Nurturance and care providing constitute a cornerstone of human culture. MacLean has considered the development of care giving in terms of the evolution of nursing. He points out that specific developments in the limbic system facilitate these behavioural routines. Care-giving behaviour is inherently caught up in the tangle of both the promotion of the infant's survival and the promotion of the care giver's survival. It is not always mediated by prosocial affects. Care-giving behaviour can also be brought under cognitive control and manifest in the absence of any strong prosocial affect. There are two central affects namely empathy and sympathy - that mediate caring responses. Sympathy can be elicited by projection whereas projection reduces accurate empathy. The evolutionary root of sympathy is probably central to attachment and caring behaviour, where speed and urgency of response have been more important than insight. In many forms of psychotherapy, the therapist attempts to develop skills of accurate empathy.