Attachment theory is perhaps the most well-researched framework for understanding how early life experiences shape the developing child and his or her future social functioning. Influential cultural psychologists and anthropologists object to it, however, claiming it to be incompatible with non-Western child rearing practices and values. A rapprochement is attempted here based on a biologically informed understanding of attachment patterns as relatively enduring reflections of reinforcement schedules (i.e., continuous, intermittent, and extinction) for security-seeking behavior. Those schedules give rise to, respectively, the three primary attachment classifications described by attachment theorists (secure, insecure-anxious, and insecure-avoidant). Moreover, depending on their distribution within a population, those patterns establish the group-level payoff structures that define individualist and collectivist cultures. In this way, attachment and culture reflect the same evolutionary impulse-security-seeking. They interact as hierarchically interlocked contingencies, each serving as a deep source of stability for the other. Neither is cortically represented-attachment is primarily embodied (subcortical, scheduleinduced) and culture is distributed (group-level payoffs). The products of culture (rituals, customs, social practices) are cortically represented. This bidirectional biobehavioral-cultural model establishes the cultural compatibility of attachment theory, and challenges some evolutionary conceptions of it.