Foundational concepts in psychology are introduced to "27% of all full-time students" in postsecondary institutions each year (Scheirer & Rogers, 1985), constituting an annual North American class size of more than one million adults. In part, these numbers reflect the growth in popularity and perceived value of academic psychology since it was made part of university and college curricula. Understandably, teachers of psychology and their professional organizations have expended considerable effort to set the pedagogical goals for this introduction to the topic (e.g., Gilliland, 1932; Goodwin, 1992; Irion, 1976; Sanford, 1910; Wolfle, 1942). Primary among these goals is that of imparting to students academic psychology's orientation, guiding principles, and facts, on the assumption that there is agreement about the conceptual heart of the discipline. The present study is intended to contribute to the identification of the conceptual core of the introductory psychology curriculum.
Scrutiny of the introductory textbook is a common strategy for determining core psychology concepts. However, empirical investigations of textbook content are divided on the issue of content consistency. A number of studies employing gross measures of topic coverage (e.g., page counts devoted to a topic) in different texts at a single time point (Griggs, Jackson, & Napolitano, 1994), in the same text over time (Griggs & Jackson, 1996), and in different texts over time (Webb, 1991) give an impression of coherence and stable consensus about the introductory conceptual corpus. Other studies using similar approaches suggest a picture of variation and inconsistency (Harari & Jacobsen, 1984; Weiten, 1988). Efforts at identifying core concepts using more fine-grained analyses of index terms (Boneau, 1990; Quereshi, 1993; Quereshi & Sackett, 1977; Quereshi & Zulli, 1975), glossaries (Boneau, 1990; Zechmeister & Zechmeister, 2000) or page-by-page content (Landrum, 1993) have led some to see convergence and coherence (Quereshi, 1993) and others to suggest that there is little compelling evidence of a sizeable set of common concepts (Zechmeister & Zechmeister, 2000).
A variety of methodological issues have undoubtedly contributed to the equivocal character of work in this area, including differences in chosen sets of textbooks to study; extraneous sources of content variance in the indices, glossaries, and textbook design; and variation in the criteria used for determining that a concept is common to a number of textbooks. This state of affairs leaves ample room for interpretive disagreement about the extent and nature of consensus about core concepts. Whereas Quereshi (1993) reported that recent texts were "more comprehensive and more similar to each other" (p. 220) than previously examined texts, Zechmeister and Zechmeister (2000) found "evidence for incoherence rather than coherence, instability as opposed to stability..." (p. 6) when they examined Quereshi's (1993) data.
The point of departure for the present study is the observation that however lamentably small the number, recent studies (Landrum 1993; Quereshi, 1993; Zechmeister & Zechmeister, 2000) have nonetheless been able to identify a number of core concepts in the introductory curriculum ranging from as few as 64 (Zechmeister & Zechmeister, 2000) using a 100% inclusion criteria in 10 books, to 141 in 75% of 52 books (Quereshi, 1993). Landrum's (1993) finding of 126 concepts common to all six texts he reviewed falls in this range. The thrust of our approach is to explore further where in the introductory curriculum consensus about core concepts exists. Using a content analysis approach, we specifically sought to identify which, if any, areas in the introductory curriculum exhibit consensus about core concepts.
Two previous studies have examined concepts by topic or area. Quereshi (1993) classified 137 terms found common to 75% of 52 books into four broad areas: biopsychology, clinical psychology, learning and development, and popular psychology. …