1.The Mid-Brain Relationship

• Biological psychology studies the physiological, evolutionary, and developmental mechanisms of behavior and experience.
• It is approximately synonymous with biopsychology, psychobiology, physiological psychology, and behavioral neuroscience.
• The goal of biological psychology is to relate biology to psychological issues.
• Neuroscience includes relevant aspects of behavior but also covers more detail about anatomy and chemistry.
• Biological psychology is not just a field of study but also a perspective.
• It holds that understanding behavior requires understanding how it evolved and how brain and organ functions control behavior.
• Our thoughts and actions are influenced by brain mechanisms that evolved because they enhanced survival and reproduction.
• A significant part of biological psychology involves brain functioning.
• The human brain has distinct subareas, as seen in dorsal and ventral views.
• At the microscopic level, the brain contains neurons and glia.
• Neurons convey messages to other neurons, muscles, and glands, and vary greatly in size, shape, and function.
• Glia, generally smaller than neurons, have many functions but do not convey information over long distances.
• The activities of neurons and glia produce a vast range of behavior and experience, though how they do so is still being studied.
• Biological psychology is regarded by some as the most interesting topic in the world, rivaled only by cosmology.
• Cosmology asks fundamental questions about the existence and nature of the universe.
• Biological psychologists ask why consciousness exists, whether it is a necessary function of the brain, and how certain brain activities become conscious.
• Researchers explore specific questions such as the biological factors predisposing people to psychological disorders, promoting recovery after brain damage, and understanding how humans learn language so easily.

Biological Explanations of Behavior

• Common-sense explanations of behavior often refer to intentional goals, such as “He did this because he was trying to…” or “She did that because she wanted to…”
• However, intentions are not always necessary to explain behavior, especially in animals and sometimes even in humans.
• A 4-month-old bird migrating south for the first time likely does not know why it is doing so.
• Similarly, when the bird lays an egg and defends it from predators, it does not know why.
• Humans also sometimes do things, like yawning or laughing, without fully understanding the purpose behind these actions.
• Biological explanations of behavior differ from common-sense explanations and can be categorized into four types: physiological, ontogenetic, evolutionary, and functional.
• A physiological explanation relates a behavior to the activity of the brain and other organs, focusing on the body’s machinery, such as how hormones influence brain activity or how brain activity controls muscle contractions.
• An ontogenetic explanation describes how a structure or behavior develops, considering the influences of genes, nutrition, experiences, and their interactions.
• For example, the ability to inhibit impulses develops gradually from infancy through the teenage years, reflecting the maturation of the brain’s frontal parts.
• An evolutionary explanation reconstructs the evolutionary history of a structure or behavior.
• For example, goose bumps in frightened people are a vestigial response inherited from ancestors, where hair erection made animals appear larger and more intimidating to predators.
• A functional explanation describes why a structure or behavior evolved as it did, identifying the advantage it provided, especially in larger populations.
• For instance, many species have a camouflaged appearance that helps them avoid predators, which is a functional adaptation.
• Some species also use behavior as part of their camouflage. For example, zone-tailed hawks mimic vultures in appearance and flight, allowing them to catch prey more easily because their prey disregards them as a threat.
• Functional explanations of human behavior can be controversial, as many behaviors thought to be part of our evolutionary heritage might have been learned instead.
• Understanding behavior often involves combining these approaches, as understanding one aspect, like function, can help explain another, such as evolution.
• Ideally, a comprehensive understanding of behavior should integrate physiological, ontogenetic, evolutionary, and functional perspectives.

