Hi. We all know that depression is a major disorder of the mind, yet it's quite prevalent. Many theories have been proposed to explain how such an apparently maladaptive trait could have evolved and become so widespread. And I have my own theory:
Depression evolved because while it's bad for the individual, it is good for the group. Think back to how our ancestors evolved. Depression typically happened when an individual experienced something bad that reduced his/her fitness, for example, a man lost a limb (something that reduced his fitness) when hunting for an animal, and he became depressed. Or when a child was born with disfigurement of his/her face (a reduction of their fitness), he/she would also become depressed. These people's depressed states caused them to eat less, which means more food for the group, and they would also lose the motivation to do anything, which means they would not take their anger or resentment out on their group or otherwise do anything to disrupt their immediate social environment. They also withdrew from sex, which leaves more partners available for the healthy individuals. So, depression evolved because it prevented organisms that have been struck down by life from threatening the survival of the group. We can actually see a modern-day example of the benefit of depression. We all know the phenomenon of a "loser", who is usually male. Such a male typically has inferior genetics, and he cannot secure a mate. So, he has reduced fitness. Nature has selected for such men to experience depression, because if they aren't depressed, and instead exhibit anger that is very frequently seen with men, they could very well walk into a crowded shopping mall with a gun and start shooting people. Depression would cause these men to become too sad to do anything, and this would have preserved the group.
This post was edited by JessiWan on Jul 25 2023 07:30pm