Sunday, May 08, 2005

g, working memory, specific CHC abilities and achievement

[Another set of “hidden on my hard disk analyses" that now see the light of day.]

Much has been written, both in the theoretical and applied intelligence theory/assessment literature, about
  • The definition of g (general intelligence),
  • Whether g exists,
  • The importance of g in the prediction of a wide variety of outcomes, and
  • If g exists, the importance of specific broad and narrow stratum abilities above and beyond g in the prediction of outcomes

By way of background, I have previously summarized the primary issues in “Betwixt, Behind, and Beyond g.” (Editorial note - please read this prior information before going further in this post.) In those prior writings I presented SEM analyses (of the WJ III norm data) that supported the hypothesis that working memory (actually, cognitive efficiency as defined by Gs and working memory) has a strong causal relationship to g (i.e., if you believe g is a workable and sound construct.) I also summarized research suggesting that a number of broad and narrow CHC abilities are significant above and beyond the influence of g.

So....what is this topic of this current post? Simple. To combine the working memory--> g information processing causal hypothesized model with the more traditional psychometric g+specific abilities research model.

Using the same norm samples as described in Betwixt, Behind, and Beyond g, I ran SEM causal models that defined g via the broad CHC latent abilities of Gv, Ga, Glr, Gf, and Gc. Additionally, adhering to a general information processing causal CHC model (click here to see prior relevant post), Gs and memory span (MS) are specified to be casually related to working memory, and working memory is in turn causally related to g.

The new twist is the specification of a causal path from g (as defined above) to achievement variables (letter-word identification; word attack) plus the inclusion of any significant paths from the cognitive efficiency variables (Gs and working memory) and/or the CHC abilities (that define the measurement model for g) to the dependent achievement latent variables.

All plausible models are presented and can be viewed by clicking here (Editorial note – for each age group presented, the models reported are all equally plausible. The model fit statistics did not identify any of the models in the two age groups as being better fits than the others).

Enjoy. I’d like to encourage the readers of this blog to offer interpretations and hypothesis for the various models. My only comment is that if you believe in g, the hypothesis that g is strongly related to working memory is supported (actually, to the broader notion of cognitive efficiency). Furthermore, some specific CHC abilities are again found to provide potentially important insights above and beyond the effect of g within a CHC-based information processing model.

For all who immediately shout “but what about parsimony?....what about Occam’s Razor?”….I defer to Stankov, Boyle & Cattell, R. (1995; Models and paradigms in personality and intelligence research. In Saklofske, D. & Zeidner, M. (Eds.) International Handbook of Personality and Intelligence. New York: Plenum Press), who state, within the context of research on human intelligence, that:

  • “While we acknowledge the principle of parsimony and endorse it whenever applicable, the evidence points to relative complexity rather than simplicity. Insistence on parsimony at all costs can lead to bad science. “

1 comment:

John Garruto said...

This is somewhat askew of what I have learned about 'g'. In fact, I still remember reading about how you might see those measures of efficiency (i.e. Gs and Gsm) as being less 'g' loaded as opposed to the other constructs (particularly Gf, Gv, and Gc).

To say that these skills of effiecency are related to g makes sense and it seems many past assessments of cognitive ability have incorporated these constructs in their tests. However, is the relationship noted to be substantial or weak?

Also, there has been discussion of the relationship of MW to Gf. In fact, I have seen the relationship with some tasks such as CF and UD on the WJ-III (discussed in an earlier post). Again, that depends on the nature of the task too (a 2X2 matrices task with a convoluted pattern may not have a high working memory load). However, I pose-is it a greater question of you just have to have it in order to have 'g', or is one dependent on another?

Case in point: I have been querying if Gv is related to reading ability-the research seems to point to no, which is counterintuitive. In a post on the IAPCHC listserv, it was connotated that you need some Gv skill just as you need to be able to breathe to get the task done, but having a strong ability there will not necessarily beget strong skill in reading (if I have it right.)

Long story longer-is Gsm related to g by virtue of the fact that Gsm is the very first (or second step) with auditory input needed for encoding and therefore is needed in general (in other words, to get to the other skills leading to g) or can we really conceptualize those students who have strong Gsm and Gs as having a degree of cognitive ability? What of those students who have an MR profile but can do a digit span of 6 numbers, or can do well with divided attention?

Not at all being contrary, just want to learn more.