Description

The Semantic Categorization Test (SCT-25) is a neuropsychological assessment tool designed to evaluate the organization of semantic memory, conceptual categorization abilities, and the capacity to identify relationships between concepts based on shared characteristics.

The test is based on Rosch’s prototype theory of categorization, which proposes that concepts are organized around typical representations or prototypes. The SCT examines the ability of individuals to recognize typical and atypical members of semantic categories and is particularly useful in the assessment of semantic processing.

The target populations include individuals with semantic memory impairments, such as semantic dementia or aphasia, people with general cognitive difficulties, and research populations investigating conceptual organization and semantic cognition.

Objective

The primary objective of the SCT-25 is to assess the individual’s ability to organize and process semantic information through categorization tasks.

The test evaluates the ability to recognize similarities between concepts, classify objects into meaningful categories, and distinguish between highly typical and less typical category members.

It can contribute to the assessment of semantic memory disorders, cognitive impairment, and changes in conceptual knowledge associated with neurological conditions.

Structure and Content

The SCT-25 includes words or visual stimuli representing different semantic categories, such as animals, tools, and fruits. The stimuli include both highly representative examples and atypical category members.

The assessment may involve different tasks, including:

semantic free classification, where participants group items according to conceptual similarity;

typicality judgments, where participants evaluate how representative an item is of a category;

and category verification tasks, where participants determine whether an item belongs to a specific category.

Scoring Method

The main scoring indicator is the percentage of correct categorizations.

Additional performance measures may include:

reaction time during categorization,

typicality ratings,

and degree of prototypicality of responses.

Interpretation is based on accuracy and processing speed. Higher accuracy reflects more effective semantic organization, whereas reduced accuracy, atypical categorizations, and slower responses may indicate difficulties in semantic processing.

Normal performance is generally considered above 85% accuracy, while scores below 70% may indicate significant semantic categorization difficulties, taking into account factors such as age and educational level.

Data Analysis and Use

The SCT-25 data can be analysed using descriptive statistics, reliability measures, correlation analyses, and comparisons between clinical and non-clinical groups.

The test is useful in clinical neuropsychology for assessing semantic memory impairment and monitoring cognitive changes over time. It may also be applied in research examining conceptual knowledge, semantic networks, and cognitive organization.

The average administration time ranges from approximately 20 to 30 minutes.

Validity and Reliability

The SCT-25 demonstrates satisfactory psychometric properties. Test–retest reliability has been reported within the range of r = .78–.85, while internal consistency values are above .80.

Construct validity has been supported through factor analytic approaches, and the test demonstrates the ability to differentiate clinical populations with semantic impairments.

Studies have reported strong correlations with other semantic memory measures, supporting its convergent validity.

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., Patterson, K., Oxbury, S., & Funnell, E. (1992). Semantic dementia: Progressive fluent aphasia with temporal lobe atrophy. Brain, 115(6), 1783–1806.

Jefferies, E. (2013). The neural basis of semantic cognition: Converging evidence from neuropsychology and neuroimaging. Neuroscience, 245, 112–126.