Laboratory Exercises in Animal Behavior - Weightlifting in Humans
Weightlifting in Humans
Thus far, we have concerned ourselves with the behavior of nonhuman animals, but animal behaviorists also study human behavior. Studies of human behavior make the same assumptions and use the same general methods as studies of other animals, although there are some real differences as well. One obvious difference is that in this case the animal behaviorist is of the same species as the subject, so we might have some personal insight into the behavior in question. Interestingly, however, these personal insights are often not very helpful, at least no more so than the insights of a biologist who is very familiar with his/her nonhuman study species. The reason for this paradoxical phenomenon is rooted in the assumption that behavior is a functional response to environmental conditions and evolutionary history. So, humans or other animals need not be conscious (and are generally assumed to be not aware) of the behavioral "choices" they are making. In other words, if you asked someone why s/he did something, the answer might tell you something about the underlying psychological mechanism that helps to produce and regulate the behavior, or the social influences on the individual, but it would not necessarily tell you anything about the causation, development, function, or evolution of that behavior. On these four levels (the four principle axes of animal behavior), humans can be studied in the same ways as other animals.
Another major difference is that we might propose certain critical experimental tests of some behavioral hypotheses for nonhuman animals, but we certainly would not propose them for humans. We would not, for example, deprive an infant of all acoustic experience in an attempt to determine what role such experience might play in the development of speech. We might, however, investigate speech development in infants who are profoundly deaf. Althouh such a study would not satisfy the strict demands of proper experimental design (because subjects were not assigned to treatment groups randomly, and because other aspects of their conditions and environments were not strictly controlled), the study would provide some important information in a way that is ethically acceptable to society in general and science in particular.
A word of caution is appropriate here. Not everyone accepts the notion that humans can be studied using the same methods used with other animals. Some object because they see humans as unique and completely separate from animals, as a result of our ability to reason and communicate with language, for example. Others object because the results seem to imply that certain differences (such as between men and women) are "natural" or "biological" and are therefore reasons for gender discrimination or racial prejudice or other social injustice.
Although animal behaviorists understand these objections, and have considerable sympathy for them in many cases, they do not accept them. Humans are closely linked with other animals in every other way, which is why we use animals in medical research and product testing, so there is every reason to believe that they are linked behaviorally as well. Although it is true that humans are able to reason and communicate with language, animal behaviorists see these as natural extensions of abilities expressed in nonhuman animals. But perhaps more importantly, animal behaviorists understand that "nature" is not a moral force. Nature, or more precisely natural and sexual selection (and other evolutionary mechanisms) do not decide what is "right" or "wrong"; they only favor what works in comparison with the available alternatives. We humans decide what is right and wrong, and we should do so regardless of what nonhuman animals do "naturally," or what humans might have been selected to do in our dim evolutionary past. We should have some understanding of these aspects of human behavior, however.
In this exercise we are interested in studying the behavior of humans of high school age from the perspective of animal behavior. We will also use this exercise to introduce a new aspect of functional analysis, the concept of "sexual selection."
Sexual Selection
When Charles Darwin proposed his evolutionary mechanism of natural selection (individual differences in survival result in favorable characteristics becoming more common in the next generation), he also recognized that some features of animals could not be explained by survival advantages. For example, Darwin wondered how to explain the evolution of the peacock's colorful and elaborate tail. It seemed to Darwin that such a tail would decrease the peacock's survival, not increase it, because birds with big, bright tails would be at higher risk of predation than birds with small, dull tails. Darwin noticed, however, that usually such characterists were found only in one or the other sex. Although Darwin concentrated on characteristics found only in males (such as the peacock's tail), current animal behaviorists realize that, in theory, the process could work equally well on females as on males, and there are examples of species in which females are big and bright, and males are small and dull.
Sexual selection is the selection for traits that are concerned solely with increasing mating success. There are two types of sexual selection: "intra-sexual selection," which involves competition among members of one sex for fertilizations, and "inter-sexual selection," in which traits that are attractive to the other sex are favored. Although they are conceptually distinct, the two types of sexual selection can act at the same time, and often sexual selection is thougth to act in opposition to natural (survival) selection. In our peacock example, an intra-sexual selection advantage would predict that males with large, bright tails can defeat those with small, dull ones in fights for females. An inter-sexual selection advantage would suggest that females prefer males with large, bright tails over males with small, dull ones. Regardless of whether intra- or inter-selection (or both) explains the peacock's beautiful tail, natural selection may simultaneously favor males with small, dull tails because they are less visible to predators, so the two forms of selection may be acting in opposition to one another. Marion Petrie, a British animal behaviorist, has actually studied sexual selection in peacocks in British gardens, and finds evidence of female preference for males with big, bright tails (inter-sexual selection).
The theory of sexual selection has become quite complicated in the past 30 years, and currently rivals natural selection in complexity and explanatory power, at least for traits in which males and females of a species differ. We are interested in applying this theory to humans. Specifically, we will examine how the behavior of males who are weightlifting changes when females enter the room. For example, we might predict, on the basis of sexual selection theory, that males would do fewer repetitions of greater weight (ten reps of 200 pounds) in the presence of a female audience than when only males are present (twenty reps of 100 pounds). Would you make the same prediction for female lifters? Why or why not?
Methods
We offer two examples of methods for you to consider, but you should feel free to design your own instead of using either of ours.
Method 1.-Under the guise of lifting weights, a group of women enters the weight room. They lift some weights while secretly observing the males in the room. On the pages that they supposedly use to enter their own weights and "reps," they actually enter what the men (the subjects) lift. The female observers then compare their results to the same data collected by male observers, from another session using the same methods, to see if there is a difference in weight and number of repetitions. The same subjects should be observed by the female and male groups so that comparisons can be made "within subjects" (that is, what each subject did in the presence of females versus males).
Method 2.-Observations are made by a research team consisting of one female and one male observer. The team choses one subject, and both gather data on that subject. The female observer follows a man (the subject) around under the guise of learning how to use the weight machines. She writes down his weights and reps and then compares them with weights and reps used by the same subject to demonstrate the same machines to the male observer. Female and male pairs of observers can thus gather data on several different subjects, and all results can be pooled for analysis.
Things to Think about
At this point in our exploration of the study of animal behavior, you now have quite a bit of experience with the various elements of scientific research. For this reason, we now give you more freedom to decide what to do and how to do it. Of course, with freedom comes responsibility. In this exercise, you will decide what you should think about, but in general, you should consider questions, hypotheses, and predictions; methods and data analysis; and ways to present your results.
Tips for Teachers
We have assumed that your school has a weight-training facility. Most high schools with football and/or wrestling programs have them, so we hope our assumption is valid for your school. If it isn't, you might ask your students to "brainstorm" some alternative venues or comparisons. If you are able to use the school weight room, it's probably a good idea to enlist the cooperation of the football or wrestling coach, who can help you to set up the "ruse" your student observers choose.
Let this exercise the your students' own from beginning to end. Let them pose the questions, design the methods, implement them, and analyze the results. Ask them to decide how to report their results, and whether to let the weightlifters (their subjects) in on them.
