Psychology: Knowledge Sources & Science

Different Sources Used in Obtaining Knowledge

• Authority: Belief based on teachings from figures of authority.
• Tenacity: Refusal to alter acquired knowledge, regardless of contradictory evidence.
• A Priori: Belief without prior study or examination.
• Intuition: Acquiring knowledge without reasoning or inferring.
• Rationalism: Acquiring knowledge through reasoning.
• Empiricism: Acquiring knowledge through experience.
• Scientific Approach: Explained by determinism: observable causes determine events.
• Events have causes knowable through controlled observation.

Psychology as a Science

• Science involves a systematically organized body of knowledge about the world through experimentation and observation
• Involves solvable problems through studying observable events.
• Uses the Scientific Method: identifying a problem & forming a hypothesis, designing and conducting the experiment, and testing the hypothesis.
• The final step is communicating the research results

Psychology

• Psychology is the scientific study of human behavior and mental processes.
• Psychology studies a person’s affect (emotions), behavior (actions), and cognitions (thought process).

Determinism

• In psychology, determinism suggests that observable causes determine events.

Scientific Psychology

• Scientific psychology is a repeatable, self correcting undertaking that seeks to understand phenomena on the basis of empirical observation
• Uses empirical observation, derived from the Greek word for "experience," indicating systematic observation.
• Experience, rather than faith, should be the source of knowledge
• It is also self-correcting through repeated observation and experimentation, the method can attempt to reconcile conflicting opinions.

Scientific Observation Process

• Empirical: Based on experimentation & observation.
• Public: Any observer must be able to observe the phenomenon.
• Repeatable: Can be replicated.

Functions of a Theory

• Organize Data: provides systematic orderly display of data like a filing system for organizing results
• Generate Predictions: predictions for situations without existing data
• Greater precision in predictions improves the theory.
• Theories in psychology are often verbal and less precise than in natural sciences.
• Theories organize concepts and facts into a coherent pattern with additional observations.
• The two functions of theories include organization/description and prediction/explanation
• Both are equally important as theories bridge the gap between knowledge and ignorance.

Evaluating Theories

• Parsimony: The fewer the statements in the theory, the better.
• Precision: Different investigators agree about predictions.
• Testability: A theory must be testable to be proved or disproved.
• Ability to Fit Data: A theory must fit the data it explains.

From Theory to Hypothesis

• Theories cannot be tested directly. Experiments test hypotheses derived from a theory.

Hypothesis vs. Generalizations

• A hypothesis is a specific, testable statement evaluated from observable data.
• A generalization is a broader statement that cannot be directly tested. Generalizations can produce more than one hypothesis

Sources of Generalizations

• From Experience (Qualitative Approach): Common-sense hypothesis, encountered problems.
• From Theory (Quantitative Approach): Preferred by psychologists, involves theories of attention, perception, decision-making.

Experiments

• An experiment occurs when the environment is systematically manipulated so that the causal effect of this manipulation on some behavior can be observed
• Other aspects are held constant so the environmental conditions do not influence the experiment

Advantages of Experiments

• Better control of extraneous variation.
• Casual explanation of the phenomenon being studied.
• More economical (compared to naturalistic observation).

Why Conduct Experiments

• To test theories and provide a database for explanations of behavior.
• Critical Experiments: Pit theories against each other.
• What-if Experiments: Explore possible phenomena without a specific theory.
• To repeat or replicate a previous finding.

Variables

• An independent variable is what is MANIPULATED
• A dependent variable is what is MEASURED or OBSERVED
• Extraneous/Control variables are held constant
• Variables may change in quality or quantity and are any condition in a scientific investigation

Independent Variable

• Controlled and manipulated (to have different values) by the experimenter
• Effective selection and manipulation make the difference between a good experiment and a poor one.
• IVs include brightness of light, loudness of a tone, temperature of a room
• A variable that is treated, also called treatment conditions
• There are two types:
  • Organismic: Any physiological or psychological characteristic of an organism, or being male or female
  • Environmental: Any characteristic of the environment which may affect an organisms

Null Results

• A null result is a failure of an IV to control behavior
• It has several explanations, including:
• The IV was not important or effective
• Ineffective manipulation of the IV
• Attributed to the DV or EVs

Dependent Variable

• Measures the effect of the IV and is proposed to be affected by the IV
• Effects of manipulation of the IV is measured through the DV, stability is one criterion of a good DV
• The replication of experiments should yield the same score as it did previously
• It should be a continuous variable, and may assume any fraction of a value.

Measures of the DV

• Accuracy: Number of correct responses, frequency of successes.
• Frequency: Number of times a response is made.
• Rate: Frequency over time.
• Speed: Duration of a response.
• Latency: Length of reaction time.
• Intensity: Magnitude of the response.
• Ability: Measured through written or practical tests.