Outline principles that define the biological level of analysis and explain how these principles may be demonstrated through research.

Firstly, biological correlates to behaviour, cognition and emotion have been established through mainly the use of case and correlational studies. For example in cognition, Baker et al (1999) examined 18 ordinary children and 26 children diagnosed as having ADHD and found that Phenylethylamine levels were much lower in the ADHD subjects. Later studies done by T. Matsuishi et al (1999) and A. Kusaga (2002) have also shown this and it is now believed that the neurotransmitter Phenylethylamine is a biological correlate to ADHD. The first principle, that “there are biological correlates to behaviour” can be demonstrated by finding the link between a hormone/body part/neurotransmitter to a certain behaviour in the human population.

Secondly as experimenting on humans is often ethically and morally wrong, research on animals can be easier to carry out, and it has been confirmed that animal research can give an insight into human behaviour. To illustrate this, the hormone Oxytocin will be used. Oxytocin is a hormone present in both animals and humans have similar effects to each. For example Bales in 2003 found that prairie voles that received oxytocin had more affectionate behavioral traits and were also more likely to care for pups belonging to other females, and similarly in humans it deepens feeling of attachment. (Kosfeld 2005) The second principle, that “animal research can give us an insight into human behaviour” can be recognized as there are often biological factors that humans and animals share.

Finally “inherit behaviour” can be demonstrated through research in numerous ways. One such study conducted by Ekman (1972) attested that facial expressions aren’t created by culture but are universal and thus had to be biological in origin. Another way in which inherit behaviour may be demonstrated in research is through twin studies such as the Minnesota Twin Study (Bouchard et al 1999). In this study Bouchard showed that identical twins even when reared apart and fraternal twins had very high concordance rates of intelligence and hence this was most likely inherited.