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Neuroplasticity, Brain Fitness and Cognitive Health News


Memory Problems? Perhaps you are Multi-tasking

Today’s kids are into mul­ti-task­ing. This is the gen­er­a­tion hooked on iPods, IM’ing, video games — not to men­tion TV! Many peo­ple in my gen­er­a­tion think it is won­der­ful that kids can do all these things simul­ta­ne­ous­ly and are impressed with their com­pe­tence.

Well, as a teacher of such kids when they reach col­lege, I am not impressed. Col­lege stu­dents these days have short atten­tion spans and have trou­ble con­cen­trat­ing. They got this way in sec­ondary school. I see this in the mid­dle-school out­reach pro­gram I help run. At this age kids are real­ly wrapped up in mul­ti-task­ing at the expense of focus.

Accord­ing to a Kaiser Fam­i­ly Foun­da­tion study last year, school kids in all grades beyond the sec­ond grade com­mit­ted, on aver­age, more than six hours per day to TV or videos, music, video games, and com­put­ers. Almost one-third report­ed that “most of the time” they did their home­work while chat­ting on the phone, surf­ing the Web, send­ing instant mes­sages, watch­ing TV, or lis­ten­ing to music.

Kids think that this enter­tain­ment while study­ing helps their learn­ing. It prob­a­bly does make learn­ing less tedious, but it clear­ly makes learn­ing less effi­cient and less effec­tive. Mul­ti-task­ing vio­lates every­thing we know about how mem­o­ry works. Now we have objec­tive sci­en­tif­ic evi­dence that mul­ti-task­ing impairs learn­ing. A recent Nation­al Acad­e­my of Sci­ences study with col­lege-age stu­dents (Ref­er­ence #1 below) did an exper­i­ment where the sub­jects were to learn a task under two con­di­tions, one with no dis­trac­tions and the oth­er while lis­ten­ing to high- and low-tone beeps, attend­ing to the high ones. The total amount of learn­ing was the super­fi­cial­ly the same in both con­di­tions, but with dis­trac­tions, the learn­ing was stereo­typed and learn­ers had dif­fi­cul­ty in apply­ing what they learned to oth­er con­texts and sit­u­a­tions. The study also used func­tion­al MRI (fMRI) to assess brain activ­i­ty under test con­di­tions. The imag­ing data indi­cat­ed that the mem­o­ry task and the dis­trac­tion stim­uli engage dif­fer­ent parts of the brain and that these regions prob­a­bly com­pete with each oth­er.

The study did not address the issue of pas­sive dis­trac­tion, such as lis­ten­ing to music while study­ing. I think that music can also be a major dis­trac­tion, except for cer­tain kinds of music played under mut­ed con­di­tions (see my book Thank You, Brain, For All You Remem­ber. What You For­got Was My Fault, pages 47, 165, and 197, Ref­er­ence #2 below) .

One rea­son that mul­ti-task­ing inter­feres with mem­o­ry is that the brain real­ly does not mul­ti-task. It just fools you into think­ing so, and the way the brain does han­dle mul­ti­ple tasks makes it hard to remem­ber any­thing.

Brains Can’t Real Mul­ti-task

Our brain works hard to fool us into think­ing it can do more than one thing at a time. It can’t. Recent MRI stud­ies at Van­der­bilt (#3) prove that the brain is not built for good mul­ti-task­ing. When try­ing to do two things at once, the brain tem­porar­i­ly shuts down one task while try­ing to do the oth­er. In the study, even doing some­thing as sim­ple as press­ing a but­ton when an image is flashed caused a delay in brain oper­a­tion. MRI images showed that a cen­tral bot­tle­neck occurred when sub­jects were try­ing to do two things at once, such as press­ing the appro­pri­ate com­put­er key in response to hear­ing one of eight pos­si­ble sounds and utter­ing an appro­pri­ate ver­bal response when see­ing images. Activ­i­ty in the brain that was asso­ci­at­ed with each task was pri­or­i­tized, show­ing up first in one brain area and then in the oth­er  not in both areas simul­ta­ne­ous­ly. In oth­er words, the brain only worked on one task at a time, post­pon­ing the sec­ond task and deceiv­ing the sub­jects into think­ing they were work­ing on both tasks simul­ta­ne­ous­ly. The delay between switch­ing func­tions was as long as a sec­ond. It is high­ly like­ly, though not yet stud­ied, that the delays and con­fu­sion mag­ni­fy with increas­es in the num­ber of dif­fer­ent things one tries to do simul­ta­ne­ous­ly.

