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Number-based visual generalisation in the honeybee.

Gross HJ, Pahl M, Si A, Zhu H, Tautz J, Zhang S - PLoS ONE (2009)

Bottom Line: Using a y-maze, we found that bees can not only differentiate between patterns containing two and three elements, but can also use this prior knowledge to differentiate three from four, without any additional training.Control experiments confirmed that the bees were not using cues such as the colour of the exact configuration of the visual elements, the combined area or edge length of the elements, or illusory contours formed by the elements.To our knowledge, this is the first report of number-based visual generalisation by an invertebrate.

View Article: PubMed Central - PubMed

Affiliation: Biocentre, University of Würzburg, Würzburg, Germany.

ABSTRACT
Although the numerical abilities of many vertebrate species have been investigated in the scientific literature, there are few convincing accounts of invertebrate numerical competence. Honeybees, Apis mellifera, by virtue of their other impressive cognitive feats, are a prime candidate for investigations of this nature. We therefore used the well-established delayed match-to-sample paradigm, to test the limits of honeybees' ability to match two visual patterns solely on the basis of the shared number of elements in the two patterns. Using a y-maze, we found that bees can not only differentiate between patterns containing two and three elements, but can also use this prior knowledge to differentiate three from four, without any additional training. However, bees trained on the two versus three task could not distinguish between higher numbers, such as four versus five, four versus six, or five versus six. Control experiments confirmed that the bees were not using cues such as the colour of the exact configuration of the visual elements, the combined area or edge length of the elements, or illusory contours formed by the elements. To our knowledge, this is the first report of number-based visual generalisation by an invertebrate.

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Results of transfer tests with various pattern configurations.The pattern below each pair of bars is the sample and that above each bar is the choice pattern; the y-axis gives the choice frequency. The data represent the pooled first choices (from each foraging trip) of individual bees. (a) The configuration of dots on the sample and choice patterns is randomised. (b) The blue dot patterns in (a) are replaced with yellow stars, to see if bees can transfer their matching ability to different, unknown stimuli. (c) The sample and choice patterns are composed of different elements. (d) The choice patterns are modified so that the total area of the elements is equal. (e) The choice elements are modified so that the total edge length of the elements is equal. n = number of bees per condition. Error bars show standard error. *** denotes statistically significant difference at p<0.001, ** denotes p<0.01, * denotes p<0.05 and ○ denotes p>0.05.
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pone-0004263-g003: Results of transfer tests with various pattern configurations.The pattern below each pair of bars is the sample and that above each bar is the choice pattern; the y-axis gives the choice frequency. The data represent the pooled first choices (from each foraging trip) of individual bees. (a) The configuration of dots on the sample and choice patterns is randomised. (b) The blue dot patterns in (a) are replaced with yellow stars, to see if bees can transfer their matching ability to different, unknown stimuli. (c) The sample and choice patterns are composed of different elements. (d) The choice patterns are modified so that the total area of the elements is equal. (e) The choice elements are modified so that the total edge length of the elements is equal. n = number of bees per condition. Error bars show standard error. *** denotes statistically significant difference at p<0.001, ** denotes p<0.01, * denotes p<0.05 and ○ denotes p>0.05.

Mentions: Once the bees' performance in the basic DMTS task had stabilised, they were presented with new patterns, in which the configuration of dots was randomised. There were 19 bees in the 1st half of the transfer test when the sample was three blue dots, and 17 bees in the 2nd half of the transfer test, when the sample was two blue dots (as denoted in Fig. 3a). An individual bee visited the apparatus during a transfer test for four times on average (one visit per configuration). The bees were able to carry out this more difficult task, and attained a score of 70% (significantly different to 50%, p<0.01) for the three-dot-sample, and 79% (significantly different to 50%, p<0.001) for the two-dot-sample. The performance was significantly reversed after the sample pattern was swapped from the two-dot sample to the three-dot-sample (p<0.001, Fig. 3a). The same notations are used in all other figures. This experiment gave the first indication that the trained bees might be using the number of elements in the visual arrays as a cue to perform the matching task.


