Affiliative temperament : Concept , neurobiology and implications for antisocial behaviors

Introduction Humans are inherently social, and one can develop social bonds with other people around himself in order to adapt to the complex social environment (Young, 2008). Although humans share with animals many of the same types of social behavior such as affiliation and aggression, the establishment of hierarchy and territoriality, human affiliative behaviors are essential for the physical and psychological wellbeing and normal development of individuals, and impairments in these behaviors are clearly associated with maladaptive interpersonal patterns and psychiatric disorders (Bora, Yucel & Allen, 2009). Affiliation research dramatically increased throughout the 1990s, with a broadened emphasis on a variety of attachments including the mother-infant bond, pair bonding, and colony membership (Hammock & Young, 2007). Today, researchers in this area seek to understand the integration of hormonal states and neural circuits in regulating complex behaviors. Along with this idea, this paper will firstly specify the concept of affiliative temperament in theory. The second section will review the neurobiology of affiliative temperament with the integration of the MNS, the dopaminergic system and the neuropeptides. The third section will discuss implications of affiliative temperament for antisocial behaviors. Finally, the future directions will be mentioned. Affiliative temperament as an individual construct Affiliation behaviors are very intricate and comprise phenomena at multiple levels of analysis including physiological and psychological systems, whole individuals, short-term interactions between individuals, longer-term relationships, and groups (Weinstein & Capitanio, 2005). So it is a challenge undertaking to study their neurobiological bases. Recently, Bora et al. (2009) have reviewed the neurobiology of human affiliation behaviors mainly about human brain imaging and neuropeptide researches, which is helpful for us to understand human psychiatric disorders from neurobiology. However, we know that the brain is functional. Behaviors are not different, but the neural mechanism underlying these behaviors may be similar. That is, one neural mechanism may govern many similar behaviors. Therefore, it is unreasonable to study the neural mechanism of each behavior and almost impossible for people to study a myriad of human affiliation behaviors one by one considering researchers’ limited time and funds. One of scientific methods is to introduce some constructs. They can gather up behaviors of the similar neurobiological basis together. Methodologically, people sample typical behaviors from a construct to investigate, and then infer the neurobiology of more other similar behaviors belonging to the same construct, which makes it easier to research the relationship between brain and behaviors. For example, based on animal studies, Depue et al. (2005) have brought forward a neurobiological model about affiliative bonds from a personality point of view. However, the default of personality research is not to explain affiliation early in life, because the newborn’s personality is not innate, but gradually shapes as time goes by. In addition, personality is subject to a great deal of experiential influences, and involves abilities, standards and values, selfconcepts, and defense mechanism. In contrast, temperament emerges at birth and does not include those compounds. In what