Only monkeys and dolphins among all inhabitants on our planet are comparable in terms of their brain development to man.
A group of researchers led by Oksana Vasilieva from the Institute of Medical and Biological Problems, Moscow, assesses adaptation capabilities of monkeys in various stress situations that are likely to occur during space flights. The experiments involve only rhesus monkeys, which are not so close to man as anthropoid apes, and therefore are considered less smart.
The monkey is an inquisitive animal, especially when it is young. Placed before a monitor protected with a transparent plastic cover it starts moving the joystick aimlessly. The movements make an image appear on the screen. Sooner or later the cursor hits a certain spot that triggers a whistling sound followed by a dragee dropping into a tray placed near the joystick. The dragee smells banana. The monkey puts the delicious thing in the mouth. The reinforcer makes the monkey seek conditions that have led to it and repeat the rewarding movements of the cursor .
In this manner, conditioning is created, which lasts as long as it brings about joy or relief from pain. The conditioned response is needed for adaptation to changing existence conditions or environment.
“Here we deal with an instrumental response rather than with the classical conditioned response discovered by the Russian scientist Ivan Pavlov and associated with psychic salivation occurring when food is in sight”, says Olga Vasilieva. “For example, a dog is rewarded with a piece of sugar for dancing. It this way it learns to do things. Everything what a dog or any other animal does is an instrument to get a reward.”
Teaching monkeys to play computer games develops instrumental conditioning. The lucky hit suggests to the tested monkey that the image on the screen be somehow linked with a banana dragee, therefore it seeks to attain the reinforcer through purposeful manipulations. Then a simple task of placing the cursor on a motionless blue frame, which repeats the shape of the screen, gives way to more sophisticated jobs. By turns, the frame loses its top, bottom , left and right sides . Then two sides are removed at a time and at last only one side remains to be successively downsized by factors of two, four and eight to a 1.5cm by 2cm strip. The assignment gets more complicated when the monkey is offered to capture a moving image by predicting its direction after it bounces off the screen border.
Another monkey-oriented computer game program features wading through a maze or choosing the option, out of two available, which delivers a food reinforcer. With an instrumental reflex formed, this program may serve as a stepping stone for various tests aimed at assessing memory, manipulation dexterity, or activity of inhibition processes in the primates’ brain. Or to assess the monkeys’ abilities to manage stress in the course of testing, especially in situations which are likely to occur during space flights. It should be mentioned that for experiments involving monkeys duly authorization was obtained from the Committee on Bioethics.
Although under normal conditions all the ten monkeys were successful in over 90 per cent of computer game experiments, under stress they behaved differently. Some of them got adapted to limited manoeuvrability early and played actively. Others needed more time for adaptation as they seemed to learn from scratch, starting from simple game versions and gradually passing over to more complex ones. The third group subjects responded in a pure aggressive manner , moving the joystick disorderly and ignoring the reward even if they accidentally got it.
Zero-gravity is another critical factor of a space flight. On the ground it is imitated by submersion. In model experiments, monkeys wearing watertight suits are put to sit in a warm bath. The first three days are the hardest for the subjects, since they undergo adaptation when water fractions in their bodies are displaced. Therefore, the monkeys start playing computer games only on the fifth day and not every animal can cope with tasks assigned. In a situation where the primate feels uneasy , its brain activity is inhibited and its capability for work is low, adaptation varies from monkey to monkey. To investigate higher nervous activity in primates, American primatologists have developed a computer-based technique, which is widely applied. It is important that the monkeys work when they are willing to and not when an experimentalist wants them to work. According to Olga Vasilieva the method has a bright prospect in terms of its application. For instance, when comparing the ability to learn among man, anthropoid ape and macaque. The technique may be adapted to test the intellectual ability of handicapped children and even to develop their capabilities.
Translated by Zaghid Yusoupov
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