Mental Chronometry and the Unification of Differential Psychology

1. Mental Chronometry and the Unification of Differential Psychology Arthur R. Jensen Yi. Sangyoon

2. Mental Chronometry • Measurement of cognitive speed • Individual’s response time(RT) • Inspection Time(IT) • Major aspect of general intelligence - Sir Francis Galton(1822-1911), et, al. • Sensitive measure of individual difference

3. History of RT • First appeared in astronomy Journals • Astronomers showed individual differences in RT to the star’s transit across the hair line • Astronomer Royal at the Greenwich Observatory • Tested simple RT on thousands of people • (Galton) • Related to the nature of intelligence • (Vernon, 1987)

4. Conventional Psychometric Measurement • Mental Chronometry • Advantages of Chronometry • Advancement of Differential Psychology

5. Conventional Psychometric Measurement • Ordinal Scales • Composed of a number of separate items on which the subject’s responses are scored either R/W or P/F – Ordinal scales • Ranking, percentile raks, standardized scores(z, T, IQ), normalized scores … •  norm referenced • Do any kind of transformation of the raw scores’ rank order represents a true interval scale or a ratio scale?? • It’s depends on ASSUMPTION. • Transformed test scores contain no new information.

6. Conventional Psychometric Measurement • Ordinal Scales • Ordinal scales have many shortcomings. • Cannot make really meaningful statements about many things we want to know in differential and developmental psychology. X Y

7. Conventional Psychometric Measurement • Absence of ratio scales in differential psychology is most unfortunate. • Reductionist research necessarily be focused on discovering functional relationships • How one measured variable is related to some other measured variable •  Time  MC

8. Advantages of MC • Reliability • Repeatability • Range of Equivalency • Sensitivity of Measurement

9. The Psychometric Misconception of Mental Speed • Speeded tests in given limit time • Score is the number of identifying items completed within a time • This results have as rather small factor value • Is it minor factor ??? • This kinds of tests are different from the Chronometric methods used to measure RT and IT • We should realize that distinction between speed and power.

10. Standardizing Chronometric Methods • The units of time have been standardized throughout the history of MC  ms • But, testing conditions are not well standardized… • a severe hindrance to differential psychology • Within vs Between(*) • standardization is Essential for science field

11. Chronometry as a Primary Tool for Research on Intelligence • “Almost entire psychometric literature shows that they are best represented by a hierarchical factor structure.” • John B. Carroll (1993) • Three-stratum model The most general component of the common factor variance

12. Chronometry as a Primary Tool for Research on Intelligence • g • Cannot be characterized in therms of the information content of mental test or in terms of any observable types of behavior. • g is known not by its nature but by the variation in its loadings on a wide variety of mental tests • (Charles Spearman) • An aspect of individual differences that causes positive correlations between virtually all measurable cognitive abilities

13. Chronometry as a Primary Tool for Research on Intelligence • Chronometric and psychometric tests have much the same general factor in common • RT and IT are related to g • It is not the main purpose of mental chronometry. • It is a general tool for measuring all aspects of cognition.

14. Fundamental Findings in the Relationship of Chronometric to Psychometric g • The Problematic Meaning of Inter-Trial Variability

16. Fundamental Findings in the Relationship of Chronometric to Psychometric g • The “Worst Performance Rule”