1.3 The Many Areas of Biopsychology

Psychology is an incredibly broad and diverse field. Approaches to studying psychology are equally diverse, from looking at large patterns of behavior to the smallest components of a neuron. For example, a researcher might investigate patterns of interactions between people in a city (social psychology), which is considered a more holistic approachAn approach to science that looks at larger and more complex systems, where understanding is diminished by looking at smaller components. It's the idea that the whole is greater than the sum of its parts. (holism) to research. A holistic approach might assume that one cannot understand a complex system by looking at its smallest parts, often stated as, “the whole is greater than the sum of its parts.” An example in biology might be that a single ant is a rather simple animal with limited capabilities, but within an ant colony, with each ant doing its part, there suddenly emerge great feats of building, organizing, and achievement that one could never understand by researching a single ant. An example in psychology could be in the field of industrial-organizational psychology (I/O), where more is learned from studying how people in a company work and interact together than by just looking at the action of one employee. An emergent propertyThe idea that something unique develops from fundamental parts working together that is not understandable by looking at the individual components. is an idea that something unique and unpredictable develops from small things working together. Often it is hard (if not impossible) to understand by investigating the small, fundamental things, as the overall system is needed. For example, the neuron is a pretty amazing cell in the body, but studying the single neuron does not, as yet, tell us about how we get to the emergent property of consciousness, rationality, or perception. To understand these, we must look at how groups of neurons function together (along with sensory systems, the endocrine system, and the like) as a larger unit.

That said, there is still a great deal to learn from looking at individual things. For example, psychologists might be interested in how levels of the neurotransmitter dopamine in a specific brain region affect a rat learning to navigate a maze. This would be considered a more reductionistic approachInvestigations that research smaller and fundamental parts of a system. Biopsychology tends to be a more reductionistic branch of psychology. (reductionism), which is gaining an understanding of complex behaviors by investigating the smaller components. Researchers studying basic principles of associative learning, sensation, psychophysics, and biopsychology tend to take a more reductionistic approach to what they investigate and the theories they propose. That said, holistic and reductionistic approaches are not mutually exclusive, and a range within these approaches is often needed to understand complex behaviors. For example, to truly understand causes and treatments for drug addiction, one must bring together ideas from developmental psychology, social psychology, cognitive psychology, psychiatry and medicine, associative learning, and several branches of neuroscience and biochemistry.

Another distinction of approaches to psychology is whether the research or practice is applied or basic. An example of an applied approachResearch and practices focusing on how the outcomes are applied to solving a problem. could be someone who uses an understanding of the psychological process to help remedy a specific problem. For example, a clinical psychologist might use an understanding of psychoactive drugs (psychopharmacology) and cognitive behavioral therapy techniques to benefit the treatment of a patient with depression. Someone specializing in Applied Behavioral Analysis (ABA) might use the results of experiments on modifying behavior in rats or pigeons to better treat a child with discipline problems or someone on the autism spectrum. An applied approach in neuroscience in the medical field might be a psychiatrist, neurologist, or rehabilitation counselor who specializes in head injuries. The basic approachA line of research that attempts to understand fundamental principles and clarify understanding, without necessarily being focused on the application of the findings., on the other hand, is directed toward a greater understanding of fundamental principles without the necessity of practical or applied goals. A better understanding can, and often does, lead to better mechanisms of treatment, but that is not the primary focus of basic research. For example, basic research on genetic engineering was able to splice the DNA from bioluminescent jellyfish and corals into other animals and tissue (refer to Chapter 4 “Research Methods: Histology, Imaging, and Stimulating” and Chapter 5 “Genetics and Evolution”). These basic methods have led to techniques for identifying cancerous tumor cells because the cells are made to glow in the dark (Yang et al., 2000). Basic research on the hormone leptin (refer to Chapter 10 “Homeostasis: Hunger, Thirst, and Temperature”) has led to a better understanding of weight gain and hunger, which could create treatments for obesity, diabetes, and even depression and dementia (Friedman & Halaas, 1998; Paz-Filho et al., 2015). You will find that several of the videos, podcasts, and articles presented in this book discuss both basic and applied research about neuroscience.

