Love, Trust, and Evolution: Nurturance/Love and Trust as Two Independent Attachment Systems Underlying Intimate Relationships
Kevin MacDonald, Emily Anne Patch, Aurelio Jose Figueredo (2015)
Previous research has indicated two dimensions of attachment, Avoidance and Anxiety. The main purpose of this paper is to show that Avoidance is better conceptualized as Nurturance/Love within an evolved systems perspective on personality, and that such a reinterpretation provides a straightforward way of interpreting age changes in patterns of sex differences and heritability of attachment. The Anxiety dimension found in attachment research is conceptualized as trust in the face of threat resulting from an Internal Working Model based on experiences with the mother in situations pulling for fear and influenced by individual differences in the personality system of emotionality/neuroticism. Literature is reviewed showing that the two dimensions of Nurturance/Love and Trust have important differences, including different evolutionary functions and phylogeny, as well as different emotions, brain mechanisms, and patterns of sex differences and heritability. This model is investigated using two versions of the Experiences in Close Relationships Survey yielding measures of Anxiety and Avoidance, and the Interpersonal Adjective Scale-Revised-Big 5, the latter chosen because this personality measure is designed to measure Nurturance/Love in a manner more consistent with an evolutionary perspective on close relationships. 635 subjects participated in the study. Results supported the hypotheses of a strong negative association between Nurturance/Love and Avoidance as measured by the ECR and no association between Nurturance/Love and Anxiety as measured by the ECR. Results support the view that there are two systems underlying close relationships, Nurturance/Love as a physiological reward system designed to motivate close relationships and parental investment, and a Trust mechanism that functions to produce expectations of trust that others will help under conditions of personal threat.