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Measurements and mismeasurements in Psychology Week 1, Session 1
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About me… Kai Qin (“Kai Chin”) Professor Sir Teacher teachingpsychology.weebly.com
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How to enjoy and do well in this course? Class attendance Critical reading, thinking, writing Do not hesitate to ask questions during class! Be punctual
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Critical thinking in psychology
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Syllabus Goals Grading components Office hours
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Science & Measurements
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Science Measurement is a defining characteristics of science
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What is a measurement? A quantifiable attribute How much of …?How fast …? How long…?How many…?
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What is a psychological measurement? A quantifiable psychological attribute How much of …?How fast …? How long…?How many…?
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We make statements such as… Politicians are greedy… The driver is rude… The professor is smart. This class is awesome!!! All these require you to measure the constructs
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How would you measure… Greed Rudeness Intelligence Enjoyment
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Psychologists are obsessed with measurements circa 1000 BC. : Chinese introduced written tests to help fill civil service positions Civil Laws, Military Affairs, Agriculture, Geography 1850 : The United States begins civil service examinations. 1885 : Germans tested people for brain damage 1890 : James Cattell develops a "mental test" to assess college students. Test includes measures of strength, resistance to pain, and reaction time. 1905 : Binet-Simon scale of mental development used to classify mentally retarded children in France.
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Psychologists are obsessed with measurements 1914 : World War I produces need in U.S. to quickly classify incoming recruits. Army Alpha test and Army Beta test developed. Looked at psychopathology. 1916 : Terman develops Stanford - Binet test and develops the idea of Intelligence Quotient 1920 - 1940 : factor analysis, projective tests, and personality inventories first appear. 1941-1960 : vocational interest measures developed 1961-1980 : item response theory and neuropsychological testing developed 1980 - Present : Wide spread adaptation of computerized testing. "Smart" Tests which can give each individual different test items develop
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What about India?
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Can you really measure psychological attributes? Most psychological attributes are: latent: present but invisible abstract Some examples: Intelligence Evilness Memory Hence they need to be inferred.
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The problem How do you make strong inferences?
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The BIG QUESTION throughout the course When we measure something, what are we really measuring? Brain activity? Really? Always? Religiosity?
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Validity
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General definition: “Are your measurements actually measuring the construct you think you are measuring?” While we can obtain specific statistics for reliability (even different types), validity is more of a global assessment based on the evidence available We can have reliable measurements that are invalid The history of science has lots of examples…(see Course Manual)
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One approach of critical thinking Claim Search for evidence Example: Touch therapy, magnet therapy WHAT IS THE EVIDENCE?
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Does touch therapy work? Practitioners of TT claim to treat many medical conditions by using their hands to manipulate a “human energy field” perceptible above the patient’s skin. Claims Made for TT Relieves burns pain, nausea, fever Treats ulcers, measles, cancer Note: TT ≠ Massage therapy Rosa, L., Rosa, E., Sarner, L., & Barrett, S. (1998). A close look at therapeutic touch. J Am Med Assoc, 279, 1005.
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Finding evidence for TT If TT was true, then practitioners should have been able to locate the investigator’s hand 100% of the time. A score of 50% would be expected through chance alone. Rosa, L., Rosa, E., Sarner, L., & Barrett, S. (1998). A close look at therapeutic touch. J Am Med Assoc, 279, 1005.
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Experiment Sample: 21 practitioners Double-blinded study “Patient” had palms under practitioners’ hands: Yes vs. No 280 trials for each practitioners Correct response? 123 (44%) of 280 trials Rosa, L., Rosa, E., Sarner, L., & Barrett, S. (1998). A close look at therapeutic touch. J Am Med Assoc, 279, 1005.
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Does magnet therapy make sense?
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The approach of this CTS We assume the experiment has been done. But we ask… WHAT IS THE EVIDENCE ACTUALLY TELLING YOU? Is the measurement… Valid? Reliable? Credible?
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Measurements matter in real life Clinical Psychologists (intelligence, psychopathology) Counseling Psychologists (career interest, skill assessment) School Psychologists (readiness for school, social Adjustment) I/O Psychologists (managerial potential, training needs) Neuropsychologists (brain damage, neurological impairments) Forensic Psychology (recidivism risk)
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Why do measurements matter? Often we don’t want a measure that merely describes an attribute. Often we want a measure to predict.
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One can get really rich… even if one is full of s*** (rhyme unintended)
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Why do some people use flawed measurements?
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A good scientist… Doesn’t overstate his or her claims Acknowledges limitations Tries to rule out alternative explanation Is not defensive when questioned Relies on evidence rather than emotional argument
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The Story of Facilitated Communication https://www.youtube.com/watch?v=Dqhlv0UZUwY https://www.youtube.com/watch?v=Dqhlv0UZUwY https://www.youtube.com/watch?v=OxEqaIYucrw https://www.youtube.com/watch?v=OxEqaIYucrw
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Take home message “Any sufficiently advanced technology is indistinguishable from magic.”
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My aim for you Be skeptical, but not cynical.
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Learning goal Psychology will not give you answers to many questions. But it will equip you with the skills needed to evaluate the answers to these questions that others – and yourself – have given.
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Announcements No class next week Complete the online questionnaires (see Course Manual for url) Read the Course Manual
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