As one can imagine, there are numerous ways of studying the relationship between behavior, the body, and the brain. There are several subdisciplines that have their own approaches and contributions while sharing many common interests. Here are just a few of the most common: Behavioral neuroscienceA broad field interested in biological components of behavior often drawing from neuroanatomy and physiology, genetics, computer science, and chemistry. is a rather broad field interested in biological principles of behavior. This field uses research techniques in physiology, genetics, computer science, biology, behaviorism, and chemistry to understand behavior in humans and other animals. A subfield of behavioral neuroscience is physiological psychologyAn area of behavioral neuroscience that often uses animal models to investigate the brain and behavior., which focuses on the neural and biochemical mechanisms underlying complex behaviors such as learning, memory, addiction, and sleep by directly working with the brain and nervous system in animal models (refer to Figure 1.9). A structure in the brain called the hippocampus is highly involved in certain kinds of memory formation. A physiological psychologist might place a very thin recording device in a specific area of a rat’s hippocampus (e.g., CA1) and record activity of the cells in that area while the rat learns or recalls running through a maze. Researchers in this field often have a strong background in biology, anatomy, physiology, chemistry, and physics as well as animal behavior and associative learning and memory.

PsychophysiologyA line of research most often using noninvasive ways to record and image the brain using human participants. sounds a lot like physiological psychology, and the two fields are often confused with one another. Psychophysiologists are also interested in brain activity (physiology) and behavior, but they do not typically use animal models or vivisection (live dissection). They most often employ human participants and recording devices that measure, for example, heart rate (electrocardiogram [ECG]), specific brain waves (electroencephalography [EEG]), or deep brain activity (functional MRI). For example, one might record a particular brain wave that corresponds with getting feedback on an incorrect decision. This brain wave, or event-related potential (ERP), might show different amplitude and latency (time) depending on a person’s choices. I currently run a psychophysiology laboratory. Figure 1.10 shows a former student and me applying an EEG cap to a participant. Electrodes in the cap recorded electrical activity generated by the cells (neurons) in the outer cortex of the brain.

My students and I also work with an apparatus that monitors physiological responses to stress and arousal. For example, we place an electrode on the forehead to measure facial muscle activity. This electromyogram (EMG) detects the slightest expressions. We put electrodes on the fingers to measure tiny levels of perspiration with a device called an electrodermal activity amplifier (EDA). We also measure heart rate and heart rate variability using an electrocardiogram (ECG) (refer to Figure 1.12). This apparatus monitors stress and arousal levels of individuals even if the reaction is extremely fast. In this experiment, we can look at momentary stress or arousal levels when a participant is taking risks in a gambling game.

PsychopharmacologyA discipline interested in studying the biochemistry and drugs that affect the nervous system and alter cognition, perception, consciousness, and behavior. is the study of the effects of psychoactive substances on behavior, ranging from psychoactive drugs used in the treatment of psychological ailments like schizophrenia and depression to the effects of recreational drugs (legal and illegal) such as cocaine, heroin, marijuana, and alcohol. Chapter 14 “Psychopharmacology, Recreational Drugs, Tolerance, and Sensitization” is all about psychopharmacology and recreational drugs, but we will also talk about psychopharmacology in the chapters on neuron communication (refer to Chapter 2 “Functional Anatomy”), stress (refer to Chapter 12 “Emotions and Stress”), the anxiety of depression (refer to Chapter 15 “Addiction, Developmental Disorders, Anxiety, and Affective Disorders”), and other neuropsychiatric disorders (refer to Chapter 16 “Other Neuropsychiatric Disorders, Brain Injuries, and Brain Pathologies”).

