Empiricism and Determinism
Science is based on certain philosophical assumptions including empiricism (knowledge based on sensory experience or objective observations) and determinism (events have causes, nothing happens without a cause)
Inductive vs Deductive Method
Inductive: experiment-first-and-explain-later approach
Deductive: explain-first-and-verify-later approach; deductive reasoning first proposes a theory and then verifies it
Null vs Alternative Hypothesis
Null: two variables are not related
Alternative: variables are related; cause-and-effect
Reliability and Validity: Definition and Types
*Important for good scientific measurement
See Chapter 11’s Flashcards
Experimental Research: Independent vs Dependent Variables
Independent: directly manipulated
Dependent: affected by independent variable
Independent/Dependent Examples:
- Stressful situation/amount of stuttering
- Amount of b/g noise/amount of diff. hearing speech
Types of Single Subject Design (2)
*AB design is similar to a case study; baselines are established (A) and treatment is offered (B), and the progress is summarized in a case study
*Two types: ABA and ABAB
A=baselines, B=treatment, A=treatment withdrawl, B=reinstatement of treatment
- Multiple-Baseline design: effects of treatment are demonstrated by showing that untreated skills did not change and only the treated skills did
- 3 types: across subjects, settings, and behaviors
Experimental vs Descriptive Research
Experimental: permits us to actively manipulate conditions; cause-and-effect
Descriptive: helps us understand what already exists
Descriptive Research: Classification vs Criterion Variables
These variables in some kinds of descriptive research
- Classification variable: analogous to the independent variable in experimental research
- Criterion variable: analogous to the dependent variable in experimental research
Classification/Criterion Example: Group status (dementia vs not)/Performance measures
Descriptive Research: Types (6)
- Ex post facto research AKA causal-comparative studies (retrospective or case studies)
- Survey research (questionnaires, interviews)
- Comparative research AKA standard-group comparisons
- Developmental research AKA normative research (independent variable: maturation; 3 methods: longitudinal, cross-sectional, and semilongitudinal)
- Correlational research (correlation does not imply causation; direction: pos/neg and strength: high/low of relationship; Pearson r)
- Ethnographic research (observation and description of naturally occurring phenomena)
Evaluation of Research: Internal vs External Validity
Internal: Degree to which data in study reflect a true cause-effect relationship; no confounding variables
External: Generalizability; “To which people and situations can these results be generalized?”; degree to which internally valid results can be generalized
Threats to Internal Validity (8)
- Instrumentation (mechanical/electrical probs, inappropriate testing materials, judges may reduce validity and make observation/scoring mistakes)
- History (life events; e.g., recent surgery)
- Statistical regression (a behavior that goes from an extreme high/low point to an average level; e.g., hoarse voice may change due to statistical regression vs tx)
- Maturation
- Attrition (losing participants as experiment progresses)
- Testing (change in dependent variable because it has been measured more than once, e.g., administration of pre- and posttests)
- Subject selection biases
- Interaction of factors
Threats to External Validity (3)
- Hawthorne effect (extent to which results are affected by participants’ knowledge that they are taking part in an experiment or that they are being treated differently than usual)
- Multiple-treatment interference (incl. “order effect”)
- Reactive or interactive effects of pretesting (e.g., may increase awareness prior to tx)
Statistical Techniques for Organizing/Summarizing Data (3)
- Measures of central tendency: mean, median, mode
- Measures of variability: refers to dispersion in data set; e.g., range, interquartile range, standard deviation
- Measures of association/correlation