Number-based visual generalisation in the honeybee.

Gross HJ, Pahl M, Si A, Zhu H, Tautz J, Zhang S - PLoS ONE (2009)

Results of transfer tests with various pattern configurations.The pattern below each pair of bars is the sample and that above each bar is the choice pattern; the y-axis gives the choice frequency. The data represent the pooled first choices (from each foraging trip) of individual bees. (a) The configuration of dots on the sample and choice patterns is randomised. (b) The blue dot patterns in (a) are replaced with yellow stars, to see if bees can transfer their matching ability to different, unknown stimuli. (c) The sample and choice patterns are composed of different elements. (d) The choice patterns are modified so that the total area of the elements is equal. (e) The choice elements are modified so that the total edge length of the elements is equal. n = number of bees per condition. Error bars show standard error. *** denotes statistically significant difference at p<0.001, ** denotes p<0.01, * denotes p<0.05 and ○ denotes p>0.05.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2629729&req=5

pone-0004263-g003: Results of transfer tests with various pattern configurations.The pattern below each pair of bars is the sample and that above each bar is the choice pattern; the y-axis gives the choice frequency. The data represent the pooled first choices (from each foraging trip) of individual bees. (a) The configuration of dots on the sample and choice patterns is randomised. (b) The blue dot patterns in (a) are replaced with yellow stars, to see if bees can transfer their matching ability to different, unknown stimuli. (c) The sample and choice patterns are composed of different elements. (d) The choice patterns are modified so that the total area of the elements is equal. (e) The choice elements are modified so that the total edge length of the elements is equal. n = number of bees per condition. Error bars show standard error. *** denotes statistically significant difference at p<0.001, ** denotes p<0.01, * denotes p<0.05 and ○ denotes p>0.05.
Mentions: Once the bees' performance in the basic DMTS task had stabilised, they were presented with new patterns, in which the configuration of dots was randomised. There were 19 bees in the 1st half of the transfer test when the sample was three blue dots, and 17 bees in the 2nd half of the transfer test, when the sample was two blue dots (as denoted in Fig. 3a). An individual bee visited the apparatus during a transfer test for four times on average (one visit per configuration). The bees were able to carry out this more difficult task, and attained a score of 70% (significantly different to 50%, p<0.01) for the three-dot-sample, and 79% (significantly different to 50%, p<0.001) for the two-dot-sample. The performance was significantly reversed after the sample pattern was swapped from the two-dot sample to the three-dot-sample (p<0.001, Fig. 3a). The same notations are used in all other figures. This experiment gave the first indication that the trained bees might be using the number of elements in the visual arrays as a cue to perform the matching task.

Bottom Line: Using a y-maze, we found that bees can not only differentiate between patterns containing two and three elements, but can also use this prior knowledge to differentiate three from four, without any additional training.Control experiments confirmed that the bees were not using cues such as the colour of the exact configuration of the visual elements, the combined area or edge length of the elements, or illusory contours formed by the elements.To our knowledge, this is the first report of number-based visual generalisation by an invertebrate.

View Article: PubMed Central - PubMed

Affiliation: Biocentre, University of Würzburg, Würzburg, Germany.

ABSTRACT
Although the numerical abilities of many vertebrate species have been investigated in the scientific literature, there are few convincing accounts of invertebrate numerical competence. Honeybees, Apis mellifera, by virtue of their other impressive cognitive feats, are a prime candidate for investigations of this nature. We therefore used the well-established delayed match-to-sample paradigm, to test the limits of honeybees' ability to match two visual patterns solely on the basis of the shared number of elements in the two patterns. Using a y-maze, we found that bees can not only differentiate between patterns containing two and three elements, but can also use this prior knowledge to differentiate three from four, without any additional training. However, bees trained on the two versus three task could not distinguish between higher numbers, such as four versus five, four versus six, or five versus six. Control experiments confirmed that the bees were not using cues such as the colour of the exact configuration of the visual elements, the combined area or edge length of the elements, or illusory contours formed by the elements. To our knowledge, this is the first report of number-based visual generalisation by an invertebrate.

Show MeSH