Category structure modulates interleaving and blocking advantage in inductive category acquisition

Category structure modulates interleaving and blocking advantage in inductive category acquisition Paulo F. Carvalho (pcarvalh@indiana.edu) Department of Psychological and Brain Sciences, 1101 E 10th St Bloomington, IN 47405 USA Robert L. Goldstone (rgoldsto@indiana.edu) Department of Psychological and Brain Sciences, 1101 E 10th St Bloomington, IN 47405 USA Abstract taught. For example, Elio and Anderson (1984; see also, Sandhofer & Doumas, 2008) have proposed that learning should start with low variability items and later introduce items with greater variability. Another proposal is that items that present the same generalization should be presented close together in temporal sequence (e.g., Elio & Anderson, 1981; Mathy & Feldman, 2009). More recently, researchers have proposed interleaving items from the categories being taught (i.e., presented in alternating fashion), rather than grouping items together from the same category. The advantage of alternating categories has been observed in different kinds of concepts such as artists’ styles (Kornell & Bjork, 2008), bird species (Kornell, Castel, Eich, & Bjork, 2010; Wahlheim, Dunlosky, & Jacoby, 2011), novel category learning in children (Vlach, Sandhofer, & Kornell, 2008) and also mathematical operations in primary school students (Taylor & Rohrer, 2010). Initial accounts of this advantage for interleaving related the interleaved presentation with spacing of exemplars. However, Kang and Pashler, (2012) used a procedure similar to the one used by Kornell and Bjork (2008), but with added presentation conditions. In one experiment, the authors compared categorization performance in a generalization test preceded by one of four conditions: (1) blocked, (2) interleaved, (3) blocking in which every presentation of a painting was followed by an unrelated filler task (Temporal Spaced Condition), and (4) when all exemplars from the same painter were presented simultaneously (Blocked Simultaneous Condition). The results showed that only the interleaved condition resulted in better performance than the blocked condition, thus providing evidence that greater temporal spacing of presentations is not the critical factor in the interleaved advantage. The authors argue that the real advantage of interleaving might be a result of the greater opportunity to contrast and compare examples, making the differences between the artists’ styles more salient (see also, Goldstone, 2003; Goldstone & Steyvers, 2001). Further evidence for this proposal was provided in a second experiment in which the interleaved and blocked conditions were compared to a simultaneous presentation of two paintings by different artists. This latter condition Research in inductive category learning has demonstrated that interleaving exemplars of categories results in better performance than presenting each category in a separate block. Two experiments indicate that the advantage of interleaved over blocked presentation is modulated by the structure of the categories being presented. More specifically, interleaved presentation results in better performance for categories with high within- and between-category similarity while blocked presentation results in better performance for categories with low within- and between-category similarity. This interaction is predicted by accounts in which blocking promotes discovery of features shared by the members of a category whereas interleaving promotes discovery of features that discriminate between categories. Keywords: category learning; order effects; interleaving; Introduction How to present information so that learning and memory are optimized is an important issue in teaching and training contexts (Rohrer & Pashler, 2010). It has long been demonstrated that spacing repeated presentations of the same information results in better memory than repeating the same information at a single occasion, even when time and number of presentations are equated (Ebbinghaus, 1885). This memory phenomenon, known as the “Spacing Effect,” is a highly robust finding (Delaney, Verkoeijen, & Spirgel, 2010; Proctor, 1980) that has been shown both in experimental situations with words and pictures and more applied situations such as flashcard studying (Kornell, 2009). Although demonstrating the critical importance of carefully considering how to present information, the importance of maximizing memory for specific concepts or problems might not be as relevant as learning general concepts. Indeed, in educational contexts, often times inferring what characterizes or defines a concept or problem is more relevant than memorizing a single instance of that concept or fact. In this sense, a more interesting question might be to know whether the way instances are presented influences inductive learning and subsequent generalization of the acquired knowledge. The question of how to present information in order to optimize category learning and generalization has been raised before and several proposals have been put forward. Some of these proposals are related to the categories being