The Brain and Conscious Experience

• Explaining birdsong in terms of hormones, brain activity, and evolutionary selection is generally unproblematic, but applying physical explanations to human behavior can be more complex.
• For example, if you say, “I became frightened because I saw a man with a gun,” a neuroscientist might say, “You became frightened because of increased electrochemical activity in the central amygdala of your brain.”
• This raises the question: Are both explanations correct, and if so, how are they connected?
• Biological explanations of behavior bring up the mind-body or mind-brain problem, questioning the relationship between the mind and the brain.
• Dualism is a common belief among nonscientists, suggesting that the mind and body are different substances that exist independently.
• René Descartes defended dualism and proposed that the mind and brain interact at a single point, which he suggested was the pineal gland.
• Despite Descartes’ defense, nearly all current philosophers and neuroscientists reject dualism due to its conflict with the law of conservation of matter and energy.
• The law of conservation states that matter and energy in the universe have been fixed since the Big Bang, and a non-material mind could not influence physical matter or cause muscle movements.
• The alternative to dualism is monism, the belief that the universe consists of only one kind of substance.
• Monism can be divided into three categories:
  • Materialism: The view that everything that exists is material or physical, and that all psychological experiences can eventually be explained in physical terms.
  • Mentalism: The view that only the mind exists, and the physical world depends on the mind’s awareness. This idea is difficult to test and is not widely accepted.
  • Identity Position: The view that mental processes and brain processes are the same thing, described in different terms. This view suggests that every mental experience corresponds to brain activity, much like describing the same painting in different ways.
• The identity position emphasizes that the mind is not the brain itself but is brain activity, similar to how fire is not a “thing” but a process.
• Monism is adopted as a working hypothesis because experiences and brain activities seem inseparable—stimulation of the brain provokes an experience, and experiences evoke brain activity.
• While researchers assume monism, questions about the relationship between brain activity and consciousness remain unresolved.
• Questions include why consciousness arises from brain activity, whether it is important or accidental, what kind of brain activity produces consciousness, and how it does so.
• Consciousness is difficult to define, much like other concepts such as time.
• The function of consciousness is not clear, and some psychologists argue that many nonhuman species are conscious because their complex behavior suggests it.
• Others argue that even if nonhuman animals are conscious, consciousness might not be a useful scientific concept.
• Solipsism is the belief that only one’s own mind exists or is conscious, while others may be like robots or dream characters.
• Solipsism is rarely taken seriously, but it is difficult to imagine evidence that could definitively refute it.
• The problem of other minds questions how we can know if other people or animals have conscious experiences.
• David Chalmers distinguishes between the easy problems and the hard problem of consciousness.
• Easy problems include understanding the difference between wakefulness and sleep and the mechanisms that enable attention.
• The hard problem of consciousness involves explaining why and how brain activity is associated with conscious experiences.
• Scientists and philosophers agree that the hard problem cannot be answered currently, and there is no clear hypothesis to test it.
• The identity position suggests that mental processes and brain processes are the same, described in different terms.
• According to the identity position, mind and brain activity are inseparable and one cannot have mental activity without brain activity.
• Monism is adopted as a working hypothesis because experiences and brain activities appear inseparable.
• Questions remain about why consciousness arises from brain activity, whether it is important or accidental, and what specific brain activities produce consciousness.
• Consciousness is difficult to define, similar to other commonly used but elusive concepts like time.
• Some psychologists argue that many nonhuman species are conscious due to their complex behaviors.
• Others believe that even if nonhuman animals are conscious, consciousness might not be a useful scientific concept.
• Most people are not solipsists because they reason by analogy, assuming others have minds because they look and act like themselves.
• This analogy extends to animals, with varying beliefs about the consciousness of chimpanzees, dogs, rats, fish, insects, trees, and rocks.
• In human development, there is uncertainty about when consciousness begins and how it can be known.
• The increasing sophistication of computers and robots raises questions about whether they could ever be considered conscious.
• Some argue that robots are just programmed machines, while others note that the human brain is also a machine programmed by genes and experiences.
• The debate includes whether consciousness is exclusive to carbon-based life or if it could exist in any complex, organized system.
• It remains an open question whether any evidence could persuade someone that a robot is conscious, inviting personal reflection.

Career Opportunities

• Careers related to biological psychology can be categorized into research and therapy.
• Research positions typically require a PhD in psychology, biology, neuroscience, or a related field.
• Individuals with a master’s or bachelor’s degree might work in a research lab but would not direct it.
• Many PhD holders work in colleges or universities, balancing teaching and research.
• Others hold pure research positions in government, industry, or drug company labs.
• Therapy-related fields include clinical psychology, counseling psychology, school psychology, medicine, and allied medical practices like physical therapy.
• Specializations within therapy range from neurologists, who focus on brain disorders, to social workers and clinical psychologists, who distinguish between adjustment problems and brain disorders.
• Those pursuing research careers must stay updated on new developments through conventions, consultations with colleagues, and reading research journals like Journal of Neuroscience, Neurology, Behavioral Neuroscience, Brain Research, Nature Neuroscience, and Archives of General Psychiatry.
• Professionals in fields like clinical psychology, school psychology, social work, or physical therapy should stay current on major developments without necessarily reading technical journal articles, to converse knowledgeably with medical colleagues.

