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4Chapter 1 Biopsychology as a Neuroscienceabout ourselves by studying species that are related to usthrough evolution. The evolutionary approach has provento be one of the cornerstones of modern biopsychologicalinquiry. Each discussion that relates to the evolutionaryperspective is marked by an evolutionary perspective tab.Neuroplasticity Until the early 1990s, most neuroscientists thought of the brain as a three-dimensional array ofneural elements “wired” together in a massive network of circuits. The complexity ofthis “wiring diagram” of the brain was staggering, but it failed to capture one of the brain’s most important features. In the last two decades, research has clearlydemonstrated that the adult brain is not a static network ofneurons: It is a plastic (changeable) organ that continuouslygrows and changes in responseto the individual’s genes andBlog-Onexperiences. The discovery ofI have a website with blogneuroplasticity, arguably theposts, a link collection, andsingle most influential discovother items: www.biopsyc ery in modem neuroscience, is.com. Keep an eye out forcurrently influencing many“blog-on” boxes—theylogicalindicate that material on my areas of biopsycho research.Aneuro plasticitytabsite is relevant to what youmarkseachdiscussionorhave just been reading.study of neuroplasticity.1.1 What Is Biopsychology?Biopsychology is the scientific study of the biology ofbehavior—see Dewsbury (1991). Some refer to this fieldas psychobiology, behavioral biology, or behavioral neuroscience; but I prefer the term biopsychology becauseit denotes a biological approach to the study of psychology rather than a psychological approach to the study ofbiology: Psychology commands center stage in this text.Psychology is the scientific study of behavior—the scientificstudy of all overt activities of the organism as well as all theinternal processes that are presumed to underlie them (e.g.,learning, memory, motivation, perception, and emotion).The study of the biology of behavior has a long history,but biopsychology did not develop into a major neuroscientific discipline until the 20th century. Although it is notpossible to specify the exact date of biopsychology’s birth,the publication of The Organization of Behavior in 1949 byD. O. Hebb played a key role in its emergence (see Brown& Milner, 2003; Cooper, 2005; Milner, 1993). In his book,Hebb developed the first comprehensive theory of howcomplex psychological phenomena, such as perceptions,emotions, thoughts, and memories, might be producedby brain activity. Hebb’s theory did much to discreditthe view that psychological functioning is too complexto have its roots in the physiology and chemistry of thebrain. Hebb based his theory on experiments involvingboth humans and laboratory animals, on clinical casestudies, and on logical arguments developed from his ownM01 PINE5576 09 SE C01.indd 4insightful observations of daily life. This eclectic approachhas become a hallmark of biopsychological inquiry.In comparison to physics, chemistry, and biology,biopsychology is an infant—a healthy, rapidly growinginfant, but an infant nonetheless. In this text, you willreap the benefits of biopsychology’s youth. Because biopsychology does not have a long and complex history,you will be able to move quickly to the excitement of current research.1.2 What Is the Relation betweenBiopsychology and the OtherDisciplines of Neuroscience?Neuroscience is a team effort, and biopsychologists areimportant members of the team (see Albright, Kandel, &Posner, 2000; Kandel & Squire, 2000). Biopsychology canbe further defined by its relation to other neuroscientificdisciplines.Biopsychologists are neuroscientists who bring to theirresearch a knowledge of behavior and of the methods ofbehavioral research. It is their behavioral orientation andexpertise that make their contribution to neuroscienceunique (see Cacioppo & Decety, 2009). You will be ableto better appreciate the importance of this contributionif you consider that the ultimate purpose of the nervoussystem is to produce and control behavior (see Grillner &Dickinson, 2002).Biopsychology is an integrative discipline. Biopsycholo gists draw together knowledge from the other neuroscientific disciplines and apply it to the study of behavior. Thefollowing are a few of the disciplines of neuroscience thatare particularly relevant to biopsychology:Neuroanatomy. The study of the structure of the nervous system (see Chapter 3).Neurochemistry. The study of the chemical bases ofneural activity (see Chapter 4).Neuroendocrinology. The study of interactionsbetween the nervous system and the endocrine system (see Chapters 13 and 17).Neuropathology. The study of nervous system disorders (see Chapter 10).Neuropharmacology. The study of the effects of drugson neural activity (see Chapters 4, 15, and 18).Neurophysiology. The study of the functions andactivities of the nervous system (see Chapter 4).1.3 What Types of ResearchCharacterize theBiopsychological Approach?Although biopsychology is only one of many disciplinesthat contribute to neuroscience, it is broad and diverse.Biopsychologists study many different phenomena, and they8/30/13 5:23 PM

