In the Jaeggi (2008) study, the researchers began by having participants complete a test of reasoning to measure their “fluid” intelligence — the ability to draw connections between things, solve novel problems and adapt to new situations. Then some of the participants received up to eight hours of training in a difficult cognitive task that required paying careful attention to two streams of information (a version of this task is now marketed by Lumosity); others were assigned to a control group and received no such training. Then all of the participants took a different version of the reasoning test.
The results were startling. The authors reported that the trained participants showed a larger gain in the reasoning test than the control group did, and despite the relatively brief period of training, this gain was large enough that it would be expected to substantially improve performance in everyday life.
A University of North Carolina study known as the Abecedarian Early Intervention Project, children received an intensive educational intervention from infancy to age 5 designed to increase intelligence. In follow-up tests, these children showed an advantage of six I.Q. points over a control group (and as adults, they were four times more likely to graduate from college). By contrast, the increase implied by the findings of the Jaeggi study was six I.Q. points after only six hours of training — an I.Q. point an hour.
Though the Jaeggi results are intriguing, many researchers have failed to demonstrate statistically significant gains in intelligence using other, similar cognitive training programs, like Cogmed’s. The Web site PsychFileDrawer.org, which was founded as an archive for failed replication attempts in psychological research, maintains a Top 20 list of studies that its users would like to see replicated. The Jaeggi study is currently No. 1. While this is an indication of the interest among psychologists in the idea that cognitive training might produce remarkable gains in intelligence, it also reflects a widespread cautiousness toward the results of a single study.
Another reason for skepticism is a weakness in the Jaeggi study’s design: it included only a single test of reasoning to measure gains in intelligence. As the cognitive psychologists Zachary Shipstead, Thomas Redick and Randall Engle note in a recent review of the cognitive training literature in Psychological Bulletin, intelligence can’t be measured with any single test; it reflects what tests of many cognitive abilities have in common. Demonstrating that subjects are better on one reasoning test after cognitive training doesn’t establish that they’re smarter. It merely establishes that they’re better on one reasoning test.
We shouldn’t be surprised if extraordinary claims of quick gains in intelligence turn out to be wrong. Most extraordinary claims are. But we shouldn’t be totally discouraged, either. Results of studies like the Abecedarian project suggest that intelligence can be increased by making improvements in people’s environments, and that this can improve people’s lives.
Carolina Abecedarian Project was a controlled experiment that was conducted in 1972 in North Carolina, United States, by the Frank Porter Graham Child Development Institute to study the potential benefits of early childhood education for poor children to enhance school readiness. It has been found that in their earliest school years, poor children lag behind others, suggesting the fact that they were ill-prepared for schooling.
The participants in this experiment were 111 infants born between 1972 and 1977. Of these, 57 were given high-quality intervention, consisting in part of educational games based on the latest in educational theory. The other 54 acted as a control group. An overwhelming majority (98 percent) of the children who participated in the experiment were African-American. The average starting age of participants was 4.4 months. Whereas other childhood programs started at age two, the Abecedarian Project started from infancy and continued for five years, a period longer than most other programs. The participants received child care for 6–8 hours a day, five days a week. Educational activities were game-based and emphasized language. The control group was provided with nutritional supplements, social services, and health care to ensure that these factors did not affect the outcomes of the experiment