Localization of function
IB Psychology· Biological approach· 14 min read
1. Core concept
Localization is the idea that specific mental functions are handled by specific brain areas — for example the hippocampus for forming new long-term declarative (explicit) memories. The evidence comes mainly from brain-damage case studies and imaging. The opposite pole is that some functions are distributed across networks and the brain can reorganise (plasticity), so strict localization is best treated as a starting model rather than the full story.
2. Key studies
IB Psychology answers must be supported by named studies. Learn these to cite as evidence:
Scoville & Milner (1957)
Case study of H.M.: removal of the hippocampus caused severe anterograde amnesia for new declarative memories but left procedural memory intact. — Localises the formation of new declarative memories, and shows memory is not a single store.
Saxe & Kanwisher (2003)
fMRI localised reasoning about others' beliefs to the temporo-parietal junction. — Imaging evidence localising a higher social-cognitive function.
3. Evaluation (AO3)
Strength — converging evidence — Case-study damage and imaging point to the same regions, strengthening the localization claim.
Limitation — cases + plasticity — Case studies like H.M. are single and unrepeatable (generalisation problem), and plasticity means damaged functions can partly relocate — so localization is not absolute.
4. Scope
5. Common Pitfalls
Wrong move:
One area is solely responsible for a function.
Why:
A frequently penalised misconception in IB Psychology exams.
Correct move:
Most functions involve networks; localization identifies a critical hub, but lesion evidence and plasticity show other areas contribute or can take over.
Going deeper
- Neuroplasticityneuroplasticity is the counter-pole — functions can move (BIO_8).
- Brain-imaging techniquesbrain imaging is the main non-lesion evidence for localization (BIO_3).