Sample response

Psychologists in the biological approach try to find specific biological correlates of behavior. Different methods are used to investigate how biological factors such as brain structures or hormones may influence behavior. Two research methods that are used in the biological approach are experiments and the case studies.

Experiments are often used by researchers within the biological approach to establish a cause and effect relationship. Experiments start with a hypothesis. To test the hypothesis, researchers manipulate an independent variable to measure the effect on a dependent variable, while attempting to keep all other variables constant.. Participants are randomly allocated to either a treatment group (where the IV is manipulated) or a control group (where the IV is not manipulated).

One example of an experiment was done by McGaugh and Cahill.  They wanted to see the effect of the hormone adrenaline on the creation of emotional memories. They hypothesized that adrenaline interacts with the amygdala to create emotional memories. Participants were randomly allocated to one of three groups.  Each group say a series of slides, but in one group (the control), a boring story was read.  In the treatment group, they heard a story about a boy who was in a car accident and had his feet severed. A very emotional story.  The third group heard the traumatic story but were given beta-blockers which inhibit the release of adrenaline.  Two weeks later, the participants were asked to answer a series of questions about the slides.

The researchers found that the participants who had heard the traumatic story remembered more details than the unemotional story. They also found that those that had heard the traumatic story but had taken beta-blockers remembered no more than those that heard the boring story.  The experiment indicates that adrenaline may play a significant role in the creation of emotional memories.

Strengths of experiments include that they attempt to control extraneous variables.  By doing so, they have high internal validity – that is, you can say that the IV most likely caused the change in the DV.  In addition, because they are highly standardized, they can be replicated.  This allows other psychologists to test the reliability of the results.

However, experiments suffer from low ecological validity due to the highly controlled environment in which the behaviour is observed. The procedures are often highly artificial – such as the one by McGaugh and Cahill. It could be argued that the results do not show us how adrenaline functions under normal conditions. Often experiments have the problem of demand characteristics, where the participants figure out the goal of the experiment and then act in a way to “help out” the researcher.  However, in biological research this is often not possible.  Blocking adrenaline seems to make it impossible for the participants to create strong memories of the story, regardless of whether the participants know the aim of the study. Finally, experiments in the biological approach often take a reductionist approach, looking at the effect of a single IV on a DV.

Another method used in the biological approach is a case study. This is an in-depth study of an individual – often with a particular condition such as brain damage. The researchers study a case in order to know more about how a particular brain structure influences a behaviour. In case studies no IV is manipulated, so it is not possible to establish cause-effect relationships. Case studies use triangulation – many different research methods (observations, interviews, surveys) are used in a single case, an often different researchers or sources or data are used.

Milner studied H.M. who due to epileptic attacks had tissue from the medial temporal lobe, including the hippocampus, removed. The result was that H.M could not store new semantic or episodic memories - he suffered from anterograde amnesia. To study HM, the researchers carried out tests (like an IQ test), observed his behaviour, interviewed him and eventually an MRI. The researchers were able to conclude that the hippocampus plays an important role in the transfer of short-term memory to long-term memory.

Case studies collect rich data.  They are also a more holistic approach to a research question.  Because case studies use triangulation, the validity of the results is confirmed within the study. The results are considered credible. However, there are limitations of case studies.  When studying participants with brain damage, there are ethical concerns about whether informed consent can be given.  In the case of H.M. who could not remember what happened 5 minutes ago, this is a problem. Another limitation is that results from case studies cannot be used to make generalizations about human behavior because they represent unique individuals. However, there are other case studies that show that the hippocampus is very important in storage of memory and support Milner’s findings. When several case studies are used together, they can show us important biological correlates of behavior.

Using a combination of methods allows researchers to get a better understanding of the role of biological factors on behaviour.  Case studies such as that of H.M. give invaluable insight into conditions that could not otherwise be studied and the experimental method can be used to establish cause-effect relationships between biological factors and behaviour.

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