Evolutionary explanations of Anorexia

Question 1

Description

Answer 1

-Evolutionary explanations explain the behaviours/ characteristics in terms of their adaptive advantage, and must have some genetic basis. The EEA explains how characteristics which make it more likely that an individual would survive, reproduce and pass on the genes question to offspring, thus securing the survival of those genes.

Question 2

The reproductive suppression hypothesis

Answer 2

• One physical effect of anorexia is amenorrhoea (absence of the menstrual cycle)
• Wasser and Barash suggest that this is an adaptive mechanism because if they give birth when environmental conditions are unfavourable, e.g. in times of famine, this would be evolutionarily disadvantageous.
• So the new born would be put under pressure due to scarce resources threatening the survival of existing offspring.
• So infertility, brought about control of food intake, might have provided our ancestors to produce children at the optimum time.
• Surbey also suggested that females adaptive ability to alter the timing of reproduction to best fi the demands of the environment can be related to nowadays we will prevent pregnancy to fit our environment the best so that it will benefit our offspring.

Question 3

The adapted to flee famine hypothesis

Answer 3

• Guisinger proposes that some features of anorexia are denial of starvation and hyperactivity and that these have evolved as a part of adaptive mechanisms.
• In the EEA and when the food sources were in short supply, there would be survival benefits to seeking food elsewhere.
• Therefore to migrate and find food efficiently respond to starvation.
• Instead to feel energetic and deny starvation would help successful migration and survival. She proposes that a very low body weight causes some individuals bodies to respond as though they must migrate from famine.

Question 4

Holland et al. (evaluation points)

Answer 4

• Suggests genetics cause of anorexia which suggests evolution because genes pass on through evolution. (indirect support)
• If evolution has prepared some people to develop AN then this has be to be genetically encoded.

Question 5

Menarche (the onset of puberty) is delayed in prepubertal girls

Answer 5

-Supports the reproduction suppressive hypothesis

Question 6

Mrosovsky and Sherry (1980)

Answer 6

• Found that many species stop eating, even though food is readily available, when they migrate.
• Supports AFFH
• However this is an animal study so lack generalisability.

Question 7

Pierce (1992)

Answer 7

• Found that rats which were starved in the laboratory would then ignore their food and exercise regularly.
• Supports AFFH
• Again animal study- generalisability issues

Question 8

Keel and Klump (2003)

Answer 8

• Meta analysis of cross cultural studies of eating disorders, they concluded that anorexia is not a culture bound disorder. It is found in all of the cultures studied (even without western influences), however the frequency is proportional to the degree of influence. More westernised = more anorexia found.
• Supports evolution as not only in westernised society; however only a partial explanation = needs socio-cultural explanations

Question 9

Bell (1985)

Answer 9

• During the middle ages many pious women fasted excessively, leading to ‘holy anorexia’ - The Roman Catholic church canonised over 85 very thin saints who were recognised for their seemingly miraculous ability to live with very little food.
• Supports evolution AN as not only in modern society
• However you could argue that as they were being praised for being thin it was encouraged by society and religion rather than through evolution.

Question 10

Guisinger claims that the AFFH…

Answer 10

• ‘Relieves therapists of the need to search for familial reasons for anorexia.’ A struggle for patients is often reported in terms of the ‘worried and uncomprehending family.’ and also the powerful biological urge to avoid food. Awareness of this causal influence can help treatment and encourages parents to be more compassionate.
• Ethical strength- reduces guilt for the anorectics

Question 11

The reproduction suppression hypothesis evaluation points

Answer 11

• The RSH only explains AN in females whereas the AFFH accounts for both men and women
• But a mans fertility rate is also effected by AN (low sperm count). But postponing fertility only has an evolutionary benefit for women because of the risk of death in childbirth.