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. XY

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 g 8 second- order factors 40 first-order factors 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”