2.The Genetics of Behavior

• Everything you do depends on both your genes and your environment.
• Environmental contributions are clear, as you smile more when life is going well and frown when it isn’t.
• Researchers studied facial expressions in people born blind, who couldn’t have learned expressions by imitation.
• The facial expressions of people born blind were strikingly similar to those of their sighted relatives.
• These findings suggest a significant role for genetics, in addition to the environment, in controlling facial expressions.
• Controversies arise when discussing the relative impact of heredity versus environment on traits like intelligence, sexual orientation, alcoholism, psychological disorders, and weight gain.
• This text does not address these controversies directly but aims to provide an understanding of the issues as they come up later in the text or elsewhere.
• The discussion begins with a review of basic genetics, which some readers may choose to skip or skim if they are already familiar with the concepts.

Mendelian Genetic

• Before Gregor Mendel’s work, scientists believed inheritance was a blending process, where properties of the sperm and egg mixed like paint colors.
• Mendel showed that inheritance occurs through genes, units of heredity that maintain their structural identity across generations.
• Genes typically come in pairs because they are aligned along chromosomes, which also come in pairs, except in cases like male mammals with unpaired X and Y chromosomes.
• Traditionally, a gene was defined as a portion of a chromosome made of the double-stranded molecule DNA, though modern genetics reveals this concept is more complex.
• Sometimes, several genes overlap on a chromosome, or genetic outcomes depend on parts of multiple chromosomes.
• Some parts of a chromosome don’t code for proteins but influence the expression of other genes.
• DNA serves as a template for synthesizing RNA molecules, which are single-strand chemicals.
• One type of RNA acts as a template for protein synthesis, with proteins determining the organism’s development.
• Some proteins form part of the body’s structure, while others act as enzymes, regulating chemical reactions.
• An individual is homozygous for a gene if they have an identical pair of genes on two chromosomes and heterozygous if they have an unmatched pair.
• Genes can be dominant, recessive, or intermediate in their expression.
• A dominant gene has a strong effect in both homozygous and heterozygous conditions, while a recessive gene shows effects only in the homozygous condition.
• For example, the gene for tasting phenylthiocarbamide (PTC) is dominant, and the gene for low sensitivity to it is recessive.
• If both parents are heterozygous for the PTC-tasting gene, their children have a 25% chance of being homozygous for high taste sensitivity (TT), a 50% chance of being heterozygous (Tt), and a 25% chance of being homozygous for low sensitivity (tt).

Sex-Linked and Sex-Limited Genes

• Sex-linked genes are located on the sex chromosomes, while genes on all other chromosomes are called autosomal genes.
• In mammals, females have two X chromosomes, and males have one X and one Y chromosome.
• During reproduction, females contribute an X chromosome, while males contribute either an X or a Y chromosome.
• If the male contributes an X, the offspring will be female; if he contributes a Y, the offspring will be male.
• The Y chromosome is small and has genes for only 27 proteins, but it influences the functioning of genes on other chromosomes.
• The X chromosome has genes for about 1,500 proteins, so sex-linked genes are often X-linked genes.
• An example of a sex-linked gene is the recessive gene for red-green color vision deficiency, which causes color deficiency in men with the gene on their X chromosome.
• A woman is color deficient only if she has the recessive gene on both of her X chromosomes.
• If 8% of X chromosomes carry the gene for color vision deficiency, then 8% of men will have the condition, but fewer than 1% of women will.
• Sex-limited genes are present in both sexes, usually on autosomal chromosomes, but are primarily active in one sex due to the influence of sex hormones.
• Examples of sex-limited genes include those controlling chest hair in men, breast size in women, crowing in roosters, and egg production in hens.

