The Price is Right: A High Information Access Cost Facilitates Category Learning

The Price is Right: A High Information Access Cost Facilitates Category Learning Michael J. Wood (mw337@kent.ac.uk) Michael Fry (mdf1@sfu.ca) Mark R. Blair (mblair@sfu.ca) Cognitive Science Program & Department of Psychology Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, CANADA It is not yet clear which resources are conserved as a result of attentional optimization. One candidate is working memory capacity: unattended object features are unlikely to be stored in memory. There is, in fact, evidence that working memory shares a close relationship with category learning: those with low working memory spans are less able to suppress task-irrelevant information, creating a need for selective attention to fill the gap (Conway, Kane, & Engle, 2003). Another resource that may be conserved is time – attending only to what is necessary is likely to result in a reduction in the amount of time required to categorize something. In either view, attending to a particular feature of an object incurs a cost – whether temporal or mnemonic – and attentional optimization minimizes the cost incurred for a successful categorization. Hayhoe and colleagues (Ballard, Hayhoe, & Pelz, 1995; Ballard, Hayhoe, Pook, & Rao, 1997; Droll & Hayhoe, 2007) provided empirical evidence of cost-benefit tradeoffs in visual perception. When performing a task along the lines of the Blocks World game (an interactive paradigm in which subjects must duplicate a target image by positioning a group of coloured boxes from a resource pool), participants generally gather information from the environment as they need it, minimizing the usage of short-term memory. However, increasing the predictability of the task encourages participants to save time by storing information in memory: time, rather than memory capacity, becomes the focus of their conservation efforts. Similar results were found in a series of studies by Gray and colleagues, many of which also employed the Blocks World paradigm (Gray & Fu, 2004; Gray, Sims, Fu, & Scholles, 2006; Fu & Gray, 2006). When the target window was occluded by a removable square, or participants were forced to make head movements in addition to eye movements in order to direct their gaze about the work area, there tended to be a switch to a memory-intensive strategy in order to save time and energy. It appears that saving time is not the only advantage of adopting a memory-based strategy in tasks along the lines of Blocks World, although the evidence is not unequivocal. Gray et al. (2006) found that participants in a memory- intensive variation of the Blocks World task made fewer errors and mastered the task sooner than others performing a standard task. While this contradicted earlier results by Gray and Fu (2004), the results of Gray et al. (2006) are supported by the research of Waldron and colleagues on interface design (Waldron, Patrick, Howes, & Duggan, 2006; Waldron, Patrick, Morgan, & King, 2007; Morgan, Patrick, Waldron, King, & Patrick, 2009). As in the Blocks Abstract Previous work in object categorization has shown that people tend to optimize their allocation of attention to object features, and suggests that attentional optimization may best be explained in terms of cost-benefit tradeoffs. In support of this idea, we found that implementing a cost for accessing information about object features in a category learning task facilitates both attentional optimization and category acquisition, contrary to the predictions of existing models. Keywords: category learning; categorization; access cost; attentional learning; optimization. An important component of proper psychological functioning is the adaptive usage of limited resources. In many situations, careful conservation of money, food, water, memory capacity, and time can be vital to survival. The choice of strategy for dealing with a particular issue depends largely on the relative availability of the various resources required – for instance, installing hardwood floors might be best accomplished by doing it oneself if money is tight and time is plentiful, while hiring a contractor might be a better idea if money is no object but the job must be done quickly. An optimal strategy for a given problem, then, balances situational priorities (urgency, desire for quality) with available resources (time, money). This characterization of optimal strategy applies equally to psychological domains such as categorization. Fiske and Taylor (1984) characterized humans as cognitive misers, meaning we will attempt to solve problems using the smallest amount of mental resources possible. Indeed, a good deal of evidence suggests that in category learning, people learn to ignore irrelevant information, thereby optimizing their allocation of attention for the task at hand (Rehder & Hoffman, 2005; Blair, Watson, & Meier, 2009; Blair, Watson, Walshe, & Maj, 2009; Blair, Chen, et al., 2009). The process of selectively allocating attentional resources to task-relevant information is labeled attentional optimization. One approach to characterizing the optimal usage of attentional resources takes the view that the benefits of attending to a piece of information must outweigh the costs. This view of attentional optimization as a process of cost- benefit tradeoffs parallels some of the decisions made in the domain of medical diagnosis. A doctor attempting to diagnose a patient will order only tests which are necessary, and even then will strike a balance between efficacy, cost, and safety. A doctor who suspects a particular condition may be more likely to order a cheap, safe blood test than expensive, dangerous exploratory surgery.