The benefits of fainting

An odd survival strategy

The benefits of shooting yourself in the foot are not always apparent at first glance.  A number of soldiers have shot themselves in the foot during a war to seek a medical discharge.  When the chances of getting killed are enormously high then this otherwise odd behaviour seems like a very logical tradeoff.  Likewise, when a person faints the ability to react to danger in a timely manner is lost.  It is hard to imagine how such a fainting strategy improves survival.  But like a self-inflicted injury during war there maybe benefits that are not immediately obvious.

When a person faints they lose the ability to stand and may fall to the ground.  After fainting the unconscious body may appear to be dead.  This may deter further attack in some circumstances.  For a potential attacker, the defenceless target may be ignored as it is no longer a source of fear.  The downside is that for some attackers hunger is the driver and fainting will not help.

Fainting as a medical strategy

The fainting response is caused by a significant drop in blood pressure and will reduce blood loss and facilitate blood clotting.  If the person is wounded then this can increase survival.  So if help is near at hand and you are bleeding significantly, then one of the best things you can do is place the back of your hand on your forehead and faint gently to the floor.

Source:
Ditto, B., Gilchrist, P. T., & Holly, C. D. (2012). Fear-related predictors of vasovagal symptoms during blood donation: it’s in the blood. Journal of behavioral medicine, 35(4), 393-399.