Measurements and mismeasurements in Psychology - PowerPoint Presentation

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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

t

eachingpsychology.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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SyllabusGoalsGrading componentsOffice hours

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Science & Measurements

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ScienceMeasurement 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…GreedRudenessIntelligenceEnjoyment

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Psychologists are obsessed with measurementscirca 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 damage1890 : 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 measurements1914 : 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 invisibleabstractSome examples:

IntelligenceEvilnessMemory

Hence they need to be inferred.

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The problemHow do you make strong inferences?

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The BIG QUESTION throughout the courseWhen we measure something, what are we really measuring?

Brain activity?

Really?

Always?

Religiosity?

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Validity

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ValidityGeneral 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 thinkingClaim  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 TTRelieves burns pain, nausea, fever

Treats ulcers, measles, cancerNote: 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 TTIf 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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ExperimentSample: 21 practitionersDouble-blinded study“Patient” had palms under practitioners’ hands: Yes vs. No

280 trials for each practitionersCorrect 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 CTSWe 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 lifeClinical 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 claimsAcknowledges limitationsTries to rule out alternative explanationIs 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=Dqhlv0UZUwYhttps://

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 youBe skeptical, but not cynical.

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Learning goalPsychology 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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AnnouncementsNo class next weekComplete the online questionnaires (see Course Manual for url)Read the Course Manual