Heredity and Environment

• Most variations in behavior result from the combined influence of many genes and environmental factors.
• The question “Which is more important, heredity or environment?” is meaningless because both are necessary for any behavior to occur.
• A more meaningful question is whether observed differences among individuals are due more to genetic differences or environmental differences.
• To determine the contributions of heredity and environment, researchers compare monozygotic (identical) twins and dizygotic (fraternal) twins.
• Monozygotic twins have the same genes, so a stronger resemblance between them than between dizygotic twins suggests a genetic contribution.
• Another method is studying adopted children, where any resemblance to their biological parents suggests a hereditary influence.
• If variations in a characteristic are largely due to genetic differences, the characteristic has high heritability.
• New biochemical methods allow researchers to identify specific genes linked to disorders, such as genes more common among people with depression.
• Identifying genes leads to questions about the gene’s association with a condition, how it produces its effect, and which environmental factors influence its effect.
• Researchers have found significant heritability in almost every behavior tested, including loneliness, neuroticism, television watching, and social attitudes.
• Religious affiliation is one of the few behaviors tested that has not shown significant heritability.

Possible Complications

• Humans are challenging research subjects due to the inability to control their heredity or environment.
• Methods to estimate hereditary influences are subject to error.
• Distinguishing between hereditary and prenatal influences can be difficult. For instance, children of parents with criminal records may show similar problems, but this could be due to prenatal factors like poor diet, lack of medical care, and substance use during pregnancy.
• A methyl group (CH3) can attach to a gene and inactivate it, potentially altering the gene’s expression based on early experiences such as malnutrition or stress. This inactivation can be passed to the next generation, blurring the line between hereditary and environmental effects.
• Genes can influence behavior indirectly by changing one’s environment. For example, genes leading to frequent temper tantrums can result in harsh reactions from others, exacerbating the hostility.
• Dickens and Flynn (2001) describe this as a multiplier effect, where genetic or prenatal influences increase a tendency, which then changes the environment to further magnify that tendency.
• An example is a child with genes for greater height, running speed, and coordination who excels at basketball. Success leads to more practice and encouragement, which in turn enhances skill and success, creating a larger advantage over time.
• The initial genetic advantage can be amplified by environmental reactions, applying to various endeavors such as sports or academics.

Environmental Modification

• Even traits with high heritability can be modified by environmental interventions.
• Some genes increase the risk of depression or violent behavior depending on environmental factors like stress or maltreatment.
• Phenylketonuria (PKU) is a genetic condition where the body cannot metabolize the amino acid phenylalanine, leading to brain impairment and mental retardation if untreated.
• Approximately 1% of Europeans carry the recessive gene for PKU, whereas fewer Asians and almost no Africans have it.
• PKU can be managed through environmental interventions. Regular testing of phenylalanine levels in babies allows for early diagnosis and treatment.
• A strict low-phenylalanine diet can minimize brain damage from PKU. This diet excludes meats, eggs, dairy, grains, and aspartame, which contains phenylalanine, and includes an expensive formula with other amino acids.
• It was once thought that the PKU diet could be discontinued after a few years, but high phenylalanine levels can continue to damage the brain into adolescence and adulthood.
• Pregnant and nursing women with PKU need to be particularly cautious as high phenylalanine levels can adversely affect the developing baby.

How Genes Affect Behavior

• A “gene for brown eyes” does not directly produce brown eyes; it produces a protein that results in brown eyes, given normal health and nutrition.
• Similarly, a “gene for alcoholism” does not cause alcoholism directly but produces a protein that increases the probability of alcoholism under certain circumstances.
• Understanding how a gene affects behavior involves specifying the circumstances and conditions involved.
• Genes can influence behavior both directly and indirectly. For instance, genes might affect brain chemicals or alter how others treat you.
• An example is a gene that makes someone unusually attractive, leading to positive social interactions which can influence their personality.
• The high heritability of human behaviors can be explained by genes affecting various aspects of the body and influencing how people interact with the individual.

The Evolution of Behavior

• Evolution is defined as a change over generations in the frequencies of various genes within a population.
• This definition includes any change in gene frequencies, regardless of whether it benefits or harms the species in the long run.
• Two key questions about evolution are:
  • How did some species evolve? This involves determining what evolved from what based on fossil evidence and comparisons of living species. For example, humans are more similar to chimpanzees than to other species, suggesting a common ancestor.
  • How do species evolve? This is about understanding the process of evolution itself, which is considered a logical necessity given the principles of reproduction and variation.
• The process of evolution includes:
  • Offspring generally resemble their parents due to genetic reasons.
  • Gene mutations introduce new heritable variations that can affect an individual’s chance of survival and reproduction.
  • Individuals with advantageous traits are more likely to reproduce and pass on their genes, making those genes more prevalent in future generations.
• The principle of natural selection is observed in both nature and artificial selection:
  • Artificial selection is used by breeders who select individuals with desired traits to reproduce, resulting in various breeds of animals and plants with specific characteristics.
  • Natural selection occurs when individuals with traits that enhance survival and reproductive success are more likely to pass on their genes, leading to the evolution of species over time.

