Brain function and psychoticism

1. Everything the brain does comes down to neurons passing messages to one another.
2. The pattern of those messages produces your cognitions, meaning what you notice, want and decide.
3. Those cognitions then drive behaviour, so a change in the chemistry between neurons can change how a person acts.
4. The chemicals that carry a message across from one neuron to the next are neurotransmitters.
5. Dopamine is the one that matters here, and it works in pathways that handle reward, motivation and movement.
6. Psychoticism is the Eysenck dimension covering lack of empathy, egocentrism, aggression and anti-social behaviour.
7. Eysenck (1992) put psychoticism down to an overactive dopamine system.

How a message crosses a synapse

1. Neurons never touch, so every message has to cross a tiny gap called a synapse.
2. An electrical impulse travels down the axon of the sending neuron until it reaches the end.
3. There the impulse makes small sacs of dopamine move to the membrane and burst open.
4. Dopamine spills into the synapse and drifts across the gap.
5. On the far side it locks onto receptors on the receiving neuron, which only fit that one neurotransmitter.
6. Fill enough receptors and the receiving neuron fires an impulse of its own, so the message carries on.
7. The dopamine left in the gap is then cleared away, either taken back into the sending neuron or broken down.
8. That clearing resets the synapse, so the next message arrives as a separate signal.

An overactive dopamine system

1. A dopaminergic neuron is one that uses dopamine, and how often it fires is normally held down by inhibition from other neurons.
2. Eysenck argued that in a high psychoticism scorer this inhibition is reduced.
3. With the brake off, dopaminergic neurons fire more often than they should.
4. Each extra firing tips more dopamine into the synapse, so more than usual sits there waiting to bind.
5. More binding at the receptors means the receiving neuron is triggered over and over.
6. You end up with excess dopamine activity right along the pathway, which is what an overactive dopamine system means.

Dopamine and offending

1. Dopamine pathways handle reward, so flooding them makes an immediate payoff feel unusually strong.
2. Feel reward that strongly and you act on it fast, which is the impulsive side of psychoticism.
3. The same over-firing is linked to aggression and to the coldness that leaves a high scorer indifferent to a victim.
4. The evidence for the link is correlational, so high dopamine activity may sit alongside psychoticism without causing it.
5. The strongest criticism of the theory as a whole is individual differences, because plenty of people with high psychoticism never offend and plenty of offenders score low.

Turning this into marks

1. Describe transmission in separate steps, from impulse to release to binding to clearing, because one summary sentence collapses several points into a single one.
2. Name dopamine and the dopaminergic neuron, because writing that a chemical crosses the gap does not secure the knowledge mark.
3. Say overactive and give 1992 for this part of the theory, since the claim is too much dopamine activity rather than too little.
4. The mark most often lost is attaching dopamine to extraversion, when dopamine belongs to psychoticism and extraversion runs through arousal in the cortex.