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103_13_full - Principles of Behavior PSYC 103 Lecture 13...

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Unformatted text preview: Principles of Behavior PSYC 103 Lecture 13: Spatial Learning and Navigation Spatial working memory Olton & Samuelson 1976 Homing paths Dead Reckoning The ability to navigate without landmarks or beacons; navigation from the current location based on internal sense of position relative to some origin or target location. Dark arrows = outward journey Dashed line = homeward journey How do they do this? Dead Reckoning •  Desert ants trained on featureless plain to find food 20m from home •  During test, when ants reached food, they were picked up and moved 600m •  Ants moved in same compass direction as if they had not been moved and went to within 1m of where home “should” have been - Design rules out: 1. pheromone trail 2. landmarks. Path integration: continuously updating information about position to keep track of location relative to location of the nest - Other researchers have found that direction is influenced by the sun compass (Santchi, 1913). - Vestibular lesion in other animals (hamsters) eliminate dead reckoning Dead Reckoning: Visual Information •  Geese transported in cart either saw all of journey, or only part. •  Those that saw whole journey went in correct direction when released. •  Those that saw only part went in direction from that last point that was visually accessible. Beacons Cues that directly guide navigation or localization. Sometimes called “proximal cues because they must be close to the goal (or the goal itself) Morris water-maze (1981) Plan of an elevated maze and the surrounding room used in the experiment by O’Keefe and Speakman (1987) to study the reaction of hippocampal place cells as rats moved through the maze (adapted from O’Keefe & Speakman, 1987). Beacons Morris (1981) water maze Rats trained in water maze: 1.  Group ‘Place’ could not see the goal (submerged in water), but goal was always in same place. 2.  Group ‘Cue’ could see both cues and goal, but goal was in new place on each trial. During test, the goal was moved for both groups. Results The Morris Water Maze: a spatial learning task Strategy 1: Cued (beacon) learning: Associate the visible platform position (or other proximal cue) with escape from the water. The platform can be moved and the rat locates it easily. …but don’t stray too far from home, or you lose sight of the cue/beacon! Strategy 2: Learn the position of the submerged platform relative to landmark cues. Inference --> encode the spatial relationships between the platform and “landmarks”. Landmarks Tinbergen (1951) Fixed location objects that can guide an animal’s navigation in relation to a target or goal; typically used when features of a goal are imperceptible at a distance 1.  Wasps preferentially use landmark objects that are large, nearby and threedimensional 2.  Learn geometric relation of multiple landmarks: With multiple landmarks, changing absolute size has little effect; only the orientation matters. Landmark encoding Snapshots and geometry Snapshot memory: compare the current view with a stored memory, or “snapshot”, of the landmarks Cartwright et al. (1983): bees trained to look 50m south of black cylinder; when cylinder is small, bees look closer. •  Size of landmark image on retina controls distance. •  However, this does not occur in gerbils. •  •  Cheng (1986) showed that rats trying to find food in previously baited spots made many errors in diagonally opposite corner - termed “rotational errors.” Suggests that rats use the environmental geometry -- i.e. relation between long and short wall. Requires impoverished environment, otherwise spatial landmarks take precedence & decrease errors Landmarks migration Emlen 1970 Early learning experience calibrates the celestial compass in indigo buntings Groups of birds were were raised in planetarium under either: 1.  2.  3.  a normal night sky (north star polar rotation) a night sky rotated around Beutlegeuse starless night sky. When migration began, the birds oriented normally, in the opposite direction, or randomly, depending on prior experience. Ink pad Cognitive Maps Local images and route maps are relatively inflexible Cognitive map: Mental representation of space If animals represent the world this way, then they should be able to take new routes when previously effective routes have been blocked or impeded. Tolman (1946): Latent learning: free exploration of a maze a satiated rat leads to subsequent ability to locate food very rapidly Shortcut: when an old route in maze is blocked, rats will take the next shortest route, even if they have very little experience with that route. Cognitive Maps Plans of the mazes used in the two stages of the experiment by Tolman et al. (1946). Throughout the experiment a light bulb was located at H. ...
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