AP Psych Unit 0: An Introduction to Psychological Science Practices (Research Methods & Data Interpretation) Study Guide

scientific attitude

mental outlook distinguished by an unbiased method & the application of empirical (knowledge based on observation or experience) approaches

1. curiosity

2. skepticism

3. humility

curiosity

1st element of the scientific attitude

• does it work?

• when put to the test, can its prediction be confirmed?

skepticism

2nd element of the scientific attitude

• what do you mean?

• how do you know?

must be healthy, meaning

• not cynical/doubting everything

• not gullible/believing everything

humility

3rd element of the scientific attitude

• that was unexpected! let’s explore further

researchers must be

• willing to be surprised

• follow new ideas

because people & other animals don’t always behave as one’s ideas & beliefs would predict

critical thinking

thinking that does not automatically accept arguments & conclusions

• examines assumptions

• appraises the source

• discerns hidden biases

• evaluates evidence

• assesses conclusions

hindsight bias

tendency to believe, after learning an outcome, that one would have foreseen it

• i-knew-it-all-along phenomenon

overconfidence

tendency to think we know more than we do, to be more confident than correct

• confidence drives us to quick thinking rather than correct thinking

perceiving order in random events

like hindsight bias & overconfidence, it’s a flaw in our common sense thinking

scientific method

self-correcting process for evaluating ideas w/ observation & analysis

1. observation

2. question

3. hypothesis

4. experiment

5. analysis & conclusions

6. sharing results

observation (SM)

1st step of the scientific method

• theory construction through observing

question (SM)

2nd step of the scientific method

• formulate inquiries/asks

hypothesis (SM)

3rd step of the scientific method

• make predictions

experiment (SM)

4th step of the scientific method

• gather/collect data

• design studies/experiments

analysis & conclusions (SM)

5th step of the scientific method

• analyze results

• draw conclusions

sharing results (SM)

6th step of the scientific method

• communicate findings to contribute to scientific knowledge

• aid other researchers/scientists through your findings

peer reviewers

scientific experts who evaluate a research article’s theory, originality, & accuracy

theory

explanation using an integrated set of principles that organizes observations & predicts behaviors or events

hypothesis

testable/falsifiable prediction

• often implied by a theory

falsifiability

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

operational definition

carefully worded statement of the exact procedures (operations) used in a research study

• also known as operationalization

• MUST be measurable

ex. human intelligence = what an intelligence test measures

replication

repeating the essence of a research study

• usually w/ different participants in different situations to see whether the basic finding can be reproduced

• if similar results are found, confidence in the reliability of the basic finding grows

non-experimental methods

case studies, surveys, naturalistic observations, correlational research

• observe & record behavior

• nothing is manipulated

• no control of variables

• single cases may be misleading

case study

non-experimental technique in which one individual or group is studied in depth in the hope of revealing universal principles

ex. brain damage, children’s minds, animal intelligence

naturalistic observation

non-experimental technique of observing & recording behavior in naturally occurring situations w/o trying to manipulate & control the situation

• does not explain behavior, but describes behavior

survey

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

• desirability bias & self-report bias affect this technique negatively, causing the data to be inaccurate

desirability bias

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

self-report bias

bias when people report their behavior inaccurately

sampling bias

flawed sampling process that produces an unrepresentative sample

• cannot compensate for an unrepresentative sample by simply adding more people

convenience sampling

collecting research from a group that is readily available

ex. friends at school

random sample

sample that fairly represents a population b/c each member has an equal chance of inclusion

• creates a representative sample, better than biased/unrepresentative samples

• bigger samples are better than smaller ones

population

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

• except for national studies, does not refer to a country’s whole population

correlational research

non-experimental technique that describes the relationship between 2 or more variables

• detect naturally occurring relationships

• assess how well one variable predicts the other

• collect data on 2 or more variables

• nothing is manipulated

• cannot specify cause & effect

correlation

measure of the extent to which 2 factors vary together & thus of how well either factor predicts the other

• does not equal causation

• suggests a possible cause-effect relationship but does not prove it

correlation coefficient

statistical index of the relationship between 2 things

• from -1.00 to +1.00

perfect positive correlation

r = +1.00

no relationship

r = 0.00

perfect negative correlation

r = -1.00

variables

anything that can vary & is feasible (practical, empirical) & ethical to measure

ex. personality test scores for identical twins, intelligence test scores predicting career achievement

scatterplot

graphed cluster of dots, each of which represents the values of 2 variables

• slope of the points suggests the direction of the relationship between the 2 variables

• amount of scatter suggests the strength of the correlation (little = weak, lots = strong)

illusory correlation

perceiving a relationship where none exists or perceiving a stronger-than-actual relationship

regression toward the mean

tendency for extreme or unusual scores or events to fall back (regress) toward the average

experimental methods

manipulate variables to see their effects, attempt to establish a cause-&-effect connection

• explore cause & effect

• manipulate 1 or more factors

• use random assignment

• manipulate the independent variable(s)