Behavioral neuroendocrinologyThe study of the interaction of hormones and the nervous system on behavior. is the study of the effects of hormones on behavior. One might investigate the relationship between the hormone cortisol and stress, oxytocin and love, or testosterone and aggression. My students and I have been measuring cortisol levels in participants playing competitive games. Participants place a sterilized cotton swab under their tongue for two minutes to collect saliva. We use the saliva to measure cortisol levels, which can be a good indicator of the expected levels of cortisol in the blood. Cortisol is a hormone released from the adrenal gland in response to stress. We analyze cortisol levels before and after playing the game to see if stress is affected by winning or losing, and whether the participants felt the game was fair (Shapiro et al., 2017).

PsychoneuroimmunologyThe study of the relationship between behaviors, thoughts, the nervous system, and the immune system. looks at the relationship between the nervous system, behavior, and our immune system. We know, for example, that stress and stress hormones can hinder the immune system, increase chances of infections, and elevate the risk of contracting diseases. It’s one of the reasons that you might get a cold during finals week (Segerstrom & Miller, 2004). Psychoneuroimmunology is part of the growing field of Health Psychology interested in the relationship between thoughts and behavior on physical and mental health.

Cognitive neuroscienceThis field uses the techniques of other subdisciplines to look at aspects of cognition such as perception, attention, decision-making, and language. is related to several other subdisciplines with the primary goal of understanding the biological influences on cognitive processes such as language, consciousness, learning, memory, attention, and decision-making. This field can use animal models but typically focuses on humans. Research in this area often uses neuroimaging techniques such as fMRIs, PET scans, and EEGs to look at neural correlates of cognitive processes. A subfield of cognitive neuroscience is neuroeconomicsA subfield of cognitive neuroscience looking at the brain and nervous system during economic or financial decisions., which is the study of the biological influences of making economic decisions. Basic principles of neuroeconomics can use animal models to look at brain functions when an animal is choosing between different food reward parameters such as amount, quality, or probability. There are also some fascinating studies using brain imaging to look at people making decisions about money, gambling, winning, and losing (Loewenstein et al., 2008).

Behavioral geneticsAn area of research interested in how genetics influences behavior and other aspects of psychology. Research often involves twin studies but is also interested in genetic testing and engineering. looks at the role of genetics in animal behavior (including humans) and is one of the fast-growing fields in neuroscience. This type of research often looks at family members, especially twins, who show similar traits such as obesity, depression, or the development of dementia (loss of cognitive functions). However, there is also research on the genetic influence of personality traits, cognitive abilities, political affiliations, or propensity for addictions. Behavioral geneticists also have the tools to identify specific sequences of DNA (genetic markers) that correspond with or contribute to behavioral traits or predispositions to develop neurological disorders. We are also able to manipulate the genetics of animal models by removing sections of DNA or taking the DNA from one organism and splicing it into another.

Behavioral genetics is interconnected with evolutionary psychologyThe study of the influence of natural selection, adaptation, and evolution on behaviors and mental processes., which looks at how our natural history (our evolutionary past) and pressures brought on by natural selection affect our behavior today. Evolutionary psychologists investigate many topics, from sexual attraction and mate choice to aggression and violence. One example of how our natural history and evolution affect our behavior is in the food we crave and find delicious. During our evolutionary past, simple sugars, salts, and fats were necessary for survival, but not necessarily easy to come by in nature. So, we have a system in our brain that has evolved to find the tastes of these foods to be highly valuable, motivating, and rewarding (Sharma et al., 2013). However, today, in our society, these foods are abundant and easily accessible, which may contribute to the problems of obesity and diabetes.

Comparative psychologyA line of research that focuses on comparing the cognition, learning, memory, and perception of different species of animals. is the study of how psychological principles are similar or different between species of animals. This component of comparative psychology typically looks at the learning, memory, and cognition of different species of animals without the influence of drugs or live dissection (vivisection). I started my career as a comparative psychologist. I studied how animals made decisions when the reward was uncertain, that is, how animals take risks. I worked with honeybees at the University of Hawaii, and we trained honeybees to fly between an open window in our lab and their hive. In the window were placed two targets (differing in color or odor) that were associated with sugar rewards that differed in concentration, amount, and variability. The honeybee would fly into an open window in our lab and make choices, and these choices told us which option it preferred (refer to Figure 1.13). I did similar studies with starlings (a small bird) at Oxford University, looking at how amount and delay of reward affected choice behavior. While this was considered basic research, the work in this area had applications to behavioral economics. Comparative psychologists typically do research in well-controlled laboratory environments to control for confounding variables that might influence behavior. Other researchers in biology and zoology often research animals in their natural environments.

