1.4 Notes on The Science of Psychology: Methodology, Research Design, and Ethics
Science as a Scientific Discipline and Pseudopsychology
Psychology is a scientific discipline; its cornerstone is systematic research used to gain knowledge for the semester.
This portion introduces the methodology of psychology as a science.
Pseudopsychology refers to areas that sound psychological but are not grounded in science.
types of pseudopsychology:
Mesmerism involved a healer moving magnets or empty hands over a person's body to adjust the balance of fluids or to induce a trance.
phrenology: a now-discredited practice that involved the measurement of bumps on the skull to determine personality traits and mental abilities. (assessment on skull)
Physiognomy: the study of facial features and expressions with the belief that they can reveal character or personality traits.
Spiritualism: the belief that the spirits of the dead can communicate with the living, often through mediums, which gained popularity in the 19th century as a way to explore the afterlife.
Psychoanalysis: A therapeutic approach founded by Sigmund Freud that emphasizes the exploration of unconscious thoughts and emotions to understand human behavior.
The key distinction between psychology and pseudopsychology is the use of systematic research methods, the scientific method, and critical thinking.
Critical thinking means evaluating how we know what we know and not simply accepting claims at face value.
Two main thinking errors that undermine critical thinking:
Confirmation bias: seeking information that supports preexisting beliefs and neglecting contradicting evidence.
Belief perseverance: continuing to believe despite contradictory evidence, often because of a desire to maintain the belief.
Science tries to reduce these errors by emphasizing critical thinking and evidence.
Goals of Psychological Science: Describe, Predict, Explain, and Control
Describing things (What is it?): descriptive research describes characteristics or behaviors.
Descriptive example: developmental psychologists study how children at different ages act, what behaviors they have, and what developmental stages they go through.
Descriptive results are often reported as measures of central tendency and variation.
Examples of central tendency: mean, median, and mode.
Typical statement: "On average, children of this age …" (descriptive summaries).
Describing data involves summarizing a sample, not making broad generalizations yet.
Predicting things: correlational research describes relationships between two variables.
The relationship is summarized by a correlation coefficient, denoted as r.
Range: r \,\in\,[-1,1]; the closer the absolute value is to 1, the stronger the relationship.
Interpretation:
Positive relationship: as one variable increases, the other tends to increase (e.g., class attendance and grades).
Negative relationship: as one variable increases, the other tends to decrease (e.g., course absences and grades).
The strength of the relationship affects how well one variable can predict another.
Example: strong positive relation between attendance and grades implies knowing attendance helps predict grades.
Explaining things (Understanding causes): experimental research aims to explain and understand causal relationships.
If we understand that X causes Y (e.g., reward increases a behavior), we can use that knowledge to control or modify behavior.
Practical and ethical balance is required: some manipulations are not allowed due to ethical concerns.
Controlling or manipulating phenomena: experimentation tests cause-and-effect and allows control over variables.
Basic Experimental Terminology: Variables and Causation
Independent variable (IV): manipulated variable; the presumed cause.
Dependent variable (DV): outcome variable; the measured effect.
In an experiment, the cause-effect relationship is the link between the IV and DV.
Experimental Design: Groups and Random Assignment
Experimental group: receives the treatment/manipulation.
Control group: does not receive the manipulation; serves as a baseline for comparison.
Random assignment: participants are randomly assigned to experimental or control groups (e.g., coin flip).
Purpose: ensure the only systematic difference between groups is the IV manipulation, minimizing confounds.
Data, Statistics, and Scientific Practice
Psychology collects data, analyzes data, and uses statistics to test theories.
Descriptive statistics summarize a sample:
Central tendency measures: mean, median, mode.
Example formula for the mean: \text{mean} = \frac{1}{n} \sum{i=1}^{n} xi
Inferential statistics determine whether observed differences are likely due to chance.
Common inferential tools include:
t-test
Analysis of Variance (ANOVA)
Regression
These tests help compare groups (e.g., experimental vs control) and assess significance.
