The Handy Psychology Answer Book. Lisa J. Cohen

activities than people with a different variety of that gene. In tests of necessity, scientists disrupt the neural activity and show that this impairs the psychological behavior in question. For example, if a rat’s hippocampus is removed, the rat will not be able to learn new mazes. This shows that the hippocampus is necessary for creating new memories. In tests of sufficiency, an increase in the specific type of neural activity increases the behavior in question. If rats are given a drug that increases the level of the chemical vasopressin, they show more social behavior. This supports that vasopressin is sufficient to initiate male rats’ social behavior. Research that shows association, sufficiency and necessity in a brain-behavior relationship is far stronger than research that only shows association. In sum, we have to be cautious in how we interpret neurobiological research and take care not to over-interpret the findings.

      What role has the study of brain damage played in the history of neuroscience?

      Long before the development of today’s brain imaging technology people still suffered from various kinds of brain disease and trauma. People had strokes or serious brain injuries, for example, from wars or from industrial accidents. By carefully studying the changes in behavior that accompanied these brain traumas and then mapping the affected parts of the brain on autopsy after the person died, scientists have learned a tremendous amount about how different psychological functions map onto different parts of the brain. As mentioned above, Alexander Luria, the famous Russian neuropsychologist, made great advances in the field by studying brain-injured soldiers in World War II. With today’s brain imaging methods, however, the lesions to the brain can be identified while the person is still alive.

      COGNITIVE SCIENCE

      What is cognitive science?

      Cognitive science can be seen as an outgrowth of the cognitive revolution. Cognitive scientists use tools of evolutionary psychology, linguistics, computer science, philosophy, and neurobiology to investigate mental phenomena from a scientific vantage point. One of the aims of cognitive science is to create complex computer programs to model psychological and brain processes. Cognitive scientists address a broad range of psychological problems including memory, language, learning, and decision-making. Theories of neural networks address how the vast network of brain cells, or neurons, work together to create complex behaviors. Out of these investigations, many remarkable technological innovations have developed, including voice recognition software and advances in robotics.

      Can the mind be reduced to mathematical equations?

      Computer models of human psychology are based on mathematical rules. It is a philosophical question whether the mind can ever be wholly explained by a finite set of mathematical equations. A new branch of philosophy called neurophilosophy endorses this view while the holistic tradition of William James, the Gestalt theorists, and the humanistic psychologists would argue that the whole is more than the sum of its parts. As of now, there is no definitive answer to this question. Another controversy regarding cognitive science and artificial intelligence involves the concept of qualia. This refers to the subjective quality of a mental process, the yellow of yellow, the sadness of sad. AI may well be able to model the neurological processes underlying the perception of the color yellow, but can it explain how these neuronal firing patterns produce the experience of yellow? At present, we simply do not know the answer to these fundamental philosophical questions.

      What is artificial intelligence?

      Artificial intelligence (AI) is a computer-based model of intellectual processes. AI scientists build computer programs to simulate human intelligence. Their implicit assumption is that psychology can be reduced to mathematical algorithms, the set of mathematical rules from which computer programs are built. As of yet, AI has been restricted to relatively simple aspects of human psychology, such as visual perception and object recognition. Nonetheless, AI models have become increasingly sophisticated and have taken on the complex problem of learning. How can a computer program modify itself in the face of new information? Pattern recognition software depends on a kind of teaching. The programs are designed to respond to incoming feedback from the outside world. Responses that are reinforced are strengthened and those that are not reinforced are weakened. In this way, AI is similar to both the behaviorist and evolutionary models of psychology.

      PSYCHOLOGY AS A SCIENCE

      What is the purpose of psychological research?

      Psychological research provides the absolute foundation of modern psychology. It is the bread and butter, the bricks and mortar, of the science of psychology. Research allows us to study the questions of psychology in a rigorous and systematic way so psychology can be more than a collection of subjective opinions and anecdotal observations.

      Is psychological research ever completely objective?

      Arguably, no. Human behavior is too complex, and influenced by too many factors to ever presume 100 percent certainty in our conclusions. Even the best studies depend to some extent on subjective judgments. Therefore we aim for the most rigorous methods possible, accounting for possible confounds, biases, and limitations in our research. That is also why we employ the peer review method for quality control before publishing our studies in journals, so that other experts in the field can independently and anonymously review each paper. Empirical research is the most rigorous method we have but it is not a crystal ball. Luckily, the best way to refute erroneous research is more research. Research can be used to correct its own mistakes.

      What is a variable?

      A variable is the building block of psychological research. It is the fundamental unit of a study. Any trait or behavior that we wish to study is translated into a variable so that we can measure it with numbers. We use the term variable because we are studying traits that vary across individuals or across time. If we want to study the relationship between red hair and school achievement, we must first operationalize our traits of interest, that is turn them into variables. We will code hair color as 1 = red hair, 0 = not red hair. We will operationalize school achievement by using grades, translating A through F into a 13-point scale, (A+ = 13, A = 12, A-= 11, B+ = 10, etc.). Having translated our traits of interest into numerical variables, we can now use mathematics to calculate the relationships between the variables. This, in effect, is the nuts and bolts of psychological science.

      What are the major methods used in psychological research?

      A number of different methods allow flexibility in the way we conduct psychological research. In experimental studies the variables are controlled and manipulated to give the maximum precision to our observations. The drawback of such control is that we cannot know how well the behavior observed in the artificially controlled environment will generalize to everyday life. In an observational study, we systematically observe behavior in its natural environment. We sacrifice a degree of control and precision for naturalism. Cross-sectional studies assess behavior at one point in time. Longitudinal studies observe behavior over a period of time, sometimes over decades. In quantitative studies, behavior is quantified into numbers. Even though quantitative research is the most common form of psychological research, qualitative research has gained more attention recently. This involves careful observation without the use of numbers.

      How have laws changed to protect people from abusive scientific experiments?

      The history of scientific research with human subjects has been fraught with abuses. Examples abound, including the Nazis’ murderous experiments on concentration camp victims and the infamous Tuskegee experiments of the 1930s in which poor and uneducated African-American men with syphilis were deliberately deprived of available treatments.

      Psychological research is not excluded from this disturbing history. Examples include Stanley Milgram’s work in the 1960s, in which subjects were falsely led to believe that they were causing pain, injury, and even death by administering electric shocks to another