Methods (Pt.3): Measuring And Manipulating
P S YC H 1101 P ROF. DAVID P IZ AR RO DAY 4
For course information please visit:
www.cornellpsych.net
*science is as good as the methods used by scientists
how do psychologists choose their methods?
Which Level Of Analysis To Explain The Phenomenon? E V O L U TIO N
BIOL OGY
C U LTU R E
IND IVID UAL D E VE LOP M E NT
IND IVID UAL D IFFE R E NC E S/ P E R SON AL IT Y
SIT UAT I ON/SOC I AL CONT E X T
*levels of analysis example: why are humans violent?
How Do Psychologists Select Their Method? (Cont’d) • •
Level of analysis! Do they have a particular theoretical view?!
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Methods often determined by what you already believe about the nature of a phenomenon.
Discrete Vs. Dimensional Theories Of Emotion (much more on this later in the semester)
FAC S CO D ING S Y S TE M
P H Y SIOL OG IC AL AROUS AL
How Do Psychologists Select Their Method? (Cont’d) • •
Level of analysis! Do they have a particular theory they are looking to defend?!
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Methods often determined by what you already believe about the nature of a phenomenon.!
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*example—are emotions best described as many discrete categories or as a set of dimensions? !
How convenient are the available methods? !
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familiarity! availability ! ease ! cost
some examples
Methods Involving Animals
*Aplysia californica
* M u s mus culus
*example: fear conditioning •
Consistent pairing of an auditory tone with the delivery of a shock!
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Tone by itself causes fear response!
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Easily measured in mice (e.g, freezing behavior)
sour ce: https://w w w.ted.co m/t alk s/lau r ie_ santo s
Methods Involving (Human) Brains • • •
Measuring brain activity associated with thoughts/behaviors (correlation)! Naturally-occurring lesions from accidents or disease (quasi-experiment)! Direct brain stimulation (experimental manipulation)
Example: Electroencephalography (EEG) •
measures electrical activity in the brain !
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good temporal resolution (milliseconds)!
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poor spatial resolution! (fairly) non-intrusive
Example: Functional Magnetic Resonance Imaging (fMRI) •
measure of blood flow to areas of brain (oxygenation)!
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correlational, but often paired with experimental task!
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decent spatial resolution!
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expensive, can be uncomfortable
poor temporal resolution (signal lags)!
Example: Transcranial Magnetic Stimulation (TMS) •
Electromagnetic induction over scalp!
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Disrupts neuronal activity in targeted region!
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(For now) penetration is limited to 5-6 cm deep!
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minor side-effects (headaches, scalp discomfort, rare chance of seizure)
Using EEG & TMS To “Remote-Control” A Human Being
Physiological Methods
Developmental Methods • • •
Cross-sectional (e.g., compare 3 yr. olds to 5 yr. olds)!
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Experimental methods...
Longitudinal (e.g., look at kids at age 3, then again at age 5).! Twin Studies (identical vs. fraternal, reared together vs. reared apart)!
example: preferential looking techniques
Reaction Time Measures •
e.g, Implicit Associations Test (Greenwald, McGhee & Schwartz, 1998)!
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Simple computer-based categorization task!
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Measures association between concepts!
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e.g., race, age, gender and “good” vs. “bad”!
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take one! https:// implicit.harvard.edu
Manipulating Social Context
“Triangulating” Scientific Truth: Multiple Methods Yield Reliable Conclusions • •
Reliance on an single methods yields limited ability to draw conclusion!
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We learn through poking, prodding, measuring, and repeating over and over again…
Progress comes from “triangulating”--looking across multiple levels of analysis, using various methods. !