psych 101

Psychology

The scientific study of behavior and mental processes.

William James

Associated with functionalism: studied how thoughts and behaviors help people adapt and function.

Wilhelm Wundt

Often called a founder of modern/experimental psychology; opened the first psychology laboratory in 1879.

Edward Titchener

Associated with structuralism and introspection; tried to break conscious experience into basic elements.

Max Wertheimer

Founder of Gestalt psychology; emphasized that the whole is more than the sum of its parts.

Mary Whiton Calkins

First female president of the American Psychological Association (APA).

Margaret Floy Washburn

First woman to earn a PhD in psychology.

Psychodynamic perspective

Behavior is influenced by unconscious/internal conflicts and motives; strongly associated with Sigmund Freud.

Behavioral perspective

Focuses on observable, measurable behavior and how learning/conditioning shapes behavior; associated with Watson and Skinner.

Humanistic perspective

Emphasizes free will, personal growth, self-actualization, and human potential; associated with Maslow and Rogers.

Cognitive perspective

Studies thinking, memory, perception, language, problem solving, and how information is processed.

Biological perspective

Examines how the brain, nervous system, hormones, genes, and other biological processes influence behavior.

Evolutionary perspective

Examines how behaviors or mental tendencies may have developed because they helped survival or reproduction.

Sociocultural perspective

Examines how social situations, groups, culture, and society influence behavior and mental processes.

Scientific method

Identify a question/problem → do background research → form a hypothesis → test it → analyze results → report conclusions → revise/replicate as needed.

Why is critical thinking important in psychology?

It helps evaluate evidence, question assumptions, detect bias, and avoid accepting claims without sufficient support.

Naturalistic observation

Watching behavior in a natural setting without manipulating it. Pro: realistic behavior. Con: little control, observer bias/reactivity, and cannot establish causation.

Laboratory study

Research conducted in a controlled setting. Pro: strong control over variables. Con: behavior may not generalize well to real life.

Case study

An in-depth investigation of one person, group, or unusual case. Pro: rich detail. Con: may not generalize to other people.

Survey

Collects self-report data by asking people questions. Pro: can gather data from large samples quickly. Con: wording, response, and sampling bias.

Correlation coefficient

A number from -1.00 to +1.00 that shows the direction and strength of the relationship between two variables.

Positive correlation

As one variable increases, the other tends to increase (or both decrease together).

Negative correlation

As one variable increases, the other tends to decrease.

Correlation strength

The closer the absolute value of r is to 1.00, the stronger the relationship; the closer to 0, the weaker.

Does correlation prove causation?

No. A correlation shows a relationship but does not prove that one variable causes the other.

Independent variable (IV)

The variable the researcher manipulates or changes.

Dependent variable (DV)

The outcome the researcher measures.

Confounding variable

An outside variable that changes with the IV and could provide another explanation for the effect on the DV.

Random selection

Choosing participants randomly from a population to make the sample more representative.

Random assignment

Placing participants into experimental/control groups by chance to balance preexisting differences between groups.

Experimental group

The group that receives the treatment or manipulation of the independent variable.

Control group

The comparison group that does not receive the treatment, or receives a placebo/standard condition.

Placebo

An inactive or fake treatment used so expectations can be separated from the actual effect of a treatment.

Single-blind study

Participants do not know which condition/group they are in, but the researchers do.

Double-blind study

Neither the participants nor the researchers interacting with them know who is in the treatment versus control/placebo group.

Neuron

A specialized cell that receives, processes, and sends information throughout the nervous system.

Dendrites

Branchlike structures that receive incoming signals from other neurons.

Soma (cell body)

Contains the nucleus and keeps the neuron functioning; integrates incoming information.

Nucleus of a neuron

Contains the cell's genetic material (DNA).

Axon

Long fiber that carries an electrical signal away from the cell body.

Myelin sheath

Fatty insulating layer around some axons that speeds neural transmission.

Nodes of Ranvier

Gaps in the myelin sheath where the action potential is regenerated, allowing the signal to travel faster.

Axon terminals

Endings of an axon that release neurotransmitters into the synapse.

What causes an action potential?

If the summed input to a neuron reaches threshold, voltage-gated channels open and an action potential begins.

Action potential

An all-or-none electrical impulse that travels down the axon: depolarization is followed by repolarization and a refractory period.

All-or-none principle

Once threshold is reached, an action potential fires at full strength; stronger stimuli increase firing frequency, not action-potential size.

How does one neuron communicate with another?

An action potential reaches the axon terminal → neurotransmitters are released into the synaptic cleft → they bind to receptors on the next cell.

Central nervous system (CNS)

Brain and spinal cord; processes information and coordinates responses.

Peripheral nervous system (PNS)

All nerves outside the brain and spinal cord; carries information to and from the CNS.

Somatic nervous system

Part of the PNS involved in voluntary skeletal-muscle movement and sensory information.

Autonomic nervous system

Part of the PNS that controls involuntary functions of organs, glands, and smooth/cardiac muscle.

Sympathetic nervous system

Arouses the body for action: fight-or-flight; increases heart rate and mobilizes energy.

Parasympathetic nervous system

Calms the body and conserves energy: rest-and-digest.

