Numerous behaviors are used by people to express affection. Some theories[3] suggest that affectionate behavior evolved from parental nurturing behavior due to its associations with hormonal rewards. Research also verifies that expressions of affection, although commonly evaluated positively, can be considered negative if they pose implied threats to one's well being. Furthermore, affectionate behavior in positively valenced relationships may be associated with numerous health benefits. Other, more loving type gestures of affectionate behavior include obvious signs of liking a person. Affection can also shape infants' brains.[