With reference to one study, outline the effect of one agonist or one antagonist on human behaviour.

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

The command term “outline” requires candidates to give a brief account or summary of the effect of one agonist or one antagonist on human behaviour.

An agonist is a molecule that can bind and activate a receptor to induce a biological reaction. Candidates may either use an example of an endogenous agonist, such as a neurotransmitter, or an exogenous agonist, such as a drug. Antagonists inhibit the activation of receptor sites.

Relevant studies should demonstrate the effect of the chosen agonist or antagonist. Relevant research includes, but is not limited to:

• Rasmusson and Dadar (1979), Antonova et al. (2011); Rogers and Kesner (2003) – scopolamine and its effects on spatial memory consolidation
• Martinez and Kesner (1991) – physostigmine as an ACh agonist in the consolidation of spatial memory
• Leyton (2013) – alcohol as a dopamine agonist and increased activity in the nucleus accumbens
• Guo et al (2014) – dopamine / Romach et al (1999) – dopamine antagonist
• Crockett et al (2010) – SSRIs as a serotonin agonist in the study of prosocial behaviour
• any study of an effect of a neurotransmitter on human behavior.

If a candidate outlines the effect of one agonist or antagonist without reference to a relevant study, award up to a maximum of [5].

If a candidate addresses a relevant study but does not outline the effect of one agonist or antagonist, award up to a maximum of [4].

Animal research may be used to describe an effect of an agonist or antagonist, but the response must then be linked to human behaviour. If there is no explicit link to human behaviour, a maximum of [6] should be awarded.

If a candidate outlines the effect of more than one agonist or antagonist, credit should be given only to the first agonist or antagonist.

HL:

There were many strong responses that focused on the role of agonists or antagonists on behaviour. However, many candidates struggled to apply terminology correctly, using terms like "excitatory" and "inhibitory" neurotransmitters as synonyms for agonists and antagonists.

Candidates often did not understand why SSRIs are considered indirect agonists and so were not able to clearly outline the effect of the drug. Some candidates also incorrectly identified tryptophan as an agonist for serotonin when describing Passamonti et al. (2012)

Although animal research was acceptable, it needed to be linked to human behaviour. Often, candidates did not make this link effectively.

SL:

The majority of responses were able to clearly outline the role, function and effects of agonists and/or antagonists on human behaviour. Top band responses also provided a detailed description of neurotransmission and the role of neurotransmitters with regards to human behaviour, as well as giving an appropriate example. The majority of responses used Antonova et al. (2011), Crockett et al. (2010) and Martinez & Kesner (1991). Weaker responses did not explicitly link the use of animal studies to human behaviour, or provided a generic statement concerning the link.

There were many candidates who described hormones instead of neurotransmitters, who confused agonists with antagonists or who described irrelevant research from other approaches, many responses provided unnecessary descriptions and evaluations of concepts and research.