Concreteness/abstractness of stimulus-words and semantic clustering in right brain-damaged patients.

Fifteen right brain-damaged patients and 15 normal controls were tested for learning, delayed recall and semantic clustering abilities using two lists of two/three-syllable words. The first list consisted of 12 familiar, concrete, high-imageability nouns belonging to three semantic categories and the second of 12 abstract, low-imageability, familiar nouns also belonging to three semantic categories. The right brain-damaged patients proved to have a learning and semantic clustering deficit for concrete but not for abstract words. This was interpreted as evidence for a selective right hemisphere capability for processing concrete, high-imageability words.