During a research study, participants were told that they "were likely to end up alone later in life." those led to feel excluded became not only more likely to engage in self-defeating behaviors, such as underperforming on an aptitude test, but also less able to regulate their behavior. these destructive behaviors show the effects of

I believe the answer is: ostracism

ostracism refers to the act of knowingly excluding oneself from the social group.
If we live without any support of others, we would tend to perceive the problems in our life to be bigger that they actually are since we have to face them all alone. This will increase the likelihood of depression and self defeating behaviors.

South central region