Effect of referent object familiarity on verbal learning in the sighted and the blind

In a series of paired-associate tasks we investigate why some highly concrete nouns are easier to remember than other highly concrete nouns, even when such word attributes as imagery value are held constant. In Experiment 1 both the congenitally blind and the sighted remembered nouns with referents highly familiar to the blind better than nouns with referents of low familiarity to the blind. Although this effect was anticipated for the blind, it was unexpected for the sighted because the referents of low familiarity to the blind have been visually experienced by the sighted and are as easy for the sighted to image as the referents highly familiar to the blind. Experiments 2 through 5 explore why the extent to which the blind are familiar with an object should predict verbal learning for the sighted. As it turned out, referents that were familiar to the blind were also familiar to the sighted. After ruling out various alternative explanations we were able to conclude that it is the extent of perceptual experience with a noun's referent, irrespective of the modality through which the experience is acquired, that determines ease of verbal learning. Any theory that accounts for the concrete-noun effect must also be able to account for the effect of referent familiarity, and our results are discussed within this context.