Purpose of the Questionnaire (Scale)

The Semantic Categorization Test (SCT) was developed by Rosch and Mervis (1975) and evaluates the organization of semantic memory, the ability for conceptual categorization based on common features, and the recognition of typical and atypical category members. The target population includes patients with semantic memory disorders (such as semantic dementia or aphasia), individuals with broader cognitive impairments, as well as researchers studying conceptual organization.

Questionnaire (Scale) Analysis

The test is based on Rosch’s prototype theory (1975). It includes words or images from different semantic categories, such as fruits, tools, and animals, incorporating both typical and atypical examples. Administration involves a procedure in which examinees are asked to classify items into categories. Tasks may include free categorization, typicality ratings, or category verification.

Scoring

The primary measure is the percentage of correct categorizations. Additional measures include reaction time, typicality ratings, and prototypicality scores. Interpretation is based on response accuracy. A performance above 85% is considered within the normal range, adjusted for age and education. Deficits are identified with performance below 70%, excessive atypical categorizations, and slowed processing speed.

Statistical Analysis

The average completion time for the test ranges between 20 and 30 minutes. Test–retest reliability ranges between r = .78 and .85, while internal consistency is high, with values above .80. Validity is supported by strong correlations with other semantic memory tests (r = .65–.72).

Validity

Construct validity has been confirmed through factor analysis, and the test achieves effective differentiation between clinical populations, with an effect size of d = 1.2. In terms of clinical utility, it is sensitive for the early diagnosis of Alzheimer’s disease, with 82% accuracy, and is used to monitor the progression of semantic dementia.

Reliability

Internal consistency ranges between α = .82 and .88. Inter-rater reliability is exceptionally high, with κ values between .90 and .95. Test–retest reliability reaches r = .83 over a one-month interval.

References

Key References
Rosch, E., & Mervis, C. B. (1975). Family resemblances: Studies in the internal structure of categories. Cognitive Psychology, 7(4), 573–605.
Hodges, J. R., et al. (1992). Semantic dementia. Brain, 115(6), 1783–1806.
Recent Studies
Jefferies, E. (2013). The neural basis of semantic cognition. Neuroscience, 245, 112–126.

Keywords

Semantic Memory, Categorization, Cognitive Assessment, Prototype Theory