The comparative study of behavior in animals also takes place in biology and zoology departments. This research tends to look at natural behaviors, and that tells us about environmental pressures, adaptation, and the evolution of behaviors and the nervous system. For example, when I did the work with starlings, I was part of Oxford University’s Behavioral Ecology Research Group. Behavioral ecologyThe study of animal behavior in both natural and artificial environments with a focus on the theories of why behaviors would naturally occur including theories of evolutionary pressures. studies the theoretical influences of evolution on behavior, such as how animals make foraging decisions to maximize their energy (optimal foraging theory) or how they evolved to use tools (Davies et al., 2012). When I was at Oxford, a fellow researcher found that a species of crow from the islands of New Caledonia would create tools to solve problems. Behavioral ecology is a subfield of ethologyThe study of natural behaviors by animals, with research often conducted in natural environments.. Ethologists are typically members of biology or zoology departments within a university and use techniques to conduct research on animal behavior in the wild. While a comparative psychologist often looks for common principles of behavior such as associative learning, an ethologist looks for species-specific behaviorsBehaviors, such as bird songs or migration patterns, that are unique to particular species.—or the unique behaviors that animals naturally show. Ethologists often connect animal behavior to theories related to natural selection and genetics—although learning, socialization, and experience also play essential roles in theories in ethology. For example, an ethologist might be interested in bird migration, animal communication in apes, aggression displays in wolves, cooperation in meerkats, or foraging in blue jays. Biologists Konrad Lorenz, Nikolaas Tinbergen, and Karl von Frisch shared the Nobel Prize in Physiology or Medicine for their work in animal behavior (Dewsbury, 2003).

Most of the previously mentioned research subdisciplines follow a basic approach to neuroscience and behavior, though there are exceptions. There are also some areas of neuroscience that focus on application and directly helping people and other animals. Clinical neuroscienceA field interested in investigating underlying causes of and treatments for neuropsychiatric disorders. Clinical neuroscientists typically earn a PhD. applies an understanding of the nervous system and evidence-based practices to help people with neuropsychiatric disordersThe broad term that covers all neurodegenerative, mental, and mood disorders such as Alzheimer’s disease, Parkinson’s disease, schizophrenia, depression, bipolar disorder, anxiety disorders, and several others.. A clinical neuroscientist may also conduct research to understand disorders better, create more accurate diagnostic tools, and create more effective treatments. While a clinical neuroscientist might get a PhD, a person studying and practicing psychiatryA subspecialty in medicine interested in understanding and treating neuropsychiatric disorders. Psychiatrists earn an MD and can prescribe psychoactive medication in their treatment. will go to school to be a medical doctor (MD). A psychiatrist will also work with patients with neuropsychiatric disorders and may research causes and better treatment options. A psychiatrist also can prescribe psychoactive medications in their treatment protocols, and they often work with or consult a neurologistThe medical field that specializes in neurological disorders such as brain injury and diseases of the brain and nervous system.. Neurologists are medical doctors specializing in neurological disorders but may focus on issues like brain injury or neurodegenerative disorders like Alzheimer’s disease and/or Parkinson’s disease.

I have oversimplified these professions and subdisciplines, and I am sure those who work in these fields would likely add many items to the list of things they do and their interests. It should also be noted that many of these subfields of neuroscience have common interests with other fields. For instance, there are now researchers focusing on neurotheology, which studies the relationship between the brain and religion; or neuroesthetics, which looks at the brain, art, design, and music; and the aptly named field of neurolaw, which looks at what neuroscience and brain imaging can tell us about legal rules, standards, and sentencing.