unit 0 reading all notes (PSYCH)

how is psychology a science?

its findings are the result of a scientific approach based on careful observation + testing; requires scientific attitude

3 elements of a scientific attitude

• curiosity

• skepticism

• humility

critical thinking importance

• examining assumptions

• appraising the source

• discerning hidden biases

• evaluating evidence

• assessing conclusions

3 roadblocks to critical thinking

• hindsight bias

• overconfidence

• perceiving order in random events

hindsight bias

• aka “I knew it all along phenomenon”

• tendency to believe we would’ve foreseen an outcome after it occurred

overconfidence

• results partly from our bias to seek info that confirms them

• the tendency to overestimate the accuracy of your knowledge, judgments, and predictions, being more certain than correct

perceiving order in random events

• leads to the overestimation of the importance of common sense thinking

non-experimental methods

• case studies

• naturalistic observation

• surveys

what do non-experimental methods do

DESCRIBE but not EXPLAIN behavior

why operational definitions are used of procedures and concepts

to enable others to replicate studies

correlation

the degree to which 2 variables are related + how well one predicts the other

positive correlation

2 factors increase or decrease together

negative correlation

one variable increases while the other decreases; vise versa

correlation coefficient

• describes the strength + direction of a relationship between 2 variables on a +1.00 (perfect positive correlation) to a -1.00 (perfect negative correlation) scale

• helps figure out how closely things vary together

scatterplot

• a graphed cluster of dots, each of which represents the values of two variables

• the slope of the points suggests the direction of the relationship between the two variables

• the amount of scatter suggests the strength of the correlation (little scatter=high correlation)

• data on a relationship may be recorded via this

correlational research is a non-experimental method, meaning:

• can indicate the possibility of a cause-effect relationship but doesn’t prove the direction of the influence/underlying 3rd variable

• can enable prediction since they show how factors are related

illusory correlations

random events we notice and falsely assume are related

regression toward the mean

• the tendency for extreme or unusual scores to fall back toward their average

• can cause superstitious thinking

characteristics of experimentation to isolate cause-and-effect

• manipulation of variables of interest

• random assignment; to minimize confounding variables (such as preexisting differences between the experimental group and control group)

• independent variable + dependent variable

• single-blind procedure; subjects unaware to control social desirability bias

• double-blind procedure; subjects + research conductors unaware to avoid placebo effect + experimental bias

single-blind procedure

• where the subjects are unaware which treatment they are receiving

• controls social desirability

double-blind procedure

• where both subjects and research conductors are unaware which treatment they are receiving/administering

• avoids placebo effect + experimental bias

random assignment

• def

• purpose is to reduce potential confounding variables

control group

• def

• purpose is to allow researchers to determine a cause-and-effect relation between the independent variable and dependent variable

does correlation = causation

NO; correlation SUGGESTS a possible cause-effect relationship but does not prove it

quantitative research

• a research method that relies on quantifiable, numerical data to represent degrees of a variable

• ex: Likert scale; questionaire responses range from “strongly disagree” to “strongly agree”

quantitative research

• a research method that relies on in-depth, narrative data that are not translated into numbers

• ex: structured interviews

design examples

• experimental

• correlational

• case study

• naturalistic observation

• twin study

• longitudinal

• cross-sectional

laboratory environment goals

• to be a simplified reality—simulates + controls important features of everyday life to test general theoretical principals

• it is the resulting principles— NOT the specific findings that help explain everyday behaviors

• goal focuses less on specific behaviors than on revealing general principles that help explain many behaviors

APA 4 ethical considerations

• informed consent/assent

• confidentiality

• debriefing

• safety of participants

falsifiable

the possibility that an idea, hypothesis, or theory cn be disproven by observation or experiment

replication

repeating the essence of a research study, usually w/ different participants in different situations, to see whether the basic finding can be reported

case study

a non-experimental technique in which one individual or group is studied in depth in the hopes of revealing universal principals

naturalistic observation

a non-experimental technique of observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation

survey

a non-experimental technique for obtaining the self-reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group

social desirability bias

bias from people’s responding in ways they presume a researcher expects or wishes

self-repot bias

bias when people report their behavior inaccurately

sampling bias

a flawed sampling process that produces an unrepresentative sample

random sample

a sample that fairly represents a population because each member has an equal chance of inclusion

population

all those in a group being studied, from which random samples may be drawn

variable

anything that can vary and is feasible and ethical to measure

placebo

fake pill; inactive drug

placebo effect

• when a person's physical or mental health appears to improve after taking a placebo or 'dummy' treatment

