Psych 1 Midterm 1 (Intro - Learning) Ch 1-6

Operationalizing a variable

specific ways of measuring or manipulating an abstract variable in a particular study

Descriptive research

“What do people do, on average?”

Measure one variable at a time with the goal of describing what is typical

Limitations: can’t test relationships among variables

Strengths: can measure many variables

Correlational research

“What kinds of people do this or what’s associated with what?”

Measures two or more variables in the same sample of people, then observes the relationship between them

Limitations: can’t identify causal direction of relationship

Strengths: can measure many variables

Experimental research

“Why do people do this? What causes these behaviors?”

One variable is manipulated and the other is measured; can provide evidence that one variable causes another

Limitations: can only examine a few variables in one study, not all variables can be manipulated

Strengths: can establish causal direction of a relationship

Random sampling/ random selection

Choosing a sample of participants for a study without bias

eg. dialing random digits on the phone or pulling names out of a hat

Scatterplot

A figure used to represent a correlation

Negative correlation = high scores on one variable go with low scores on the other variable

Positive correlation = high score on one variable go with high scores on the other (and low scores go with low)

Zero correlation = no systematic relationship between the two measured variables

Random assignment

A random method is used to decide which participants will receive each level of the IV

Only used in experiments

Construct validity

How accurately the operationalizations used in a study capture the variables of interest

Reliability: how much a measure yields consistent results each time i’s administered

External validity

When the sample in the study can generalize to the population of interest

Matters most in descriptive research; getting a precise estimate of what people in a broader population do or think

Internal validity

The ability of a study to rule out alternative explanations for a relationship between two variables

Matters most in experiments

Presence of a confound

Confound

When experimental groups accidentally differ on more than just the IV; studies with confounds have poor internal validity bc it is an alternative explanation

Mean, Median, Mode

Mean: average of a group of scores

Median: the middlemost scores; when even number of scores, median is the average of the middle two

Mode: the most common score in the batch

Variability + standard deviation

The extent to which the scores in a batch differ from one another

Standard deviation: used to quantify variability; calculates how much on average a batch of scores varies around its mean: find distance between each individual score and the mean, then compute the average of these distances

Effect size

Describes strengths of relationship between manipulated or measured variables

Correlation coefficient or, for an experiment, the difference between the two group means divided by the standard deviations of the two groups

Correlation coefficient = r

Quantifies direction and strength of correlation

Absolute value of r captures effect size

r = .10 → weak effect size; r = .30 → medium effect size; r = .50 and above → large effect size

d = statistical calculation of effect size representing difference between two means

How far apart two group means are in standard deviation units

d = .20 → small effect size; d = .50 → medium effect size; d = .80 and above → large effect size

Descriptive statistics

Graphs or computations that describe the characteristics of batch of scores

e.g. distribution, central tendency, or variability

Summarize participants’ differing responses in terms of what was most typical and how much people’s responses varied from average

Inferential statistics

Use sample results to infer what is true about the broader population

Statistical significance

Estimate whether results obtained came from a particular population

Calculates how likely it is that sample result came from a population were there is no relationship

Null hypothesis + P value

Assumption that there is truly no relationship between variables in population

Researches reject null hypothesis if sample’s result would have only rarely come from a null-hypothesis population

• p = < .05 ; statistically significant

P value: significant result (low p-value) does not mean hypothesis is true, means that data is unlikely to occur under null hypothesis

Meta-analysis

Researchers locate all studies that have tested same variables and mathematically average them to estimate effect size of entire body of studies

Why might a study not be replicable?

