Individual influences on behavior

Biological Bases of Behavior (PSY, BIO)

  • The nervous system- Includes the peripheral nervous system and central nervous system. The nervous system is responsible for regulating and determining someone's behavior in his or her environment.
  • Neurons (e.g., the reflex arc)- specialized cells that pick up and transmit nerve impulses.
    • Reflex arc- a set of neurons that are responsible for receiving reflexive nerve impulses (e.g. If you touch a hot frying pan, the neurons contained within the reflex arc will immediately react, causing you to withdraw your hand.)
  • Neurotransmitters- chemicals utilized by neurons to communicate and transfer nerve impulses to other structures in the body (e.g. muscle fiber).
    • There are excitatory neurotransmitters (e.g. acetylcholine, norepinephrine) and inhibitory neurotransmitters (e.g. dopamine, serotonin)
    • With regards to behavior, various neurotransmitters affect different regions of the brain, which can cause someone to feel and behave a certain way.
      • Example: Serotonin is a neurotransmitter that is responsible for feelings of happiness and well-being. High levels of serotonin would likely cause someone to behave happily (high levels of self-care, socializing, etc.)
  • Structure and function of the peripheral nervous system (PNS)- consists of all outside nerve fibers that are not included within the brain or spinal cord. The PNS functions to send nerve impulses from our limbs (skin, muscles) and trunk (organs) to the central nervous system for processing.
  • Structure and function of the central nervous system (CNS)- consists of the brain and spinal cord. Its function is to receive and process nerve impulses from the PNS. It is also responsible for thought processing and body movement.
    • The brain
      • Forebrain-consists of the cerebrum, thalamus, the limbic system, and hypothalamus. Responsible for abstract thinking, logic, and emotions.
      • Midbrain- consists of the tegmentum, tectum, and cerebral peduncles. Responsible for the production of dopamine, which regulates habituation and motivation. Also plays a role in vision and hearing.
      • Hindbrain- consists of the cerebellum, pons, and medulla. Responsible for vital bodily functions (motor control, respiratory and digestive reflexes) as well as sexual arousal.
      • Lateralization of cortical functions- some of our bodies' functions occur predominantly by one side of the brain.
        • Left brain functions include: processing the right visual field, grammar, positive emotions, speech, and writing.
        • Right brain functions include: processing the left visual field, negative emotions, recognition of emotions, and spatial skills (e.g. facial recognition).
      • Methods used in studying the brain
        • Imaging of brain structures (e.g. CAT or CT scan {Computerized Axial Tomography}, MRI {Magnetic Resonance Imaging})
        • Imaging of brain functions (e.g. PET scan {Positron Emission Tomography}, fMRI {Functional Magnetic Resonance Imaging}
        • Measures of chemical activity of the brain
        • Computer brain scans
    • The spinal cord- a bundle of nerve fibers located within the spinal column, which connects the majority of the body to the brain.
  • Neuronal communication and its influence on behavior (PSY)
    • Dopaminergic neurons are stimulated by dopamine (a neurotransmitter that affects mood -> affects behavior)
    • Defective neurons can cause Parkinson's disease (impaired motor movements, loss of feeling) and Alzheimer's disease (changes in mood, impaired movement and memory)
  • Influence of neurotransmitters on behavior (PSY)
    • Neurotransmitters are chemicals that allow neurons to communicate with each other
    • Types of Neurotransmitters:
      1. Endorphins- released during extreme pleasure or pain, can have numbing effect on pain.
      2. Norepinephrine- regulates alertness, learning, and long-term memory (deficiency can lead to mood disorders).
      3. Gamma-Amino Butyric Acid (GABA)- reduces the excitability of neurons (deficiency can cause anxiety and depression).
      4. Serotonin- regulates mood, sleep, libido (deficiency can cause anxiety and depression).
      5. Dopamine- plays a role in learning and ability to concentrate.
      6. Acetylcholine- regulates memory, sleep, and plays a role in learning (deficiency is associated with dementia)
      7. Epinephrine (Adrenaline)- intensifies mood (released during fight or flight)
  • The endocrine system
    • Components of the endocrine system
      • Hypothalamus- controls the actions of the endocrine system.
      • Adrenal gland- release adrenaline during "fight or flight" situation.
      • Hypophysis (Pituitary gland)- secretes growth and reproduction hormones. Also secretes neurotransmitters.
      • Reproductive organs- Ovaries produce estrogen and progesterone, testes produce testosterone.
      • Thyroid gland- regulates consumption of energy/ metabolism.
      • Parathyroid gland- controls release of parathyroid hormone (PTH) and levels of calcium within the body (high levels of PTH cause the body to increase levels of calcium in the blood, where it becomes available to the bones).
      • Pineal body (gland)- regulates levels of melatonin (hormone that plays a role in sleep cycles). Allows the nervous system to send signals to the endocrine system.
      • Pancreas- secretes digestive enzymes (exocrine pancreas) and insulin (endocrine pancreas).
    • Effects of the endocrine system on behavior
