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Evolved Decision Making

Evolved Decision Making. Peter M. Todd Cognitive Science, Informatics, and Psychology, Indiana University & Center for Adaptive Behavior and Cognition (ABC), MPI, Berlin with Peter DeScioli and Rob Kurzban. Max Planck Institute for Human Development Berlin. What should I eat?.

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Evolved Decision Making

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  1. Evolved Decision Making Peter M. Todd Cognitive Science, Informatics, and Psychology, Indiana University & Center for Adaptive Behavior and Cognition (ABC), MPI, Berlin with Peter DeScioli and Rob Kurzban Max Planck Institute for Human Development Berlin

  2. What should I eat?

  3. How can I decide? 152 types of street food, ~500 pages, 1200+ vendor reviews…

  4. Visions of Cognition Superhuman unbounded rationality BoundedRationality The Adaptive Toolbox

  5. The adaptive toolbox A collection of decision mechanisms, including simple heuristics and rules of thumb... Some evolved/pre-wired, some learned... Applicable to specific decision tasks and in particular domains... That rely on and exploit the structure of information in the environment... To yield ecological rationality.

  6. For more info, see our book.... Also, see our new book coming soon: Ecological Rationality: Intelligence in the World

  7. Two types of heuristics Choose between options by searching for as little information as possible Search for the options themselves, stopping with as little search as possible

  8. Which US city has more inhabitants, San Diego or San Antonio?

  9. Which US city has more inhabitants, San Diego or San Antonio? Americans: 62% correct Germans: ? correct Germans: 100% correct (but not any more…)

  10. The Recognition Heuristic Definition: To decide between two objects on some dimension, if you recognize only one, pick it This only requires search for recognition knowledge Ecological Rationality: This heuristic works well when recognition knowledge is correlated with the decision dimension

  11. Animals use recognition heuristics Evolutionary roots of recognition use: Rats use recognition to decide whether to try a new food: try it if they recognize it from another rat Bulls use anti-recognition in mate choice: Fish, birds, and humans use mate copying

  12. “Paying for the name…….”

  13. Which city is bigger? DresdenLeipzig Cues Recognized? yes yes National capital no no Soccer team no yes Intercity train yes yes State capital no yes University yes yes How to decide? Weight/add or tally all available cues, or use just one?

  14. Search: How to find things How do we choose among options that are not all present to us at once? Search is required whenever resources are distributed in space or time, e.g.: • food • mates, friends • house/apartment • jobs

  15. The problem of finding things When searching, another better alternative could always be found, so the real problem is: when to stop search—exploit the current item, and when to keep looking—explore further? This explore/exploit tradeoff in an ongoing dynamic process—also in business Evolution has built mechanisms to explore quickly and exploit as much as possible

  16. Features of employee search No going back: once an alternative is passed, there’s little chance of returning to it No looking forward: upcoming range of possible alternatives is largely unknown Mutual search: You must choose an employee, and convince him/her to join your company How to decide when to stop and “exploit” the current option, or explore for someone else? Search using an aspiration level, or satisfice (Herbert Simon, 1955)

  17. Heuristics for mutual search Use an aspiration level dependent on one’s own market value to speed up mutual search But how to determine one’s own value on the job market in a quick and simple way? Answer: learn one’s own value during an initial “testing” period based on unexpected feedback, and use this as aspiration level

  18. Testing search rules empirically What rules are people likely to use in such mutual sequential searches? Those we have evolved to use in related settings, e.g. mating How can we observe ongoing mate choices in individuals, without having to follow people for years? We need sped-up mate choice in a microcosm...

  19. Speed dating...

  20. How does speed-dating work? • ~20 men and ~20 women gather in one room (after paying $30) • Women sit at tables, men move in circle • Each woman talks with each man for 5 min. • Both mark a card indicating whether they want to meet the other ever again • Men shift to the next woman and repeat • (now happening worldwide, with many variations)

  21. What happens next Men’s/women’s “offers” are compared Every mutual offer gets notified by email, with other’s contact info After that, it’s up to the pairs to decide what to do To study mutual search heuristics, we ran our own speed-dating sessions….

  22. Separate “dating” booths

  23. One of the booths (with camera, mics)

  24. A “date” in progress

  25. How people searched Speed-daters appeared to follow an aspiration-adjustment heuristic in deciding to make offers to people they expected offers from Similar heuristics may be used in organizational search problems like hiring or finding corporate partners

  26. Selecting the right tool Problem associated with having lots of tools in the toolbox: When to pick each to use? However it works, the tool-selection mechanism must be simple, fast, & frugal too Mind has evolved to detect cues for different types of problems and choose proper tools Cues in workplace can lead people to think they’re in a friendship/cooperative setting or anonymous competitive setting and choose decision tools accordingly

  27. Conclusions • Organizations as goal-seekers must make good decisions within constraints • Good choices can be made with little info processed by appropriate tools from toolbox • Tools include heuristics for choice, allocation, and search for resources • Selecting tools must be done on basis of cues from environment, again simply • Can we set up work environments so they elicit decision tools we want on the job?

  28. How to be rational Given our mental constraints (Herbert Simon): • Human memory, cognitive capacity, and time are limited, i.e. bounded • Moreover, most real-world problems cannot be solved by optimization The only plausible/possible approach is: • to make decisions within our bounds by using approximate methods: heuristics, shortcuts, “rules of thumb”, that make “quick and dirty” decisions • We can’t use all available information, so we have to search for (limited) information to use

  29. A well-studied search example: the Secretary Problem A company faces this challenge: • 100 job applicants with unknown distribution of typing speeds will be seen • Applicants are interviewed in sequence and announce their typing speed • Search can be stopped at any time by hiring the current candidate, but no returning to earlier applicants How can the company maximize its chances of hiring the best secretary?

  30. Solving the Secretary Problem Goal: Maximize chance of finding best option Approach: Set aspiration level by sampling a number of options that balances information gathered against risk of missed opportunity Solution: Sample N/e (= .368*N), or 37% Rule (set aspiration after seeing first 37% of apps) Other approaches: maximize mean return with a much shorter initial search period (~10%)

  31. Implications • People will aim to stop their search for options quickly • People will use feedback about what they can “afford” to adjust their aspirations (so we can shape their decisions by ordering options) • People will use social info from others to adjust their own preferences and shorten their search • In these ways, (too) many options need not scare off decision makers

  32. Examples in Games • Double auction: buyers/sellers set prices for goods—behavior is rational and prices converge quickly • Cues indicate that cost/benefit should be used • Public goods: players can keep money or contribute to “public account”, get more back • Cues to social interaction/group identity, e.g. glances, cheap talk, punishment, lead to more giving to public account • Dictator game: eye spots induce more giving

  33. Examples in social relations Organizations contain many types of social relations: friends, mates, trade partners, leader-follower, boss-worker, etc. Crucial to know what relationship you’re in Cues can signal relationship type E.g. friendship (vs. exchange partner) signified by friend ranking you above others (DeScioli & Kurzban 2009)

  34. Conclusions The ecological rationality approach to studying simple decision heuristics emphasizes the match between: • heuristics specified in terms of info search, stopping, and decision building blocks • how structured information in the decision environment can be exploited by heuristics This approach (with multiple methodologies) helps us predict how people make decisions, e.g. about what to eat, and influence choices by constructing appropriately-structured environments

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