So what has this got to do with mem­o­ry? Well, if you try to mem­o­rize the first task and the brain imme­di­ate­ly switch­es to the sec­ond task, per­for­mance of the sec­ond task inter­feres with con­sol­i­da­tion of the mem­o­ry of the first task. In my ear­li­er arti­cle on mem­o­ry con­sol­i­da­tion, I explained how ear­ly mem­o­ry is vul­ner­a­ble to inter­fer­ence and must be pro­tect­ed from dis­trac­tions and new infor­ma­tion in order for the mem­o­ry to be made per­ma­nent. Like­wise, there are proac­tive effects where­in what you learn on the first task can inter­fere with learn­ing on the sec­ond. All these prob­lems are com­pound­ed if there are three or more tasks in a “mul­ti-task­ing” expe­ri­ence.

Mul­ti-task­ing and School Per­for­mance

A study of 517 Cal­i­for­nia high-school stu­dents found that grades were low­er in those who social­ly inter­act­ed via MySpace, instant mes­sag­ing (IM) accounts, or who used cell phones. In the study (4), stu­dents answered a ques­tion­naire on what social net­work­ing devices they used and when they used them. The answers were paired with the grades (from the pre­vi­ous year and the most recent report card).

In this study, 72% of the stu­dents had a My Space account, 76% had a cell phone, and 68% had an IM address. Those who had a MySpace account had sig­nif­i­cant­ly low­er grades than those with­out an account. The same was true for those that used IM, com­pared with those who did not. Cell phone use was also asso­ci­at­ed with low­er grades and the effect was mag­ni­fied if text mes­sag­ing was used on cell phones. Not sur­pris­ing­ly, if these devices were used dur­ing home­work, the grades were even low­er than for stu­dents who used these tech­nolo­gies out­side of home­work. Almost half report­ed text mes­sag­ing dur­ing class time, and their grades were low­er than the stu­dents who only used IM out­side of class.

These are cor­re­la­tion­al data and do not prove that using these devices caus­es low­er grades. But it is a good bet. Mul­ti-task­ing, as when using the com­mu­ni­ca­tion devices while try­ing to do home­work or learn in class, can be expect­ed to inter­fere with mem­o­ry. Poor mem­o­ry yields low­er grades.

Bill KlemmW. R. (Bill) Klemm, D.V.M., Ph.D. Sci­en­tist, pro­fes­sor, author, speak­er As a pro­fes­sor of Neu­ro­science at Texas A&M Uni­ver­si­ty, Bill has taught about the brain and behav­ior at all lev­els, from fresh­men, to seniors, to grad­u­ate stu­dents to post-docs. His recent books include Thank You, Brain, For All You Remem­ber. What You For­got Was My Fault and Core Ideas in Neu­ro­science.



- #1 Foerde, K., Knowl­ton, Bar­bara J., and Pol­drack, Rus­sell A. 2006. Mod­u­la­tion of com­pet­ing mem­o­ry sys­tems by dis­trac­tion. Proc. Nat. Acad. Sci. 103: 11778–11783.
— #2 Klemm, W. R. 2004. Thank You Brain for All You Remem­ber. What You For­got Was My Fault. Benec­ton Press. 312 pages.
— #3 Dux, P. E., Ivanoff, J., Asplund, C. LO., and Marois, R. 2007. Iso­la­tion of a Cen­tral Bot­tle­neck of Infor­ma­tion Pro­cess­ing with Time-Resolved fMRI. Neu­ron. 52 (6): 1109–1120
— #4 Pierce, Tamyra, and Vaca, Rober­to. 2007. Dis­tract­ed: aca­d­e­m­ic per­for­mance dif­fer­ences between teen users of MySpace and oth­er com­mu­ni­ca­tion tech­nolo­gies. Pro­ceed­ings EISTA. Orlan­do, FL. July.

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3 Responses

  1. Thanks for sub­mit­ting this post to our blog car­ni­val. We just pub­lished the 41st edi­tion of Brain Blog­ging and your arti­cle was fea­tured!

    Thank you.


  2. Seth says:

    that seems very true when i do more then one thing i cant remem­ber every thing i was doing

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