Global perception in small brains: topological pattern recognition in honey bees

Abstract

A series of experiments with honey bees demonstrate that their small brains nevertheless possess the ability for topological perception. Bees rapidly learned to discriminate patterns that are topologically different, and they generalized the learned cue to other novel patterns. By contrast, discrimination of topologically equivalent patterns was learned much more slowly and not as well. Thus, although the global nature of topological properties makes their computation difficult, topology may be a fundamental component of the vocabulary by which visual systems represent and characterize objects.

Fig. 1.

(Left) Y-maze apparatus for training and testing bees. Scale applies to the apparatus. (Right) Stimuli and results of experiments 1 and 2. (a) Training stimulus pair. (b–f) Test stimulus pairs. Bars and numbers show relative frequencies of choices in favor of the positive (+) and negative (-) stimuli, as measured after training and in various transfer tests. Light and dark bars depict results from experiments 1 and 2, respectively. n1 and n2 are the numbers of choices analyzed in experiments 1 and 2, respectively, and p1 and p2 are the respective values associated with a χ² test for significant difference from random-choice behavior.

Fig. 3.

Training (a) and test stimulus (b) pairs used in experiment 4. They were rotated to control the possible role of local differences in pattern intensity on discrimination. See text for details. The choice frequencies, number of choices (n), and P value in a χ² test for significant differences from random choice are given in the figure.

Fig. 2.

Stimulus and results of experiment 3, in which bees were trained to distinguish between an S and a ring with the S as the positive stimulus.

Fig. 4.

Learning curves for experiment 5 a and b. Triangles depict performance in distinguishing between two topologically different stimuli (an S and a ring, as in Fig. 2). Circles depict performance in distinguishing between two topologically equivalent stimuli (a disk and a square). The dashed line depicts the random choice level (50%). Twelve blocks were run for each pair of stimuli to attain the plateaus of the learning curves. Total choices in each block range from 28 to 43.

Fig. 5.

(A) The power spectra (2D Fourier transformation) of the S vs. the ring, and of the disk vs. solid square, used in experiments 5 and 6. The differences in power spectra between the S and the ring and between the disk and the square {Sum [(X - Y)²]} are 2.10 and 19.63, respectively. (B) The power spectra of three pairs of stimulus figures used in experiment 1.