(PET) — Scientist have identified hotheads and tiptoers, schmoozers and loners, divas, dullards and fearless explorers, and they have learned that animals, like us, often cling to the same personality for the bulk of their lives. — Global Animal

New York Times, Natalie Angier

I recently tried taking a couple of online personality tests, and I must say I was disappointed by the exercise. I was asked bland amorphisms like whether I was “someone who tends to find fault” with people (duh), is generally “friendly and agreeable” (see previous response), and always “does a thorough job” (can I just skip this question?).

Nowhere were there any real challenges like the following: Let’s say you are very hungry, and you go over to your favorite food dish. Inside you see, in addition to the standard blend of peanuts and insect parts, a bright pink plastic frog. How long before you work up the nerve to eat your dinner anyway? Or: You have just been ushered into a room that is in every way familiar, except that somebody has put a scrap of old, brown carpet in the middle of the floor. Do you keep your distance from the novelty item, or do you rush over and start pecking at it?

These and other vividly tangible gems are taken from the burgeoning field of animal personality research, the effort to understand why individual members of the same species can be so mulishly themselves, and so unlike one another on a wide variety of behavioral measures. Scientists studying animals from virtually every niche of the bestial kingdom have found evidence of distinctive personalities — bundled sets of behaviors, quirks, preferences and pet peeves that remain stable over time and across settings. They have found stylistic diversity in chimpanzees, monkeys, barnacle geese, farm minks, blue tits and great tits, bighorn sheep, dumpling squid, pumpkinseed sunfish, zebra finches, spotted hyenas, even spiders and water striders, to name but a few. They have identified hotheads and tiptoers, schmoozers and loners, divas, dullards and fearless explorers, and they have learned that animals, like us, often cling to the same personality for the bulk of their lives. The daredevil chicken of today is the one out crossing the road tomorrow.

Researchers are delving into the source and significance of all these animal spirits. They are asking questions like, when geese start on a wild goose chase, what sort of goose will lead the flock, and why do the rest choose to follow it? They are devising computer models to explain how different personality types can be maintained in a given animal population, and they are exploring the upsides and drawbacks of different personal styles.

In his studies of fishing spiders, for example, J. Chadwick Johnson, now at Arizona State University, has discovered that some juvenile female spiders are exceptionally voracious predators and thus grow into beefy, fecund adults. But the avarice has a potential downside. The big-mouthed female spiders have a nasty habit of cannibalizing potential mates before copulation, and without sperm to fertilize their eggs, all their hard-won superfecundity could go to waste.

Other scientists are exploring personal qualities that span phylogenies and allegories: Recent research suggests that highly sensitive, arty-type humans have a lot in common with squealing pigs and twitchy mice, and that to call a hypersensitive person thin-skinned or touchy might hold a grain of physical truth.

Some critics complain that the term “animal personality” is a bit too slick, while others worry that the entire enterprise smacks of that dread golem of biology, anthropomorphism — assigning human traits to nonhuman beings. Researchers in the field, however, defend their lingo and tactics. “Some of the behavior patterns we’re talking about are similar to what we call personality in human psychology literature,” said Max Wolf of the Max Planck Institute in Germany. “So why not call it personality in other animals?”

Alison M. Bell of the University of Illinois at Urbana, who studies personality in stickleback fish, said: “We’re not being cute and anecdotal, we’re looking at consistent differences in behavior that we can test and measure.”

Reporting in this month’s issue of the journal Animal Behaviour, researchers from the University of Glasgow addressed the widespread concern that the findings of animal personality studies, so often performed on captive subjects, may be laboratory artifacts, with scant relevance to how the creatures behave in nature.

Working with a group of 125 wild-caught blue tits over the course of two winters, Katherine A. Herborn and her colleagues first typed each bird’s personality in the lab, focusing on two key traits: neophobia, or fear of novelty, and the willingness to explore one’s surroundings. They put pink plastic frogs in the birds’ food dish and clocked the time it took each bird to feed. All the birds noticed the luminous intruder.

“You could see they were agitated, hopping around the cage,” said Ms. Herborn, who is completing her doctorate. But some of them shrugged off their fear and started feeding within seconds, while other birds kept distant for several minutes. Researchers also offered the birds a mix of familiar and novel enclosures and measured how long it took each tit to seek out new perches and poke through strange new compartments.

The researchers then released the tagged birds back into the wild and continued monitoring their neophobic and exploratory tendencies by changing bowl colors at existing feeding stations and adding new bird feeders elsewhere. “This was a much harder part of the study, and involved a lot of lugging around of batteries” for tracking equipment, Ms. Herborn said.

Despite the experimental challenges, the results were clear. Birds that had been frog-averse in captivity were every bit as skittish toward color changes outdoors, and the high explorers when caged were similarly adept at finding new feeding opportunities far afield. A bird in the lab worked like a bird in the bush.

And for birds of a feather to goose step together, someone must make the first move. As they reported last summer in Animal Behaviour, Ralf H. J. M. Kurvers of Wageningen University in the Netherlands and his colleagues sought to learn why when certain barnacle geese would start moving, others would honkily follow. They could find no obvious correlation between leadership and standard pluses like large size, maleness or social dominance. The only reliable predictor of goose leadership was boldness — the willingness to approach a new item like a scrap of carpet. Geese are not stupid. The boldest birds also proved the most adept at finding new food patches, and if you’re looking for grazing advice in a crowd, why not follow the goose with the golden track record?

Scientists suspect that small inherited predispositions are either enhanced or suppressed by experience, and computer models show that tiny discrepancies at the start can become enormous over time, through feedback loopings of positive reinforcement. Evidence is also emerging that certain physical setpoints affect temperament globally. Notable among such setpoints is the relative rate at which one’s nervous system processes sensory information.

“There are low information processors who don’t attend much to their environment and bulldoze through life,” said David Sloan Wilson of the State University of New York at Binghamton. “Then there are the sensitive ones who are always taking things in, which can be good because information is valuable, but it can also be overwhelming.”

Studies of highly sensitive people show their delicacy is “domain general,” Dr. Wilson said. Not only are they “exceptionally moved by symphonies” and find graphic depictions of violence “too hard to bear,” but they are also sensitive to drugs like caffeine, and their skin is easily irritated by the wrong soap, sunscreen and fabric. Highly sensitive pigs squeal a lot; highly sensitive people feel a lot. Sure, it’s painful at times. But just switch on some Bach and I’ll squeal my thanks for thin skin.