      • Hormones and neurotransmitters affect mood, sexual arousal, and circadian rhythm (wake-sleep cycles).
  • Behavioral genetics- describes the relationship between behavioral traits and inherited genes.
    • Genes, temperament, and heredity
      • Part of our personality encoded for in our genes, the rest is influenced by environmental factors.
      • Our personality is largely defined by our temperament, or our nature (how "moody" we are).
      • We are likely to think and behave like our parents, due to the inheritable factors of personality.
    • Adaptive value of traits and behaviors
      • Your traits and behaviors are capable of changing and adapting in response to different experiences and environments.
      • Example: If you move to a city that has a high level of crime you may become more wary of strangers, and decide to walk your dog during the day, instead of at night.
    • Interaction between heredity and environmental influences
      • The characteristics of someone's personality that are encoded by genetics collaborate with the person's environment to create their behavior (and more long-term, personality).
      • Studies have shown that when twins were raised separately (in different environments), they behaved more similarly than a pair of randomly chosen people, but still exhibited different personalities.
      • Phenylketonuria (PKU) is a genetic disease in which the afflicted individual is unable to break down the amino acid phenylalanine, leading to extreme mental retardation. The treatment: create an environment that completely avoid all foods containing phenylalanine.
  • Influence of genetic and environmental factors on the development of behaviors
    • Experience and behavior (PSY)
      • Our experiences in life help shape our personalities and how we choose to behave.
    • Regulatory genes and behavior (BIO)
      • Regulatory genes- control the expression of other genes (e.g. encoding for various proteins and microRNAs).
      • Epigenetics- Genes that modify their expression without changing the overall genetic code. This changes the phenotype without changing the genotype. Epigenetics are largely influenced by the environment, but can also be inherited.
      • Example: DNA methylation, the process by which a methyl group is added to a strand of DNA, preventing the expression of some genes.
    • Genetically based behavioral variation in natural populations
      • Within animal and human populations there are different genes that encode for various behaviors.
      • e.g., Within a population of wolves, some are genetically programmed to behave more aggressively. These wolves will likely kill more prey.
  • Human physiological development (PSY)
    • Prenatal development- ovulation/conception -> zygote -> blastocyst -> embryo -> fetus -> born baby
    • Motor development
      • Infancy reflexes
        1. Stepping reflex- if the sole of an infant's foot touches a flat surface, they will place one foot in front of the other (also known as the "walking reflex")
        2. Tonic neck reflex-if a baby's head is turned to the side, the baby will extend its arm on that side, and bend the opposite arm.
        3. Blinking reflex- if a baby sees a bright flash of light or experiences a gust of wind, it will blink its eyes
        4. Rooting reflex- if you stroke a baby's cheek they will turn in that direction and open their mouth (seeking mother's nipple)
        5. Babinski reflex- if you stroke a baby's foot, its big toe will extend upward, and the toes on its other foot will spread apart.
        6. Palmar grasp reflex- if you stroke a baby's palm their fingers will close and their hand will grasp your finger (or whatever is stroking its palm).
        7. Swimming reflex- if a baby is placed face down in water it will make coordinated swimming movements.
        8. Startle (moro) reflex- if a baby hears a loud noise or sees a sudden movement they will become startled. It will then cry and extend its neck and limbs.
        9. Sucking reflex- if an object touches the roof of a baby's mouth it will begin to suck.
      • Progression of infancy motor development:
        1. Baby is prone (lying face down, flat), can lift head (~2 months)
        2. Can use arms to lift chest and roll over (~3 months)
        3. Can sit alone (~6 months)
        4. Can stand with support (~7 months)
        5. Can crawl (~9 months)
        6. Can walk with support (~10 months)
        7. Can stand alone (~12 months)
        8. Can walk alone (~13 months)
      • Lifespan motor development:
        1. Reflexive movement- (0-1 year) include involuntary movements (e.g. blinking, grasping, sucking)
        2. Rudimentary movement- (0-2 years) these are the first voluntary movements (e.g. crawling, sitting, standing)
        3. Fundamental movement- (2-7 years) child is beginning to coordinate his limbs (e.g. running, catching a ball)
        4. Specialized movement- (7-14 years) fundamental movements are mastered and applied to completing specific actions (e.g. playing sports, riding a bike, gymnastics)
        5. Application of movement- (14+ years) movements are applied and refined throughout the span of one's lifetime
    • Developmental changes in adolescence
      • Female changes: Growth of breasts, pubic hair, underarm hair, menstrual period, increased oil and sweat production (acne), overall body growth.
      • Male changes: growth of pubic, facial, and underarm hair, deepening of voice, increased oil and sweat production (acne), ejaculation, development of testes, penis, seminal vesicles, and prostate gland.

