Note: This was in a first draft of our textbook IB Psychology: A Student’s Guide but was later removed because of it’s complexity in nature, and the fact that it doesn’t thread as well as other studies on system one and two decision making.

Morality and Decision Making

The prefrontal cortex plays a crucial role in executive functions, also known as cognitive controls.

Our behaviour and our mental processes are closely related; most behaviour involves a conscious decision to act or not. So we’ve seen already that murderers have lower function in their PFC and people with damage to their PFC have higher levels of aggression and violence than controls. We’re now going to look more closely at the relationship between the PFC, morality and decision making.

Understanding cognition is an important part of the IB Psychology course and when studying criminal behaviour we can’t focus solely on the biological factor. Understanding the cognitive (i.e. mental processing) factors involved in violent and aggressive behaviour is important to fully appreciate further the relationships between our brain, our mind and our behaviour. Cognition is a broad term and so in this context we’re going to focus on moral judgements and decision making.

In order for society to function properly it requires citizens to understand what morally acceptable and unacceptable behaviour is. Morality is about knowing what is right and wrong. Acting violent and aggressive towards one another while not inherently immoral, is not beneficial for society. If people don’t understand morals and socially acceptable behaviour, perhaps they would be more likely to act in unacceptable ways (and thus break the law). Thus, when confronted with decisions about how to act in situations that require considerations of moral implications, perhaps violent criminals aren’t as good as “normal” people, which is why they respond violently when put in situations where they are provoked.

Many criminals are also diagnosed with anti-social personality disorder (ASPD). Humans are social animals which means we like to work in groups and behaving in a socially acceptable manner is valued by most members of society.

Research has suggested that damage to the PFC during childhood results in an impairment of developing knowledge about morals and making ethical judgements (Anderson, 1999 in Ciaramelli). But how does the prefrontal cortex promote behaviour and making decisions to act in appropriate ways that will promote social and moral behaviour?

Let’s look at some moral dilemmas and see how you’d respond? Also, take a note of how long it takes you to respond to the following scenarios and their questions:

Scenario 1 – The Trolley Scenario: You are standing near train tracks and you see a runaway train carriage (a trolley) heading towards five people – if it hits them it will kill them instantly. You can save those five people by pulling a lever on the tracks next to you that will divert the carriage from the track it’s currently on (heading towards the five people) onto another track. However, there is one person standing on the other track and they will be killed if you pull the lever.

Is it appropriate to save the five people by pulling the lever and killing one person?

Scenario 2 – The Footbridge Scenario: You are standing on a footbridge that is going over the train tracks and something similar to the scenario above is happening – a trolley is heading towards five people. You can push someone off the footbridge where you’re standing to hit the carriage and the trolley will stop, saving the five people’s lives but killing the person you pushed.

Is it appropriate to save the five people by pushing the one person to their death?

Which of these scenarios did you find easier to answer? Did one take longer than the other?

Most people take longer to contemplate the footbridge scenario than the trolley scenario. You would feel more guilt, wouldn’t you, because it was you that had to directly kill the person on the footbridge.

The two scenarios above are examples of moral dilemmas. Moral dilemmas are situations or scenarios where a person is faced with two or more conflicting values or requirements. Do you kill one person to save the life of five others? These dilemmas take careful consideration. They are very popular scenarios in discussions around ethics and morals. You might come across these in your TOK classes.

The footbridge scenario is an example of a personal moral dilemma. A personal moral dilemma because it involves some moral violation of another person. It causes violation through bodily harm to someone else directly. The personal moral dilemmas involve a lot emotion and careful reasoning.

The trolley is an example of an impersonal moral dilemma – your action to pull the lever will save five people and the person killed wasn’t done so directly by your own hands. It has less emotional implications than the footbridge dilemma.

Don’t worry – there is no generally accepted “right” answer to these scenarios. When making moral decisions that have serious implications individuals must consider the situation in regards to their own thinking and values.

When confronted with these moral dilemmas, research has shown that people generally take more time to consider and think about their response to the personal moral dilemmas. Moreover, when doing these tasks in an fMRI machine there is high activity in the prefrontal cortex. And it’s not just the decision making that is the reason the PFC is being activated, it is the moral and emotional implications that is activating the PFC. Researchers have concluded this by conducting studies where they also give non-moral dilemma questions (e.g. is it appropriate to buy a new TV instead of having your broken one repaired for the same price?) These questions still require thinking and planning, but the same level of emotion is not involved as it’s about a TV – not other people’s lives!

The studies using these scenarios generally involve presenting a selection of moral (personal and impersonal) dilemmas and non-moral dilemmas on a screen while participants are in an fMRI machine. Their response time (RT) and their brain activity are measured as the contemplate the scenarios.


Here’s the trolley problem from BBC4.