Discuss the relationship between genetics and behaviour.

Refer to the paper 1 section B assessment criteria when awarding marks. These can be found under the “Your tests” tab > supplemental materials.

The command term “discuss” requires candidates to offer a considered review of the relationship between genetics and behaviour.

Candidates may address one behaviour to demonstrate depth of knowledge or may address more than one behaviour to demonstrate breadth of knowledge. Both approaches are equally acceptable.

Relevant areas of the relationship between genetics and behaviour may include, but are not limited to:

• mental health
• intelligence
• aggression
• personality.

Relevant studies may include, but are not limited to:

• Bouchard et al.’s (1990) reports on the “Minnesota Twin Studies”
• Plomin and Petrill’s (1997) research into the heritability of IQ in twin and adoption studies
• Kendler et al.’s (2006) twin study on genetics and depression.
• Caspi et al.’s (2003) study on genes and depression
• Weissman et al.’s (2005) longitudinal family study on depression.
• Gilbertson et al.’s (2002) study on PTSD in veterans.

Critical discussion may include, but is not limited to:

• methodological and ethical considerations related to research into the relationship between genetics and behaviour
• how the research findings have been interpreted and applied
• implications of the research findings
• assumptions and biases
• areas of uncertainty
• supporting and/or contradictory evidence.

SL:

In general, candidates demonstrated a good understanding of the relationship between genetics and behaviour and there were a wide range of studies used in response to this question. Those occurring most frequently were Bouchard et al.'s (1990) reports on the "Minnesota Twin Studies", Kendler et al.'s (2006) twin study on genetics and depression, and Caspi et al.'s (2003)study on genes and depression. 

The best answers tended to focus on the effect of genes on one behaviour (for example, intelligence, depression) which allowed them to explore in depth the issue of nature versus nurture and the limitations of genetic research. Strong answers demonstrated accurate and detailed knowledge and understanding of how behaviours can be genetically determined as well as understanding the research methods involved such as twin and kinship studies. The best candidates also demonstrated an understanding of the nature versus nurture debate and were able to explore the opposing environmental factors and explore interactionist approaches such as diathesis stress.

Some high-quality answers included reference to DNA and how it is passed down from one generation to the next, reference to the Falconer model and reference and explanation of genetic predisposition/vulnerability and epigenetics. However Wedekind (1995) was also often used inappropriately without linking to major histocompatibility complex (MHC) gene.

Weaker answers made reference to evolutionary studies not well linked to genetics (Fessler, Curtis, Ekman) or a lack of a clear presentation of relevant research with a link to genetics. Candidates made generic evaluative points relating to the methodology of studies presented rather than critically discussing the issue of the influence of genes on behaviour which limited their critical thinking marks.

HL:

This was the most popular choice of essay question. On the whole, candidates showed competent knowledge and understanding of the relationship between genetics and behaviour. Well-written responses provided detailed explanation of the conceptual context underlying the relationship between genetics and behaviour with the majority of responses focusing on depression or aggression. The higher scoring responses provided research that was clearly described and effectively used. Such responses also evaluated the studies well but also developed the critical thinking required for a top-quality response by discussing applications and implications of research and acknowledging discussion points such as reductionism versus interactionism, diathesis-stress, etc.

Weaker responses were those that did not address the command term so critical thinking in terms of balanced discussion of the relationship between genetics and behaviour was lacking. These responses showed very limited use of relevant terminology. Such responses focused on methodological evaluation that was not elaborated on or justified or just focused on ethical issues of the research which were of minimal relevance in this essay. Unfortunately, many responses were awarded very low marks as they focused on other biological factors such as evolution so that studies selected were not well-linked to genetics such as Fessler (2006) or Curtis (2004). Furthermore, Wedekind (1995) was also often used inappropriately without explicitly linking to the major histocompatibility complex (MHC) gene.