Spotting books and countries: New approaches to estimating and conceptualizing prior intelligence

Abstract

We aimed to design alternative estimates of pre-morbid/prior intelligence to the National Adult Reading Test (NART) and the Spot-the-Word (STW) in order to tap non-vocabulary based knowledge stores. The rationale for the development of the new tests was that more cognitively able individuals acquire and retain more ‘singular facts’ from their environment. Such facts appear to include knowing how to pronounce irregular words and knowing whether a letter string is a word. We examine if they also include whether a word string is a book title or whether a line drawing is the outline of a country. In the new Spot-the-Book test, subjects were required to identify the real book from a real book-fake book pair of titles. The Spot-the-Country test involved identifying which of two named countries is shown in a line-drawn outline of its borders. There were 126 participants (75 women and 51 men) with mean age 42.2 years (SD = 16.5) and from a wide range of social and occupational backgrounds. Participants undertook a battery of tests including the NART and STW, two tests of more fluid-type ability (Digit Symbol and Matrix Reasoning from the WAIS-III UK), and the two new tests: Spot-the-Book and Spot-the-Country. These new tests had high internal consistencies and were highly correlated with the established measures, suggesting that they have concurrent validity. Spot-the-Book test correlated highly with the NART ( r = .75, p < .001) and the STW ( r = .72, p < .001). Spot-the-Country correlated strongly with the NART ( r = .53, p < 0.001) and the STW ( r = .41, p < .001). A principal components analysis suggested that the Spot-the-Book and Spot-the-Country both loaded onto a crystallised-type intelligence factor. The new tests, especially Spot-the-Book, suggest that it might be possible to estimate pre-morbid ability without using vocabulary-based measures. The further work needed to develop these tests is discussed, as are the implications for our understanding of crystallised intelligence.