1.3 What Types of Research Characterize the Biopsychological Approach?approach their research in many different ways. In orderto characterize biopsychological research, this section discusses three major dimensions along which approaches tobiopsychological research vary. Biopsychological researchcan involve either human or nonhuman subjects; it can takethe form of either formal experiments or nonexperimentalstudies; and it can be either pure or applied.Human and Nonhuman SubjectsBoth human and nonhuman animals are the subject ofbiopsychological research. Of the nonhumans, mice andrats are the most common subjects; however, cats, dogs,and nonhuman primates are also commonly studied.Humans have several advantages over other animalsas experimental subjects of biopsychological research:They can follow instructions, they can report their subjective experiences, and their cages are easier to clean.Of course, I am joking about the cages, but the joke doesserve to draw attention to one advantage humans haveover other species of experimental subjects: Humansare often cheaper. Because only the highest standards ofanimal care are acceptable, the cost of maintaining ananimal laboratory can be prohibitive for all but the mostwell-funded researchers.Of course, the greatest advantage humans have as subjects in a field aimed at understanding the intricacies ofhuman brain function is that they have human brains. Infact, you might wonder why biopsychologists wouldbother studying nonhuman subjects at all. The answer liesin the evolutionary continuity of the brain. The brains ofhumans differ from the brains of other mammals primarily in their overall size and the extent of their corticaldevelopment. In other words, the differences between thebrains of humans and those of related species are morequantitative than qualitative, and thus manyof the principles of human brain functioncan be clarified by the study of nonhumans(see Nakahara et al., 2002; Passingham, 2009; Platt &Spelke, 2009).Conversely, nonhuman animals have three advantagesover humans as subjects in biopsychological research.The first is that the brains and behavior of nonhuman subjects are simpler than those of human subjects.Hence, the study of nonhuman species is more likely toreveal fundamental brain–behavior interactions. The second advantage is that insights frequently arise from thecomparative approach, the study of biological processesby comparing different species. For example, comparingthe behavior of species that do not have a cerebral cortexwith the behavior of species that do can provide valuableclues about cortical function. The third advantage is thatit is possible to conduct research on laboratory animalsthat, for ethical reasons, is not possible with humansubjects. This is not to say that the study of nonhumananimals is not governed by a strict code of ethics (seeM01 PINE5576 09 SE C01.indd 55Demers et al., 2006; Goldberg & Hartung, 2006)—it is.However, there are fewer ethical constraints on the studyof laboratory species than on the study of humans.In my experience, most biopsychologists display considerable concern for their subjects, whether they are oftheir own species or not; however, ethical issues are notleft to the discretion of the individual researcher. Allbiopsychological research, whether it involves human ornonhuman subjects, is regulated by independent committees according to strict ethical guidelines: “Researcherscannot escape the logic thatif the animals we observe are Blog-Onreasonable models of our Concerned about the ethicsown most intricate actions, of biopsychological researchthen they must be respected on nonhuman species?as we would respect our own Go to www.biopsyc.com/sensibilities” (Ulrich, 1991, animalresearchp. 197).Experiments and NonexperimentsBiopsychological research involves both experiments andnonexperimental studies. Two common types of nonexperimental studies are quasiexperimental studies and casestudies.Experiments The experiment is the method used byscientists to study causation, that is, to find out what causeswhat. As such, it has been almost single-handedly responsible for the knowledge that is the basis for our modernway of life. It is paradoxical that a method capable of suchcomplex feats is so simple. To conduct an experimentinvolving living subjects, the experimenter first designstwo or more conditions under which the subjects will betested. Usually, a different group of subjects is tested undereach condition (between-subjects design), but sometimesit is possible to test the same group of subjects under eachcondition (within-subjects design). The experimenterassigns the subjects to conditions, administers the treatments, and measures the outcome in such a way that thereis only one relevant difference between the conditionsbeing compared. This difference between the conditions iscalled the independent variable. The variable measuredby the experimenter to assess the effect of the independentvariable is called the dependent variable. If the experiment is done correctly, any differences in the dependentvariable between the conditions must have been caused bythe independent variable.Why is it critical that there be no differences betweenconditions other than the independent variable? The reason is that when there Simulate Elementsis more than one differof an Experiment atence that could affectMyPsychLabthe dependent variable,it is difficult to determine whether it was the independent variable or the unintended difference—called a8/30/13 5:23 PM

