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"Long
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August 03, 2010
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The evolution of animal personalities
May 30, 2007
Courtesy Santa Fe Institute
and World Science staff
Animals differ strikingly in character and temperament, biologists
say, but just recently has it become clear that personalities are a widespread phenomenon in the animal kingdom. A bird in which
personality differences have been studied, the Carolina Chickadee. Authors
of a report in the April Journal of General Psychology found that
individual chickadees display "strong behavioral consistency despite...
major change[s] in social context," a sign of individual
personalities. (Image courtesy U.S. National Institutes of Health) Why do different personality types exist within one population when, at first sight, one would expect one type to be more successful than another? Why are individuals not more flexible considering that personality rigidity sometimes leads to seemingly inefficient behavior? Why do we find the same types of traits correlated with each other in very different kinds of animals? The authors began with two observations. First, personality variations often involve basic differences in overall willingness to take risks. Second, individuals are often confronted with a trade-off between current and future reproduction: the more one invests in current reproduction, the less resources remain for future opportunities, and vice versa. Send us a comment
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Personality differences have been documented in more than 60 species including primates, rodents, birds, fish, insects and
squid, said researchers who presented a study on the subject in the May 31 issue of the research journal
Nature.
In the work, Max Wolf of the University of Groningen, The Netherlands, and colleagues offered an evolutionary explanation for the origin of animal personalities, defined as consistent behavior over time and in different situations.
The issue is poorly understood, according to the group.
Under evolutionary theory, a population’s gene pool changes as more successful individuals reproduce more, and thus spread their genes—while
poorly adapted individuals’ genes tend to die out. These considerations
raise three questions, according to Wolf and colleagues:
This led the authors to argue that in many cases a simple underlying principle shapes personalities: the more an individual stands to lose in terms of future reproduction, the more cautious it’s likely to be, over time and all kinds of situations.
Using a mathematical model, the researchers found that this fundamental trade-off can give rise to populations where some individuals put more emphasis on future reproduction than others. Those who invest in future reproduction evolve to be consistently risk-averse in different contexts, such as encounters with predators and aggressive interactions.
Those who focus on current reproductive success are more
risk-prone, according to Wolf, who is currently at the Santa Fe Institute
in New Mexico.
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Animals differ strikingly in character and temperament. Yet just recently has it become clear that personalities are a widespread phenomenon in the animal kingdom, biologists say. Personality differences have been described in more than 60 species including primates, rodents, birds, fish, insects and mollusks, said researchers who presented a study on the subject in the May 31 issue of the research journal Nature. In the work, Max Wolf of the University of Groeningen, Germany, and colleagues offered an evolutionary explanation for the origin of animal personalities, defined as consistent behavior over time and in different situations. The issue is poorly understood, according to the group. Evolution is the principle that a population’s gene pool changes as more successful individuals reproduce more, and thus spread their genes through the group—while poorly adapted individuals’ genes tend to die out. This raises three questions, according to Wolf and colleagues: Why do different personality types exist within one population when, at first sight, one would expect one type to be more successful than another? Why are individuals not more flexible considering that personality rigidity sometimes leads to seemingly inefficient behavior? Why do we find the same types of traits correlated with each other in very different kinds of animals? The authors began with two observations. First, personality variations often involve basic differences in overall willingness to take risks. Second, individuals are often confronted with a trade-off between current and future reproduction: the more one invests in current reproduction, the less resources remain for future opportunities, and vice versa. This led the authors to argue that in many cases a simple underlying principle shapes personalities: the more an individual stands to lose in terms of future reproduction, the more cautious it’s likely to be, over time and all kinds of situations. Using a mathematical model, the researchers found that this fundamental trade-off can give rise to populations where some individuals put more emphasis on future reproduction than others. Those who invest in future reproduction evolve to be consistently risk-averse in different contexts, such as encounters with predators and aggressive interactions. Individuals who focus on current reproductive success are more risk-prone.