"Long before it's in the papers"
April 29, 2008

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Training may boost type of intelligence

April 29, 2008
Courtesy PNAS
and World Science staff

Re­search­ers say a brain-train­ing reg­i­men con­sis­ting of a tough work­ing mem­o­ry task boosts scores in flu­id in­tel­li­gence, or gen­er­al prob­lem-solving abil­ity. 

Gen­er­al in­tel­li­gence, some psy­chol­o­gists ar­gue, can be sep­a­rat­ed in­to “flu­id” and “crys­talline” com­po­nents. Flu­id in­tel­li­gence ap­plies to all prob­lems, where­as crys­tal­lized in­tel­li­gence con­sists of skills use­ful for spe­cif­ic tasks. 

Af­ter in­i­tially giv­ing study participants a stand­ard test for flu­id in­tel­li­gence, Uni­vers­ity of Mich­i­gan psy­cholo­g­ist Su­sanne Jaeggi and col­leagues gave them a se­ries of train­ing ex­er­cises de­signed to im­prove work­ing mem­o­ry. The train­ing was giv­en to four groups, who re­peat­ed the ex­er­cises for 8, 12, 17, or 19 days, de­pend­ing on the group. 

Af­ter the train­ing, the re­search­ers re-tested the sub­jects’ flu­id in­tel­li­gence. Al­though the per­for­mance of un­ trained con­trols im­proved slight­ly, the trained sub­jects showed a sig­nif­i­cant per­for­mance im­provement, the re­search­ers re­ported. This im­provement al­so in­creased with time spent train­ing. The sci­en­tists sug­gest the ex­er­cises strength­ened “ex­ec­u­tive pro­cess­es” in the brain that func­tion in problem-solving.

The regimen consisted of having people watch a series of com­puter screen dis­plays while let­ters were read to them aloud. View­ers were asked to con­tin­ually de­cide whether the cur­rent pair of sti­muli being pre­sented, matched the pair pre­sent­ed a certain num­ber of times pre­vious­ly.

The task is meant to make demands on working mem­ory, the type needed to hold in­for­ma­tion in the brain avail­able for im­me­diate use. A com­mon example is keep­ing a phone num­ber actively in mind long enough to reach a phone and dial it.

Until now, psy­chol­o­gists knew of no way to in­crease flu­id in­tel­li­gence scores, other than to prac­tice the  flu­id in­tel­li­gence tests them­selves, Jaeggi and col­leagues said. Their find­ings are pub­lished in this week’s early on­line is­sue of the re­search jour­nal Pro­ceed­ings of the Na­tio­n­al Aca­de­my of Sci­en­ces.

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Researchers say a brain-training regimen designed to improve working memory also increases scores in fluid intelligence, or general problem-solving abil ity. General intelligence, some psychologists argue, can be separated into “fluid” and “crystalline” components. Fluid intelligence applies to all problems, whereas crystallized intelligence consists of skills useful for specific tasks. After initial ly giving subjects a standard test for fluid intelligence, Un ivers ity of Michigan psycholo gist Susanne Jaeggi and colleagues gave subjects a series of training exercises designed to improve their working memory. The training was given to four groups, who repeated the exercises for 8, 12, 17, or 19 days, depending on the group. After the training, the researchers re-tested the subjects’ fluid intelligence. Although the performance of un trained controls improved slightly, the trained subjects showed a significant performance improvement, the researchers reported. This improvement also increased with time spent training. The scientists suggest that the training exercises strengthened multi ple “executive processes” in the brain that function in problem-solving. Up to now, psychologists believed that the on ly way to increase fluid intelligence is through direct practice of the tests themselves, rather than by training, Jaeggi and colleagues said. Their findings are published in this week’s ear ly online issue of the research journal pnas.