IQ tests and theory trends: Google Ngram visualizations

This past week I read a very intriguing article in the New York Times about a new data visualization tool offered by Google-- the Google Books Ngram Viewer. I then ran across a legal blog post where someone had investigated trends in different law terms...and I couldn't help myself but to give it a try.

As described by Robert Ambrogi at the legal blog:

"Using data drawn from the millions of books it has digitized covering the years 1500 to 2008, it lets you see and compare the frequency of words and phrases as they were used in books over a span of years or centuries. As Google puts it: “The Ngram Viewer lets you graph and compare phrases from these datasets over time, showing how their usage has waxed and waned over the years.”

I first had to experiment with how the entered terms worked. The terms are case sensitive. I checked each phrase with a variety of permutations to maximum the "hit rate"...and then ran some phrases together to ascertain and compare trends.

Below are my results with a few comments--the data tend to speak for themselves. I found that most of what I searched for did not emerge until after 1940...so that is where each graph starts. It is also important to note that the graphs only go up thru 2008...it would be nice to see the graphs up today

Cool stuff. Double click on each graph to enlarge.

This chart suggests that the cognitive ability domains of Gv (Visual Processing), Ga (Auditory Processing), and Processing Speed (Gs) have become hotter topics than Gf (Fluid Intelligence), Gc (Crystallized Intelligence), Gsm (Short term Memory), and Glr (Long term Retrieval). Interesting.

One very clear observation. Among the non-Wechsler intelligence batteries, the Stanford Binet has dropped dramatically over time, while the "newbies" on the IQ testing block (WJ, DAS, KABC, CAS) have made been the focus of more writing since 1990. Note, "Wechsler Intelligence", when included, is the clear winner across time. I left it out so the trends for the "other" batteries would be more distinct.

As I have written about many times, contemporary Cattell-Horn-Carroll (CHC) intelligence theory has become the consensus theory of intelligence. This interesting graph supports this conclusion, especially from 1997 to 2008. Also, if one clicks on the search term in the summary table, one is taken to a page of the Google books that included the term. Click here to see example for CHC theory.

I think many of the trends noted above are due to emergence of Gf-Gc theory to CHC theory with the publication of the 1989 WJ-R. I've written about this critical theory-to-practice birth period here and here.

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IQ test battery publication timeline: Atkins MR/ID Flynn Effect cheat sheet

As I've become involved in consulting on Atkins MR/ID death penalty cases, a frequent topic raised is that of norm obsolescence (aka, the Flynn Effect). When talking with others I often have trouble spitting out the exact date of publication of the various revisions of tests, as I keep track of more than just the Wechsler batteries (which are the primary IQ tests in Atkins reports). I often wonder if others question my expertise...but most don't realize that there are more IQ batteries out there than just the Wechsler adult battery....and, in particular, a large number of child normed batteries and other batteries spanning childhood and adulthood. Thus, I decided to put together a cheat sheet for myself..one that I could print and have in my files. I put it together in the form of a simple IQ battery publication timeline. Below is an image of the figure. Double click on it to enlarge.

An important point to understand is that when serious discussions start focusing on the Flynn effect in trial's, most often the test publication date is NOT used in the calculation of how obsolete a set of test norms are. Instead, the best estimate of the year the test was normed/standardized is used, which is not included in this figure (you will need to locate this information). For example, the WAIS-R was published in 1981...but the manual states that the norming occurred from May 1976 to May 1980. Thus, in most Flynn effect discussions in court cases, the date of 1978 (middle of the norming period) is typically used. This makes recall of this information difficult for experts who track all the major individually administered IQ batteries.

Hope this helpful...if nothing else...you must admit that it is pretty :)  Click on image to view.






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