Diminishing Cognitive Capacities in an Ever Hotter World: Evidence From an Applicable Power-Law Description

Modeling and evaluating a series of power law descriptions for boundary conditions of undiminished cognitive capacities under thermal stress.

Thermal stress degrades cognition, but precisely which components are affected, and to what degree, has yet to be fully determined. With increasing global temperatures, this need is becoming urgent. Power-law distributions have proven their utility in describing differing natural mechanisms, including certain orders of human performance, but never as a rationalization of stress-altered states of attention.

From a survey of extant empirical data, absolute thresholds for thermal tolerance for varying forms of cognition were identified. These thresholds were then modeled using a rational power-law description. The implications of the veracity of that description were then identified and analyzed.

Cognitive performance thresholds under thermal stress are advanced as power-law relationships, t = f(T) = c[(T - T_ref)/T_ref]^-α. Coherent scaling parameters for diverse cognitive functionalities are specified that are consistent with increases in deep (core) body temperature. Therefore, scale invariance provides a "universal constant," viz, 20% detriment in mental performance per 10% increase in T deviation, from a comfortable reference temperature T_ref.

We know the thermal range within which humans can survive is quite narrow. The presented power-law descriptions imply that if making correct decisions is critical for our future existence, then our functional thermal limits could be much more restricted than previously thought.

We provide our present findings, such that others can both assess and mitigate the effects of adverse thermal loads on cognition, in whatever human scenario they occur.