Effects of moderate thermal environments on cognitive performance: A multidisciplinary review

Abstract

The effect of the thermal environment on performance and productivity has been a focus of interest among indoor environmental researchers for nearly a century, but most of that work has been conducted in relative isolation from the cognate disciplines of human performance evaluation. The present review examines thermal environmental effects on cognitive performance research conducted across multiple disciplines. After differentiating performance from productivity, we compare the two dominant conceptual models linking thermal stress to performance; (1) the inverted-U concept and (2) the extended-U relationship. The inverted-U specifies a single optimum temperature (or its corresponding subjective thermal sensation) at which performance is maximised. In contrast, the extended-U model posits a broad central plateau across which there is no discernible thermal effect on cognitive performance. This performance plateau is bounded by regions of progressive performance decrements in more extreme thermal conditions. The contradictions between these opposing conceptual models might derive from various confounding factors at play in their underlying research bases. These include, inter alia, environment-related, task-related, and performer-related factors, as well as their associated two-way and three-way interaction effects. Methodological discrepancies that might also contribute to the divergence of these conceptual models are evaluated, along with the proposed causal mechanisms underlying the two models. The weight of research evidence reviewed in this paper suggests that the extended-U hypothesis fits the relationship between moderate thermal environments and cognitive performance. In contrast to the inverted-U relationship, implemention of the extended-U in indoor climate control implies substantial reductions in building energy demand, since it permits the heating and cooling setpoint deadband to expand across the full width of the thermal comfort zone, or even slightly further during emergencies such as peak demand events on the electricity grid. Use of personal comfort systems can further extend the thermostat setpoint range beyond the comfort zone.

Productivity and physiological responses during exposure to varying air temperatures and clothing conditions

“…49 Performance during the finger-tapping test was stable over a specific exposure range likely due to no significant clothing and temperature differences observed at 26°C and 36°C. As indicated in previous research, 4,38,50 the lower motor performance at 16°C in contrast to 26°C and 36°C suggests that cold exposure could undermine manual motor performance. This could be attributed to low skin and tendon temperatures and slow muscle conduction velocity in cold environments.…”

“…high body temperatures (Figures 7and 8) in hot environments. 4,45 Additionally, the results of this study indicated that wearing fewer clothing items had a tendency to increase the sustained attention levels, especially in cold environments. This could be attributed to the significant difference in attention levels between the 0.3 clo and 0.9 clo conditions, with higher performance at 0.3 clo.…”

“…The results also indicated that performance deteriorated more under short temperature exposures than long exposures. 4,40 Hancock et al 39 reported that this could be attributed to an interaction effect between duration and temperature exposure, thus implying some form of habituation. Similarly, the relationship between overall calculation test performance and PMV* (Figure 9) showed an obvious performance change trend line only during the first minute, similar to the trend shown for PPD 47 ; this also suggested that performance was most affected by thermal comfort at the beginning of test.…”

The impact of a view from a window on thermal comfort, emotion, and cognitive performance

“…Some studies found that moderately higher temperatures incurred significantly reduced cognitive performance [103]. However, the effect of moderate heat stress on cognitive performance is still controversial [104]. Therefore, we cannot conclude that the visual connection through a window has a positive impact on the various cognitive abilities of the occupants of the space, but it does enhance the working memory and concentration.…”

Differences in Occupants’ Satisfaction and Perceived Productivity in High- and Low-Performance Offices

“…While some studies document direct linkages of temperature and self-reported performance at work [34][35][36], there is still disagreement about "ideal" set-points. Some authors suggest lower temperatures to address distraction and complaints [37] while others make the case in favor of warmer indoors, without losses on reported perceived productivity [38,39]. The other dimension that has been studied was "ventilation rate" (i.e., supply of outdoor air) due to its indirect influence on workers' performance, caused by the impact of ventilation on thermal comfort, air quality, and concentration of indoor generated pollutants [40,41].…”