6Chapter 1 Biopsychology as a Neuroscienceconfounded variable—that led to the observed effectson the dependent variable. Although the experimentalmethod is conceptually simple, eliminating all confoundedvariables can be quite difficult. Readers of research papersmust be constantly on the alert for confounded variablesthat have gone unnoticed by the experimenters.An experiment by Lester and Gorzalka (1988) illustrates the prevention of confounded variables with goodexperimental design. The experiment was a demonstration of the Coolidge effect. The Coolidge effect is the factthat a copulating male who becomes incapable of contin uing to copulate with one sex partner can often recommence copulating with a new sex partner (see Figure 1.2).Figure 1.2   President Calvin Coolidge and Mrs. Grace Coolidge.Many students think the Coolidge effect is named after a biopsychologist named Coolidge. In fact, it is named after President CalvinCoolidge, of whom the following story is told. (If the story isn’t true,it should be.) During a tour of a poultry farm, Mrs. Coolidge inquiredof the farmer how his farm managed to produce so many eggs withsuch a small number of roosters. The farmer proudly explained thathis roosters performed their duty dozens of times each day.“Perhaps you could point that out to Mr. Coolidge,” replied theFirst Lady in a pointedly loud voice.The President, overhearing the remark, asked the farmer, “Doeseach rooster service the same hen each time?”“No,” replied the farmer, “there are many hens for each rooster.”“Perhaps you could point that out to Mrs. Coolidge,” repliedthe President.M01 PINE5576 09 SE C01.indd 6Before your imagination starts running wild, I shouldmention that the subjects in Lester and Gorzalka’s experiment were hamsters, not students from the undergraduate subject pool.Lester and Gorzalka argued that the Coolidge effecthad not been demonstrated in females because it ismore difficult to conduct well-controlled Coolidgeeffect experiments with females—not because femalesdo not display a Coolidge effect. The confusion, according to Lester and Gorzalka, stemmed from the fact thatthe males of most mammalian species become sexually fatigued more readily than the females. As a result,attempts to demonstrate the Coolidge effect in femalesare often confounded by the fatigue of the males. When,in the midst of copulation, a female is provided with anew sex partner, the increase in her sexual receptivitycould be either a legitimate Coolidge effect or a reaction to the greater vigor of the new male. Because femalemammals usually display little sexual fatigue, this confounded variable is not a serious problem in demonstrations of the Coolidge effect in males.Lester and Gorzalka devised a clever procedure tocontrol for this confounded variable. At the same timea female subject was copulating with onemale (the familiar male), the other maleto be used in the test (the unfamiliarmale) was copulating with another female. Then, bothmales were given a rest while the female was copulatingwith a third male. Finally, the female subject was testedwith either the familiar male or the unfamiliar male.The dependent variable was the amount of time thatthe female displayed lordosis (the arched-back, rumpup, tail-diverted posture of female rodent sexual receptivity) during each sex test. As Figure 1.3 illustrates, thefemales responded more vigorously to the unfamiliarmales than they did to the familiar males during thethird test, despite the fact that both the unfamiliar andfamiliar males were equally fatigued and both mountedthe females with equal vigor. The purpose of this example—in case you have forgotten—is to illustrate thecritical role played by good experimental design in preventing confounded variables.Quasiexperimental Studies It is not possible forbiopsychologists to bring the experimental method tobear on all problems of interest to them. Physical or ethical impediments frequently make it impossible to assignsubjects to particular conditions or to administer theconditions once the subjects have been assigned to them.For example, experiments on the causes of brain damagein human alcoholics are not feasible because it would notbe ethical to assign a subject to a condition that involvesyears of alcohol consumption. (Some of you may bemore concerned about the ethics of assigning subjectsto a control condition that involves years of sobriety.) In8/30/13 5:23 PM

Mean Lordosis Duration (minutes)1.3 What Types of Research Characterize the Biopsychological Approach?head injury, more likely to use other drugs, and morelikely to have poor diets. Accordingly, quasiexperimental studies have revealed that alcoholics tend to havemore brain damage than nonalcoholics, but such studies have not indicated why.Have you forgotten Jimmie G.? His condition was aproduct of long-term alcohol consumption.3530Male 1Male 12520Male 2Male 21510Male 357Male 1Unfamiliar GroupFamiliar GroupCopulated with onemale, then with adifferent one, andthen with yetanother oneCopulated with onemale, then with adifferent one, andthen with the originalone againCase Studies Studies that focus on a single case orsubject are called case studies. Because they focus on asingle case, they often provide a more in-depth picturethan