March 3rd, 2009 Introduction to Tool Use and Causal Understanding What is learned - associative learning of causal understanding? 3 Case Studies: • Tool Selection • Gravity • Tool Manufacture How are causal relations learned? Insight & Creativity • Using the environment in novel ways to achieve goals Planning & Forethought • Thinking ahead • Responding to stimuli that aren’t in sight Causal Understanding • “Folk Physics” • Understanding something about how the world works • Mediating forces What Event is learned? Associative vs. Causal Outcome Associative learning: Predict the outcome – what is going to happen next? Causal understanding: WHY and HOW does the outcome occur? What is learned? Associative vs. Causal Associative: Yellow ball moves after contact with blue ball Causal: Mediating forces – “force” imparted by blue ball is blocked by the barrier Mediating forces: • Different levels of complexity Visible factors Invisible factors Psychological factors Explanatory Attitude Can non-human animals recognize the functional properties of tools? • Hauser and colleagues – cottontop tamarins Hauser and colleagues – cottontop tamarins Varied colour, texture, shape and size • Colour & texture are not ‘functional’ changes • Shape & size could be ‘functional’ changes All canes set in the correct spatial arrangement Monkeys preferred the non-functional changes Sensitive to changes in potential functionality Similar results found with capuchins • Fujita, Kuroshima & Asai, 2003 Included transfer tests in which an obstacle or a trap was on ‘drag path’ • Capuchins failed on these transfers Understand spatial relationship between tool and food, but not tool, food and environment New Caledonian crows Select tools of appropriate length in sight and out of sight In sight: Out of sight (Abel only) -Two strategies: -Match distance or -Choose longest -What if length was un-usable? -Abstract representation (keep representation of tool and intended goal in mind) Trap in the middle of the tube Learned the task: • 1 out of 4 capuchins • 2 out of 5 chimps Transfer tests showed that capuchins used a distance based rule Chimps didn’t use distance based rule Associative rule still possible • Insert stick on side of trap Failure to adjust behaviour on inverted tests • But there’s no penalty for not adjusting! • Human adults don’t adjust either • Instructional problem? Too many factors? • Tool, food and environment • Adjusted task to remove tool use Allows subjects to pull or push • Prefer to pull Distance and trap rules are not available New Caledonian crows Similar transfer tests: 3/6 solved the transfers plus a trap-table task In the wild, elephants commonly use branches to repel flies Too long or too bushy branches presented to captive elephants In the wild, tear pandanus leaves Barbed edges of leaf can be used to “fish” for insects in dead wood “cultural variation” in tool manufacture Naive birds can create pandanus tools without teaching In the lab: • http://users.ox.ac.uk/~kgroup/tools/movies.sht ml Always inserted straight wire first Insightful? Blaisdell, Sawa, Leising & Waldmann, 2006 Common Cause Causal Chain Light Light Tone Light Tone Food Light Food Test: Intervene-Tone or Observe-Tone Causal explanation: • If Tone just occurs, maybe Light came on first and was ‘missed’ Check for food! • If I caused the Tone to occur, Light didn’t happen don’t check for food Associative explanation: • If there is an association between the tone & food, shouldn’t matter whether you caused it or not check for food at same rate. Chain always check Rats respond in accordance with causal reasoning, not associative processes Causal Markov condition • During common-cause condition, tone and light should be causally independent • But, rats receive only tone or food following the light – they are NOT independent of each other Thus, does net not strictly follow causal Bayes Criticism: • Lack of evidence could be based on inability to properly instruct animals • http://www.youtube.com/watch?v=FZmx0jml1jk • http://www.youtube.com/watch?v=pIAoJsS9Ix8& feature=related