The investigation examined the effects of formal and semantic intralist stimulus similarity (ISS) on transfer of stimulus differentiations in the A-B, A-C paradigm.

Labels are one source of our judgments. By assigning labels to objects, we not only create references but we also group prior and current experiences together. The goal of this research is to investigate how labels influence our judgments. Previous research on inductive generalization shows that labels can be more important than physical characteristics (the labeling effect), but the mechanism for this effect remains unclear. There are two differing views regarding the role of labels. One view proposes that labels are not essentially different from physical features: shared labels increase overall similarity between two items in the same way as shared physical features. The other view suggests that people have a naïve theory that shared labels are more special than shared physical features. The goal of this dissertation is to provide evidence that complements these conflicting views. I suggest that the role of labels varies depending on the background knowledge: types of categories (living things vs. man-made objects), amount of knowledge (number of exemplars people could list for the category), and types of labels (categorical vs. indexical). The results from four experiments showed that, for living things, the labeling effect is strong and depends less on the amount of knowledge; for man-made objects, the labeling effect is weak and depends on the amount of knowledge.

In episodic recognition memory, differentiation is the assumption that a study item's pre-existing memory trace is updated when additional study for that item is provided. The differentiation models commonly suppose that episodic memory encoding conforms to this process. Although these models have received considerable support within the literature, results inconsistent with their predictions have also been found. The present paper examined conflicting findings that resulted from study list strength manipulations with rhyming word stimuli and semantically related stimuli. As part of the investigation into this discrepancy, 79 university students participated in a computer-based recognition memory task. In this task, word categories of varying length (short vs. long) and word type (rhyming vs. taxonomic) were presented either five times or once within a mixed study list. Following study, an old-new response paradigm was used to examine recognition memory performance. Results from both the rhyming and taxonomic category stimuli were largely consistent with the previous findings in the literature, indicating that word type does appear to influence recognition memory, even within a mixed study list. These findings are interpreted primarily in terms of word type similarity predictions made by one of the differentiation models. Other possible explanations are also discussed.