Table 1.

Empirical tests of the brain cooling hypothesis.

Prediction	Confirmed	Species (area)
(1) Rises in brain temperature should precede the onset of yawns	– Gallup and Gallup (2010)	– Humans (oral temperature)
	– Shoup-Knox et al. (2010)	– Rats (prelimbic cortex)
	– Shoup-Knox (2011)	– Rats (prelimbic cortex)*
(2) Decreases in brain temperature should follow yawns	– Gallup and Gallup (2010)	– Humans (oral temperature)
	– Shoup-Knox et al. (2010)	– Rats (prelimbic cortex)
	– Shoup-Knox (2011)	– Rats (prelimbic cortext)* (preoptic area)

^*Indicates a replication of this effect in an independent sample of this species.