Territory and NavigationTerritory and NavigationPart II NavigationPart II Navigation

NavigationNavigation

We talked about territorialityWe talked about territorialityTo get around a territory an animal must To get around a territory an animal must know where it is goingknow where it is goingIndeed, for most any animal that moves, it Indeed, for most any animal that moves, it needs to have a way of knowing where it needs to have a way of knowing where it has been and where it is goinghas been and where it is goingThere are many ways this can be There are many ways this can be accomplished, from complex cognitive accomplished, from complex cognitive mechanisms to simple odour trailsmechanisms to simple odour trails

Path IntegrationPath Integration

Simplest form of Simplest form of navigation that uses navigation that uses memorymemoryCataglyphisCataglyphis, the Long , the Long Legged Desert Ant Legged Desert Ant Twisting outgoing Twisting outgoing path, but a direct path path, but a direct path home.home.

Path IntegrationPath Integration

Animal Stores Animal Stores direction and distancedirection and distanceSimple vector Simple vector mathematicsmathematicsAnimal must maintain Animal must maintain a running calculationa running calculationError will be Error will be cumulativecumulativeHow could it be How could it be improved?improved?

Path Integration and LandmarksPath Integration and Landmarks

While ‘integrating’ the animal could, While ‘integrating’ the animal could, periodically, take a fix.periodically, take a fix.Probably from the stars or the sunProbably from the stars or the sun Clock shift experiments show this to be true!Clock shift experiments show this to be true!Same thing sailors used to do with a Same thing sailors used to do with a sextant (or a GPS today)sextant (or a GPS today)But stellar position changes over time, But stellar position changes over time, animal cannot have stellar positions animal cannot have stellar positions hardwired! hardwired!

Beacons and LandmarksBeacons and Landmarks

A beacon directs behaviour towards itA beacon directs behaviour towards itA landmark points toward a goal, along A landmark points toward a goal, along with other cueswith other cuesBoth are used by many animalsBoth are used by many animalsThere have been some great strides made There have been some great strides made in understanding various species’ use of in understanding various species’ use of landmarks in the last 20 yearslandmarks in the last 20 years

Bees!!Bees!!So, the bee seems So, the bee seems to be matching the to be matching the SIZE of the retinal SIZE of the retinal image with the size image with the size of the image in of the image in memorymemoryColour change has Colour change has no effectno effectMaking the landmark Making the landmark a ‘wireframe’ has no a ‘wireframe’ has no effecteffect

Training Half size test

Double Size test

Two LandmarksTwo Landmarks

Bees are sort of half using Bees are sort of half using angular informationangular information3 Peak places of search in the 3 Peak places of search in the Stretch testStretch testCollett, Cartwright, Cheng and Collett, Cartwright, Cheng and their colleaguestheir colleagues

Training

Rotation Test

Stretch Test

Landmark Use in PigeonsLandmark Use in Pigeons

Ken Cheng’s (1989) Ken Cheng’s (1989) workwork

Landmark

Goal

Tests of Pigeon Landmark UseTests of Pigeon Landmark Use

Animal searches along the Animal searches along the same axis of landmark shiftsame axis of landmark shiftDoes not COMPLETELY Does not COMPLETELY follow the landmarkfollow the landmarkBut, does not shift search But, does not shift search in the other directionin the other direction

Landmark

Search

Further tests of….Further tests of….Now the shift is up down, so the animal Now the shift is up down, so the animal searches in the ‘up/down’ axissearches in the ‘up/down’ axis

Landmark

Search

The Vector Sum ModelThe Vector Sum Model

Cheng concluded that the pigeons must Cheng concluded that the pigeons must be adding self – goal and goal to landmark be adding self – goal and goal to landmark vectors.vectors.This is the only model that explains the This is the only model that explains the search patternssearch patternsEureka!Eureka!

ConclusionsConclusions

Animals can use many sources of Animals can use many sources of information to navigateinformation to navigateMultiple sources usually point to the same Multiple sources usually point to the same placeplaceHierarchical representations I thinkHierarchical representations I think