Media Releases

Higher-income students have an edge when it comes to working memory

July 20, 2016

Toron­to, ON – Uni­ver­si­ty of Toron­to and MIT researchers have dis­cov­ered impor­tant dif­fer­ences between low­er and high­er-income chil­dren in their abil­i­ty to use “work­ing mem­o­ry,” a key brain func­tion respon­si­ble for every­thing from remem­ber­ing a phone num­ber to doing math in your head.

Using func­tion­al MRI (fMRI) to mea­sure and map the brain activ­i­ty of a group of mid­dle-school­ers, the researchers – work­ing in col­lab­o­ra­tion with Har­vard Uni­ver­si­ty – were able to phys­i­cal­ly doc­u­ment that the low­er-income stu­dents test­ed had less work­ing mem­o­ry capac­i­ty than their high­er-income peers.

The results of their study were pub­lished today in Devel­op­men­tal Sci­ence.

“It’s nev­er been shown before that low­er-income chil­dren have this qual­i­ta­tive­ly dif­fer­ent brain response for this very basic abil­i­ty that is essen­tial to almost all cog­ni­tion,” says the study’s lead researcher, Amy Finn of U of T’s Depart­ment of Psy­chol­o­gy.

Finn said researchers went a step fur­ther and also demon­strat­ed these dif­fer­ences in work­ing mem­o­ry had an impact on aca­d­e­m­ic mea­sures of achieve­ment – in this case a stan­dards-based math test – col­lect­ed from the schools of the stu­dents who were exam­ined.

The researchers say it is a major step toward under­stand­ing the neu­ro­science of the income-achieve­ment gap, and although by no means a com­plete expla­na­tion, is also sig­nif­i­cant because it links brain func­tions to aca­d­e­m­ic test scores.

“We knew that there were dif­fer­ences in the neur­al struc­ture of chil­dren from low­er-income ver­sus high­er-income fam­i­lies, but we didn’t know if that real­ly mat­tered for solv­ing prob­lems,” says Finn.

“Now that we’ve shown this, we might be doing some­thing which is impor­tant along the way to help­ing low­er-income stu­dents suc­ceed.”

All 67 stu­dents test­ed for the study were enrolled in either the eighth or sev­enth grades in schools in the Boston area and recruit­ed through adver­tise­ments and after-school pro­grams. They were also eth­ni­cal­ly diverse, and with a rough­ly equal num­ber of boys and girls.

In the study, researchers focused on regions of the brain, such as the pre­frontal cor­tex, which are impor­tant for high-lev­el func­tions.

They observed that the high-income stu­dents large­ly kept this region of the brain in reserve until the tasks began to get more dif­fi­cult, but the low­er-income chil­dren relied on it more often and to a greater extent than high­er-income chil­dren, even for rel­a­tive­ly sim­ple prob­lems.

That sug­gests there is a dif­fer­ence in how low­er-income chil­dren to tap into their work­ing mem­o­ry – which is how the brain orga­nizes and holds infor­ma­tion in mind that it can’t imme­di­ate­ly see, says Finn.

Finn says she’s con­cerned peo­ple will inter­pret the data to con­clude that these phys­i­cal dif­fer­ences between the brains of low­er-income and high­er-income chil­dren are some­how hard-wired. Noth­ing could be fur­ther from the truth, she says.

“The brain is a very plas­tic organ, and all of this can be changed with the right kind of train­ing and bet­ter oppor­tu­ni­ties,” says Finn. “Just because we’re observ­ing this in the brain, doesn’t mean it is set in stone.”

Finn says some of the dif­fer­ences had prob­a­bly nev­er been observed before because of anoth­er kind of gap – an inher­ent bias in the income lev­el of the pop­u­la­tions researchers nor­mal­ly test.

Most cog­ni­tive neur­al sci­ence is con­duct­ed on peo­ple who are from mid­dle and upper- mid­dle class back­grounds because it’s less expen­sive to study pop­u­la­tions near the uni­ver­si­ty than to reach out to low­er-income com­mu­ni­ties, says Finn.

While the study didn’t mea­sure envi­ron­men­tal fac­tors, low­er-income sta­tus is also relat­ed to such things as more chron­ic stress, Finn notes.

“No mat­ter the rea­son, it doesn’t change the fact that their work­ing mem­o­ry is qual­i­ta­tive­ly dif­fer­ent.”

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Amy Finn
Depart­ment of Psy­chol­o­gy
Uni­ver­si­ty of Toron­to

Larysa Woloszan­sky
Media Rela­tions Offi­cer
Uni­ver­si­ty of Toron­to

Sean Bet­tam
Com­mu­ni­ca­tions, Fac­ul­ty of Arts & Sci­ence
Uni­ver­si­ty of Toron­to