Friday, November 16, 2007

The brain clock temporal resolution (g) power hypothesis--more evidence

[Double click on image to enlarge]

My first post to the IQ Brain Clock was re: an article published in the journal Intelligence that suggested the human brain may have an underlying domain-general brain clock. I was very excited about the possibility of a "temporal g" (general intelligence) brain mechanism, a mechanism that may explain a diverse array of research findings regarding the importance of temporal processing and human performance in many domains. This first article (by Rammsayer and Brandler, 2007), in large part, was the impetus for me starting this humble specialized blog.

I am excited to report that Rammsayer and colleagues have followed up this original study with one based on a larger sample (including the sample in the 2007 publication). The new, and IMHO very important, article is:
  • Helmbold, N., Troche, S. & Rammsayer, T. (2007). Processing of temporal and nontemporal information as predictors of psychometric intelligence: A structural-equation-modeling approach. Journal of Personality, 75 (5), 985-1006. (click here to view)
  • Recent research suggests a functional link between temporal acuity and general intelligence. To better understand this relation, the present study took advantage of a large sample (N5260) and structural equation modelling to examine relations among temporal acuity, measured by various tasks, speed of information processing as measured by the Hick reaction time task, and psychometric intelligence. Temporal acuity and the Hick task showed common variance in predicting psychometric intelligence. Furthermore, timing performance was a better predictor of psychometric intelligence and mediated the relation between Hick task performance and psychometric intelligence. These findings are consistent with the idea that temporal acuity reflects a basic property of neural functioning that is relevant to intelligence-related aspects of mental activity including speed of information processing.
A few comments (some exact quotes..others paraphrased and edited) from the article (with emphasis by the blogmaster):

  • There is a large literature demonstraing a relation between higher mental ability and faster speed and of efficiency of processing on simple sensory, memory,and decision tasks. The most frequently used elementary cognitive tasks (ECTs) in this field include inspection time, simple and choice reaction time following the rationale of Hick (1952).
  • Current explanations for the observed relationship between psychometric intelligence and measures obtained from ECT's usually refer to the concept of "neural efficiency" as being responsible for faster and less error-prone information processing in individuals with high mental abilities.
  • The authors base their research on the Temporal Resolution Power Hypothesis (TRPH) which, in essence, is based on the idea that temporal accuracy as assessed by psychophysical timing tasks--in analogy to on ECT's---might reflect basic processes related to neural efficiency. A theoretical context for this notion is affored by the master clock hypothesis....where the oscillation rate of a general clock mechanism in the human central nervous system (CNS) is responsible for the coordination of a wide range of mental activities. According to this view a high temporal resolution power or a high oscillation rate of a general timing mechanism should influence information processing by leading to shorter task completion times and less interference from distracting sources of information.
  • According to the TRPH...finer temporal resolution would be associated with better abilities in both speeded and unspeeded mental ability tests....this, in turn, is a fundamental contributor to psychometric intelligence.
  • These results from this new study are consistent with the idea that temporal acuity is the more important variable in relation to psychometric intelligence and indeed appears to be sufficient to account for the well-replicated effects linking speed of information processing to the general Intelligence-related abilities of the individual.
  • The results presented provide a strong case for the idea that temporal abilities, relative to mere mental speed, are a more important predictor of performance on general intelligence tests
A few final comments. First, the importance of these findings, IMHO, can't be overstated. The reaction time g research is based on a massive literature base and is the dominant theoretical explanation of a possible neural basis for general intelligence (g). The fact that two studies now suggest the temporal g may be more explanatory than reaction time g is a huge deal! Conversely, the presence of only two research studies argues for caution in making too much of these findings. However, as I've written elsewhere, there is a large body of research across disciplines that continues to point to the importance of temporal processing and the possibility of an internal brain clock. Check out the IQ Brain Clock EWOK for a sample of this body of literature.

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1 comment:

Chris Chatham said...

Kevin - fascinating research. I'm going to read this and will try to post on it, of course with a very large hat tip :)

bTW, did you get my email to the iap address? I'm worried it got spam trapped.