A group of Ss rated nouns on abstractness-concreteness (C), emotionality, (e), and three semantic scales. A second group of Ss learned a list of 16 paired associates (PA) constructed from these nouns. Rated C and e were co varied on both the stimulus and response side of pairs. The rated capacity of the nouns to evoke imagery (J) was held constant. While the covaried attributes did affect learning, the pattern of high-low C differences was different than previous studies with I covaried. These results were interpreted as support for noun I being the effective variable underlying the C effect in PA learning.A recent series of studies (e.g., Paivio, 1965;Paivio, Yuille, & Smythe, 1966) has shown that noun concreteness (C), especially of the stimulus term, is related positively to paired-associate (P A) learning. This effect has been linked theoretically to the imagery (I) evoking capacity of nouns (cf. Paivio, 1967). Thus, concrete noun stimuli presumably elicit images that can serve as mediators in PA learning. Support for this hypothesis has been obtained from a number of sources, for example, concrete nouns exceed abstract nouns in their rated capacity to evoke I (Paivio, Yuille, & Madigan, 1968), and Ss report using imagery more often to mediate concrete rather than abstract pairs of nouns (Paivio et ai, 1966).In an attempt to demonstrate that the effect of noun C is due to covarying I, Paivio et al (1966) conducted two experiments. In one they manipulated stimulus and response C while controlling rated I, and in the second I was varied while C was held constant. Although stimulus I was found to have a positive effect with C controlled, supporting the hypothesis, noun C was also found to have an effect independent of I. Paivio et al (1966) suggested that this latter effect may have been due to insensitive measures of C.Since the precise determination of the variables contributing to the effects of noun C is essential to the imagery hypothesis proposed by Paivio (1965), a further examination of the relationship between I and C in learning appears necessary. Recently, Paivio et al (1968) obtained 7-point scale ratings of C and I, as well as production meaningfulness data, for 925 nouns. These data permit a test of whether C has an effect on PA learning with I controlled. Paivio et al (1968) report that although C and I correlate .83 in the total sample, 51 nouns show considerably higher ratings on I than C. The use of this "peculiar" subsample of nouns permits independent manipulation of C. A secondary purpose of this study was to determine, if possible, how the 5 I nouns differ from the rest of the sample. Paivioet al (1968) observed that these nouns tend to have evaluative connotations, and special attention was paid to that dimension of meaning. METHOD Noun ratings. Twenty-seven Ss (10 males, 17 females) rated 40 nouns on each of five bip.olar 7-point scales. The nouns were chosen from the 925 nouns used by Paivio et al (1968). Twenty of the nouns (abstract nouns) were selected from the group of 51 "unu...