Chapter 3 The Experimental Research Approach ♣ ♣ Experimental Research approach: A quantitative approach designed to discover the effects of presumed causes Causation   The Psychological Experiment   Experimental Research Settings    Back to Brief Contents

3.1 Causation -1 Causation: ■ whose meaning is debated by philosophers ■ in everyday language: manipulation of one event - cause produces another event - effect Cause A contextually dependent event that makes something else exist  Back to Chapter Contents

3.1 Causation -2 Effect The difference between “what would have happened” (no treatment) and “what did happen when a treatment is administered” Causal Relationship ■ J. S. Mill (1874): 4 canons used to experimentally identify causality  Back to Chapter Contents

3.1 Causation -3 Causal Relationship ■ J. S. Mill (1874): 1. Method of agreement The identification of the common element in several instances of an event 2. Method of difference The identification of the different effects produced by variation by only one event (ex: Experimental vs. Control)  Back to Chapter Contents

3.1 Causation -4 Causal Relationship ■ J. S. Mill (1874): 3. Joint methods of agreement and difference Method of agreement → hypothesis → tested by the Method of difference 4. Method of concomitant variation The identification of parallel changes in two variables (IV & DV; independent v. & dependent v.; 獨變項 & 依變項 ) Extension of the M. of difference ( 兩組以上 )  Back to Chapter Contents

3.1 Causation -5 Causal Relationship ■ Cause of Malaria (Exhibit 3.1) bad air of the lowlands quinine → malaria parasite mosquitoes ( 三斑家蚊 ) balanced set of social, economic, and biological factors  Back to Chapter Contents

3.1 Causation -6 Causal Relationship  Necessary Condition 必要條件 A condition that must exist for an effect to occur  Sufficient Condition 充分條件 A condition that will always produce the effect under study  Necessary and Sufficient Condition 充要條件 Complete explanation of the occurrence of the event Will never change 但是個體行為很複雜，難找到充要條件  Back to Chapter Contents

3.1 Causation -7 Causal Relationship ■ Position of Falsification The belief that the best that can be said about a theory or prediction is that it is “not yet falsified” Popper: A confirmation of an experiment → the hypothesis tested has survived the test Experiment fails to confirm a prediction or a theory → the prediction or theory being tested is falsified  Back to Chapter Contents

3.1 Causation (end) Causal Relationship  Deese (1972) Causation: large network of cause-and-effect relations Any study: a small part of the overall system  Back to Chapter Contents

3.2 The Psychological Experiment -1 J. S. Miller (1874): three criteria must be met to identify a cause-and-effect relationship 1. The cause must precede the effect 2. The cause must be related to the effect 3. No plausible alternative explanations must exist for the effect other than the cause  Back to Chapter Contents

3.2 The Psychological Experiment -2 The Psychological Experiment: (Zimney, 1961) Objective Observation Of Phenomena That Are Made to Occur In a Strictly Controlled Situation In Which One or More Factors Are Varied and Others Are Kept Constant  Back to Chapter Contents

3.2 The Psychological Experiment -3 Advantages of the Experimental Approach  Causal Inference Causal description: Describing the consequences of deliberately varying a treatment Causal explanation: Clarifying the mechanisms by which a causal relationship holds  Control  Ability to Manipulate Variables  Back to Chapter Contents

3.2 The Psychological Experiment (end) Disadvantages of the Experimental Approach  Does Not Test Effects of Nonmanipulated Variables  Artificiality Fig 3.1 Fig 3.1  Inadequate Method of Scientific Inquiry  Back to Chapter Contents

3.3 Experimental Research Settings -1 Field Experimentation  Exp. conducted in a real-life setting  Example IV: Clothing (Formal vs. Informal) DV: Amount of time for a store employee to approach and acknowledge the confederate  Natural behavior, setting, treatment Fig 3.2 Fig 3.2  Disadvantage-less control of extraneous variables  Back to Chapter Contents

3.3 Experimental Research Settings -2 Laboratory Experimentation  Exp. conducted in the controlled environment of a lab.  Strength is control over extraneous variables  Weakness—artificiality  Back to Chapter Contents

3.3 Experimental Research Settings -3 Internet experiments  Advantages Access to diverse population Bring experiment to participant Large sample  high statistical power Direct access to motivational confounding — By noting the differential dropout rate between treatment conditions Cost savings—lab space, equipment, etc  Back to Chapter Contents

3.3 Experimental Research Settings -4 (end) Internet experiments  Disadvantages Multiple submissions Lack of control — Randomization must be included in the design Self-selection Dropout  Back to Chapter Contents