A dynamical model of general intelligence: the positive manifold of intelligence by mutualism

Han L.J. van der Maas, Conor V. Dolan, Raoul P. P. P. Grasman, Jelte M. Wicherts, Hilde M. Huizenga, & Maartje E. J. Raijmakers
Psychology Department, University of Amsterdam

Scores on cognitive tasks used in intelligence tests correlate positively with each other, i.e., they display a positive manifold of correlations. The positive manifold is often explained by positing a dominant latent variable, the g-factor, associated with a single quantitative cognitive or biological process or capacity. In this paper we propose a new explanation of the positive manifold based on a dynamical model, in which reciprocal causation or mutualism plays a central role. It is shown that the positive manifold emerges purely by positive beneficial interactions between cognitive processes during development. A single underlying g-factor plays no role in the model. The model offers explanations of important findings in intelligence research, such as the hierarchical factor structure of intelligence, the low predictability of intelligence from early childhood performance, the integration/differentiation effect, the increase in heritability of g, the Jensen effect, and is consistent with current explanations of the Flynn effect.

Accepted by Psychological Review (May 2006)

Preprint

Simulation tools:

Mac

PC

The simulation tools use R (http://cran.r-project.org/). R is `GNU S', a freely available language and environment for statistical computing and graphics which provides a wide variety of statistical and graphical techniques: linear and nonlinear modelling, statistical tests, time series analysis, classification, clustering, etc. Please consult the R project homepage for further information.

If you are new to R, you may want to consult one of the manuals. See, for instance, R for beginners, in the contributed manual section.

PC: Odesolve can be installed from internet (Cran binaries) by the install package menu in R. Unzip the mutualism package and put it in the directory library within the R directory (in program files) on your harddisk. In this library directory you will also find the odesolve library that you just installed from the Cran web site.

Mac (OSX):

start R

choose from the dropdown menu 'packages & data': 'package installer'

if not selected choose select: 'Cran binaries'

if unchecked check: 'At system level (in R framework)'

if checked uncheck: 'install dependencies'

click: 'Get List'

select preferred Cran mirror and click: 'ok'

select 'odesolve'

click: 'Install Selected'

quit R

download mutualism(osx).zip

unpack in the same library directory you will find the odesolve library that

you just installed from the Cran web site

start the shell Mac OSX Terminal

type:

R CMD INSTALL mutualism

close terminal

restart R

type:

library("mutualism")

After installation you load the library mutualism by typing library(mutualism).

Help about the library can be found with help(mutualism).

Examples of simulations can be run with example(mutualism). This will run the code for each figure of the paper.