Double-blind studies: both participants and researchers are unaware of group assignments.
Purpose: minimize placebo effects and observer/expectancy biases.
Placebo effect: improvements due to expectation rather than the actual treatment.
Example: a medication given to the experimental group may appear effective because participants expect to improve.
Debiasing via double-blind design helps reduce this effect.
The Scientific Method and Research Process
Systematic procedure:
Question driven by literature review and existing knowledge.
Theory: an idea about how variables are related.
Hypothesis: a testable statement derived from the theory.
Operational definitions: specify exactly how variables will be measured.
Sampling: select a representative sample to generalize findings.
Representative sample: chosen to reflect the population of interest.
Data analysis and drawing conclusions are followed by:
Replication: other researchers replicate the study to verify results.
Peer review: independent experts evaluate the methods and conclusions.
Ethics in psychology research:
Participants must be protected: informed consent, confidentiality, respectful treatment.
Coercion and excessive deception are avoided.
If deception is used, it must be corrected afterward (debriefing).
Do not fabricate data or plagiarize;
Integrity in reporting findings is essential.
Operationalization, Replication, and Practicalities
Researchers operationalize variables to measure them concretely in a study.
A good theory leads to testable hypotheses and measurable variables.
Ethics require balancing scientific curiosity with participant welfare and rights.
Summary: Building Foundations for Psychology
This chapter frames psychology as a science grounded in systematic research and critical thinking.
It contrasts science with pseudoscience and highlights thinking errors that threaten objectivity.
It outlines the evolution from describing to predicting to explaining to controlling psychological phenomena.
It introduces core research designs (descriptive, correlational, experimental), key variables (IV, DV), and ethical considerations.
It emphasizes methodological rigor (random assignment, double-blind procedures, replication, peer review) as central to the discipline.
The chapter sets the foundation for future topics (descriptive and inferential statistics, methods in learning, etc.).
\text{mean} = \frac{1}{n} \sum{i=1}^{n} xi
r \in [-1,1], \quad |r| \text{ closer to } 1 \text{ indicates stronger linear relationship}
t = \frac{\bar{X}1 - \bar{X}2}{SE}
F = \frac{MS{Between}}{MS{Within}}
Antiquity fallacy
when a person believes something only because people have believed it for a long time. This can lead to the perpetuation of outdated or inaccurate assumptions in psychological research, emphasizing the need for critical evaluation of traditional beliefs.
ex: A person believes that using a phonebook is the best way to find a phone number because phonebooks have been used for many years.
Belief Perseverance
maintains an idea even when evidence suggests it is incorrect
Alicia insists that her brother will quit smoking, even though he promised to quit many times before and failed to succeed. Which critical thinking error does this illustrate?
A person continues to believe that psychics can predict the future despite studies showing otherwise.
Phrenology
In the 1800s phrenology promoted the idea that bumps in the skull revealed personality characteristics and mental abilities.
Confirmation bias
is evidenced when a person prefers information that supports what the person already believes.
When Arjun reads his daily horoscope, he is often struck by how true it seems to him. Furthermore, when he reads about the characteristics of his astrological sign, Leo, he identifies with the description of a strong confident individual. Arjun became curious and read other descriptions of the astrological signs. He was disillusioned to find out that he also identified with the positive descriptions of the other signs. Arjun believed in the validity of his Leo horoscope due to the fallacy of:
Authority fallacy
is evidenced when a person believes something because a prominent figure believes it.
Emotional reasoning
is evidenced when a person believes something because of how it makes the person feel rather than how logical it is.
Bandwagon fallacy
when a person believes something because lots of other people believe it
Black or white fallacy
takes an absolute or extreme belief when a more moderate belief would be more accurate.
Emilio believes that the breakup of a relationship is all his partner's fault and refuses to consider anything he might have done wrong. Emilio is engaging in the: