Sync or be sunk.
It`s one of nature`s basic rules for meeting, mating and communicating, say scientists who are studying how:
– Fish swim in precise schools and birds swerve in perfect formation.
– People pick up each other`s conversational beats.
– Animals match their mating urges to the season.
– Internal rhythms time human sexual maturity.
The inner beat.
Remember how John Travolta in ”Saturday Night Fever” strode down the street, keeping time with his own, internal rhythm?
It doesn`t happen just in the movies.
When people talk, they unconsciously move their bodies in time with their speech, say researchers who have analyzed filmed conversations. Not only does the speaker coordinate speech and movement, but listeners also pick up the beat.
The synchronization is too rapid for our eyes to detect, but it shows up clearly in detailed analyses of sound motion pictures, according to psychologist William Condon of the Boston University School of Medicine.
”You`ll see the speaker`s arm going out for three frames, his head down for three, leg out for three. During the same three frames, the first part of the word may be being emitted by the speaker.” At the same time, the listener may close his eyes for three frames, open them for the next three, flex his fingers for three and turn his head for three.
No one is sure what drives these tempos, but they seem to be as natural as breathing. Even infants match their mother`s rhythms, said Dr. Joseph Jaffe, a psychiatrist at New York State Psychiatric Institute.
”Deep down, we believe there are biological clocks that time social behavior, just as they time respiration, heart rate. . . . Babies can make discriminations within a fraction of a second and be trained to manipulate them,” Jaffe said.
These early rhythms may set the stage for developing conversational skills, Jaffe said. ”We always believed conversation starts with the first syllable of the first word, such as `Mamma,` and the final crowning glory is dialogue. Now it looks like at least the rhythmic skills precede the other part.”
Faulty rhythms may be a factor in some social and developmental problems. When Condon analyzed films of people with dyslexia, he found that the right side of the body was moving in synchronism with the person`s speech, but the left side was out of phase. Movements on the left side matched the spoken rhythm but were as many as seven frames late.
And films of one autistic girl showed her turning toward sounds 47 frames late, Condon said.
Some researchers believe the closer the match between two people`s speech and movement rhythms, the better their rapport. A couple falling in love tend to make ”long, languorous movements together” and to mirror each other`s body language more than do casual acquaintances, Condon said.
Conversely, misunderstandings between people-and even between racial or ethnic groups-may happen when they`re literally out of sync.
Condon has studied only a few conversations between blacks and whites but sees differences that could hamper communication.
”Both synchronize their movement with their speech but in different ways,” Condon said. For example, he said a person from one background may move his right hand with the beginning consonant, the left with the vowel and both with the concluding consonant, whereas a person from another background would sustain the movement all the way across.
Deborah Tannen, an associate professor of linguistics at Georgetown University and author of ”That`s Not What I Meant,” (Ballantine, $2.95)
analyzed a taped dinner table conversation among three New Yorkers, two Californians and a Briton.
”I started out the study thinking I was going to find out each person`s individual style, but the three people who had similar backgrounds were doing certain things in common that had a positive effect with each other but a negative effect with the others,” Tannen said.
Length of conversational pauses seems to be a key.
”Whichever group has the faster-paced style is seen as dominating the conversation and cutting people off,” Tannen said. ”It`s not that they`re intending to do it, but the amount of pause they`re anticipating comes and goes before the other person realizes it.”
”I`m absolutely certain that`s what was going on” in recent conversations between Nancy Reagan and Raisa Gorbachev at the summit in December, Tannen said. Gorbachev was described as a ”chatterbox who dominated conversations,” but really she was just trying to fill what would be awkward pauses in a fast-paced Russian conversation. Reagan, on the other hand, was waiting for what she considered an appropriate pause.
Tannen added: ”. . . It`s really staggering that all around the world the group that tends to be slower speaking with longer pauses is negatively stereotyped as stupid and uncooperative.”
Consider the quandary of creatures who can`t just pick up the phone to arrange dates with potential mates.
Figuring out when and where to meet takes a special kind of synchronism, especially in animals that reproduce only at certain times of the year. Courtship displays, including specific sounds and movements, help coordinate reproductive rhythms, writes Roger Caras in his book, ”The Private Lives of Animals” (McGraw Hill, $12.95).
In some animals-for example, mayflies and tiny flies called midges-mass nuptial flights are precisely timed to the season and hour.
Being late for a date is more than a social gaffe in the animal world. It can be a life-or-death matter for the next generation. In temperate climates, the breeding cycles of many species are timed so that young are born in the spring, when food is most plentiful. This gives the youngsters time to grow and develop enough to fend for themselves by the next winter.
Cues from the environment help seasonal breeders keep track of the time. Day length is one of the best cues, because unlike temperature or rainfall, it repeats the same cycle each year.
Migration complicates matters.
”An animal that faced a flight of 5,000 or 6,000 miles between summering and wintering grounds could not survive as a species if individuals received the inner signals to mate at the wrong end of the trip,” Caras writes. ”If the salmon lays its eggs at the seaward end of its journey instead of in the sweet water of its own natal stream, the salmon would cease to be.”
Compared with animals that have to schedule their sexual urges with travels and seasonal cycles, humans seem relatively simple. Yet how the body synchronizes sexual maturity with growth so that puberty comes at the right time still is a mystery, said Dr. Robert Kelch, professor and chairman of pediatrics at the University of Michigan.
”We don`t really understand what are all the cues for human sexual maturity,” he said. Factors such as exercise, genetics and even the altitude at which a person is raised may affect the timing.
In humans the reproductive system becomes nearly fully mature during gestation and early infancy, then shuts down and remains inactive during childhood.
But long before a youngster shows signs of sexual maturity, changes begin as the child sleeps. Around age 8 in girls and 9 to 10 in boys, the pituitary gland at the base of the brain begins sending pulses of a hormone called LH into the bloodstream. LH prompts the production of sex hormones by the girl`s ovaries and the boy`s testes.
What starts the LH pulses? Animal studies suggest that spurts of another hormone, GnRH, trigger LH release. GnRH comes from the hypothalamus, a part of the brain involved in control of appetite, temperature and other body functions. The brain`s changing sensitivity to the sex hormones estrogen and testosterone may in turn regulate GnRH release.
The big mystery is what controls the brain`s sensitivity to hormones. Chemical messengers called neurotransmitters may play a role. Kelch plans to study the problem by using a scanning technique that shows the brain at work. By studying children before and after puberty, he hopes to see when and where different neurotransmitters are working in the brain and how their activity changes at different ages.
For as long as people have been watching flocks of birds and schools of fish, they`ve wondered how the animals manage to fly or swim in such apparently perfect synchronism. They start out going one way, then suddenly shift direction, remaining in a tight group.
”The assumption always was that there had to be a leader there,” said Frank Heppner, honors professor of zoology at the University of Rhode Island. Researchers came up with all sorts of ideas to explain how the group knew how to follow the leader, everything from sound communication to pressure waves.
”The problem was how on earth, if you`ve got 10,000 birds or 50,000 birds, would they pick a leader. Would this be some kind of king bird or an election?”
In truth, there is no leader, said Wayne Potts, a postdoctoral fellow at the University of Florida in Gainesville, who analyzed high-speed films of bird flocks. Potts got interested in the problem because he had flown military aircraft in formation and knew how difficult abrupt maneuvers are.
When a flock of birds turns, the turn spreads through the flock like a wave through water, Potts discovered.
”If the flock banks left, the turn always starts on the right,” Potts said. ”That indicates the birds are turning into the flock, not away.”
Often the birds turn to avoid danger, such as a falcon trying to attack. So any bird near the source of danger can initiate the turn.
The turn spreads from bird to bird at a speed of about 38 milliseconds
(thousandths of a second), three times faster than a bird`s reaction time. Apparently the birds see the wave coming and react before it gets to their immediate neighbors, Potts said.
That idea is bolstered by his discovery that birds nearest the point where the turn begins take about 62 milliseconds to respond. The second set of neighbors takes about 48 milliseconds, and birds farther in respond faster and faster.
Heppner is using the mathematical idea of chaos to understand bird maneuvers. Chaos theory seeks predictable rules underlying unpredictable results.
Heppner came up with three rules for turning bird flocks:
First, ”if you`ve got a bunch of birds all flying in the same direction, some fraction will randomly change direction at some time.”
Next, ”if one of your neighbors ahead of you turns toward you, you will also turn in the same direction.”
Finally, ”if more than a certain fraction of your neighbors turn in a certain direction, you`ll turn the same way.” Because birds` eyes are on the sides of their heads, they act as ”wide-angle lenses,” allowing the birds to see movement in all directions, he said.
The next step is to use the rules to develop a computer model of flying bird flocks.
Heppner concludes that synchronism can be simpler than it looks.
”When you look at these flocks of birds, if you`re thinking in terms of human experience, you have to invoke leadership and intelligence to explain how humans could do the same things. But it`s very possible that very complicated things could have a simple foundation.”
A STOPWATCH AT EVERY TURN
Examples of synchronism can be found in almost every phase of life. Here are some:
– Frog choruses-In many tropical and semitropical regions, thousands of frogs of as many as two dozen species call at the same time and place. The main function is to attract and stimulate females, who face the daunting task of picking out a male of the right species from the croaking crowd.
– Odors from male mice stimulate sexual receptivity in female mice. If the females are in a group, the males` odors synchronize the females`
reproductive cycles.
– Flowering plants time their blooming and nectar production with peaks in pollinator activity. For example, flowers that attract hawkmoths (large nocturnal moths) open in the evening, giving off powerful fragrances.
– In kangaroos, timing between offspring is carefully controlled. The female breeds again as soon as one baby is born. The second fertilized egg begins dividing but stops at the 100-cell stage and continues development only when the first baby is old enough to take care of itself.
– Animals that live where nature offers little protection from predators must match themselves to their surroundings. But when the colors of the environment change with the season, so must the animals. Ptarmigan and weasels synchronize their color changes with nature`s, from brown in the summer to white in the winter.
– In some parts of Asia and the western Pacific, dense swarms of fireflies cluster in trees, where the males flash in unison.
– In experiments, mice housed together tend to synchronize their activity patterns, showing similar timing of rest, eating and moving around.
