Monoamines and decision making during contests in the hermit crab Pagurus bernhardus

During fights animals are expected to make a series of strategic decisions that involve interactions between information about the contest and the individual's nervous system that produce a change in behaviour. Biogenic monoamines such as serotonin ('5-HT') and dopamine are thought to prime decision-making centres for appropriate responses during aggressive interactions in crustaceans, and circulating levels vary both between individuals and during agonistic encounters. Aminergenic systems operate in diverse animal taxa and in this study we assayed circulating levels of S-HT and dopamine following shell fights in the common European hermit crab, Pagurus bernhardus. The two roles in these fights, attacker and defender, perform different activities but, in both, S-HT increased and dopamine declined in response to engaging in a fight. In defenders but not attackers, giving up was correlated with low 5-HT and dopamine. In attackers, motivation to initiate a fight was positively correlated with dopamine levels. Circulating monoamines are therefore involved in decision making during these aggressive encounters. (c) 2007 The Association for the Study of Animal Behaviour Published by Elsevier Ltd. All rights reserved.

Information gathering and decision making about resource value in animal contests

Contestants are predicted to adjust the cost of a fight in line with the perceived value of the resource and this provides a way of determining whether the resource has been assessed. An assessment of resource value is predicted to alter an animal's motivational state and we note different methods of measuring that state. We provide a categorical framework in which the degree of resource assessment may be evaluated and also note limitations of various approaches. We place studies in six categories: (1) cases of no assessment, (2) cases of internal state such as hunger influencing apparent value, (3) cases of the contestants differing in assessment ability, (4) cases of mutual and equal assessment of value, (5) cases where opponents differ in resource value and (6) cases of particularly complex assessment abilities that involve a comparison of the value of two resources. We examine the extent to which these studies support game theory predictions and suggest future areas of research. (C) 2008 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Professional perspectives on decision making about the long-term care of older people

With the increasing pressure on social and health care resources, professionals have to be more explicit in their decision making regarding the long-term care of older people. This grounded theory study used 19 focus groups and nine semi-structured interviews (99 staff in total) to explore professional perspectives on this decision making. Focus group participants and interviewees comprised care managers, social workers, consultant geriatricians, general medical practitioners, community nurses, home care managers, occupational therapists and hospital discharge support staff. The emerging themes spanned context, clients, families and services. Decisions were often prompted by a crisis, hindering professionals seeking to make a measured assessment. Fear of burglary and assault, and the willingness and availability of family to help were major factors in decisions about living at home. Service availability in terms of public funding for community care, the availability of home care workers and workload pressures on primary care services influenced decision 'thresholds' regarding admission to institutional care. Assessment tools designed to assist decision making about the long-term care of older people need to take into account the critical aspects of individual fears and motivation, family support and the availability of publicly funded services as well as functional and medical needs.