# Neurotransmission

> IB Psychology · IB Psychology 2027 First Assessment
> Source: https://www.owlsprep.com/study/ib-psychology-bio-neurotransmission/

The process of neurotransmission and its influence on human behaviour.

## Learning objectives

- The process of neurotransmission and its influence on human behaviour.

## How often is this tested?

Based on OwlsPrep's analysis of official CIE IB_PSYCH P1 past papers (2019–2025): **Neurotransmission** appears **5 times** in the last 7 years — **2.2%** of all P1 questions (5 of 228).

Most-tested forms: Essay: Discuss (22 marks) (3), SAQ: Describe (9 marks) (2).

## Core concept

Neurotransmission is how neurons communicate. An electrical impulse reaches the end of one neuron and triggers the release of neurotransmitter molecules into the synapse; these cross the gap and bind to receptors on the next neuron, making it more or less likely to fire (excitatory vs inhibitory); leftover transmitter is then broken down or reabsorbed (reuptake). Agonists amplify a transmitter's effect and antagonists reduce it. Because mood and behaviour ride on this signalling, changing it changes behaviour — but, because neurons act in combination, any cause-and-effect claim should be treated with caution.

## Key studies

IB Psychology answers must be supported by named studies. Learn these to cite as evidence:

**Fisher, Aron & Brown (2005)** — Dopamine-rich reward pathways (VTA, caudate) were active during romantic love. — *Links a specific transmitter system to an emotional behaviour.*

**Caspi et al. (2003)** — Variation in the serotonin transporter — which controls reuptake — affected depression risk under stress. — *Shows how one step in neurotransmission (reuptake) feeds through to behaviour.*

## Evaluation (AO3)

**Strength — mechanistic and drug-testable** — The process gives testable targets — SSRIs act on reuptake — allowing causal manipulation.

**Limitation — correlational and interacting** — Linking a transmitter to a behaviour is largely correlational, and each transmitter interacts with many systems, so 'more X → behaviour Y' oversimplifies.

## Scope

> **note**
>
> The process and its behavioural link are the focus; broader messenger roles (hormones) are BIO_4, and drug treatments are developed in Health and well-being.

## Common pitfalls

- **Wrong:** Naming a neurotransmitter and its effect without explaining the process of neurotransmission.
  - Why it fails: A frequently penalised misconception in IB Psychology exams.
  - Correct: Credit comes from explaining the mechanism (release → receptor → excitatory/inhibitory → reuptake) and THEN linking the chosen transmitter to a behaviour — not just stating 'dopamine causes pleasure'.

---

From [OwlsPrep](https://www.owlsprep.com) — free study guides for A-Level, IB, AP and IGCSE, written against the official syllabus. Canonical page: https://www.owlsprep.com/study/ib-psychology-bio-neurotransmission/