Tuesday, November 01, 2005

g (general intelligence) is a hot topic

It is interesting that during the past week (on the IAP CHC listerv) there has been an extended thread regarding the construct of g (general intelligence) and how it is operationalized in different intelligence batteries (click here for post re: this thread and a link to an important set of comments made by John Horn in 1999).

Today there has also been a focus on g on the NASP listserv, this thread dealing with the often reported finding that Gf maybe isomporphic with g.

Given the above, I realized that I've been remiss in reminding people of John "Jack" Carroll's final thoughts regarding the Gf-g relationship and Horn's anti-g position.

Jack's last formal publication (2003) was his chapter (The higher-stratum structure of cognitive abilities: Current evidence supports g and about ten broad factors) in Helmuth Nyborg (Ed.), The scientific study of general intelligence: Tribute to Arthur R. Jensen. Elsevier Science/Pergamon Press. In this chapter he analyzed various correlations matrices from the WJ-R.

Before his death and the publication of this chapter, Jack Carroll distributed a pre-publication copy of his chapter and allowed me to post it to the IAPCHC listserv archive folders. I'm now (click here) providing a link to a copy of the pre-pub draft for readers who do not have copies of Nyborg's text.

Of interest to the recent listserv threads are the following g-related comments by Jack Carroll (emphasis in italic added by this blogmaster). I do not pretend to speak for Dr. Carroll, but his last publishedchapter provides fairly specific statements regarding his g-thoughts at the time.
  • "The results show that there is indeed a factor Gf (Fluid Reasoning) that is significantly separate and different from factor g, tending to disconfirm any view that Gf is identical to g."(p. 11 of pdf pre-pub chapter).
  • Horn's comment suggests that he conveniently forgets a fundamental principle on which factor analysis is based (a principle of which he is undoubtedly aware)--that the nature of a single factor discovered to account for a table of intercorrelations does not necessarily relate to special characteristics of the variables involved in the correlation matrix; it relates only to characteristics or underlying measurements (latent variables) that are common to those variables. I cannot regard Horn's comment as a sound basis for denying the existence of afactor g, yet he succeeded in persuading himself and many others to do exactly this for an extended period of years." P.16-17 of pdf pre-pub chapter).

1 comment:

Anonymous said...

Thanks for making this material available. The listserv comments about "what Horn and Carroll might say to each other if they were in the same room" reminded me of this chapter and several conversations I had with my father.