Egocentric orientation
Egocentric navigation is useful when the environment is stable and lacks useful cues for orientation. While chasing prey, the predator may pay reduced attention to the surroundings. This can lead to situations when environmental cues are not at its
disposal if the prey suddenly disappears. Fiset et al. (2000) have shown that dogs can solve such problems by relying on linear egocentric information which codes the spatial relationship between the dog and the location of the object that has disappeared. In a follow-up study looking for the mechanism of this ability, Fiset et al. (2006) found that dogs are able to use very precise directional cues (less than 5 deg of angular deviation); they prefer to rely on directional information and disregard information on distance.
Dogs can find their way back to a target if they are deprived of any visual and auditory environmental information during the outward journey (Seguinot et al. 1998). It is assumed that the information about the distance travelled and the direction and magnitude of turnings enables the dogs (and other animals) to calculate the direction of the return path as well as the distance to the target (path integration). Dogs performed surprisingly well in such tasks when they were walked along an L-shaped 20-50 m path (without the possibility of seeing or hearing) in a large hall. When released at the end of the journey, dogs made the corresponding turn, pointing their body towards the target, and were also able to correctly judge the distance to be travelled before searching locally for the target (see Figure 7.1).
- 24 m
40 m
10 m
40 m
130 m
Figure 7.1 The testing of short-cuts In dogs, (a) In a field experiment Chapuis and Varlet (1987) took dogs to visit two baited locations from a starting point. After being released dogs walked first to the nearest location and then took a short-cut towards the furthest place, (b) Blindfolded and earplugged dogs are taken on an L-shaped route and then released from the end point (R) to find out whether they find their ways back to the baited starting point, (c) Dogs can perform optimal detouring (choosing the shorter path) when the goal is hidden. In trials with an opaque fence dogs mostly choose the shorter path; however, if they can see the target (food) through the fence, continuous visual contact takes control over the behaviour and acts against the preference for the shorter path (Chapuis et al. 1983). ■ ■ ■ ■ the dog's path; —, outward journey; +, starting position; location of reward/target; R, point of release.
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