False positive: a statistically signifiant finding that does not reflect a real effect ; small sample size

HARKing: hypothesizing after the results are known

p-hacking: using different approaches to find a p value just under .05

Underreporting nonsignificant events: only reports the variables that showed strong effects and does not mention the others

Institutional Review Board (IRB)

A panel of researchers, teachers, and other citizens, who determine whether the study upholds the community’s ethical stanards

Three ethical principles of research

Autonomy: people have the right to make their own decision about participating in the study; researchers can’t coerce people to participate; informed consent: researchers explain the procedure risks and benefits, participants decide whether to take part

Beneficence: research is evaluated on its risks and benefits to the participants and on the research outcomes potential benefit to society

Justice: research should not be conducted disproportionately on one segment of population; participants of research should be representative of the people who will benefit from research

Three R’s of ethics of animal experimentation

Replacement: researchers should find alternatives to using animals in research when possible i.e. computer simulations

Refinement: researchers should modify experimental procedures to minimize or eliminate animal distress

Reduction: researchers should adopt experimental designs and procedures that require the fewest animal subjects possible

Mesmer and his magnetism - Paris 1778

Animal magnetism: magnetic energy that controls our organ and can be manipulated to help people heal

The Commission - to find out if it was real or fake

• determined Mesmer and his treatments were fake

• the cause is imagination “the enemy of reason”

D’Elsons Plea: wouldn’t imagination be a valuable tool in the medical profession?

Mesmer = biggest quack → mesmerized

Proximate explanation

Point to immediate causes of the behavior (within lifetime of an individual)

Ultimate explanation

Point to long-term causes of the behavior

Darwin’s key findings

Variation: within species

Heredity: traits passed down from generation to generation

Competition: in the competition to survive and reproduce, some individuals with certain traits have an advantage, these people will be more likely to pass on those traits to future generations

As environment change, so too do the most advantageous traits

“Our modern skull houses a stone age mind”

We have tendencies from thousands of years ago that may or may not fit in the modern day

Evolution takes time and lags behind changes in environments

Evolutionary cuteness “kindchenschema”

Set of facial and bodily features that activate caretaking motivation

Glocker et. al: manipulated babies to be more or less cute; higher cuteness → higher willingness to take care of them

Naturalistic fallacy

Belief that characteristics as a result of natural selection are inherently good

Kin selection

Passing on genetic material by helping those related to you

Requires relatedness

Direct reciprocity

Helping someone so that that person can help you in the future

Requires repeated interactions

Indirect reciprocity

Helping someone so that someone else sees that and will help you in the future

Requires observation

Punitive Higher Power and behavior

Yilmez + Bachiapeli study: a punishing higher power → people are more likely to be charitable

Why are humans more predisposed to share and help others?

We live in large groups, infants need a lot of care, and cooperation is needed for helping

Cerebral cortex

Outermost layer of the brain; supports cognitive skills, complex emotions, and complex mental activity, including your sense of mind and self

Neurons

Cellular building blocks of brain

Motor neurons: sends signals to make the body take action

Sensory neurons: carries information from the outside world and within the body to the brain

Interneurons: connects neurons and interprets, stores, and retrieves information about the world, allowing you to make informed decisions before you act

Top-down perspective

Functions are communicated from levels of the brain where much of the complex functions reside through various levels down to the body to take specific basic actions

Neurodiversity

The appreciation of the range of differences in brain functioning among individuals

Nerves

Collection of neurons

Carry signals to and from the brain, relating perceptions, thoughts, and feelings into actions

Central Nervous System (CNS)

Composed of nerves of brain and spinal cord; information from body travels to brain by way of the nerves in your skull

Peripheral Nervous System (PNS)

Composed of the nerves outside of the brain and spinal cord; connects the parts of the body to the brain

Made up of Somatic Nervous System and Automatic Nervous System

Somatic nervous system

Allows us to feel external sensations from and control volitional movement of the body

Voluntary commands

E.g. the touch of a feather on your arm

Automatic nervous system

Allows us to feel internal sensations and controls automatic movements of the organs, such as heartbeat

Made of Sympathetic nervous system and Parasympathetic nervous system

Sympathetic nervous system

Division of automatic nervous system that acts on blood vessels, organs, and glands in a way that prepare body for action, especially in threatening situations

