Is the acquired-pleasantness effect in paired-associate learning free from confounding by meaningfulness and similarity?

Conducted 3 paired-associate learning experiments, with a total of 228 undergraduates, in which nonsense syllables were paired with either pleasant (P) or indifferent (I) pictures. Results show that despite P pictures being more meaningful and similar to each other than I pictures, neither of these variables confounded the superior performance found with P-paired syllables. P-paired syllables did not become more meaningful as measured by probability of giving an association, variability of associations, or rated association value. While the P-paired syllables were judged more similar than the I-paired they did not produce greater clustering in free recall. Nor did syllables paired with high-similarity words prove to be learned faster than syllables paired with low-similarity words. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1973 American Psychological Association