Contrasting graded effects of semantic similarity and association across the concreteness spectrum

Abstract

Evidence from healthy individuals and neuropsychological patients with deep dyslexia or semantic refractory access dysphasia suggests that abstract and concrete concepts have different dependencies upon associative and similarity-based representational frameworks. However, the importance of information about semantic similarity for concepts that lie across the full concreteness spectrum has not been investigated. Here we report the performance of healthy individuals on an odd-one-out task involving semantically related word triplets that showed continuous variation for the key variables of concreteness, similarity strength, and association strength. In addition, data from a stroke aphasic patient tested on a matching-to-sample task based on the same abstract, middle-concreteness, and concrete stimuli are also presented. The effects of similarity and association strength upon performance were both shown to interact significantly with concreteness, but in opposite directions. The effect of semantic similarity increased with concreteness but the effect of association decreased with concreteness. This research provides further evidence for the proposal that abstract and concrete words have different dependencies upon associative and similarity-based information. It also develops the proposal by providing data that are consistent with a graded and not binary or ungraded model of the relationship between concreteness and these two forms of semantic relationship.

Keywords:

• Abstract
• Concrete
• Conceptual knowledge
• Association
• Similarity
• Semantics

Acknowledgments

We are extremely grateful to Jonathan Bartlett at the London School of Hygiene and Tropical Medicine for his help with the statistical analyses, and would like to thank the study participants for giving so generously of their time. This work was undertaken at University College London Hospitals/University College London (UCLH/UCL), who received a proportion of funding from the Department of Health's National Institute for Health Research (NIHR) Biomedical Research Centres funding scheme. The Dementia Research Centre is an Alzheimer's Research Trust Coordinating Centre. This work was supported by an Alzheimer's Research Trust Research Fellowship to S.C.

Notes

¹Separate Likert scales of 1–7 were used to rate semantic association and similarity independently in response to criticism of the methodology used by Crutch and Warrington (2007) and Crutch et al. (2009), whereby participants rated distractors on a scale of –3 (very similar) through 0 (no relation) to +3 (very associated). This scale suggests that words are similar, associated, or not related at all, when in fact it is difficult to part semantic association from semantic similarity. Allowing two separate ratings for association and similarity on the 7-point scale does not force control subjects to choose similarity over association or vice versa.

²In the context of the comparison with normal and reverse concreteness effects, it is of note that UM-103, unlike the other patients cited above, failed to show the typical concreteness effect on an independent task.