• sometimes not feasible

• results may not generalize to other contexts

• not ethical to manipulate certain variables

experiment

research method in which an experimenter manipulates 1 or more factors (independent variables) to observe the effect on some behavior or mental process (dependent variables)

• by random assignment, the experimenter aims to control other relevant factors

experimental group

(in an experiment) group exposed to the treatment or independent variable

control group

(in an experiment) group not exposed to the treatment or independent variable

• contrasts w/ the experimental group

• serves as a comparison for evaluating the effect of the treatment or independent variable

random assignment

assigning participants to experimental & control groups by chance, minimizing preexisting differences between the different groups

• equalizes experimental & control groups

• helps control possible confounding variables

single-blind procedure

experimental procedure in which the research participants are ignorant (blind) about whether they have received the treatment or a placebo

• help control social desirability bias

double-blind procedure

experimental procedure in which both the research participants & the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo

• commonly used in drug-evaluation studies

• researchers check a treatment’s actual effects apart from the participants & staff’s belief in its healing powers

• reduce experimenter bias

placebo effect

experimental results caused by the expectations alone

• any effect on behavior caused by the administration of an inert (chemically inactive) substance or condition which the recipient assumes is an active agent

• thinking you are getting a treatment can boost spirits, relax the body, & relieve symptoms

independent variable

(in an experiment) factor that is manipulated

• variable whose effect is being studied

• can vary independently of other factors

dependent variable

(in an experiment) outcome that is measured

• variable that may change when the independent variable is manipulated

• can vary depending on what takes place during the experiment

confounding variable

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

• outlier variable, unexpected

experimenter bias

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

validity

extent to which a test or experiment measures or predicts what it is supposed to do/experiment tests what it is supposed to test

quantitative research

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

• quantity

ex. Likert scale

Likert scale

where questionnaire responses fall on a continuum such as from “strongly disagree” to “strongly agree”

qualitative research

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

• quality

ex. structured interviews to understand the causes & consequences of individuals’ aggression

structured interview

asking questions in a set order to collect data from a topic

• interviewer asks a set of prepared closed-ended questions in the form of an interview schedule, which they read out exactly as worded

• have a standardized format, meaning the same questions are asked to each interviewee in the same order

ethics codes

from the American Psychological Assocation (APA) & the British Psycholocal Society (BPS)

1. obtain informed consent

2. protect participants from greater-than-usual harm & discomfort

3. keep info about individual participants confidential

4. fully debrief people

informed consent

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

• called informed assent in the case of minors

• 1st of the ethics codes

protection from harm

protect participants in experiments/research from harm

• 2nd of the ethics codes

protection of participant confidentiality

keep info about the participants confidential

• 3rd of the ethics codes

debrief

postexperimental explanation of a study including its purpose & any deceptions to its participants

• 4th of the ethics codes

Instutional Review Boards (IRBs)

established to enforce the ethics codes

• compromised of at least 5 people — must include at least 1 scientist, at least 1 non-scientist, & at least 1 community representative

• screen research proposals & safeguard “the rights, welfare, & well-being of human research participants”

descriptive statistics

numerical data used to measure & describe characteristics of groups

• measures of central tendency

• measures of variation

ex. histogram

histogram

bar graph depicting a frequency distribution

measures of central tendency

single score that represents a whole set of scores

• mode

• mean

• median

mode

most frequently occurring score(s) in a distribution

• simplest measure

mean

arithmetic average

• total sum of all the scores divided bu the number of scores

median

midpoint of a data distribution or 50th percentile

• arrange all scores from highest to lowest, half will be above median & half will be below the median

• if there are 2 numbers in the middle, add them together & divide by 2

percentile rank

percentage of scores that are lower than a given score

ex. 79th percentile = score is higher than 79% of other scores

skew

representation of scores that lack symmetry around their average value

positively skewed/right skewed

the tail of the distribution points to the right

negatively skewed/left skewed

the tail of the distribution points to the left

measures of variation

the similarity or diversity of scores

• range

• standard deviation

range

difference between the highest & lowest scores in a distribution

• highest score minus lowest score

standard deviation

computed measure if how much scores vary around the mean score

• gauges whether scores are packed together or dispersed

• assembles info about how much each individual scores differ from the mean

normal curve

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

• most scores fall near the mean (~68% fall w/in 1 standard deviation of it)

• fewer & fewer scores lie near the extremes

• also called a normal distribution

inferential statistics

numerical data that allow one to generalize, to infer from sample data the probability of something being true of a population

• help determine if results can be generalized to a larger population

meta-analysis

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

null hypothesis

assumption that no difference exists between groups

alternative hypothesis

states the opposite of one’s hypothesis

statistically significant

statistical statement of how likely it is that a result occurred by chance, assuming there is no difference between the populations being studied

effect size

strength of the relationship between 2 variables

• larger size = more 1 variable can be explained by the other

• smaller size = less 1 variable can be explained by the other