查尔斯达尔文在他的着作“人与动物的情感表达”中观察到狒狒打哈欠以威胁敌人。在暹罗斗鱼和豚鼠中也报道了类似的行为。另一方面，Adelie企鹅打哈欠是他们求爱仪式的一部分。 Alessia Leone和她的团队进行的一项研究表明，在社交环境中有不同类型的打哈欠来传达不同的信息（例如，移情或焦虑）。 Leone的研究涉及一种称为gelada的猴子，但人类的打哈欠也可能因其功能而异。很明显，打哈欠是由生理因素引起的。神经递质水平的波动引发哈欠。打哈欠的生物学益处在其他一些物种中很明显，但在人类中并不那么明显。至少，打哈欠会短暂地提高警觉性。在动物中，打哈欠的社交方面有充分的记录。虽然打哈欠在人类中具有传染性，但研究人员尚未确定打哈欠的心理是否是人类进化的遗留物，或者它是否仍然起着今天的心理作用。
新加坡国立大学Assignment代写：社交环境
In his book “Emotional Expressions of Humans and Animals”, Charles Darwin observed yawning to threaten the enemy. Similar behavior was reported in Siamese fighting fish and guinea pigs. On the other hand, Adelie penguins yawning is part of their courtship ritual. A study by Alessia Leone and her team showed that there are different types of yawning in a social environment to convey different information (eg, empathy or anxiety). Leone’s research involves a monkey called gelada, but human yawning may also vary depending on its function. Obviously, yawning is caused by physiological factors. Fluctuations in the level of neurotransmitters trigger yawning. The biological benefits of yawning are evident in other species, but not so obvious in humans. At the very least, yawning will temporarily increase alertness. In animals, the social aspects of yawning are well documented. Although yawning is contagious in humans, researchers have not yet determined whether the mentality of yawning is a legacy of human evolution, or whether it still plays a psychological role today.