Common Misunderstandings About Evolution

• The idea that using or not using a body part causes evolutionary changes, such as smaller little toes due to lack of use, is based on Lamarckian evolution, which has been discredited. Lamarck proposed that acquired characteristics could be inherited, but no mechanism for this has been found. Evolution does not work by altering genes through use or disuse of features; rather, it relies on genetic variations and their effects on reproduction.
• The assertion that humans have stopped evolving due to modern medicine and welfare programs is flawed. Evolution is not solely about survival but about reproduction. If individuals with certain genes have more children, those genes will spread, indicating that evolution continues regardless of modern advancements.
• Evolution does not necessarily mean improvement in a general sense. It improves the fitness of individuals in terms of gene transmission to future generations. Fitness is defined by reproductive success, not by overall success or well-being. Traits that increase fitness in one environment may become disadvantageous if the environment changes.
• Evolution benefits genes rather than individuals or species. Genes use individuals to reproduce themselves. For example, a gene that promotes self-sacrifice to protect offspring may increase in prevalence if it enhances the survival of the gene’s copies through more successful reproduction.

Evolutionary Psychology

• Evolutionary psychology explores how behaviors have evolved, focusing on how natural selection may have favored genes promoting certain behaviors.
• The assumption is that any species characteristic must have arisen through natural selection and provided some advantage, although exceptions are possible.
• Examples of evolutionary explanations include species evolving specific types of vision suited to their way of life, mammals and birds investing energy in maintaining body temperature, and differing eating habits related to species’ needs.
• Some characteristics, however, have debatable links to natural selection. For instance, aging and death might not be directly due to genes encouraging us to stop competing with offspring, and differences in sexual behavior between men and women are complex and debated.
• Altruistic behavior, which benefits others at a cost to oneself, presents a challenge for evolutionary psychology. While it occurs in humans and some non-human animals, it is often rare and may have underlying self-interested motives.
• In non-human species, apparent altruism is sometimes linked to self-interest, such as crows calling attention to food to attract others for protection or meerkats emitting alarm calls that also benefit themselves.
• The spread of a gene for altruistic behavior is questioned because such behaviors must result in increased reproduction for the gene to become prevalent.
• Group selection, where altruistic groups might outperform less cooperative ones, is controversial due to the potential for non-cooperative individuals to out-reproduce cooperative ones within the group.
• Reciprocal altruism suggests individuals help those who will return the favor, and this system relies on recognizing and remembering others to prevent exploitation. This explains why altruism is more common in humans, who have advanced sensory and memory capabilities.
• Kin selection is another explanation, where genes that promote altruistic behavior toward relatives (who share many of one’s genes) can spread if the benefits to the relatives outweigh the costs to the altruist.
• Evolutionary psychology aims to understand behaviors by exploring functional explanations and different habitats, but it faces criticism for proposing untested explanations.

3.The Use of Animals in Research

• Certain ethical disputes, such as abortion and the use of animals in research, often resist resolution due to differing views on what is considered ethical and proper.
• The animal welfare controversy is especially relevant to biological psychology, as much of our understanding of the brain and behavior comes from research involving laboratory animals.
• This research varies from observational studies and painless experiments to more invasive procedures where animals do not have the option to refuse.
• The ethical dilemma involves balancing the desire for greater knowledge with the need to minimize distress and harm to animals used in research.

