to determine whether a particular thermal condition is comfortable for individuals. A seven-point thermal sensation scale has been used extensively, which is suitable for describing a one-dimensional relationship between physical parameters of indoor environments and subjective thermal sensation. However, human thermal comfort is not merely a physiological but also a psychological phenomenon. Thus, it should be investigated how scales for its assessment could benefit from a multidimensional conceptualization. The common assumptions related to the usage of thermal sensation scales are challenged, empirically supported by two analyses. These analyses show that the relationship between temperature and subjective thermal sensation is non-linear and depends on the type of scale used. Moreover, the results signify that most people do not perceive the categories of the thermal sensation scale as equidistant and that the range of sensations regarded as ‘comfortable’ varies largely. Therefore, challenges known from experimental psychology (describing the complex relationships between physical parameters, subjective perceptions and measurement-related issues) need to be addressed by the field of thermal comfort and new approaches developed.

Explaining the individual processes leading to adaptive comfort: Exploring physiological, behavioural and psychological reactions to thermal stimuli

Behavioural, physiological and psychological adaptive processes are presumed reasons for the discrepancies between predicted mean vote and observed comfort votes during field studies. However, few are known about the individual portions of these processes. An experimental design was developed, which aims at identifying those portions and is meant for climate chambers with operable windows facing the exterior. This article looks in detail at behavioural and physiological reactions together with their effect on the perceived level of comfort. By means of multivariate regression analyses, these reactions are analysed in order to assess differences due to variations in indoor/outdoor conditions as well as the number of interactive opportunities. One of the results shows that the restriction to keep the window closed is counterbalanced by an increased amount of physiological reactions, such as an increased level of skin temperature, together with an increase of still permitted actions such as drinking. The results highlight the importance of detailed insights into single aspect of adaptive processes for a better understanding of the phenomenon called ‘adaptive comfort’. Such approach is novel and important because a detailed knowledge and quantification of the occupant’s comfort perception in naturally ventilated buildings permits a planning with less uncertainty.

Comfort-related feedforward information: occupants’ choice of cooling strategy and perceived comfort

ABSTRACT Approaches to provide feedforward information to building occupants about the impact of potential actions on individual thermal comfort levels are scarce. Even less is known about the effect of such information on the decision process of occupants to interact with their built environment and their level of comfort after such decisions. In a naturalistic study, participants (Nu2009=u200976) were given a choice of four actions to counteract thermal discomfort induced by constantly rising room temperatures: removing a piece of clothing, opening the window, switching on the ceiling fan or switching on the air-conditioning. After receiving information about the potential change in comfort and energy consumption of these options, they had to confirm or revise their choice. The vast majority of participants initially chose to open the windows (Nu2009=u200928) or remove a piece of clothing (Nu2009=u200937); only a few chose the ceiling fan (Nu2009=u20092) or the air-conditioning (Nu2009=u20099). About one-third (Nu2009=u200923) revised their choice of action; most of them (Nu2009=u200915) indicated an influence from the provided information. In conclusion, feedforward information can be a useful tool to combat overheating problems by increasing energy-aware behaviour and thermal acceptance.

Quantifying individual adaptive processes: first experiences with an experimental design dedicated to reveal further insights to thermal adaptation

Due to more frequent unusual weather phenomena being observed, there is an urgent need to identify and quantify the abilities of occupants to adapt to climate changes. The adaptive comfort model identifies behavioural, physiological and psychological adaptive processes. However, besides giving a statistical approximation of their general effect on the thermal perception vote, little is known about the individual contributions of the three types of adaptive processes to this effect. Knowing such portions would enable us to extend the existing comfort models in such a manner that they incorporate adaptive (re-)actions of the occupant. This could be used for the design of passively cooled buildings, particularly with regard to interaction between occupants and the building (envelope) for individual adjustment of the thermal indoor environment. This article describes first experiences with a new experimental design dedicated to reveal further insights to the adaptive processes along with the description of requirements for the inside–outside climate chamber currently under construction in Karlsruhe.