U0, L4: Techniques in Experimental Psychology

Experimental Method

Research technique used to investigate cause & effect relationships b/w variables

• In an experiment, the researcher manipulates 1 variable & measures its effect on another variable

Independent Variable

Variable that the researcher changes/manipulates in an experiment

• Factor that the researchers are testing to see if it causes changes in behavior/outcomes

Dependent Variable

Variable that is observed & measured for changes in an experiment

• Outcome/response that may be affected by independent variable

Confounding Variables

Variables that weren’t accounted for/controlled in the study but still affect results

• Can distort true effect of the independent variable on the dependent variable, making it difficult to determine causality

Operational Definitions

Specifies how a researcher will measure & manipulate variables in a study

• Outlines exact procedures.operations used to define & quantify abstract

• Ensure consistency & clarity in research, allowing other researchers to replicate study & verify its findings

Experimental Group

Group of participants who are exposed to the independent variable

Control Group

Group of participants who were not exposed to independent variable

• Provides baseline for comparison w/ experimental group

Random Assignment

Research method used to assign participants to diff groups in an experiment randomly

• Ensures each participant has an equal chance of being assigned to any condition, helping to minimize bias/ensure that the groups are comparable at the start of the study

Placebo Effect

Phenomenon where individuals experience improvement in their condition solely bc they believe they are receiving a beneficial treatment, rather than due to any active ingredient/physiological mechanism

Experimenter Bias

Researcher’s expectations/beliefs abt outcome of a study influence results.

• Affects how study is conducted/how data is interpreted, → inaccurate conclusions

Single-Blind Study

Research design where participants = unaware of whether they belong to experimental or control group, but researchers conducting study know

Double-Blind Study

Research design where both participants & the researchers conducting study are unaware who belongs to experimental or control group

Placebo Condition

Administering the placebo to 1 group of participants while the other group receives the actual treatment being tested

• Placebo = typically given to control group

Sample

Refers to subset of individuals/cases selected from a larger pop for study

• Samples = used in research to make inferences abt pop as a whole

Representative Sample

Subset of individuals selected from a larger pop in such a way that it accurately reflects demographics, characteristics, & diversity of that pop

• By including diverse range of participants that mirrors pop’s composition, researchers can minimize biases & inc likelihood that their results are applicable to broader group they rep

Random Sample

Ensures that each participant in the study has an equal opportunity to be included, which helps minimize the influence of researcher bias & inc generalizability of the findings to pop as a whole

Sample Bias

Occurs when the sample = not representative of larger pop, → inaccurate/misleading results

• Essential to minimize sample bias to ensure validity & generalizability of research findings → broader pop

Generalizability

Extend to which research findings obtained from a sample can be applied/generalized → larger pop

• Reflects degree of confidence researchers have in extending their conclusions beyond the specific individuals/cases studied