Reasons for Animal Research

• The underlying mechanisms of behavior are similar across species, and studying simpler nonhuman species can provide insights into more complex systems. For example, nonhuman vertebrates have brains and behaviors that resemble those of humans in their chemistry and anatomy, and invertebrate nerves follow the same basic principles. Research on squid nerves, which are thicker and easier to study than human nerves, exemplifies this approach.
• We are intrinsically curious about other forms of life and natural phenomena. Just as we invest in exploring life beyond Earth, we are interested in understanding animal behaviors such as how bats navigate in the dark, how migratory birds find their way, and how fish schools swim in unison.
• Studying animals helps us understand human evolution. By examining how species differ from one another, such as the evolutionary development of larger brains in primates compared to other species, we gain insights into our own evolutionary history.
• Certain experiments cannot be conducted with humans due to legal or ethical constraints. For instance, inserting electrodes into the brains of rats allows researchers to explore the relationship between brain activity and behavior, addressing questions critical for medical progress. This raises ethical concerns about whether such research is acceptable for nonhumans if it is deemed unacceptable for humans.

The Ethical Debate

• Researchers sometimes observe animals in their natural environments across different times of day, seasons, and dietary changes without causing inconvenience or ethical issues. These observations do not generally raise ethical concerns.
• However, other experiments involve invasive procedures such as brain damage, electrode implantation, and drug or hormone injections, which some people view as cruel and respond to with tactics ranging from peaceful demonstrations to violent actions, including bombings and threats against researchers.
• Michael Conn and James Parker (2008) quote a spokesperson for the Animal Defense League who suggests that sacrificing a small number of lives to save millions of non-human lives is justified, highlighting the extreme views held by some activists.
• Despite the ethical concerns, animal experimentation has been crucial for medical research, leading to advancements in preventing and treating diseases such as polio, diabetes, measles, smallpox, and heart disease.
• Many Nobel Prizes in physiology or medicine have recognized research conducted on nonhuman animals.
• The development of treatments for diseases like AIDS and Alzheimer’s relies heavily on animal research, and significant progress in biological psychology research would be impossible or very slow without animal studies.

Degrees of Opposition

• Opposition to animal research varies in intensity and perspective.
• Minimalists support some animal research under specific conditions, considering factors like the potential value of the research, the level of distress to the animal, and the type of animal used. They advocate for strict regulations to ensure ethical practices.
• Abolitionists hold a more extreme view, believing that all animals have the same rights as humans and equate killing animals to murder, regardless of the purpose. They view keeping animals in cages as a form of slavery and believe that it is wrong to use animals for research because they cannot give informed consent. One abolitionist stated, “We have no moral option but to bring this research to a halt. Completely. . . . We will not be satisfied until every cage is empty” (Regan, 1986).
• Abolitionists often argue that most animal research is painful and not significantly beneficial, but for them, the moral imperative against using animals is paramount, regardless of the research’s potential benefits or pain level.
• The core disagreement between abolitionists and animal researchers revolves around two ethical principles: “Never knowingly harm an innocent” versus “Sometimes a little harm leads to a greater good.”
• Permitting animal research involves unavoidable pain or distress, while banning it would impede significant medical advancements and end practices like animal-to-human transplants, such as using pig heart valves for heart disease.
• The heated nature of the debate often prevents researchers from publicly expressing nuanced views. Many acknowledge that not all research is justified and express genuine concern for animal welfare, with some researchers choosing vegetarianism.
• Researchers commonly set personal ethical boundaries and choose not to conduct experiments they deem too distressing for the animals involved. The point at which they draw this line varies among individuals.

Possible Compromise

• Researchers strongly believe that some animal research is justified due to its potential to address crucial scientific questions.
• They agree on the need to use fewer animals and to minimize pain and discomfort whenever possible.
• Researchers support efforts to improve animal welfare and refine research methods to enhance ethical practices.
• The legal standard for animal research emphasizes “the three Rs”: reduction (using fewer animals), replacement (substituting animals with computer models or other alternatives when possible), and refinement (modifying procedures to minimize pain and discomfort).
• In the United States, institutions receiving government research funds must have an Institutional Animal Care and Use Committee (IACUC) that includes veterinarians, community representatives, and scientists. This committee evaluates proposed experiments, ensures they meet ethical standards, and specifies procedures to minimize pain.
• Similar regulations and committees oversee research involving human subjects.
• Research laboratories must adhere to national laws concerning cleanliness and animal care standards.
• Other countries have similar laws, and scientific journals require researchers to confirm compliance with all relevant laws and regulations.
• Professional organizations, such as the Society for Neuroscience, publish guidelines for the ethical use of animals in research.