Cooperation Between Dead Reckoning (Path Integration) and External Position Cues

Abstract

Dead reckoning (also called path integration) is the process by which a navigating organism derives its current position relative to an Earthbound reference point from its own locomotion. Dead reckoning requires the continuous estimation of changes in direction and location through self-generated signals and the computation of position on the basis of these signals.(i) Hymenopterous insects measure rotations and translations mainly with the help of optical references such as the Sun and translational visual flow. By contrast, mammals are able to estimate their position on the basis of purely ‘internal’ information; that is, signals generated in the vestibular system by inertial forces, somatosensory feedback, and efference copies (copies of central commands that control the performance of rotations and translations). Obviously, the assessment of the angular and linear components of locomotion is much more precise if it is assisted by external references than if this is not the case.(ii) Only man-made dead reckoning systems yield precise position information through the twofold integration over time of inertial signals deriving from angular and linear acceleration. On the biological level, all species tested so far seem to rely on a simplified form of path ‘integration’: in certain test situations, arthropods and mammals (including humans) commit similar systematic errors. This suggests that species from unrelated taxa update position according to a similar algorithm.

Mechanisms of homing in the fiddler crabUca rapax2. Information sources and frame of reference for a path integration system

“…First, what is the frame of referenceegocentric or exocentric -in which the goal location is encoded? There is ambiguity in the literature about what constitutes egocentric and exocentric reference systems (Etienne et al, 1999). Path integration was originally formulated in exocentric coordinates (Mittelstaedt and Mittelstaedt, 1973); it might conceivably be encoded that way, and this can be explicitly tested (Benhamou, 1997).…”

Is habitat selection in the wild shaped by individual‐level cognitive biases in orientation strategy?

“…While the effect was small, we suggest that this may not necessarily be due to a weak relationship between habitat selection and orientation strategy, but to our ability to detect bias towards each strategy. Our probe trial was biased towards allocentric individuals and so we were unable to distinguish between individuals that used an egocentric strategy and those that used a mixed strategy (Etienne et al 1996(Etienne et al , 1998Marchette et al 2011). Future studies could attempt to tease apart biases towards allocentric or egocentric cues, or a mixed strategy to obtain a clearer estimate of how these biases influence habitat selection.…”

“…Our probe trial was biased towards allocentric individuals and so we were unable to distinguish between individuals that used an egocentric strategy and those that used a mixed strategy (Etienne et al . 1996, 1998; Marchette et al . 2011).…”

Mammalian Navigation, Neural Models and Biorobotics

“…An essential question is whether path-integration and the use of landm arks do interact (Etienne et al, 1998a). Path-integration depends on a hardwired m echanism which functions throughout the organism ' s locom otor activity, independently of learned site-dependent cues, but which leads to cumulative errors.…”