1. Research Methods

dependent variable (DV)

the outcome measured in an experiment

independent variable (IV)

the variable manipulated by the researcher to observe its effect

controlled variables

factors kept constant to ensure that any changes in the dependent variable are due to the independent variable alone

predictor variables

a type of independent variable that is not manipulated directly, often due to ethical concerns. used to predict outcomes in the dependent variable

confounding variables

variables that can influence both the independent and dependent variables, leading to spurious correlations

ex. In a plant watering experiment, different plant species could confound results if not controlled for

spurious correlations

occur when two variables appear to be related but are actually influenced by a third variable

correlation

a statistical measure that indicates the direction and strength of a relationship between two variables, represented by the correlation coefficient (r), which ranges from -1 to 1

positive correlation

both variables increase

negative correlation

one variable increases while the other decreases

zero correlation

no significant relationship

correlation coefficient strength

the closer the value of r is to 1 or -1, the stronger the correlation

ex. r = 0.8 indicates a strong positive correlation

P-values

a statistical measure indicating the probability that results occurred by chance; less than 0.05 is considered statistically significant in psychology

Type I Error

a false positive, concluding that an effect exists when it does not

ex. Claiming a patient has cancer when they do not

Type II Error

a false negative, failing to detect an effect that is present

ex. missing a cancer diagnosis

Signal Detection Theory (SDT)

used to determine how well a signal (meaningful information) can be detected amidst noise (irrelevant information); involves measuring responses to stimuli under varying conditions

thresholds

the minimum level of stimulus intensity required for detection

ex. auditory thresholds determine the faintest sound a person can hear

D’ (D Prime)

a measure of sensitivity in Signal Detection Theory, indicating how well one can distinguish between signal and noise. a higher D’ value indicates better sensitivity

ex. in a quiet room, hearing your name is easier (high D’) while in a noisy cafeteria, it becomes more challenging (low D’)

hit rate & false alarm rate

metrics that help quantify performance in signal detection tasks; a high hit rate with a low false alarm rate indicates effective signal detection

Capgras Syndrome

a psychological condition where a person believes that a loved one has been replaced by an identical imposter