*** Appendix - The status of cognitive maps in insects, according to recent research

Back to: a model of spatial navigation in insects *** SUMMARY of conclusions reached References

Menzel, Brandt, Gumbert, Komischke and Kunze (2000) claim that some insects e.g. (honeybees) possess two spatial reference systems:

(i) an egocentric (observer-centred) system, also known as specialised route memory (SRM), which makes use of path integration and a sequence of landmarks; and

(ii) an allocentric (world-centred) system, which combines multiple views and movements in a common frame of reference.

The authors refer to the latter system as a general landscape memory (GLM). They suggest it is learned by bees during their reconnoitring flights around a new hive, and is only activated when the SRM cannot be used. They speculate about how the GLM is implemented at the neural level: it may simply list each landmark with its vector to the hive, or it may include multiple sequential views of landmarks, acquired during reconnaissance flights, or it may store the landmarks in a spatial memory, with a graph structure.

Giurfa and Capaldi (1999, p. 237) define a cognitive map as "a form of spatial memory, in which the geometrical relationships between defined points in space are preserved", from which it follows that "a cognitive map should allow novel short-cutting to occur".

Experiments designed to test novel short-cutting in bees produced conflicting results during the 1980s and 1990s. Recently, studies have shown that honeybees can use novel routes (Menzel, Brandt, Gumbert, Komischke and Kunze, 2000). Tests were performed near a prominent landmark (a steep, isolated hill). Foraging bees were captured at the training station and released at different sites, up to 180 degrees from their original bearings. Nevertheless, the bees generally managed to re-orient themselves towards the hive. Bees released at much greater distances, which they had never visited before, were unable to do this.

Novel short-cutting has been claimed by other researchers (e.g. Giurfa and Menzel, 2003), who summarise their findings as follows:

Furthermore, route-trained bees carrying a trans-ponder enabling harmonic radar to locate them were captured and released at a novel site, either when leaving the feeder to return to the hive, or when arriving empty at the feeder... Both groups of bees first flew their usual vector when released at a novel site, but then headed towards the hive after a phase of circling flights. Again, beacon orientation and navigation according to landscape features were excluded. Most importantly, bees sometimes also decided to fly back to the feeder first rather than directly to the hive. These and additional experiments can be explained by assuming that during their orientation flights, bees learned different locations in their surroundings and attached to the landmarks characterizing these locations local vectors pointing towards the hive...[T]he fact that bees foraging at a distant and constant feeder could decide to fly first back to the feeder rather than directly to the hive indicates a form of spatial memory in which some geometrical relationships between defined points in space are preserved, in agreement with Tolman's seminal paper...

However, alternative explanations have been proposed, and the existence of cognitive maps or even a GLM is disputed (Collett and Collett, 2002; Harrison and Schunn, 2003; Giurfa and Capaldi, 1999).

Giurfa and Capaldi suggest that "all around the nest, different landmark constellations might be linked to different flight vectors. In this way, bees might find their way home from any novel release site within this area, providing that it lies between two identifiable sites that give rise to different, established flight vectors. This type of vector map is different from a cognitive map..." (1999, p. 241).

Recently, Harrison and Schunn (2003) have tried to establish that egocentric processing is computationally cheaper than allocentric or exocentric processing, and that the cognitive map hypothesis is redundant, even for rats.

Back to: a model of spatial navigation in insects *** SUMMARY of conclusions reached References