geomancer
02-10-2011, 09:15 PM
Science 28 January 2011:
Vol. 331 no. 6016 pp. 401-402
DOI: 10.1126/science.1199780
Insect Swarm Intelligence
Honeybee Democracy by Thomas D. Seeley Princeton University Press, Princeton, NJ, 2010. 279 pp. $29.95. ISBN 9780691147215.
Lars Chittka and Alex Mesoudi
The reviewers are at the Research Centre for Psychology, School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK.
E-mail: [email protected]
The swarming behavior of honeybees constitutes one of the most astounding phenomena in group decision-making among animals: When a new queen is raised in the honeybee hive, her predecessor departs along with approximately 10,000 workers. Rather than en masse erratically searching around for a new location (as a group of vertebrates might), the bee swarm does something remarkable. It acts, in a sense, like a single being: pausing, collecting information, carefully considering its options, and then making a unanimous decision about where to move. The consensus can take days to reach. Several hundred scouts fan out across a territory of up to 70 km2 seeking a potential home, such as a hollow tree with a knothole entrance. Successful scouts return to the swarm and advertise the location of their discovery, but there is initially much disagreement among scouts and difference in the quality of sites found. The swarm must come to an agreement, however. Individual bees won't survive on their own, nor will groups of bees without their queen. If the polling about where to move takes too long, the swarm risks exposure to severe weather conditions that may spell the end of the whole endeavor. And if the group chooses a poor-quality site, the colony will not survive the winter. When Martin Lindauer, Nobel laureate Karl von Frisch's most successful student, first described the debate among scouts to his mentor, von Frisch exclaimed: “Congratulations! You have witnessed an ideal parliamentary debate; your bees can evidently change their decision when other scouts have to announce a better nesting site” (1). Having dedicated decades to the study of this unique, pluralistic decision-making process, Tom Seeley offers an engaging and fascinating account of it in Honeybee Democracy.
Seeley writes with infectious enthusiasm, and indeed there is much to be enthusiastic about. When he took over the study of collective bee decision-making from Lindauer in the 1970s, many mysteries remained. How is a cohesive relocation of several thousand worker bees and a reluctant queen that hasn't seen daylight since her nuptial flight at least a year earlier initiated? How do scouts explore the landscape and evaluate the suitability of cavities for nesting sites? Back at the swarm, how do they convey the quality of their discoveries? How is agreement reached in the absence of any top-down, centralized moderation of the debate? What ensures that the consensus converges on the best option? What is the signal for lift-off? Once the swarm is airborne, how can some hundred informed scouts guide a “school-bus sized cloud,” containing several thousand individuals, over a distance of several kilometers to an inconspicuous knothole? Incorporating findings from innumerable ingenious experiments by the author, Honeybee Democracy includes answers to all the above questions.
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Pondering collective intelligence. Tom Seeley during a 1974 pilot study of a swarm choosing its home.
CREDIT: JOHN G. SEELEY/COURTESY THOMAS D. SEELEY
Some ingredients of Seeley's approach are worth highlighting. He strongly advocates starting an investigation with the inductive (bottom-up) approach used by von Frisch and Lindauer before him. Carefully observing your study organism in its natural setting, taking everything in, you get to know your study organism thoroughly from many angles—and let unexpected or inexplicable phenomena pop out for you. Only then do you develop testable hypotheses and rigorous experiments to zero in on how particular processes might be explained. Surprisingly, even though many great behavioral biologists have adhered to this philosophy, it is now fashionable to use instead a top-down, hypothesis-driven approach: starting with what you and pretty much everyone else expects and either confirming or rejecting that. It is hard to see how one would ever explore genuinely new territory in this way. Seeley's simple message is, keep your eyes open for the unexpected.
Another ingredient of the author's success is the elegance and simplicity of his experiments. In times when researchers are often assessed not by intellectual contribution or productivity but instead by the amount of funding they secure, Seeley shows that cutting-edge science can be produced with “equipment obtainable from the local shopping mall” (as Francis Ratnieks observes on the book's dust jacket). Indeed, many of the experimental procedures he used are simple like sushi (and equally exquisite). Some require considerable courage, however: one simultaneously exposed Seeley to the risk of falling from a tree, being attacked by angry bees, and being killed by cyanide gas. One senses that he carried out experiments in the golden age before the blight of “health and safety” and “risk assessment.” The book is also pleasantly free of any pretense of an applied justification for the work. Although at one point Seeley inadvertently defused a tense cold war confrontation between the United States and the Soviet Union by pointing out that what was thought to be chemical weapons residue was actually bee excrement, his work was inspired entirely by the quest for scientific discovery. Funders and policy-makers today need reminding that pure, blue-skies research is a component of any healthy society.
