Social relationships and the management of stress.

Two different types of social relationships exist in mammalian social systems: dominance relationships and social bondings. This article shows that both are crucial for the management of stress. The following general conclusions are derived: (1) In stable social systems, established dominance relationships result in predictable behaviour. As a consequence, low positions in the hierarchy do not necessarily lead to enhanced endocrine stress responses. Under conditions of instability, however, distinct increases in the activities of the pituitary-adrenocortical- and the sympathetic-adrenomedullary systems are found; (2) The ability to establish and to respect dominance relationships is a prerequisite to build up stable social systems. Whether this ability is realized, however, depends on social experiences made during behavioural development. The time around puberty seems to be essential for the acquisition of those social skills needed to adapt to unfamiliar conspecifics in a non-stressful and non-aggressive way; (3) Stress responses can be ameliorated by the presence of members of the same species. This phenomenon is called social support. In general, social support cannot be provided by any conspecific, but the ability to give social support is restricted to bonding partners. In most mammalian species mothers are important bonding partners for their infants. In some species bondings also occur between adult individuals; and (4) On a physiological level the bonding partner reduces the activities of the pituitary-adrenocortical- and the sympathetic-adrenomedullary systems. On a psychological level he/she can be regarded as a 'security-giving and arousal-reducing structure'. This is true irrespective of whether the bonding partner is the mother, in the case of an infant, or a male or a female in the case of an adult individual.