Fluid or Crystalline Intelligence

The Kaufman, Kaufman, Liu, and Johnson (2009) study found that academic skills, crystallized intelligence, and fluid intelligence were all significantly associated to years of formal schooling. Fluid intelligence and school-related intelligence were both substantially associated to education. The study also discovered that among academic talents, writing and reading had a weaker correlation with years of formal schooling than math. Men outperformed women on the arithmetic test, but the opposite was true for the writing test. Other gender differences were determined to be insignificant in the study. Kaufman et al.(2009) concluded that crystallized intelligence and fluid intelligence related equally well to education attainment indicating that previous studies with Wechsler’s adult scales may not be directly relevant to purer measures of crystallized intelligence and fluid intelligence. The study also concluded that the results are directly applicable to neuropsychological evaluation when test batteries employ tests grounded on Cattell-Horn-Carroll (CHC) model as opposed to more traditional Wechsler scales. The study also concluded that the significantly higher correlation between education attainment and math, relative to the coefficient for writing and reading, indicates that causality between math skills and education attainment is a result of the specific influence of formal instruction on an individual’s later math skills.

Implications for the Field of Psychology

The findings of this study can be applied in the field of psychology. The impacts of education and other demographic variables on academic test, memory and cognitive performance have been employed to develop Wechsler memory scale. Traditionally, education (relative to other demographic factors) has accounted for the greatest part of variance on neuropsychological test and has offered important data about individual’s best estimate of pre-morbid functioning. Additionally, the connection between crystallized intelligence, fluid intelligence and education attainment in a large normal representative sample of adults aged between 19and 90 is particularly noteworthy. The information on gender differences can also play a critical role in neuropsychological evaluation. Although male advantage in math is well known, little is known regarding female advantage in writing. The results of this study therefore indicate that gender ought to be treated as a critical demographic variable when trying to establish a person’s pre-morbid writing ability, particularly in adults. Equally, the findings for reading ability are important for neuropsychological evaluation. Among all academic skills tested, reading was the only one which did not relate considerably to the age covariate. Reading skill can be employed by neuropsychologists to estimate a person’s pre-morbid ability. In general, the findings of the study are directly applicable to neuropsychological evaluation when test batteries employ tests grounded on Cattell-Horn-Carroll (CHC) model as opposed to more traditional Wechsler scales. The study also concluded that the significantly higher correlation between education attainment and math, relative to the coefficient for writing and reading, indicates that causality between math skills and education attainment is a result of the specific influence of formal instruction on an individual’s later math skills.

Method/Participants

The participants in this study included two samples of adults. Each sample ranged from young adults to old age (between 22 and 90 years). The sample consisted of portions for standardization samples for the KTEA-II brief form and KBIT-sample that range from younger adulthood to old age. The total number of participants in KTEA-II brief form was 555 while KBIT-2 was 570. There were 291women in KBIT-2 sample and 282 in KTEA-II sample. The rest were male. Ethnic groups that participated in the study include European Americans, Native Americans, Asian Americans, Latinos, and African Americans. In total, there were 570 adults who took part in this study. There were two instruments employed in KBIT-2 sample. They include the verbal score, and non-verbal score. Verbal score was employed to measure vocabulary knowledge, reasoning, verbal comprehension and a broad range of general information regarding the world. In KTEA-II brief, they were three instruments used. They encompass the reading score, math score, and writing score. The reading score was grounded on performance of two parts namely comprehension and recognition. The 46 comprehension items required reading a given passage and providing oral answers to inferential or literal questions and the 37 recognition items required reading as well as pronouncing irregular words that do not adhere to phonetic rules. The math score comprised of 67 items that covered a wide range of application and computation skill categories and the participants were required to provide solutions to mathematical questions as well as provide oral answers to items that place much emphasis on real-life applications of mathematical concepts. The writing score had 46 items that evaluated communication of ideas in writing with reduced influence of creativity or reasoning and without requiring reading. Some of the skills that were measured encompass spelling irregular and regular words, writing original sentences, competing sentences, filling in missing words, and adding capitalization and punctuation. The study conducted five Univariate Analysis Covariances (ANOVA) using three measures of academic skills namely writing, reading, and math and two cognitive measures. Independent variables encompassed educational attainment and gender. The study employed SPSS to test whether the slope of DV were same across a broad range of education or gender groups. The study also employed moment correlation coefficients to compute between five DVs and education attainment.

Strengths/ Limitations

One of the strengths of the study is that it used large sample (N= 1125). The use of large sample size increased the validity and reliability of the research findings. Because of the large sample size, the results of the study can be applied to larger population or can be generalized. One of the shortcomings of the article is that it relied on some sources which are more than 20 years old. For instance, the study this article “Reynolds C. R., ChastainR. L., KaufmanA. S., McLean, J. E. Demographic characteristics and IQ among adults: Analysis of the WAIS-R standardization sample as a function of the stratification variables, Journal of School Psychology, 1987, vol. 25 (pg. 323-342)”. The other article that was more than 20 years include Bridgeman, B,  Wendler, C.Gender differences in predictors of college mathematics performance and in college mathematics course grades, Journal of Educational Psychology, 1991, vol. 83 (pg. 275-284)“. Using articles more than 20 years to support the findings of the study reduces the validity and reliability of the results. The study could instead use recent articles to support its findings since old articles are in most cases outdated.

References

Kaufman, A.S., Kaufman, J.C., Liu, X., & Johnson, C.K. (2009). How does education attainment

and gender relate to fluid intelligence, crystalline intelligence, and academic skills of ages 22-90 years? Archives of Clinical Neuropsychology, 24(2), 153-163. https://academic.oup.com/acn/article/24/2/153/3215/How-do-Educational-Attainment-and-Gender-Relate-to