E.g. breathing and heart rate increase

Parasympathetic nervous system

Division of the automatic nervous system that returns body to a resting state by counteracting actions of the sympathetic system

E.g. eating and sex

Spinal cord

The major bundle of nerves in the spine that connects body and brain

Damage can result in a loss of feeling (sensory) and movement (motor) of the body, even though the body still exists

Endocrine system

A network of glands that release hormones into the bloodstream to regulate the body’s activities

Able to coordinate hormone release with CNS and PNS

Transmits info more slowly than nervous system, but messages reach more of body’s nooks and crannies and have a more lasting effect

Pituitary gland

Master endocrine gland, located underneath hypothalamus and base of brain

Produces its own hormones and regulates hormone production in other glands

• Modulates hunger, sexual arousal, and sleep

• Communicates with male and female sex glands to produce sex hormones such as testosterone and estrogen, influencing growth, sexual development, and brain development

Adrenal glands

Located on top of kidneys

Produce a variety of hormones including adrenaline and cortisol, that are central to the stress response

Dendrite

Receive chemical messages from other neurons

Cell body

Collects neural impulses, contains the cell nucleus, and provides life-sustaining functions for the cell

Gray matter

Axon + terminal branches

Transports electrical impulses to other neurons via the terminal branches (sometimes called terminal buttons)

White matter

Terminal branches convert these impulses into chemical messages

Myelin sheath

A layer of fatty tissue that covers and insulates an axon to ensure that electrical messages travel fast and meet less resistance

Made up of glia

Glia

Support cells that make up myelin sheath around neurons to insulate, support, and nourish neurons and modulate neuronal function

Action potential

Rapid change in voltage created by a neuron when it is sufficiently stimulated to surpass a critical threshold; serves as the basis for neural signaling

The capacity to communicate with other neurons

A wave of change in electrical potential that rushes down the axon

Neuron’s extracellular fluid

Membrane separating the intracellular and extracellular fluid is selective

Positively charged ions rest outside the cell; extracellular fluid is positive compared to negative intracellular environment

Resting potential

-70 milli volts

If neuron is strongly negatively polarized, a neuron can’t fire an action potential

Ion channels

Allow chemical ions to enter and exit neuronal membrane to generate voltage for the resting and action potentials

If other neurons sufficiently stimulate a neuron’s dendrites, ion channels open and allow an influx of positively charged ions into the neuron

• chain reaction happens and spreads down the axon, more channels open

• Depolorization: when a neuron’s voltage becomes more positive; first phase of the action potential

Voltage threshold

-55 millivolts

The voltage necessary for a neuron to start an action potential

Ion channels open rapidly, positively charged ions flood in, neuron’s voltage then surges rapidly and becomes positive as it passes zero

Significance of action potential

The bases for neural signaling

E.g., causing a muscle to twitch, traveling up the optic nerve into the brain to transmit a signal about light entering the eye

Repolorization

Neuron rapidly returns to its resting potential

Refractory period

Period of time required for a neuron to return to its resting state before it can fire another action potential

Lasts a few milliseconds

Excitatory messages

+Moving the neuron’s voltage closer to its threshold

If excitatory outweigh inhibitory enough to reach threshold, then neuron fires an action potential

Inhibitory messages

-Moving the neuron’s voltage farther away from its threshold

If inhibitory outweigh excitatory, much less likely to reach threshold necessary for firing

Synapse

The gap where a sending neuron communicates with the dendrites or cell body of the receiving neuron

Neurotransmission

Allows the electrical message to bridge the synaptic gap by converting the electrical signal into a chemical one, allowing neurons to transmit their signals to one another

Neurotransmitter

The chemical messenger released at the terminal branch to allow communication between neurons

Target neurons have receptors that bind with specific neurotransmitters

When neurotransmitter binds to receptor, ion channels open, changes in ion flow across neuron's cell membrane, an electrical signal is generated in the target neuron