Nonetheless, the work might have considerable implications beyond the question of how honeybee swarms move house. Seeley argues that human groups—juries, committees, governments—could learn from how bees make decisions. He suggests minimizing a leader's influence, allowing each group member to contribute their opinions in an independent and unbiased manner, and only reaching a single group decision once a democratic quorum has been reached. Seeley even put these rules into practice as head of Cornell University's Department of Neurobiology and Behavior by minimizing his own influence, encouraging minority views, and making decisions through secret ballot.
Yet we should not ignore the disanalogies between human and bee decision-making. Human groups are frequently not united by common interest in the way that honeybee swarms are united by shared kinship. The former often comprise conflicting factions each fighting for their own self-interest. And when human groups do act as cohesive units, they are often too cohesive, with their members rarely acting as independent decision-makers like honeybee scouts. Conformity prevents dissenting views and conflicting evidence from being considered, often with disastrous consequences—such as when NASA ignored warnings that a component on the Challenger shuttle was faulty and went ahead with its doomed launch (2). Moreover, whereas honeybee swarms are cooperative by virtue of shared kinship, groups of people are cooperative partly through conformity (3). Eliminating conform ity may eliminate decision-making errors, but it may also reduce the cohesiveness that maintains human groups in the first place.
It is to Seeley's credit that he stimulates such a wide-ranging debate over the similarities and differences in group decision-making among species. In addition, Honeybee Democracy offers wonderful testament to his career of careful investigation of a remarkable natural phenomenon. The breadth and depth of the studies reported in it should inspire all students of animal behavior.
References
↵ M. Lindauer, in Experimental Behavioral Ecology, B. Hölldobler, M. Lindauer, Eds. (G. Fisher, Stuttgart, 1985), pp. 5–7.
↵ J. K. Esser, J. S. Lindoerfer, J. Behav. Decis. Making 2, 167 (1989). CrossRef
↵ R. Boyd, P. J. Richerson, Culture and the Evolutionary Process (Univ. Chicago Press, Chicago, 1985).
Vol. 331 no. 6016 pp. 401-402
DOI: 10.1126/science.1199780
Insect Swarm Intelligence
Honeybee Democracy by Thomas D. Seeley Princeton University Press, Princeton, NJ, 2010. 279 pp. $29.95. ISBN 9780691147215.
Lars Chittka and Alex Mesoudi
The reviewers are at the Research Centre for Psychology, School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK.
E-mail: [email protected]
The swarming behavior of honeybees constitutes one of the most astounding phenomena in group decision-making among animals: When a new queen is raised in the honeybee hive, her predecessor departs along with approximately 10,000 workers. Rather than en masse erratically searching around for a new location (as a group of vertebrates might), the bee swarm does something remarkable. It acts, in a sense, like a single being: pausing, collecting information, carefully considering its options, and then making a unanimous decision about where to move. The consensus can take days to reach. Several hundred scouts fan out across a territory of up to 70 km2 seeking a potential home, such as a hollow tree with a knothole entrance. Successful scouts return to the swarm and advertise the location of their discovery, but there is initially much disagreement among scouts and difference in the quality of sites found. The swarm must come to an agreement, however. Individual bees won't survive on their own, nor will groups of bees without their queen. If the polling about where to move takes too long, the swarm risks exposure to severe weather conditions that may spell the end of the whole endeavor. And if the group chooses a poor-quality site, the colony will not survive the winter. When Martin Lindauer, Nobel laureate Karl von Frisch's most successful student, first described the debate among scouts to his mentor, von Frisch exclaimed: “Congratulations! You have witnessed an ideal parliamentary debate; your bees can evidently change their decision when other scouts have to announce a better nesting site” (1). Having dedicated decades to the study of this unique, pluralistic decision-making process, Tom Seeley offers an engaging and fascinating account of it in Honeybee Democracy.
