Transcript Slide 1
Learning A “relatively permanent change in behavior as a result of experience” - what is learning? - which behaviors are learned? - why learn or when will learning evolve? - evolution of learning and forgetting A simple experimental example Can fish learn about predation risk in a body of water through chemical cues? 1) They react with an appropriate anti-predatory behavior 2) They retain this reaction for a period of time DW TSE + + PO PO Farm raised juvenile brown trout Short-term effects 4-days later 21-days later A “relatively permanent change in behavior as a result of experience” Socially acquired predator avoidance Eagle alarm Leopard alarm Snake alarm Infants N=24 <5 6-10 11-15 >15 Raptors Non-raptors Goshawk Snake Bateleur Tawny Fish Eagle Eagle Eagle Vulture Bee-eater Juveniles N=53 Non-raptors Raptors Goshawk Snake Bateleur Martial Crowned Tawny Fish Harrier Owl Eagle Eagle Eagle Eagle Eagle Vulture Stork Bustard Adults N=55 Raptors Goshawk Snake Martial Crowned Tawny Fish Hawk Owl Eagle Eagle Eagle Eagle Eagle Eagle Non-raptors Vulture How do infants come to recognize the association between an alarm call and 1-2 predators? 100% 4% 64% 14% 3% Probability of adult alarm calling after infant alarm call by avian species – Reinforcers? 100 Responses of infants to playbacks of adult alarm calls 100 Number of infants responding correctly incorrectly 100 3/4 4/5 5/6 6/7 • Vervets habituate to call (learn it’s a false alarm) • Learning of vervet eagle alarm extends to starling raptor alarm habituation • But learning does not extend between classes of predators Vervet eagle alarm Starling eagle alarm Vervet eagle alarm Vervet leopard alarm Starling eagle alarm Vervet leopard alarm Learning curves associated with locating and extracting nectar as a function of experience detections Simple recognition learning – In this example, birds learn who their neighbors are and associate them to a particular place – the territory boundary songs per min “Dear-enemy” effect Learning is a proximal cause of animal behavior because learning itself is a strategy/trait subject to natural selection Under this perspective we can redefine learning as a tool that allows individuals to adjust their behavior to the local state of their world – i.e., to the set of local spatial, temporal, and social circumstances Learning is a proximal cause of animal behavior because learning itself is a strategy/trait subject to natural selection Under this perspective we can redefine learning as a tool that allows individuals to adjust their behavior to the local state of their world – i.e., to the set of local spatial, temporal, and social circumstances. - Where is food and what make-up is it? - Who are my territorial neighbors – do I recognize them? - What predators are nearby and what are their intentions? Learning is a proximal cause of animal behavior because learning itself is a strategy/trait subject to natural selection Under this perspective we can redefine learning as a tool that allows individuals to adjust their behavior to the local state of their world – i.e., to local spatial, temporal, social, and causal relationships Where is food and what make-up is it? Who are my territorial neighbors – do I recognize them? What predators are nearby and what are their intentions? - recognizing kin from non-kin - social hierarchies: recognizing strangers from non-strangers - remembering past interactions (winners and losers) - recognizing high quality mates Dave Stephen’s Model Evolution of Learning Low ignore experience experience is useful within generation, and learning anew is favored each generation learn Between-generation Predictability High ignore experience Low ignore experience If offspring’s environment is nearly identical, fixed genetic transmission is favored over costly learning High Within-lifetime Predictability experience in the past is not useful it is useful Summary: - Learning is a likely element of proximal causation for most of the behaviors discussed in the remainder of the class - More importantly, the entire learning process is under evolutionary selection pressure - We can broadly understand the evolution of learning in response to the predictability of an organism’s environment in its own lifetime and beyond or we can ask detailed questions about the evolution of learning under specific contexts with a cost-benefit analysis …. Dave Stephen’s Model High within-lifetime predictability Low between-generation predictability learn e.g. members of each new generation may find food in different places, but there is always value in being able to learn where food is The conditions that bring about learning should be reliable correlates of the state of the world the animal needs to adjust to This differs from classical views of learning that assumed: (1) The ability to learn is an unadulterated good (2) Learning abilities are human-like: general and unlimited Br d Parasitism Tailorbird feeding a Plaintive Cuckoo Brown-headed Cowbird