psych 101 chapter 2: psychology's scientific method
longitudinal design
- special type of systematic observation that measures variables of interest over time - measures occur in multiple waves over time of the same group of participants - Lewis Terman (1925) began a study of gifted children on into adulthood - even though longitudinal studies attempt to demonstrate causality, the most well-conducted, excellent longitudinal studies cannot prove causation -- good because the genetics and situations are the same but bad because a few people do not represent the whole population
sample
- the group that the study is using - used as a way to more closely resemble the population
experimental design
- the researcher manipulates one of the variables to see if it influences the behavior in question - if the behavior changes when one of the variables is manipulated, then the manipulated variable caused the behavior to change - uses random assignment by dividing the participants randomly into 2 groups
theory
- the scientific method begins with a ____, which is a broad idea or set of closely related ideas that tries to explain certain behaviors - they tell us about the relationship between variables on a conceptual level - they try to explain why certain things occur and make predictions about future observations
formulating hypotheses and prediction
- the second step in conducting scientific research
correlation coefficient (r)
- the strength of the relationship between two variables - numeric values fall between -1.00 and +1.00, number determines strength and -/+ sign determines direction
cross-sectional design
- type of correlational study in which variables are studied at one point in time - a developmental psychologist interested in intelligence would use this design -- good because it provides a variety of subjects but bad because they are only studied at one point in time and genetics may be different and affect the intelligence of each individual
descriptive statistics
- used to describe and summarize data in a meaningful way - shows the big picture
scientific method
- using the _____ is what make psychology a science - researchers in psychology use this when conducting research
inferential statistics
-mathematical methods used to determine if the data sufficiently support the hypothesis; to test predictions - determine a statement of probability that tells what the odds are that the difference was due to chance - statistical significance - confidence level
confederate
a person who is given a role to play in the study so that the social context can be manipulated
reliable
a research finding is considered ____ when the study has been replicated again and again and yields similar findings
statistical significance
a statement of probability that the results occurred simply by chance alone
meta-analysis
a statistical procedure that summarizes a large body of evidence from the research literature on a particular topic. researchers combine results across various studies to establish the body of knowledge
placebo
an innocuous, inert substance that has no effect on the behavior of the participants. however, the participants are unaware of this; they believe they actually received manipulation
demand characteristics
any aspect of the study that communicates to participants how the experimenter wants them to behave
data collection
applies mathematical procedures to understand what the data (info collected in study) mean
causation
correlation is not ____; correlation only states that there is a relationship between the variables, not that one causes another
value of correlational research
correlational research allows: - research of variables that cannot be manipulated - predictions to be made among variables - research that may be unethical in any other way - study of everyday experiences (like natural disasters) - measurement of multiple variables (can asses whether a relationship between 2 variables is explained by a 3rd, 4th, or even 5th variable)
measure of dispersion
determines how much the score varies from each other, or the difference among the scores
range
distance (subtract) between the highest and lowest scores
control group
exactly like the experimental group except there is no manipulation of the variable - used as a comparison group
independent variable
- "cause" - the variable that is manipulated in an experiment - can sometimes be the social context in which a person finds themselves - context can be manipulated with the help of a confederate
dependent variable
- "effect" - result of the manipulation of the independent variable - sometimes referred to as the dependent measure - researchers measure changes in this variable
debriefing
- after the experiment has been conducted - participants are informed of the experiment's purpose and the methods that were used in the experiment
deception
- allowed only if telling the participants in advance about the expected outcome of the study could potentially alter the participants' behavior and therefore invalidate the results of the experiment - informed consent is validated, so participants should have the option of withdrawing consent after the study once they find out what it is about
hypothesis
- an idea that is arrived at logically from a theory - a prediction, a statement that can be tested
mean
- average of the data - most common measure of central tendency - also a key component to calculating other statistical measures
drawing conclusions
- based on what was found after data analysis - after publication, replication is key. having other researchers repeat the study and get the same/similar results is important to psychology - reliability
ethical research
- carried out ethically - overcome personal biases - obligation to research participants to anticipate issues their study might cause and to inform participants of possible side effects or consequences
testing through empirical research
- collecting and analyzing data through empirical research - the researcher must decide what participants to use in their research - operational definition - data collection
