What is Psychology?
Scientific Methods in Psychology
The science of psychology
Psychology
-Definition: Psychology is the scientific study of how humans perceive, feel, think, behave, interact with others, and understand themselves.
Sub-fields of psychology
Physiological/biological (i.e., brain chemistry, genetics, brain activity for certain tasks).
Educational (i.e., reduce dropout, teacher training, teaching methods)
Developmental (i.e., mental/cognitive/emotional processes throughout the life span).
I/O (human factor) (i.e., productivity, job training, efficiency, job satisfaction, computer design).
Social (i.e., group process, social thinking)
Counseling (mental health)
Clinical (cf. psychiatry)
Why science?
(a) Recognize a problem (hypothesis),
(b) Define the problem (operational definition),
(c) Construct a strategy (research method),
(d) Organize information (data collection/statistical analysis),
(e) Explain the problem,
(f) Monitor and evaluate the problem-solving.
Critical thinking
-Why has to be scientific?
Gut feelings, common sense, and intuition often lead to error/bias.
-Examples:
(a) Intuition:
-Intuition tells us that events do not come in streak and cluster.
But it frequently occurs in reality and random data. So expect streaks in gambling (i.e., TT then T or H?)
-How many people do you think you need to find a birthday match in a group? 366 Or 23?
-Which of the following sequences of heads and tails would be most likely: HHHHHH, HHHTTT, or HTTHTH?
(b) Hindsight bias (i.e., I-knew-it-all-along phenomenon)
The tendency to believe, after learning an outcome, that one would have foreseen it.
G1: Separation weakens romantic attraction—Not surprising--Out of sight, out of mind.
G2. Separation strengthens romantic attraction—Not surprising--Absence makes the heart grow fonder”
(c) Overconfidence
-The tendency to think that we know more than we actually do.
(i.e., How long will it take to unscramble a five-letter word? (OCHSA->Chaos)
(i.e., Folding a sheet of paper itself 100 times—Roughly how thick would it then be? The correct answer is 800 trillion times distance between the earth and the sun).
Conduct Research
-Be humble, curious, and skeptical
-Think critically: Do not blindly accept arguments and conclusions, but examine assumptions, find hidden values, evaluate evidence, and assess conclusions.
An Observation (a fact) (a depressed friend committed suicide)
Multiple observations (other depressed people, too)
Curious, humble, critically thinking
Set up a hypothesis (depression leads to suicide)
Test it! (How?)
Find a principle
Repeat the sequence
More principles (depression leads to drinking)
A theory (Depression is related to suicide, drinking, low self-esteem, lack of interest)
(A theory is an explanation using an integrated set of principles that organizes and predicts observations)
Research Methods
1.Case study: One or more individuals in great depth to find things true of all
-Economical
-Can be misrepresentative
2. Survey: Asking people to report their behavior or opinions.
-More representative than case study
-Results may be only descriptive rather than cause-effect
-Subject to “Wording Effect” (“revenue enhancers” than “taxes”)
-Subject to “False consensus effect”: The tendency to overestimate the extent to which others share our beliefs and opinions (i.e., Republicans believe others are also republicans).
3. Naturalistic observation: Watching and recording the behavior of organisms in their natural environment.
-Describes behavior in interest but not explain it (cause-effect)
-Not artificial
-Cannot control variables interested.
4. Experiment: A research method in which a researcher manipulates one or more factors to observe the effect on other factors in a controlled setting (holding other variables constant).
-Independent variable (smoking): A variable that is manipulated to see its effect
-Dependent variable (cancer): A variable that is measured to see its change in response to manipulations (changes) in the independent variable.
-Confounding variable (pot, drinking): A variable that confounds the relationship between IV and DV.
Things you need to Know
-Operational definition: A statement of the procedures (operations) used to define research variables (i.e., cutting a wrist more than once requiring more than a week hospitalization).
-Population: All the cases in a target group
(i.e., Marbles of two colors mixed well in a large jar)
-Sample (i.e., jurors): Members drawn from a population intending to represent the population (i.e., marbles of two colors mixed well in a small jar).
-Random sample: Each member of a target group has an equal chance of being selected for a sample. Individuals selected for a sample are representative of a target group (population).
-Descriptive statistics
Mode: The most frequently occurring score in a distribution.
Median: The middle score in a distribution, 50th percentile.
Mean: The arithmetic average of a distribution.
Range: The gap between the lowest score and the highest score.
Standard deviation: A measure of how much scores deviate from one another (scores packed together or dispersed?)
-Scatter plot: A graphed cluster of dots, each dot representing the values of two variables (i.e., # of cigarettes and weight)
-Correlation Coefficient: A statistical measure of the extent to which two factors vary together. How two factors are related to each other?
Range: -1.00 to +1.00) (Direction and Strength)
Correlation indicates the possibility of a cause-effect relationship, but it does not prove causation).
-Illusory Correlation: The perception of a relationship where none exists.
(EX) More babies are born when the moon is full.
Sugar made children hyperactive.
Cold weather or being wet in winter cause one to catch a cold.
Infantile couples more likely to conceive a child after adopting a child.
-Statistical Significance: A statistical criterion for rejecting the assumption of no differences in a particular study (t or F scores).
-Double blind procedure: An experimental procedure in which both the researchers and research participants are ignorant (blind) about whether the participants received the treatment, a contrasting treatment (i.e., writing), or a placebo—No experimenter or participant effect.
-Placebo effect: Any effect on behavior caused by an inert substance (sugar pill) or condition that is believed to be a presumed active agent (drug).
-Replication: Repeat the essence of a study with different participants.