• just thinking you are getting a treatment can boost your spirits, relax your body, + relieve symptoms

independent variable

in an experiment, the factor that is being manipulated; the variable whose effect is being studied

confounding variable

in an experiment, a factor other than the factor being studied that might influence a study’s results

experimenter bias

bias caused when researchers may unintentionally influence results to confirm their own beliefs

dependent variable

in an experiment, the outcome that is measured; the variable that may change when the independent variable is manipulated

validity

the extent to which a rest or experiment measures or predicts what it is supposed to

reliability

the consistency of a measurement

reliability vs validity

• reliability is the consistency of a measurement, while validity is the accuracy of whether a test measures what it claims to measure

• both concepts are required to evaluate how well a tool (like a survey, test, or observation method) assesses human behavior and mental processes

descriptive statistics

• numerical data used to measure and describe characteristics of groups

• includes measures of central tendency and measures of variation

• summarizes data; assesses if data can be generalized

histogram

a bar graph depicting a frequency distribution

3 measures of central tendency

• mode

• mean

• median

central tendency

a single score that attempts to describe/represent a whole set of scores

mode

the most frequently occurring score(s) in a distribution

mean

• the arithmetic average of a distribution

• obtained by adding the scores + dividing by the # of scores

median

• the middle score in a distribution after arranging scores in order of least to greatest

• half scores above it; half below

percentile rank

• the percentage of scores that are less than a given score

• ex: if you are in the 79th percentile in a math competition, your score is higher than 79% of your peers

skewed distribution

• a representation of scores that lack symmetry around their average value

• lopsided distribution from extreme outliers

  • the mean can be biased/disctoret by a few atypical scores

2 measures of variation

• range

• standard deviation

variation

natural differences and diversity that exist among individuals

range

the difference between the highest and lowest scores in a distribution

standard deviation

• a computed measure of how much scores vary around the mean score

• a measure of distance from the mean

normal curve

• a symmetrical, bell-shaped curve that describes the distribution of many types of data

• most scores fall near the mean

• fewer and fewer scores lie near the extremes

• empirical rule (68-95-99.7 rule)

the measure of central tendency most influenced by skewed data/extreme scores in a distribution

the mean

in a normal distribution, __ of the scores in the distribution falls within one standard deviation on either side of the mean

68%

empirical rule

• 68-95-99.7 rule

• normal distribution

  • 68.3% of data falls within 1 standard deviation

  • 95.4% of data falls within 2 standard deviations

  • 99.7% of data falls within 3 standard deviations

3 principles to determining whether it is safe to infer a population difference from a sample difference

• representative are better than biased (unrepresentative) samples

• bigger samples are better than smaller ones

• more estimates are better than fewer estimates

  • estimates based on only a few unrepresentative cases are imprecise

reliability

reproducibility or consistency of measurements in an experiment

inferential statistics

• help us determine if results can be generalized to a larger population (all those in a group being studied)

• numerical data that allows one to generalize— to infer from sample data the probability of something being true of a population

meta-analysis

a statistical procedure for analyzing the results of multiple studise to reach an overall conclusion

statistical significance

• a statistical statement of how likely it is that a result (such as a difference between samples) occurred by chance, assuming there is no difference between the populations being studied

• reflects the real world rather than chance

• minimum standard typically considered statistically significant is 5%

  • result considered significant if occurred by chance 5 or fewer times in 100 repetitions of study

p-value

• probability value

• measures how strongly the data contradicts the null hypothesis

• a tool for assessing evidence against the null

• a smaller p-value suggests stronger evidence against the null hypothesis

z-score formula

Z score = (Score-Mean)/Standard Deviation

effect size

• the strength of the relationship between two variables

• the larger the effect size, the more one variable can be explained by the other

what does a statistical significance of 0.05 mean?

means that youaccept a 5% maximum risk of claiming a finding is real when it actually happened just by random chance

skewed statistics vs inferential statistics

skewed statistics summarize data while inferential statistics determine whether data can be generalized to other populations

informed consent (informed assent for minors)

• giving potential participants enough info about a study to enable them to choose whether they wish to participate

• part of APA ethical considerations

debriefing

• the post experimental explanation of a study, including its purpose and any deceptions to its participants

• part of APA ethical considerations

confederates

those who pretend to be fellow participants but are actually part of the experiment

Institutional Review Boards (IRBs)

• established by universities + research organizations to enforce ethical standards

• comprised of at least 5 people, which must include: one scientist, one non-scientist, and one community representative

can researchers’ values influence their choice of topics?

• ya bro

• values can often color “the facts” — our observations and interpretations; sometimes we see what we want or expect to

• psychologists’ values influence their choice of research topics, their theories and observations, their labels for behavior, and their professional advice

null hypothesis

researchers’ initial assumption that no difference exists between groups

alternative hypothesis

a revised hypothesis if null hypothesis is rejected after studying statistics

confidence interval

a range of values that likely includes the population’s true mean value

practical significance

• does NOT equal statistical significance

• varies based on effect size

• asks whether that effect is large enough to matter in the real world

statistical significance vs practical significance

• statistical significance: proves that an effect is unlikely to be caused by random chance

• practical significance: asks whether that effect is large enough to matter in the real world