Information Foraging in the Unknown Patches across the Life Span

Information Foraging in the Unknown Patches across the Life Span Jessie Chin 1 (chin5@illinois.edu), Brennan Payne 1 (payne12@illinois.edu), Andrew Battles 2 (battles2@illinois.edu), Wai-Tat Fu 3 (wfu@illinois.edu), Daniel Morrow 1 (dgm@illinois.edu), Elizabeth A. L. Stine-Morrow 1 (eals@illinois.edu) Department of Educational Psychology, 2 Department of Electrical & Computer Engineering, Department of Computer Science University of Illinois at Urbana Champaign 405 N Mathews Ave Urbana, IL 61801 USA Abstract This study used a word search puzzle paradigm to examine the effects of task environment and individual differences in ability on information foraging. Younger and older adults attempted to maximize the number of items found in a set of 4 puzzles in which they were at liberty to search within a puzzle or switch between them. Younger adults demonstrated faster uptake (i.e., number of words found as a function of time) from individual puzzles than older adults but experienced more deceleration of rates during the search. Additionally, older adults switched less often and their switching was less dependent on the uptake rate compared to younger adults. Both younger and older adults stayed longer than was optimal in a patch, older adults were especially likely to persevere suboptimally. Collectively, these results suggest that individuals may differentially optimize information gain through self-regulation of exploration and exploitation. Keywords: Information foraging; cognitive aging; adaptive behavior. information uptake; Introduction Self-regulation of cognition in natural environments almost always involves alternating phases of exploration, which entails search in the service of deciding how effort will be allocated, and exploitation, or task engagement in which effort is allocated to meet task-specific goals. Information Foraging (IF) models are predicated on an analogy between these regulatory processes and the way in which animals forage for food in the wild. Information foraging has been used to account for how people search for information in external environments, such as the WWW (e.g., Fu & Pirolli, 2007; Payne et al., 2007; Pirolli & Card, 1999) and in memory (Hills et al., 2010, 2012). However, even though IF presents a compelling metaphor, there is actually very little empirical research investigating the alignment between IF principles and how people interact with the environment to search and make use of information sources (Metcalfe & Jacobs, 2010). There is also little work that has examined how individual differences afford or constrain search in and uptake from information sources. In this study, we used a simple word search puzzle to explore these issues. According to the IF theory (Fu & Pirolli, 2007; Pirolli & Card, 1999), certain basic properties of animal foraging can be applied to the way human seek and consume information. First, food is distributed in the wild in clusters, or “patches,” that vary in their profitability (i.e., potential yield) and in their tractability (i.e., how much of an investment of resources is needed for exploitation; e.g., apples on low branches or high branches). Resources in the patch are often finite and unknown to the foragers in advance, though “scent cues” may provide hints about profitability of the patch. Second, as patches become depleted, the rate of uptake decelerates. Third, the forager faces a tradeoff between gaining nutrients from exploiting a patch and consuming energy from exploring for food (e.g., to move among patches). The optimal foraging theory predicts that animals will stay in a patch until the expected rate of gain falls below the overall rate of gain, which takes into account the cost of moving to a new patch (Charnov, 1976; Stephens & Kreb, 1986). Finally, because food is crucial to survival, foragers work to maximize their food uptake and rarely revisit a depleted patch (Stephen, Brown & Ydenberg, 2007; Stephens & Krebs, 1986). There are similarities and differences between animal foraging and human information foraging. For example, information is often clustered into patches (e.g., particular forms of print resources, webpages), though units of information are often hard to quantify in everyday life. Although information seekers may sometimes find it difficult to estimate profitability and tractability before visiting a patch, they may judge the richness or relevance of information based on their knowledge or expertise. Learners often selectively allocate their attention to materials as long as they perceive themselves to be learning, and disengage if they perceive their rate of learning to decrease below a threshold (e.g., Metcalfe, 2002; Metcalfe & Kornell, 2005). While information seekers have been found to adjust their search behavior to the statistical structures of the task environments (e.g., Fu & Pirolli, 2007), given the limited computational capacity and imperfect knowledge of human beings, the decision to explore a new task or exploit the current one is often suboptimal due to the biased representation of the local environment (e.g., Simon, 1956). For example, Payne, Duggan and Neth (2007) found, in a series of cognitive foraging experiments, that switch decisions could not be entirely predicted by the rate of gain from a patch. Rather, people tended to switch more than optimal without monitoring the real-time change of expected gain. Finally, empirical studies show that information seekers often revisit information patches (e.g. Payne et al., 2007). In fact, unlike food, information will not be exhausted after consumption. Therefore, the benefit of