without using spatial representations. Expert and nonexpert learners, however, often use spatial models strategically to help remember and understand when reading new information (Cariglia-Bull and Pressley, 1990) and when using diagrams to understand technical texts (Hegarty and Just, 1993; Simon, 2001).
Chess has been a major task in cognitive analyses of expertise. de Groot (1978) conducted pioneering studies comparing the chess playing of grand masters with that of lesser ranked but highly competitive players. He wanted to identify the cognitive skills and strategies that enabled grand masters to outscore their opponents. His hypothesis was that masters would show greater breadth of search (by thinking through a greater number of possible moves) and greater depth of search (by thinking through more “if I do this, and my opponent does that …” possibilities). To test this hypothesis, he asked masters and non-masters to think aloud while they selected moves. Neither masters nor skilled opponents thought exhaustively through all possibilities, though both groups did show impressive breadth and depth of searches. Yet somehow, masters selected “better” moves than did their opponents.
Chase and Simon (1973) hypothesized that the difference between masters and non-masters involved spatial pattern learning; masters “see” the arrangements of chess pieces in larger and more meaningful chunks and are faster at recognizing different board patterns. As a test of this hypothesis, they created configurations of pieces on schematic chessboards, and asked masters and non-masters to study the configurations in order to identify them in a later recognition test. Some patterns were realistic and fitted the rules of chess, whereas others were determined by randomly assigning identical sets of pieces to positions on the board. Masters and non-masters showed similar levels of memory for randomly determined boards, whereas masters significantly outperformed non-masters in remembering meaningful patterns. Expertise in chess helps players recognize meaningful spatial patterns and remember them easily and well. Highly skilled players excel at thinking through moves, reflecting their deep and easily accessed knowledge of the spatial patterns of games. Differences between players reflect depth of knowledge of spatial patterns in the domain of chess.
Expertise in chess (like expertise in the sciences, mathematics, humanities, and arts) is, therefore, specific to a domain. Experts generally are not more intelligent, nor do they think more deeply (Ericsson and Charness, 1994). The fluent reasoning and problem solving that characterize expertise result from the build-up of a store of domain-specific knowledge (Bransford et al., 1999).
Given this position about expertise in general, what does it mean to have expertise in spatial thinking? In what ways might expertise in spatial thinking be domain specific and in what ways might it cut across all domains where spatial thinking is useful? Because spatial imagery, a form of human memory, is the realm of spatial thinking best understood by cognitive psychologists, we begin by discussing spatial imagery and memory.
People remember and think about spatial information in many forms. Perceptual images, for example, preserve many of the features of the original input modality, such that imagining visual experiences results in activation of the visual cortex, or auditory experiences of the auditory cortex, and so forth (Barsalou et al., 2003). Experts and novices use perceptually rich images to help them think about the kinematics and dynamics of physical systems such as springs (Clement, 2003) and interlocking gears (Schwartz and Black, 1996). Spatial thinking that taps perceptual images is embodied in the sense that images of a thinker’s physical actions, such as physically pulling a