Alpha males need more than just size
Being the biggest is not always the best, and politicking is an important skill, a new study of chimpanzees suggests.
Friendly tactics, along with aggression, help smaller chimpanzees become alpha males of their group, according to the study led by Anne Pusey of the University of Minnesota.
Typically a chimpanzee group has 6 to 12 males competing for the rank of alpha male, the top-ranking male who gets his pick of food and females. In many species, the largest, strongest male rises to power because he is best able to attack and intimidate others. But Pusey's recent work suggests that smaller males can also gain alpha rank.
Her group analyzed data collected from a group of chimpanzees at the Gombe National Park in Tanzania between 1989 and 2003 to see if friendly gestures helped males gain alpha position. Specifically, researchers studied the benefit of a male chimp grooming other males. Grooming helps eliminate parasites and is seen as a friendly and relaxing activity.
Pusey's group found that the largest of the three alpha males, Frodo, acquired and kept his alpha male position solely by aggression. Freud, an average-size male, kept his alpha position by using some aggressive techniques but also grooming others to gain their favor.
Wilkie, the smallest of the three alpha males, spent the most time grooming others to keep his top position. Though he exhibited some aggressive behavior - walking with a swagger and strutting with his hair standing on end - he never physically attacked others.
Smaller males, said Pusey, "had to work harder to keep friends because they were smaller," but doing so could effectively help maintain a desirable social status.
BOTTOM LINE: Smaller males can become alpha males by using friendly gestures to make allies.
CAUTIONS: The study was a small one and larger studies are needed to confirm these findings.
WHAT'S NEXT: Study the behavior of more alpha males in other chimpanzee groups to confirm this relationship between size and grooming.
WHERE TO FIND IT: February edition of American Journal of Primatology
SENA DESAI GOPAL
Colors have associations - red for danger and blue for tranquility. Scientists have tried to understand how these perceptions affect performance on cognitive tasks - which colors help get the job done - but their experiments have yielded conflicting results.
Now, a new study led by Ravi Mehta and Rui Zhu of the University of British Columbia says it depends on both the color and the task at hand.
Red focuses attention on detail while blue frees creative thoughts. That pattern emerged from studying subjects solving anagrams, proofreading lists, or designing a toy using computers with different color displays.
Faced with anagrams of words involving risk, for example, study subjects were more accurate if the words were on a red background. Asked to dream up a toy from 20 shapes in either blue or red, the subjects designed more practical toys from red parts, and more original toys from blue parts. Judges made their decisions using black and white photocopies.
BOTTOM LINE: The beneficial effect of colors varies depending on the task at hand.
CAUTIONS: The results, compiled in a study at a North American university, may not apply to other cultures.
WHAT'S NEXT: Colors we use in daily life could be attuned to the tasks involved, from warning labels to the classroom walls.
WHERE TO FIND IT: Science, Feb. 5
ELIZABETH COONEY 