Lesson 2: Thinking Like a Psychological Psychologist

Alternative hypothesis

The statement a researcher tries to prove, claiming there is a statistically significant effect, difference, or relationship between variables

Empirical; empiricism

Concerned with observation and/or the ability to verify a claim (I can measure it)

Falsifiability; falsifiable; falsify

In science, the ability of a claim to be tested and—possibly—refuted; a defining feature of science.

Inductive reasoning

A general conclusion is made from a set of observations (e.g., noting that “the driver in that car was texting; he just cut me off then ran a red light!” (a specific observation), which leads to the general conclusion that texting while driving is dangerous).

Deductive reasoning

A general rule determines the interpretation of specific observations (e.g., All birds have feathers; since a duck is a bird, it has feathers).

Null hypothesis

Assuming that there is no relationship between variables

P-value (probability value)

The probability that the results occurred by chance if the null hypothesis is true.

Objective

Measuring something that is right or wrong (no bias).

Subjective

Something that you can measure or watch without having potential bias because of the subject (person).

Type I error

The error of rejecting the null hypothesis when it is true (false positive). You think there’s a relationship, but there isn’t. Ex: Saying caffeine helps memory when it actually doesn’t. (I found something- but it’s wrong)

Type II error

The error of failing to reject the null hypothesis when it is false (false negative). You think there’s no relationship, but there actually is. Ex: Saying caffeine doesn’t help when it actually does. (I missed something)

Ideas that are consistent with scientific thinking

Empiricism (I can measure it) and reasoning (logical thinking)

Ideas that are contradictory with scientific thinking

Tradition, anecdote, intuition, and authority

Karl Popper

He introduced the idea of falsifiability—scientific claims must be testable and able to be proven false.

Correlation

Shows if two variables are related, but it does not prove one causes the other.

Theory Definition in Everyday Life

A guess

Theory Definition in Science

A well-supported explanation based on lots of evidence.