Fighting for Intelligence: A Brief Overview of the Academic Work of John L. Horn

Abstract

John L. Horn (1928–2006) was a pioneer in multivariate thinking and the application of multivariate methods to research on intelligence and personality. His key works on individual differences in the methodological areas of factor analysis and the substantive areas of cognition are reviewed here. John was also our mentor, teacher, colleague, and friend. We overview John Horn’s main contributions to the field of intelligence by highlighting 3 issues about his methods of factor analysis and 3 of his substantive debates about intelligence. We first focus on Horn’s methodological demonstrations describing (a) the many uses of simulated random variables in exploratory factor analysis; (b) the exploratory uses of confirmatory factor analysis; and (c) the key differences between states, traits, and trait-changes. On a substantive basis, John believed that there were important individual differences among people in terms of cognition and personality. These sentiments led to his intellectual battles about (d) Spearman’s g theory of a unitary intelligence, (e) Guilford’s multifaceted model of intelligence, and (f) the Schaie and Baltes approach to defining the lack of decline of intelligence earlier in the life span. We conclude with a summary of John Horn’s unique approaches to dealing with common issues.

Examining the structural validity of the SSIS SEL brief scales—Teacher and student forms

“…Such strong interrelationships between factors could arise for a variety of reasons—not all of which would indicate that CASEL domains are isomorphic. Just as the strong correlation between height and weight in the general population does not indicate that these measurements are not distinct (McArdle & Hofer, 2014), strong correlations between domain scores on CASEL‐aligned measures does not necessarily mean that these constructs are identical. Yet, it is incumbent on proponents of the CASEL model and researchers to identify the circumstances in which differences between CASEL domain scores should theoretically emerge (e.g., differential relations with specific criterion measures; differential developmental patterns; differential responsiveness to targeted interventions).…”

“…Distinguishing between these models, therefore, will require different approaches. Explicating a similar problem [distinguishing between highly correlated factors] in the intelligence literature, McArdle and Hofer (2014) write, “What we usually require is that these factors [i.e., those we are trying to distinguish] … behave in different ways from one another. This behavior is largely external to the factor analysis so it is not determined in this way.…”

Carroll’s Three-Stratum (3S) Cognitive Ability Theory at 30 Years: Impact, 3S-CHC Theory Clarification, Structural Replication, and Cognitive–Achievement Psychometric Network Analysis Extension

“…The most salient difference between the three related CHC theories is the presence (or absence) of a higher-order general intelligence factor or ability ( g ). Horn was a staunch anti- g proponent who believed that psychometric g was nothing more than an emergent property statistical abstraction ( McGrew et al 2023 )—it did not represent a true ability or mechanism in the human brain ( Horn 1998 ; Horn and Noll 1997 ; McArdle 2007 ; McArdle and Hofer 2014 ; Ortiz 2015 ). Conversely, Carroll was a staunch proponent of psychometric g as possibly representing some form of biological substrate present in individuals that influences the speed and efficiency of information processing ( Carroll 1991 , 1993 , 1996 , 2003 ).…”

The non-Cattell-Horn-Carroll (non-CHC) Model of Ancillary Broad and Narrow Abilities

“…-d.1998) (Revelle, 2015), John L. Horn (b.1928Horn (b. -d.2006) (McArdle & Hofer, 2014) and John B. Carroll (b.1916Carroll (b. d.2003) (Lubinski, 2004).…”