Receptor produces excitatory or inhibitory electrical signal in target neuron as a reaction to neurotransmitter

Inactivation of neurotransmitters

Terminate chemical message

Diffusion: neurotransmitters drift out of the synapse over time

Degradation: chemical reaction breaks down the neurotransmitter in the synapse

Reputake: neurotransmitters are reabsorbed into presynaptic terminal branches of original neuron

Three types of neurotransmitters

Amino acids: Glutamate (excitatory), GABA (inhibitory), most abundant

Monoamines: dopamine (motivation, reward), serotonin (sleep, mood)

Peptides: endorphines (pain, emotion), oxytocin (social, trust)

Psychoactive drugs

Artificial chemicals introduced into the body that “piggyback” onto the preexisting infrastructure used by your body’s own neurotransmitters

Alters psychological processes, such as mood, perception, thought and behavior

E.g. caffeine, nicotine, and alcohol

Opioids

Drugs to relieve pain e.g. morphine, fentanyl, oxycodone

Endorphins are the body’s natural opioids

Repeated exposure to opioids alters the brain so that it functions normally only when the drugs are present, resulting in addiction

Agonist

Any drug that can mimic or boost the action of a neurotransmitter

Antagonist

Chemical that competes with a naturally occurring neurotransmitter by preventing it from binding with its target receptor and it doesn’t activate the receptor

By blocking receptor activation, it blocks normal neurotransmission

Phenotype

The observable characteristics of an individual resulting from the interaction of genotype and environment

E.g. eye color and height; also physiology and mental qualities

Genotype

The genetic makeup of an organism composed of the organism’s complete set of genes

Genes

A unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring

Present in the nucleus of every cell in the body including neurons

Located on chromosomes

• rod-shaped structures in a cell’s nucleus

• humans have 23 pairs of chromosomes in every cell

• made of DNA

Gene expression

The turning on an off of genes in a particular cell to determine how that cell functions

Depends on your experiences

Epigenetics

The study of how the interactions between your genes and the environment regulate your gene expression

All aspects of your life can eventually cause modifications to gene’s environment, which over time will turn those genes on or off

Behavioral genetics

The study of how genetic factors influence trait variation between individuals

Heritability

Measures degree of heredity

How much variation in phenotype across people is due to differences in genotype

0-1

• heritability measure of 0 means genes do not contribute to how people differ with regard to a particular trait

• heritability measure of 1 means that only genetic factors are responsible

Identical/Monozygotic twins

Twins who share 100% of their genetic material because they develo0ped from the division of a single fertilized egg

Fraternal/Dizygotic twins

Twins who share 50% of their genetic material because they developed from two separate fertilized eggs

Jill Bolte Taylor

Neuroscientist who suffered a stroke

Vision obscured, couldn’t understand language, drifted off, memory problems

“The Astonishing Hypothesis” - Francis Clark

Everything humans are able to do and our emotions and personality is because of the inner workings of the brain; you are your brain and your brain is you

Brain Computer Interface (BCI)

Creates a direct communication link between brain’s electrical activity and external devices

E.g., Anne Johnson suffered a brainstem stroke, used a BCI device to translate her neural activity and has an avatar simulate her voice, allowing her to communicate her thoughts

Cerebral cortex

Largest and most outer part of the brain, lies underneath the skull

Supports complex mental activity including your sense of mind and self

Includes neocortex and subcortex

Forebrain (Neocortex)

Occipital lobe, temporal lobe, parietal lobe, frontal lobe, insular lobe

Limbic system (Forebrain - Subcortex)

Hippocampus, amygdala, basal ganglia, thalamus, hypothalamus

Midbrain

Tegmentum, ventral tegmental area, substantia nigra

Brainstem (Hindbrain)

Pons, medulla, reticular formation, cerebellum

Frontal lobe

Parietal lobe

Occipital lobe

Temporal lobe

Insular lobe