Personality (PSY)

  • Theories of personality
    • Psychoanalytic perspective- developed by Sigmund Freud, says that our personalities are comprised of unconscious memories, emotions, and thoughts. It is thought that our dreams reveal elements of our unconsciousness.
    • Humanistic perspective- developed by Carl Rogers, says that the human nature is inherently good, and that we have free will (our behavior is not determined or based on the past).
    • Trait perspective- says that our personality is determined by the presence and absence of differing levels of traits (characteristics).
    • Social cognitive perspective- says that our personality is formed through various environmental and cognitive experiences, and through observational learning, we are likely to mimic positive behaviors that we observe in others.
      • (e.g. If you see someone going to the gym everyday, and the result is a fit, muscular body, you may copy this behavior in hopes of attaining the same result).
    • Biological perspective- says that at least part of our personality is predetermined by our genetic make-up.
    • Behaviorist perspective- says that our personalities are produced by patterns of behavior that we learn according to our environment
      • (e.g. If we grow with parents that behave supportively, we are more likely to be supportive parents ourselves).
  • Situational approach to explaining behavior
    • The trait vs. state controversy (also known as the "person-situation controversy) states that the severity of someone's reaction in any given situation is dictated by their traits (personality) or by the situation itself (state).
    • Trait- personality characteristics that are stable, long-lasting, and within oneself. Traits are generally present consistently, and do not depend on the situation.
    • State- personality characteristics that are unstable, short-term and subject to change according to the environment.

Psychological Disorders (PSY)

