Educerie · IB Diploma · Psychology
Topic 1 — Topic test · mark scheme
Short questions are point-marked; questions 3(b) and 4 are banded. Naming a study is not itself creditable — the study must be used as evidence for a claim.
1Brain and behaviour — 4 marks
(a) [2]
| Names a valid technique: fMRI, PET, EEG, lesion or case study of brain damage, or animal lesioning | 1 |
|---|---|
| Outlines what it measures, e.g. fMRI detects changes in blood oxygenation as an indirect index of neural activity during a task | 1 |
(b) [2]
| Identifies that imaging shows correlation, not causation — activity in a region during a task does not establish that the region performs the function | 1 |
|---|---|
| Develops this, e.g. the region may be active incidentally or as a consequence; the scanner environment is artificial, reducing ecological validity; activity is measured indirectly via blood flow, with poor temporal resolution | 1 |
"It is expensive" is not a limitation on drawing conclusions about localisation and scores 0.
2Heritability — 3 marks
| Approximately 50 % of the variation between individuals in the trait is statistically associated with genetic variation | 1 |
|---|---|
| It is a property of a population, not of an individual — it does not mean half of one person's trait is genetic | 1 |
| It is specific to the population and environment studied and changes if environmental variation changes | 1 |
"The trait is 50 % genetic" scores 0, not 1 — it states the opposite of the concept. Do not award the first mark unless variation (or an unambiguous equivalent) is present.
3Evaluating a study — 8 marks
(a) [1]
| A repeated measures (within-participants) experiment | 1 |
|---|
Accept "quasi-experiment" with justification. "An experiment" alone scores 1; "a correlational study" scores 0.
(b) [5] — banded:
| Band | Descriptor | Marks |
|---|---|---|
| 5 | Strengths and limitations both developed, limitations organised by type (sampling, design, measurement), and a judgement stating precisely how far the evidence reaches | 5 |
| 4 | Both present; judgement general or one area thin | 4 |
| 3 | Limitations only, but well developed and varied | 3 |
| 2 | One or two limitations, asserted rather than explained | 2 |
| 1 | Generic criticism ("the sample is too small") with no development | 1 |
| 0 | Nothing creditable | 0 |
Indicative strengths — repeated measures controls for individual differences in baseline cortisol; physiological measure avoids self-report bias and demand characteristics; 34 of 40 indicates the effect is not driven by outliers.
Indicative limitations — sampling: 40 university students cannot support a claim about "the general population"; design: no control group, and cortisol follows a diurnal rhythm, so part of the change may be unrelated to the task; measurement: cortisol indexes physiological arousal, which is not the same construct as subjective stress.
The measurement point is the discriminating one; award band 5 only where the answer distinguishes arousal from the subjective experience of stress. An answer criticising only the sample size, however emphatically, cannot exceed band 2.
(c) [2]
| A valid change, e.g. add a control group performing a non-stressful task for the same duration; use a more representative sample; add a self-report measure of subjective stress | 1 |
|---|---|
| Explains why it strengthens the study, linked to the specific weakness it addresses | 1 |
The second mark requires the link. "Use more participants" with no reason scores 1.
4The biological approach and depression — 5 marks (banded)
| Band | Descriptor | Marks |
|---|---|---|
| 5 | Biological explanations presented and critically assessed, with evidence the approach cannot accommodate (cross-cultural or historical variation, life events), concluding with an interactionist judgement, ideally naming a mechanism such as diathesis–stress or epigenetics | 5 |
| 4 | Both explanation and critique present; conclusion asserted rather than argued | 4 |
| 3 | Biological explanations described accurately with limited critique | 3 |
| 2 | Description only, or critique only | 2 |
| 1 | Fragmentary relevant knowledge | 1 |
| 0 | Nothing creditable | 0 |
Indicative content — biological: serotonin and the action of SSRIs; twin concordance; elevated cortisol; structural differences. Critique: inferring cause from treatment is the treatment aetiology fallacy; the serotonin evidence is correlational and may run in either direction; MZ concordance well below 100 % shows genes are not sufficient; cortisol may be consequence rather than cause. Beyond biology: cross-cultural differences in prevalence, and change over decades far faster than genetic change permits; life events predicting onset.
An answer that only lists biological explanations cannot exceed band 2, since discuss requires more than one perspective. The strongest answers do not reject the biological approach but bound it — necessary but not sufficient.
Mark distribution
| Split | Allocation |
|---|---|
| By sub-topic | Brain and behaviour 4 · Genetics 3 · Research methods and ethics 8 · Evaluating the approach 5 |
| By objective | AO1 knowledge 4 · AO2 application and analysis 6 · AO3 synthesis and evaluation 10 |
| By command term | Evaluate 5 · Discuss 5 · Explain 5 · Outline 2 · Suggest 2 · Identify 1 |
Total: 20 marks
Educerie · original mark scheme for original questions, written against the published IB syllabus structure for Psychology Topic 1, first assessment 2027. Last reviewed 5 September 2026.