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Measurements and mismeasurements in Psychology Week 1, Session 1.

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Presentation on theme: "Measurements and mismeasurements in Psychology Week 1, Session 1."— Presentation transcript:

1 Measurements and mismeasurements in Psychology Week 1, Session 1

2 About me…  Kai Qin (“Kai Chin”)  Professor  Sir  Teacher teachingpsychology.weebly.com

3 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

4 Critical thinking in psychology

5 Syllabus  Goals  Grading components  Office hours

6 Science & Measurements

7 Science  Measurement is a defining characteristics of science

8 What is a measurement?  A quantifiable attribute How much of …?How fast …? How long…?How many…?

9 What is a psychological measurement?  A quantifiable psychological attribute How much of …?How fast …? How long…?How many…?

10 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

11 How would you measure…  Greed  Rudeness  Intelligence  Enjoyment

12 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.

13 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

14 What about India?

15 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.

16 The problem  How do you make strong inferences?

17 The BIG QUESTION throughout the course  When we measure something, what are we really measuring? Brain activity? Really? Always? Religiosity?

18 Validity

19  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)

20 One approach of critical thinking Claim  Search for evidence  Example: Touch therapy, magnet therapy WHAT IS THE EVIDENCE?

21 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.

22 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.

23 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.

24 Does magnet therapy make sense?

25 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?

26 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)

27 Why do measurements matter?  Often we don’t want a measure that merely describes an attribute.  Often we want a measure to predict.

28 One can get really rich… even if one is full of s*** (rhyme unintended)

29 Why do some people use flawed measurements?

30 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

31 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

32 Take home message “Any sufficiently advanced technology is indistinguishable from magic.”

33 My aim for you Be skeptical, but not cynical.

34 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.

35 Announcements  No class next week  Complete the online questionnaires (see Course Manual for url)  Read the Course Manual


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