  • Understanding psychological disorders- a psychological disorder is a mental disorder that includes thoughts, emotions, and behaviors that cause significant amounts of stress to the self or others. Stressful situations include inability to function/ meet personal needs, and putting themselves and/or others in danger.
    • Biomedical vs. biopsychosocial approaches
      • Biomedical approach- this approach looks at psychological disorders from a biological perspective, including factors such as genetics, brain structure, and brain chemistry.
      • Biopsychosocial approach- this approach looks at psychological disorders from a sociological/cultural perspective including factors such as education, socioeconomic standards, and expectations held by peers.
    • Classifying psychological disorders- to officially diagnose someone with a psychological disorder, clinicians reference the Diagnostic and Statistical Manual of Mental Disorders (DSM-5, fifth edition).
      • Categories include: Substance related disorders, sleep disorders, eating disorders, mood disorders, psychotic disorders, anxiety disorders, personality disorders, somatoform disorders, dissociative disorders, neurocognitive disorders.
    • Rates of psychological disorders- roughly 25% of Americans have been diagnosed with a some form of mental illness at one point in their life. About 450 million people have suffered worldwide.
  • Types of psychological disorders
    • Anxiety disorders- characterized by excessive amounts of fear or worry, includes phobias, generalized anxiety disorder (GAD), panic disorder, Post-traumatic stress disorder (PTSD), and obsessive-compulsive disorder (OCD).
    • Obsessive-compulsive disorder- a type of anxiety disorder that is characterized by obsessive, recurring thoughts, often accompanied by routines or rituals.
    • Trauma- and stressor-related disorders- characterized by anxiety and/or depression following a traumatic event. Includes post-traumatic stress disorder (PTSD).
    • Somatic symptom and related disorders- characterized by physical symptoms that are accompanied by negative thoughts, feelings, and behaviors that cannot otherwise be explained by substance use or any other psychological disorder. Includes hypochondriasis, pain disorder, body dysmorphic disorder, somatization disorder, and conversion disorder.
    • Bipolar and related disorders- a type of mood disorder, characterized by extreme mood swings, from depressive episodes (low energy, sadness, low motivation) to manic episodes (elevated mood, irritability, excessive amounts of energy).
    • Depressive disorders- a type of mood disorder, characterized by feelings of hopelessness, worthlessness, and sadness. Includes dysthymic disorder and major depressive disorder.
    • Schizophrenia- a type of psychotic disorder, characterized by a loss of touch with reality, including audio and visual hallucinations, psychosis, and delusions.
    • Dissociative disorders- characterized by memory loss, sense of detachment from self, and a skewed perception of identity. Includes dissociative identity disorder, depersonalization disorder, and dissociative amnesia.
    • Personality disorders- characterized by long-lasting, negative/ maladaptive thoughts and behaviors that create an inability to adhere to what is considered "socially acceptable." Includes paranoid, schizotypal, borderline, antisocial, schizoid, histrionic, avoidant, narcissistic, obsessive-compulsive, and dependent personality disorder.
  • Biological bases of nervous system disorders (PSY, BIO)
    • Schizophrenia- The Dopamine hypothesis of schizophrenia states that the condition stems from an irregular, hyperactive dopaminergic signal transduction. As a result, people with schizophrenia tend to have abnormally high amounts of dopamine in their brain. It has been discovered that the overactivation of the brain's D2 receptors is another common thread among schizophrenics. There is also a genetic predisposition.
    • Depression- People with depression demonstrate abnormal levels of dopamine, norepinephrine, and serotonin. High levels of cortisol, secreted by the adrenal glands, are often present in the blood. There may also be a genetic predisposition.
    • Alzheimer's disease- the formation of plaques around brain cells cause them to die. This is accompanied by the formation of tangles, long strands of proteins that prevent brain cells from receiving proper nutrients. There is often a genetic predisposition present.
    • Parkinson's disease- degeneration of substantia nigra cells in the brain leads to low levels of dopamine. (The substantia nigra cells produce dopamine that facilitates the communication of the substantia nigra with the corpus striatum). There is often a genetic predisposition present.
    • Stem cell-based therapy to regenerate neurons in the central nervous system (BIO)- brain cells (neurons, astrocytes, and oligodendrocytes) can be regenerated from neural stem cells. Regeneration of neural cells within the central nervous system can repair damage caused by degenerative diseases (e.g. Parkinson's Disease, Lou Gehrig's Disease).

Motivation (PSY)

