Age Differences in Information Foraging: Search and Switch in Word Search Puzzles Jessie Chin 1 Brennan R. Payne 1 Andrew Battles 2 Wai-Tat Fu 3 Daniel G. Morrow 1 Elizabeth A. L. Stine-Morrow 1 + 1 Department of Educational Psychology, 2 Electrical & Computer Engineering, 3 Computer Science University of Illinois at Urbana Champaign INTRODUCTION Self-regulation of cognition in natural environments almost always involves alternating phases of: •Exploration, or search that is 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 models use the analogue of how animals forage for food in the wild to explain how people regulate these processes in both external environments (e.g., Fu & Pirolli, 2007; Payne et al., 2007; Pirolli & Card, 1999) and in memory (Hills et al., 2010, 2012). One general principle is that optimal foragers adjust their patterns of search to expected information gain from particular (food) patches and search costs in switching between patches. For example, it is adaptive to continue to exploit patches as long as they are profitable, especially when the cost of switching between patches is high (Charnov, 1976).  We examined age differences in an information foraging task in patches varying in difficulty (i.e., yield relative to time allocated; profitability). Given age-related differences in speed and WM, we expected older adults to show slower information uptake, especially in the more difficult condition. More interesting was whether older adults would show differential likelihood of switching as profitability decreased (cf. Mata et al., 2009) METHODS Participants  Significant age difference (* p<.05; ** p<.01)  No age difference in the use of iPad Materials and Procedure --The word search puzzle paradigm To maximize the number of items found in a set of 4 word search puzzles on an iPad.  One puzzle was visible at a Ime  ParIcipants switched between puzzles at liberty, with a 10‐minute limit  4 puzzles, each containing 16 words from different semanIc categories RESULTS Word Search Performance: Younger adults found more words in all conditions Differences in Uptake Rates: Older adults had slower uptake rates regardless of condition Mixed Easy >Easy Mixed Hard > Hard  First attempt Differences in Switch  Young switched more in the hard puzzles than easy ones; old switched similarly across conditions  Younger with higher uptake rates (reaching asymptote quickly) switched more often. Older with better verbal ability and quicker speed switched less often (persisting in a patch longer). Correlations among #switch, total #words, mean uptake rates (MUR; word per second), verbal ability, speed, working memory and fluency (*: p<.05, +: p<.1) Differences in Revisiting the Non-Depleted Puzzles  Older adults found most of the words in their first attempt to the puzzles Differences in Perseverance  Measured by give up time (the time to find the last word to the time to leave a puzzle) Predicting Word Search Performance CONCLUSIONS  Switch was more likely in the difficult condition than the easy condition as predicted.  Younger adults showed faster uptake than older adults, but uptake was less predictive of overall performance in the old.  Older adults persevered longer, especially in the more difficult condition. Mean(SD) Age Educa;on * Verbal ** Speed ** WM** Fluency Young (N=28) 19.79 (1.23)(19~23) 14.46 (1.47) 6.87 (2.53) 11.21 (2.30) 4.15 (1.08) 15.10 (3.23) Old (N=30) 70.57 (6.33)(62~85) 16.25 (3.55) 10.69 (3.36) 9.43 (2.19) 3.46 (0.67) 16.66 (3.92) All Easy Condi;on Mixed Condi;on All Hard Condi;on 4 easy puzzles 2 easy puzzles 2 hard puzzles 4 hard puzzles High‐prototypical category exemplars Low‐prototypical category exemplars Forward only All orientaIons, both forward and backward No difference in word frequency and word length across condiIons Human Body (easy; high profitability) Birds (difficult; less profitable) #words (out of 64) All Easy All Hard Mixed Easy Mixed Hard Young 38.93 (6.35) 23.39 (7.40) 20.14 (3.00) 11.71 (3.51) Old 29.24 (6.95) 15.72 (6.15) 15.93 (3.99) 7.68 (3.39) 0 5 10 15 all easy mixed all hard #switches Total #switches young old Young|old #switch #words MUR verbal speed WM #words 0.14 -0.28 MUR 0.47* -0.13 0.68* 0.70* Verbal -0.29 -0.34+ 0.37* 0.36+ 0.14 0.24 Speed 0.09 -0.43* 0.18 0.07 0.18 0.03 0.20 0.35+ WM -0.24 -0.25 0.00 0.54* -0.14 0.44* 0.19 0.33+ 0.21 0.19 fluency -0.08 -0.01 0.31 0.21 0.25 0.18 0.15 0.36+ 0.15 0.03 0.33+ 0.36* 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 easy mixed easy mixed hard hard easy mixed easy mixed hard hard Young Old Proportion of words found First attempt More attempts Mean give up time All Easy All Hard Mixed Easy Mixed Hard Young 19.04 (9.88) 24.90 (10.89) 24.82 (12.25) 25.88 (22.89) Old 29.83 (13.95) 40.31 (18.00) 30.16 (18.87) 32.94 (20.26) Older > young Older adults were particularly likely to persevere in the difficult condition Young Old Easy Puzzle Model 1 Model 2 Model 1 Model 2 Hard Puzzle Standardized Beta Coefficients (* p<.05; **p<.01;+ p<.1) #switch -0.22 -0.19 -0.13 -0.02 -0.28+ -0.37* -0.24+ -0.26 Uptake rate 0.59** 0.82** 0.51** 0.68** 0.64** 0.48** 0.45** 0.42* Verbal 0.33+ 0.33* 0.04 0.22 Speed -0.02 -0.03 -0.13 -0.06 WM 0.02 -0.03 0.45** 0.08 REFERENCES •Charnov, E. L., (1976). Optimal foraging, the Marginal Value Theorem. Theoretical Population Biology, 9, 129–136. •Fu, W.-T., & Pirolli, P. (2007). SNIF-ACT: A cognitive model of user navigation on the World Wide Web. Human-Computer Interaction, 22, 355-412. •Hills, T., Jones, M. & Todd, P. M. (2012). Optimal foraging in semantic memory. Psychological Review, 119, 431-440. •Hills, T., Todd, P. M., & Goldstone, R. L. (2010). The central executive as a search process: exploration and exploitation in generalized cognitive search processes. JEP:General. •Mata, R., Wilke, A., & Czienskowski, U. (2009). Cognitive aging and adaptive foraging behavior. Journal of Gerontology: Psychological Sciences, 64B, 474-481. •Payne, S. J., Duggan, G. B., & Neth, H. (2007). Discretionary task interleaving: Heuristics for time allocation in cognitive foraging. Journal of Experimental Psychology: General, 136, 370-388 •Pirolli, P., & Card, S. (1999). Information foraging. Psychological Review, 106, 643-675. 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