The biological approach argues that prosocial behaviour may be hardwired in the brain.  In other words, there is a biological component of prosocial behaviour that has an evolutionary advantage.  Evolutionary theorists argue that prosocial behaviour is a form of inclusive fitness.  Animal models have also been used to show that the behaviour is “natural” rather than learned – and research on people who show extreme prosocial behaviour have indicated that there may be differences in the brain. In spite of the different ways that the question has been investigated, the biological approach has limitations.

It would make sense that prosocial behaviour is “hardwired” in the brain.  The concept of inclusive fitness argues that by helping other members of its species, an organism increases the overall “fitness” of the gene pool.  This may also be why people are more likely to help the people that are most closely related to them. Kin Selection theory argues that we are more likely to help members of our own family because we want to protect the genes and guarantee that they are passed down. 

This theory, however, is problematic.  Much of the data on people who have carried out altruistic acts are anecdotal.  It is not really possible to know the motivation for helping in most of these cases.  However, Simmons did a study to see whether close relatives were more likely to be kidney donors.  The findings were that parents were most willing to donate a kidney for one of their children, followed by siblings for each other.  The findings showed that children were less likely to donate for a parent and were least likely to donate to a stranger.  Although this is an attempt to empirically test the Kin Selection theory, the situation is only hypothetical. The artificial nature of the questionnaire may mean that the study does not actually predict behaviour.

Since it is difficult to study the biological roots of prosocial behaviour in humans, psychologists have used animal models.  Bartal et al wanted to see if helping behaviour might be hardwired in rats. In their study, they put two rats into a cage together. One rat was free and the other was put into a plastic container. The researchers wanted to see if the free rat would overcome its fear and attempt to open the plastic container. What they found was that the free rat did help the trapped rat – even when there was an alternative of eating chocolates. The researchers argued that empathy is hardwired and this empathy leads to prosocial behaviour.

As animals share several physiological and genetic traits with humans, it may be possible to generalize this study to human behaviour.  And the fact that the study is a highly controlled lab experiment allows for replication – making the theory potentially more reliable.  However, the use of animal models is problematic.  First, it is not possible to know if the rat actually experienced “empathy.”  In addition, although there is some research that shows that there may be a genetic component for empathy, there is no identification of the physiological factors that may play that role in this study.  Instead, it is assumed that since this happens in rats, it must be hardwired. Research done at the Max Plank Institute shows that children as young as 18 months help an adult in need of help.  This could indicate that helping behaviour may be hardwired in people as well.

Another way that researchers have investigated the biological origins of prosocial behaviour is to look at outliers.  Marsh carried out a study on psychopaths (low prosocial behaviour) and people that had donated a kidney to a stranger (high prosocial behaviour). In order to do this, she showed both psychopaths and kidney donors images of faces expressing fear while in an fMRI.  She found that there was a level of activity in the right amygdala in kidney donors, but almost no activity in psychopaths.  This ability to empathize and to react to another person’s fear may actually be hardwired. 

In this case, the researchers used human participants, but she is only indirectly studying actual prosocial behaviour.  There is an assumption made that higher levels of activity in the amygdala will lead to higher levels of distress which will lead to higher levels of prosocial behaviour. This may not actually be the case. However, if the sample size is large enough and the results are consistent, this could be evidence of how one biological factor may play a role in social responsibility.

Since biological arguments of prosocial behaviour are deterministic, we would expect that if social responsibility is in fact hardwired, then we should see people as naturally prosocial.  As we know, this is not the case.  There are many cognitive and social factors that may interfere and prevent people from helping others. In addition, biological arguments do not necessarily explain why people help complete strangers, sometimes at great risk to themselves.  However, animal models and studies with young children do appear to show that there is a “natural tendency” to helping others; it is just a question of whether this explains adult helping behaviour.