  • Factors that influence motivation
    • Instinct- an unlearned, innate behavior that is present throughout an entire species.
    • Arousal- there is a need to achieve the highest level of arousal (stimulation). This helps us avoid feelings of boredom.
    • Drives (e.g., negative feedback systems) (PSY, BIO)- a drive is a sense of urgency, stemming from physiological feelings of discomfort, including, thirst, hunger, and tiredness.
    • Needs- this includes drives as well as higher-level needs, such as self-actualization (realizing one's full potential, finding meaning outside one's self).
  • Theories that explain how motivation affects human behavior
    • Drive reduction theory- states that a physiological discomfort will cause someone to carry out a certain behavior to ease that discomfort. (i.e. you feel thirsty, so you drink water).
    • Incentive theory- states that we can be driven/motivated to behave in certain ways by incentives (objects/events that encourage or discourage certain behaviors).
    • Other theories (e.g., cognitive, need-based)
      • Cognitive theories of motivation
        • Expectancy theory- states that our behavior is a result of conscious choices that we make to minimize pain and maximize pleasure.
        • Goal-Setting theory- states that there is a link between goal setting and task performance, and that by setting and achieving small goals (and receiving positive feedback), we are more likely to accomplish more difficult goals later.
      • Need-based theory of motivation- "Maslow's Hierarchy of Needs", developed by Abraham Maslow, states that there are five levels of human needs (from low-level to higher-level needs). Levels include:
        1. Physiological needs- includes the need to maintain homeostasis (food, water, body temperature, oxygen, ability to reproduce).
        2. Safety needs- includes the need to feel safe and protected in one's environment.
        3. Social needs- includes the need to feel like you belong (feelings of love and appreciation, avoidance of loneliness).
        4. Esteem needs- includes the need to achieve independence, self-esteem, and to receive respect from peers.
        5. Self-actualization- when all these needs are met, one can realize one's full potential, and find external meaning.
  • Biological and sociocultural motivators that regulate behavior (e.g., hunger, sex drive, substance addiction)
    • Biological motivators- includes hunger, thirst, sex drive, body temperature, etc. (e.g., If we are hungry, we look for something to eat. If we are thirsty, we seek out water to drink.)
    • Sociocultural motivators- includes social constructs as motivators (e.g., what is socially considered the "ideal" body weight and appearance may affect how much you exercise and eat).

Attitudes (PSY)

  • Components of attitudes (i.e., cognitive, affective, and behavioral)
    • Cognitive- involves someone's beliefs and knowledge. What someone knows to be true can affect one's attitude towards certain issues. E.g., If you know that lions are dangerous, your attitude towards them may be negative and fearful.
    • Affective- involves someone's feelings or emotions, which largely shape our attitude. E.g., If you love someone, you will most likely address them with a positive, loving attitude.
    • Behavioral- involves someone's actions. Our behavior is greatly dependent on our attitude. E.g., If we have a positive attitude, we are more likely to behave productively.
  • The link between attitudes and behavior
    • Processes by which behavior influences attitudes (e.g., foot-in-the door phenomenon, role-playing effects)
      • Foot-in-the door phenomenon- this occurs when someone convinces someone else to take small steps towards something before they introduce larger, more tasking steps.
      • e.g., If a child wants to convince their parents that they should have a pet dog, they could use the foot-in-the door approach and first get a pet fish. Next they would get a hamster, then a larger animal, like a rabbit. The size and responsibility associated with the pet would slowly increase until getting a dog no longer seemed like a big undertaking.
      • Role-playing effects- when people are assigned a "social script" in which they are told how to behave in a particular social situation. E.g., Philip Zimbardo created an experiment in which people were told to act out different roles, some as prisoners, and some as guards. The results: prisoners began to adopt the attitude of real prisoners, hopeless and helpless. The guards adopted the attitude of real guards, and behaved authoritatively towards the role-playing prisoners.
      • Justification of effort- this occurs when people change their attitudes so that they will match how they behave. E.g., If someone was applying to graduate school for education, but during that process were offered a well-paying laboratory job, the person may feel pressured to justify the effort they put into getting into graduate school by deciding to attend the school, instead of taking the laboratory job.
      • Public declarations- this involves publicly declaring a belief or idea, that may or may not have been influenced by outside social pressures. The more we declare something, especially publicly, the more likely we are to convince ourselves that we believe what we are saying. E.g., In the schoolyard a child might publicly announce to his friend "Short people are stupid." If this message is supported by his friends, he is likely to repeat it, increasing his chances of truly believing that short people are stupid.
    • Processes by which attitudes influence behavior
      • Icek Ajzen's theory of planned behavior states that one's behavioral beliefs influences one's attitude towards the behavior, which then affects how someone decides to behave.
      • e.g., If someone believes that they should behave quietly while attending church, they would feel happy to comply with this behavior, and, when in church, behave quietly.
    • Cognitive dissonance theory- explains that we feel uncomfortable when we hold two conflicting beliefs, attitudes, or behaviors. E.g., A person knows that smoking cigarettes is bad for your health, but they decide to smoke anyway. In this example the belief conflicts with the person's behavior.