PSYCH 280 1st Edition Lecture 5Outline of Last Lecture I. Correlations (recap)II. Experimental Methoda. Independent variableb. Dependent variablec. Random assignmentd. Confounding variablese. Statistical significancef. Subject variableIII. Factorial Designsa. Statistical interactionsOutline of Current Lecture IV. Finish up experimental methoda. Reliabilityb. ValidityV. Judgment Heuristicsa. Uses of heuristicsb. Types of heuristicsCurrent LectureI. Experimental Method: Reliability v. ValidityReliability and validity are two extremely important concepts when it comes to experimental methods. Reliability is the extent to which a test (measure) is consistent (i.e. if you weight yourself at 8am in the morning and at 8pm at night, the measurements should be relatively close—weight fluctuates during the day, however. Validity, on the other hand, is the extent to which a test actually measures what it is supposed to be measuring.There are two types of reliability:a. Test-retest reliability: Even after redoing the test multiple times, the result is still the same.b. Interjudge reliability: Even when different researchers perform the test, the result is still the same.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.There are two types of validity:c. Face validity: The test measures what it appears (intuitively) to measure/test.d. Construct validity: The test measure produces the results that agree with an already accepted test/measure.*Important notes about reliability v. validity:e. Reliability sets an supper limit on validityf. Reliability is necessary for validityg. Reliability can exist without validity, but validity cannot exist without reliabilityh. When there is a correlation: (validity) < (reliability)2II. Judgment HeuristicsA judgment heuristic is an automatic process that uses mental “shortcuts” to make quick judgments about our word, such as: frequency of events, probabilities, danger, and risk.a. Why do we use heuristics?The use of heuristics decreases the amount of cognition resources we use. By using a judgment heuristic, people are able to cut down on the amount of mental power they have to use to makea judgment (by already having a “shortcut” available, we do not have to pause and think about every judgment we make). In short, people are mentally lazy and judgment heuristics allow us to conserve our limited cognitive resources.Also, although heuristics can sometimes backfire, the use of heuristics is not irrational or illogical—they help us out by allowing us to make quick, effortless judgments!!!Other reasons people use heuristics include:1. Conserve mental energy2. Limited cognitive resources3. Time constraints (have to act fast in an emergency)4. Missing informationc. There are two types of heuristics: availability and simulation heuristics (Simulation heuristic will be covered next lecture):The availability heuristic is defined as: judging the frequency, probability, likelihood, or chance of an event according to the ease with which relevant instances come to mind. However, there are problems with the availability heuristic. The ease that relevant instances come to mind can be influenced by many things that are unrelated to the actual frequencies, probabilities, likelihoods, or chances of that event:1. Salience: people fail to notice “non-events.” We pay more attention to the things that do happen than the things that don’t happen.2. Recency of events3. Individual interests and experiencesTo summarize the availability heuristic: People are “out of touch” with the actual frequencies, probabilities, etc of
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