case study
- conducted when a researcher takes an in-depth look at a single individual. might also provide an in-depth and detailed exploration of particular small groups like families - usually conducted by a clinical psychologist when the unique aspects of an individual's life cannot be duplicated in other individuals - tell us a great deal about an individual person but not much about people in general
correlational research
- conducted when studies are concerned with identifying relationships between 2 or more variables so it can be understood how the variables change together - variables are measured by the researcher to see how they relate
random sample
- each member of the population has an equal chance of being selected - not the same thing as random assignment!! - aims to minimize bias, including gender and ethnic bias
evaluating the theory
- evaluation never really ends. conclusions become part of the research community - which continues to question them - meta-analysis - psychologists work together in a collaborative effort to increase an overall body of knowledge - working together on the same study or sharing findings by publishing them in scientific and academic journals. can also share conclusions by presenting them at both international and national conferences
animals
- experiments using these subjects have provided a better understanding of and solutions for many human problems - APA has set housing, feeding, and maintaining psychological and physiological well-being guidelines for these types of subjects
the 3rd variable problem
- occurs when an extraneous variable that has not been measured accounts for the relationship between 2 other variables - called the confound
interviews and surveys
- one method to get info about people is to _____ them directly - when info needs to be taken from a large group, _____ can be used; it consists of questions about a person's self-reported attitudes or believes about a topic. can either be unstructured (open-ended) or structured (specific) - can be problematic because sometimes participants will answer in the way they believe is socially acceptable instead of how they really feel
observation
- requires important skills - must be systematic. must know what they are looking for, who they are observing, where and when the observations will take place, and how observations will be made
operational definition
- researchers provide an objective description of how a variable is going to be measured or observed - variables do not have only one _____; rather, it is the way a researcher interprets the variable
internal validity
refers to whether changes in the dependent variable are actually due to the manipulation of the independent variable
validity
refers to whether the experiment studied what is was supposed to study
external validity
refers to whether the experimental design is representative of real-world issues
what, how
science is not defined by ____ it investigates, but by ____ it investigates
median
score that falls directly in the center of the data set after the data set has been arranged; middle score
mode
score that occurs most frequently in the data set
measure of central tendency
shows the overall characteristics of the data
confidence level
the .05 (5%) of significance that is the minimum level of probability that scientists will accept for concluding that the differences observed are real
observing some phenomenon
the first step in conducting scientific research is ____ - acting like a detective to know why or how something is the way it is
experimental group
the group whose variable is manipulated
independent and dependent variables
the most important concepts in psychological research
population
the researcher wants to be able to draw conclusions from the results that will apply to a larger group. this group is called the _____
subset
the sample is a _____ of the population
variable
when trying to formulate a research question for your observations, it is important to operationally define how your ____ will be measured
goals of psychology
1) describe 2) predict 3) explain 4) (used to be control - changing the environment
descriptive research
1) observation 2) surveys and interviews 3) case studies
5 steps of the scientific method
1) observing some phenomenon 2) formulating hypotheses and predictions 3) testing through empirical research 4) drawing conclusions 5) evaluating conclusions
confidentiality
Researchers are responsible for the _____ of all the data collected from the participants in the experiment
conceptual replication
involves doing the same study but with different methods or different samples
direct replication
involves doing the study exactly as it was conducted previously
statistics
mathematical methods to report data
standard deviation
measures how much the scores vary, on average, around the mean. the smaller the standard deviation, the less variability there is from the mean
informed consent
must be obtained prior to the start of the experiment; participants must know in advance what will be involved in the experiment and what, if any, risks there might be
double-blind experiment
neither the experimenter nor the participants is aware of which participants are in the experimental group and which are in the control group
experimenter bias
occurs when the experimenter's expectations influence the results of the study
research participant bias
occurs when the participant's behavior during the experiment is influenced by how they believe they are supposed to be behaving
placebo effect
occurs when the participant's expectations produce an experimental outcome, even thought they did not receive manipulation
negative correlation
occurs when the variables move in opposite directions so that if one variable increases, the other variable decreases (and vice versa)
positive correlation
occurs when the variables move in the same direction so that if one variable increases, the other variable increases also (and vice versa)
