Do we form tribes for the purpose of surviving in a harsh environment, or as an attempt to group with others similar to ourselves and to exclude all others? (redeeminggod.com)
The study, as well as several others similar to it, prove that the mental attitude that you approach anything with makes a difference. (elearningindustry.com)
He regards this as part of our general psychological need to bond with others similar to ourselves, even if the other is a dog. (discovermagazine.com)