08/24/2005
Personality
The August 15 issue of Newsweek featured an article by Pat Wingert and Martha Brant titled “Reading Your Baby’s Mind”. The article describes research directed at finding out what goes on in the minds of very young babies only a few months old. It seems that these little guys and gals have a lot more going on than expected. In fact, they have some pattern recognition capabilities that exceed those of adults or even slightly older children. I was surprised to learn that a baby at 3 months or less can not only recognize a picture of its mother but can also recognize its mother in a photo that has been cut up into pieces and scrambled. Yet, as the baby becomes older and accustomed to everything in its place, this ability is lost.
The prevailing view had been that a baby’s early life is a chaotic time spent trying to mimic things that it sees and learning the most basic emotions. However, babies are more sophisticated emotionally than was thought. For example, researcher Sybil Hart at Texas Tech University has performed one experiment hundreds of times that demonstrates jealousy at an early age. A mother and her 6-month-old baby are brought into a room and the baby is placed in a high chair. Hart and the mother engage in a conversation about a children’s book, paying no attention to the baby. Typically, the baby just looks around, seeming rather bored. Then Hart leaves and brings in a doll, hands it to the mother with instructions to cuddle and play with the doll, still ignoring the baby.
In almost every case, the baby suddenly perks up and pays close attention to this new development. Soon, the baby becomes quite disturbed by all the attention paid to another “baby” and starts to cry, often emoting so strongly that it turns beet red and the experiment is concluded with appropriate soothing by the mother. This type of experiment shows clearly that the baby is showing jealousy, with the emotional outburst being easily spotted and easy to interpret.
What about more subtle emotions or reactions? Over the years, scientists have become familiar with babies’ reactions and their meanings. For example, by combining observed attention spans with how long a baby stares at something new or, in some cases, whether the baby turns away, can be interpreted as indicating interest or surprise, fear or fascination, etc. Now we have more sophisticated methods such as brain scans, computerized tracking of eye movements and MRI to see how the baby’s responses compare with those of adults.
Let’s see how the simple technique of watching how an individual reacts to something new or unexpected can be used to study another primate, the lemur. The lemur is that wide-eyed critter found on the island of Madagascar and is a lower form of primate than the monkey. Researchers were interested to see whether or not the lemur has the ability to count. Unfortunately, I’ve lost the reference to this study but do remember, hopefully, the pertinent details.
The researchers used “magic” to test the young lemurs, which have a very short attention span. The scientists used the old trick of showing the lemur a group of 1, 2 or 3 balls, then covering them and then removing the cover to reveal either none, the same or one more ball than previously. They then measured the time spent by the lemur staring at the new situation, concluding that more time spent looking at it conveys that the lemur is surprised that a missing or extra ball is present. If it’s surprised, that indicates that the lemur has a rudimentary ability to count, at least up to 2 or 3.
Other animals have demonstrated more advanced counting abilities and emotional behaviors. Yesterday, I golfed with a veterinarian and we were discussing the famed African grey parrot Alex, which I’ve mentioned on a number of occasions in these columns. Alex has an extensive vocabulary and an amazing ability to interact with people and respond intelligently to questions. The vet and I talked about how Alex seems to have a sense of humor, toying with new people by purposely giving the wrong answers to questions until reprimanded.
Some scientists criticize researchers who ascribe human characteristics or emotions, “personality” if you will, to an animal. They apparently feel that this credits the animal with more intellect than is warranted. I tend to believe that some critters have a lot more on the ball than we think. An article in the July 29 issue of Science titled “Strong Personalities Can Pose Problem in the Mating Game” by Elizabeth Pennisi ties in with this personality issue. The article notes that a quarter of a century ago, the late Stephen J. Gould and Richard Lewontin stirred up the evolutionary biology crowd with a proposal that maladaptive traits could persist if they carried with them some sort of benefit to the animal. (Incidentally, I found in Gould’s book “I Have Landed” the statement that he considered Lewontin the smartest man he ever met.)
Take an animal’s personality (if you don’t like the term personality, call it a “behavior syndrome”). What kind of possible advantage is it when a female fishing spider has such an aggressive personality that, sensing the gentle tap on the water by a male fishing spider seeking a romantic rendezvous, she eats the poor guy before he gets any further? Certainly, from the male’s standpoint, that female’s hostile personality is a maladaptation of the worst kind. From the female’s standpoint, she just killed a potential mate and a chance to pass along her genes to another generation. On the other hand, her aggressive personality has resulted in her seeking out and devouring many other tasty tidbits, which plumped her up to the point she became attractive enough to warrant a tap on the water from a potential suitor. Her hostile demeanor also serves to help her defend her territory.
Andrew Sih, a behavioral ecologist at the University of California, Davis, is one of those promoting the idea of Gould and Lewontin. Sih suggests that some animals are stuck with their dispositions and don’t have the means of modifying them. Another behavioral ecologist, J. Chadwick Johnson of the University of Toronto, Scarborough, followed the behavior of some female fishing spiders from birth to adulthood. He found that the females that were more aggressive during childhood grew to be plumper than their less aggressive contemporaries. The aggressive females were also bolder in responding to predators. When Johnson mimicked a bird tapping on the water, all the spiders dived to get away but the aggressive females came to the surface first, putting themselves in greater danger if the bird was still there. The same aggressive females were also more likely to snack on males come a courting.
A reversal of roles occurs with an insect known as the water strider. Sih split up male striders into groups of whose personalities ranged from mild mannered to very aggressive. He then monitored the successes of the various groups in their mating. The females didn’t really care for the more aggressive, macho males and would avoid them and their fellow macho companions. As a result, the more aggressive male striders fared poorly in their mating endeavors, both individually and as a group. The aggressive males didn’t have the capacity to modify their personality to fit the occasion. This certainly isn’t the case with our own species, for which both males and females can be quite adaptive in the quest for a mate.
“Whilst this planet has gone cycling on according to the law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.” So ends Darwin’s “Origin of Species” (quote taken from Gould’s book). For the sake of the male fishing spider, let’s hope the female evolves to lose her taste for potential mates.
Allen F. Bortrum
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