Ostensive definitions of words are ambiguities as to their referent. In a study of infant-mother dyads engaged in looking at picture books, 95 percent of ostensive definitions referred to the whole object depicted rather than parts, attributes, or actions. When parts were named, ambiguity was avoided by naming the part and the whole. (PJM)

Pronoun mastery demands a knowledge of speech roles and an ability to identify oneself and others in those roles. Twenty-one girls' knowledge of "my,""your," and "her" was assessed when they were speakers, addressees, and nonaddressed listeners. The children were aware of speech roles only when they themselves occupied these roles. (PJM)

Studies the perceptual relationship between temporal "before" and "after" and their spatial counterparts. Adults reported temporal "before" related to spatial "after" and temporal "after" related to spatial "before." Three-year old children better understood spatial "after" and spatial "before," suggesting a temporal/spatial semantic acquisition…

Responds to four commentaries on the article by Jones and Smith in this issue. Suggests that the comments derive from the possibility that stable concepts might not exist and from the difficulty of imagining what cognition could be without represented concepts. Discusses traditional approaches to stability and variability, and considers what…

Comments on the article by Jones and Smith in this issue. Responds to the theses that perceptual information is as much at the core of concepts as is nonperceptual information and that concepts are not represented as such but are computed on-line when needed. Presents a view of the relationship between perception and conceptual knowledge…

Comments on the article by Jones and Smith in this issue. Describes a program of research that demonstrates the important influence of perception on the structure of concepts. Proposes that both perceptual and nonperceptual information are important to conceptual structure throughout the continuum of knowledge acquisition and that perception is a…

Comments on the article by Jones and Smith in this issue. Outlines different perspectives from which the issue of conceptual development is approached, elaborating on the functions concepts serve and variations in those functions. Notes points of agreement with the perceptual knowledge view and offers comments on the research supporting the…

This commentary on the article by Jones and Smith in this issue examines whether coherent conceptual cores exist in long-term memory; abstract propositions constitute conceptual cores; concepts in long-term memory control behavior; and the primary purpose of developing and using concepts is to taxonomize the environment. (TJQ)