Some of the research involved only human subjects, of course. How to get children to comply when parents ask them to do something, for instance, has been studied only with humans. However, the principles on which the techniques of such research are based were developed in the study of animals. This is a key feature of animal research—namely, to develop an understanding of behavioral mechanisms and then use that understanding to apply the knowledge.
In physics and engineering the process is similar. Take the study of flight. Basic science elaborates the features of aerodynamics using mathematics, physics, and wind tunnel tests. This basic research determines the principles and lawful relations of flight, which engineers then translate into the design of aircraft. Because the move from armchair understanding and wind tunnels to actual flight includes important new variables, one still needs to test these translated principles. As in the move from animal research to human application, the move from physics to engineering looks for principles and then applies them, testing constantly every step of the way. No one objects by saying, "I'm terribly insulted that you would ask me to fly to Acapulco in a plane designed according to findings from wind tunnel experiments under highly contrived simulated conditions."
Over the past few decades, there has been a great expansion in methods of studying humans and nonhuman animals. We can look far more deeply at brains, genes, and communication between individual cells, and processes within the cells of animals. Also, we have increased our ability to focus on understanding thought (cognition) and emotions. The net effect of this is to understand many processes that elaborate not only human development, functioning, and health but also emotions, thought processes, worry, and other features in nonhuman animals. (For more on this convergence of humans and animals, read on.
Now, there are many topics in psychology—including leadership, group decision-making, the effects of law and policy on human behavior, witness behavior in the court room, the effects of day care, racism and its causes, teaching reading and math, marital harmony and discord, and crowd behavior—in which there is a solid base of science that rarely or never draws on animal research. It would be wrong to leave you with the impression that psychology always comes back to animal research and to omit mention of the broad scientific swath of work on the unique features of humans. But psychologists tend to do the public a similar disservice when they underplay the importance of animal research.
There are larger points in play here, including a growing sense that the lower animals are not so low and we are not so high. Many psychological characteristics and their biological underpinnings appear to be conserved—that is, many characteristics of human psychology evolved in other animals and have been retained in humans. This is why we can study fish, flies, and frogs in order to learn about ourselves. But there's also a smaller, practical point to make about the psychological technology for shaping children's behavior. Acknowledging the roots of this body of knowledge in animal research is a good way to remind ourselves how to use it properly. Next time you are tempted to give your kid a six-hour timeout so that she has ample opportunity to reflect on the moral consequences of storing used chewing gum in the couch, remember that a rat will not come to regret its trespasses in usefully behavior-changing ways no matter how long you put it in timeout—and, the research clearly shows, neither will your lovely, unique, highly advanced human child.