Sensory neurons (afferent neurons)

Carry sensory information from receptors toward the CNS.

Motor neurons (efferent neurons)

Carry commands away from the CNS to muscles or glands.

Interneurons

Neurons mainly in the brain and spinal cord that process information and connect sensory neurons with motor neurons.

Glial cells

Support, nourish, insulate, protect, and help maintain neurons; some glia form myelin.

Withdrawal reflex

Pain activates sensory neurons → signal enters the spinal cord → interneurons activate motor neurons → muscles contract and pull the body part away before conscious processing is required.

CT scan

Structural brain-imaging method that uses X-rays from multiple angles to make cross-sectional images of the brain.

MRI

Structural imaging that uses strong magnetic fields and radio waves to create detailed images of brain anatomy.

EEG

Functional method that records electrical activity from electrodes on the scalp; excellent temporal resolution but limited spatial precision.

MEG

Functional method that measures tiny magnetic fields produced by neural activity; excellent temporal resolution.

PET scan

Functional imaging that uses a radioactive tracer to measure metabolic activity such as glucose use or blood flow.

fMRI

Functional imaging that measures changes in blood oxygenation (BOLD signal) to estimate which brain areas are active.

Frontal lobe

Involved in planning, decision making, impulse control, personality, working memory, and voluntary movement.

Parietal lobe

Processes touch/body sensations and spatial information; contains the somatosensory cortex.

Temporal lobe

Important for hearing, language, memory, and object/face processing.

Occipital lobe

Primarily responsible for visual processing.

Motor cortex

Located in the frontal lobe; controls voluntary movement, mostly on the opposite side of the body.

Somatosensory cortex

Located in the parietal lobe; receives touch/body-sensation information, mostly from the opposite side of the body.

Corpus callosum

Large bundle of nerve fibers connecting the left and right cerebral hemispheres.

Broca's area

Usually in the left frontal lobe; important for speech production and language expression.

Wernicke's area

Usually in the left temporal region; important for understanding spoken and written language.

Medulla

Controls vital automatic functions such as breathing, heart rate, and blood pressure.

Cerebellum

Coordinates balance, posture, movement, motor learning, and fine motor control.

Thalamus

Major sensory relay station that sends most incoming sensory information to the cerebral cortex.

Hypothalamus

Regulates homeostasis and motivated behaviors such as hunger, thirst, body temperature, sex, and endocrine activity.

Amygdala

Important for emotion, especially fear/threat processing, and emotional learning.

Hippocampus

Important for forming new explicit memories and spatial memory.

Limbic system

A network involved in emotion, motivation, memory, and survival-related behavior; commonly includes the amygdala, hippocampus, hypothalamus, thalamus, and cingulate cortex/gyrus.

Endocrine system

A chemical communication system that uses hormones carried through the bloodstream to regulate bodily functions.

Hormones

Chemical messengers released by endocrine glands that travel through the bloodstream and affect target cells/organs.

Contralateral control

Each cerebral hemisphere largely controls and receives information from the opposite side of the body.

Split-brain patient

A person whose corpus callosum has been severed, limiting communication between the two cerebral hemispheres.

Split-brain: right visual field

Information from the right visual field goes mainly to the left hemisphere; because language is usually left-lateralized, the person can often verbally name the object.

Split-brain: left visual field

Information from the left visual field goes mainly to the right hemisphere; the person may be unable to verbally name the object but can often identify it with the left hand.

Gene

A segment of DNA that contains instructions influencing traits and biological functions.

DNA

The molecule that stores genetic information.

Epigenetics

Environmental influences can change how strongly genes are expressed without changing the underlying DNA sequence.

Purpose of twin studies

To estimate how much variation in traits is associated with genetic versus environmental influences by comparing twins with different levels of genetic similarity or different rearing environments.

Dopamine

Excitatory or inhibitory depending on receptor. Functions: reward/motivation, movement, learning. Very low activity is linked with Parkinsonian movement problems; excessive dopamine signaling in some pathways is associated with psychotic symptoms.

Serotonin

Mostly modulatory/inhibitory in many pathways. Functions: mood, sleep, appetite, and arousal. Low serotonin function is associated with some mood symptoms; dangerously high levels can cause serotonin syndrome.

Norepinephrine

Usually excitatory/modulatory. Functions: alertness, attention, arousal, and stress response. Low levels can be associated with low energy/depressed mood; high levels with hyperarousal/anxiety.

Endorphins

Inhibitory/modulatory natural opioids involved in pain relief and pleasure. Higher activity reduces pain perception; lower activity can increase pain sensitivity.

Synaptic plasticity

The ability of synapses to strengthen or weaken with experience; essential for learning, memory, and adaptation after injury.

Why do we need synaptic plasticity?

It allows the brain to learn, store memories, adapt to experience, and reorganize after damage.

Neurogenesis

The formation of new neurons.

When does neurogenesis mainly happen?

It is most extensive during prenatal and early development.

Adult neurogenesis

In adults, new-neuron formation is most strongly associated with the hippocampus; some introductory texts also discuss olfactory regions.

Why do we need neurogenesis?

It may support learning, memory, adaptation, and replacement/maintenance of certain neural circuits.