Perception Leads Reality - The Effect of Temperature on Perception

Perception, defined as the organization and identification of sensory information in order to represent and understand our environment [1], is in a state of constant flux. It should come as no surprise then, that even our body temperature can affect our perception.

Experiments have shown that our perception of time speeds up when our body temperature is increased above normal and decreased when our body temperature is cooled below normal [2]. The most common hypothesis for this phenomenon is that we have a temperature-sensitive biological or chemical clock and that temperature manipulation produces changes in arousal. Perhaps this explains why when we have a fever our sense of time is also warped!
Hypothermia also seems to affect our visual perception. In an EEG study of face recognition, it was found that hyperthermia accelerates the early stages of visual perception. In this experiment, upright and inverted faces were presented to two groups of participants, a control and a hyperthermic group. The hyperthermic group had earlier latencies in the two EEG peaks of interest, the P1 and N170.  However, the specific face sensitive response, the N170 had a significantly smaller amplitude in the hyperthermia group when compared to the controls. Furthermore, the inversion effect of the faces on the N170 remained unaffected. This result suggests that although hyperthermia impairs the detection of faces in the visual field and their initial streaming to face-specific structural mechanisms, the subsequent face-specific configural processing remains unaffected [3].
With respect to odor and taste perception, while the exact effect of our body temperature on odour perception remains unexplored, we know that temperature or heating itself increases the odour of a substance due to the release of volatile molecules. Furthermore, odour ratings rise when the temperature increases when samples are sniffed. However, ratings made retronasally rise only for solids and not liquids. This is thought to be because liquids reach body temperature faster than solids when placed in the mouth. [4]. As the prominent English writer Aldous Huxley says, “There are things known and there are things unknown, and in between are the doors of perception.” 

[1] Schacter, Psychol, 2011
[2] Wearden and Penton-Voak, Q J Exp Psychol B,1995
[3] Sun et al, Int J Hyperthermia, 2012
[4] Delwiche, Food Quality and Preference, 2004

by Apoorva Rajiv Madipakkam, Alumni AG Sterzer
This article originally appeared 2013 in CNS Volume 6, Issue 3, Heat or Cold: What's Good for the Brain?