Haber & Levin (2001): size perception

The most reported error: candidates attach the labels the wrong way round, stating the opposite of the finding. Token invariant objects (examples the same size) were judged accurately; token variant objects less accurately. Fix: invariant means does not vary, so memory holds the size; define by variation, not familiarity — a bush is familiar yet variant.

A result is what was observed; a conclusion is what researchers infer. Asked for a conclusion, do not restate it. Result: token invariant judged more accurately than variant. Conclusion: perceived size comes from stored knowledge — or, since distance held when size failed, the two are independent. Rule: if you could write it from the numbers alone, it is a result.

'Explain a strength' is not 'describe' one: naming the feature is step one. Use point, why, consequence — name a feature (estimates compared with objects' real measured sizes), say what it does (accuracy did not rest on opinion), then what it means (objectivity rises, so the gap between object types is not a scoring artefact). Naming alone stays in the lowest band.

An improvement question is not a weakness question. Saying 'the sample was narrow' identifies a weakness; the improvement is what you would change — for example testing a wider range of participants (women, children, varied visual experience) so the finding generalises. State the change and what it fixes, not the flaw restated.

A two-mark 'describe' needs two different points; the same finding reworded scores one. 'Invariant more accurate than variant' said both ways is one finding twice. Keep four ready: memory result, field result, unfamiliar worst, distance accurate regardless. On describe the difference, two side-by-side definitions score one — a connective (whereas) earns the second.

When a question names this study, the marks are for its aim, procedure, results or conclusions — not for Gregory's Constructivist Theory or Gibson's Direct Theory (which are themselves widely muddled with each other). Haber and Levin can serve as evaluation evidence about prior knowledge, but 'use the study' must be answered with the study.

Often misread as if both are unreliable. The opposite holds for distance: it was accurate for every object, even when size was judged badly. If size came from distance, good distance would give good size; it did not, so the two are independent. (Relative size is also misread: not 'smaller is always further', but the smaller image of two equal objects looks further.)