But he's wary of the brain cooling theory.

但他对大脑冷却理论持谨慎态度。

What We Say When We Yawn Gallup says his brain cooling theory of yawning is the only theory that explains all these experimental results.

当我们打哈欠时我们说什么盖洛普说他的打哈欠大脑冷却理论是解释所有这些实验结果的唯一理论。