that provided by an experiment or a quasiexperimental study, and they are an excellent source of testablehypotheses. However, there is a major problem withall case studies: their generalizability—the degree towhich their results can be applied to other cases. Becausehumans differ from one another in both brain functionand behavior, it is important to be skeptical of any biopsychological theory based entirely on a few case studies.Pure and Applied ResearchFigure 1.3   The experimental design and results of Lester andGorzalka (1988). On the third test, the female hamsters were moresexually receptive to an unfamiliar male than they were to the malewith which they had copulated on the first test.such prohibitive situations, biopsychologists sometimesconduct quasiexperimental studies—studies of groupsof subjects who have been exposed to the conditions ofinterest in the real world. These studies have the appearance of experiments, but they are not true experimentsbecause potential confounded variables have not beencontrolled—for example, by the random assignment ofsubjects to conditions.In one quasiexperimental study, a team of researchers compared 100 detoxified male alcoholics from analcoholism treatment unit with 50 male nondrinkersobtained from various sources (Acker et al., 1984).The alcoholics as a group performed more poorly onvarious tests of perceptual, motor, and cognitive ability,and their brain scans revealed extensive brain damage.Although this quasiexperimental study seems like anexperiment, it is not. Because the participants themselves decided which group they would be in—by drinking alcohol or not—the researchers had no means ofensuring that exposure to alcohol was the only variablethat distinguished the two groups. Can you think ofdifferences other than exposure to alcohol that couldreasonably be expected to exist between a group of alcoholics and a group of abstainers—differences that couldhave contributed to the neuroanatomical or intellectualdifferences that were observed between them? Thereare several. For example, alcoholics as a group tendto be more poorly educated, more prone to accidentalM01 PINE5576 09 SE C01.indd 7Biopsychological research can be either pure or applied.Pure research and applied research differ in a numberof respects, but they are distinguished less by their ownattributes than by the motives of the individuals involvedin their pursuit. Pure research is motivated primarily bythe curiosity of the researcher—it is done solely for thepurpose of acquiring knowledge. In contrast, appliedresearch is intended to bring about some direct benefit tohumankind.Many scientists believe that pure research will ultimately prove to be of more practical benefit than appliedresearch. Their view is that applications flow readily froman understanding of basic principles and that attemptsto move directly to application without first gaining abasic understanding are shortsighted. Of course, it is notnecessary for a research project to be completely pureor completely applied; many research programs have elements of both approaches.One important difference between pure and appliedresearch is that pure research is more vulnerable to thevagaries of political regulation because politicians andthe voting public have difficulty understanding whyresearch of no immediate practical benefit should besupported. If the decision were yours, would you bewilling to grant hundreds of thousands of dollars tosupport the study of squid motor neurons (neurons thatcontrol muscles), learning in recently hatched geese,the activity of single nerve cells in the visual systems ofmonkeys, the hormones released by the hypothalamus(a small neural structure at the base of the brain) of pigsand sheep, or the function of the corpus callosum (thelarge neural pathway that connects the left and righthalves of the brain)? Which, if any, of these projects8/30/13 5:23 PM

8Chapter 1 Biopsychology as a NeuroscienceTable 1.1   Nobel Prizes Specifically Related to the Nervous System or BehaviorNobel WinnerDateAccomplishmentIvan Pavlov1904Research on the physiology of digestionCamillo Golgi and Santiago Romón y Cajal1906Research on the structure of the nervous systemCharles Sherrington and Edgar Adrian1932Discoveries about the functions of neuronsHenry Dale and Otto Loewi1936Discoveries about the transmission of nerve impulsesJoseph Erlanger and Herbert Gasser1944Research on the functions of single nerve fiberWalter Hess1949Research on the role of the brain in behaviorEgas Moniz1949Development of prefrontal lobotomyGeorg von Békésy1961Research on the auditory systemJohn Eccles, Alan Hodgkin, and Andrew Huxley1963Research on the ionic basis of neural transmissionRagnor Granit, Haldan Hartline, and George Wald1967Research on the chemistry and physiology of visionBernard Katz, Ulf von Euler, and Julius Axelrod1970Discoveries related to synaptic transmissionKarl Von Frisch, Konrad Lorenz, and NikolassTinbergen1973Studies of animal behaviorRoger Guillemin and Andrew Schally1977Discoveries related to hormone producti

normal brain comes from studying the diseased or dam-aged brain; and, conversely, much of what biopsychologists discover has relevance for the treatment of brain disorders. This text focuses on the interplay between brain dys-function and biopsychological research, and each maj