Seeley writes with infectious enthusiasm, and indeed there is much to be enthusiastic about. When he took over the study of collective bee decision-making from Lindauer in the 1970s, many mysteries remained. How is a cohesive relocation of several thousand worker bees and a reluctant queen that hasn't seen daylight since her nuptial flight at least a year earlier initiated? How do scouts explore the landscape and evaluate the suitability of cavities for nesting sites? Back at the swarm, how do they convey the quality of their discoveries? How is agreement reached in the absence of any top-down, centralized moderation of the debate? What ensures that the consensus converges on the best option? What is the signal for lift-off? Once the swarm is airborne, how can some hundred informed scouts guide a “school-bus sized cloud,” containing several thousand individuals, over a distance of several kilometers to an inconspicuous knothole? Incorporating findings from innumerable ingenious experiments by the author, Honeybee Democracy includes answers to all the above questions.
View larger version:
In this page In a new window
Pondering collective intelligence. Tom Seeley during a 1974 pilot study of a swarm choosing its home.
CREDIT: JOHN G. SEELEY/COURTESY THOMAS D. SEELEY
Some ingredients of Seeley's approach are worth highlighting. He strongly advocates starting an investigation with the inductive (bottom-up) approach used by von Frisch and Lindauer before him. Carefully observing your study organism in its natural setting, taking everything in, you get to know your study organism thoroughly from many angles—and let unexpected or inexplicable phenomena pop out for you. Only then do you develop testable hypotheses and rigorous experiments to zero in on how particular processes might be explained. Surprisingly, even though many great behavioral biologists have adhered to this philosophy, it is now fashionable to use instead a top-down, hypothesis-driven approach: starting with what you and pretty much everyone else expects and either confirming or rejecting that. It is hard to see how one would ever explore genuinely new territory in this way. Seeley's simple message is, keep your eyes open for the unexpected.
Another ingredient of the author's success is the elegance and simplicity of his experiments. In times when researchers are often assessed not by intellectual contribution or productivity but instead by the amount of funding they secure, Seeley shows that cutting-edge science can be produced with “equipment obtainable from the local shopping mall” (as Francis Ratnieks observes on the book's dust jacket). Indeed, many of the experimental procedures he used are simple like sushi (and equally exquisite). Some require considerable courage, however: one simultaneously exposed Seeley to the risk of falling from a tree, being attacked by angry bees, and being killed by cyanide gas. One senses that he carried out experiments in the golden age before the blight of “health and safety” and “risk assessment.” The book is also pleasantly free of any pretense of an applied justification for the work. Although at one point Seeley inadvertently defused a tense cold war confrontation between the United States and the Soviet Union by pointing out that what was thought to be chemical weapons residue was actually bee excrement, his work was inspired entirely by the quest for scientific discovery. Funders and policy-makers today need reminding that pure, blue-skies research is a component of any healthy society.
Nonetheless, the work might have considerable implications beyond the question of how honeybee swarms move house. Seeley argues that human groups—juries, committees, governments—could learn from how bees make decisions. He suggests minimizing a leader's influence, allowing each group member to contribute their opinions in an independent and unbiased manner, and only reaching a single group decision once a democratic quorum has been reached. Seeley even put these rules into practice as head of Cornell University's Department of Neurobiology and Behavior by minimizing his own influence, encouraging minority views, and making decisions through secret ballot.
Yet we should not ignore the disanalogies between human and bee decision-making. Human groups are frequently not united by common interest in the way that honeybee swarms are united by shared kinship. The former often comprise conflicting factions each fighting for their own self-interest. And when human groups do act as cohesive units, they are often too cohesive, with their members rarely acting as independent decision-makers like honeybee scouts. Conformity prevents dissenting views and conflicting evidence from being considered, often with disastrous consequences—such as when NASA ignored warnings that a component on the Challenger shuttle was faulty and went ahead with its doomed launch (2). Moreover, whereas honeybee swarms are cooperative by virtue of shared kinship, groups of people are cooperative partly through conformity (3). Eliminating conform ity may eliminate decision-making errors, but it may also reduce the cohesiveness that maintains human groups in the first place.
It is to Seeley's credit that he stimulates such a wide-ranging debate over the similarities and differences in group decision-making among species. In addition, Honeybee Democracy offers wonderful testament to his career of careful investigation of a remarkable natural phenomenon. The breadth and depth of the studies reported in it should inspire all students of animal behavior.
References
↵ M. Lindauer, in Experimental Behavioral Ecology, B. Hölldobler, M. Lindauer, Eds. (G. Fisher, Stuttgart, 1985), pp. 5–7.
↵ J. K. Esser, J. S. Lindoerfer, J. Behav. Decis. Making 2, 167 (1989). CrossRef
↵ R. Boyd, P. J. Richerson, Culture and the Evolutionary Process (Univ. Chicago Press, Chicago, 1985).