The informational demands of the digit span tests are minimal, as only the knowledge of numbers from 1 to 9 is required. This poses a challenge to the argument that racial differences in exposure to the kinds of information that are needed in cognitive tests cause the black-white test score gap. That the black-white gap on FSD is substantially smaller than on BDS is a robust finding confirmed in this new analysis. As to black-Hispanic differences, Hispanics outscore blacks on BDS at each age, while on FDS blacks have a corresponding advantage all six Hispanic-black gaps show the same pattern, although the differences are not significant for two of the comparisons. The white-Hispanic gaps are substantial and significant on both tests across age groups, but the BDS gap is only about 50 percent as large as the FDS gap at ages 9 and 11. On BDS, the black-white difference is substantially larger than on FDS at all ages and is always highly significant. The results indicate that the black-white gap is minimal and non-significant on FDS for ages 7 and 9, while it is somewhat larger and significant at age 11. Statistically significant differences between groups, assessed using two-tailed t-tests with no assumption of equal variances, are marked with asterisks. If the gap is positive, the first mentioned group in the pair outscored the second group, and vice versa. The next table shows the gaps (Cohen’s d’s using pooled SDs) between whites, blacks, and Hispanics. The table below shows the raw mean scores, standard deviations, and sample sizes for each race/ethnicity, test, and age group: This means that the sample that I refer to as ‘whites’ includes a small number of non-whites, mostly Asians and Native Americans. The CNLSY uses three race categories: black, Hispanic, and non-black non-Hispanic. This means that mixed-ancestry individuals add some noise to the results, but this effect is minor given the low rate of interracial mating. The race or ethnicity of each child was assumed to be the same as that of his or her mother. The fact that not all of the CNLSY children were tested on each of the biennial assessment rounds adds some, probably random, error to the parameter estimates. The participants completed the FDS and BDS tests one or more times over several years, so each child may be included in one, two, or three different age bands. This should make the samples I use more or less representative. Included in my analysis are only the children of those females who are members of the representative cross-sectional sample. The original NLSY79 consists of a nationally representative cross-sectional sample and several oversamples of, for example, blacks and Hispanics. For shortness, I will refer to these groups as the 7-year-olds, 9-year-olds, and 11-year-olds, respectively. The analyses that follow will present results from digit span tests divided into three age bands: 6-8, 8-10, and 10-12 years. Among these are FDS and BDS which were given to children aged about 6 to 12 years. The CNLSY participants have taken a number of cognitive tests. All data in the current investigation are from the CNLSY. Most of them were born in the 1980s and 1990s. The researchers have estimated that about 95 percent of the children of the NLSY79 women are enrolled in the CNLSY. There is also a related longitudinal study called the CNLSY (or NLSY79 Children and Young Adults) which surveys the children of the female participants of the NLSY79. The NLSY79, famously analyzed in The Bell Curve by Herrnstein and Murray, is a longitudinal study of more than 12,000 Americans who were 14-22 years old in 1979 when the study began. Additionally, I compared the digit span performance of Hispanic American children to that of blacks and whites. However, replication is always good, so I analyzed black-white differences in the CNLSY sample, which contains FDS and BDS scores for relatively large samples of black and white children. 405, Note 22 see also my recent analysis of the DAS-II). It is well-established that the black-white gap is substantially larger on BDS than FSD (see references in The g Factor by Jensen, p. The largest number of digits that a person can repeat without error is his or her forward or backward digit span. In FDS, the digits are repeated in the order of their presentation, while in BDS they must be repeated in the reverse order. There are two variants of the test, forward digit span (FDS) and backward digit span (BDS). In digit span tests, the respondents are asked to repeat a string of digits.

Digit span backwards test