Imag­ine dial­ing a phone num­ber by hav­ing to look up each dig­it one at a time in the phone book. Nor­mal­ly, you look up the num­ber and remem­ber all sev­en dig­its long enough to get it dialed. Even with one dig­it at a time, you would have to remem­ber each dig­it long enough to get it dialed. What if your brain could not even do that! We call this kind of remem­ber­ing, “work­ing mem­o­ry,” because that is what the brain works with. Work­ing mem­o­ry is crit­i­cal to every­day liv­ing.

Con­scious thought involves mov­ing a suc­ces­sion of items through what seems like a vir­tu­al scratch-pad. Think of it like stream­ing audio/video, where “thought bites” move on to the scratch pad where they are fed into a thought process and then moved off the scratch pad to make room for the next thought bite.

We think with what is in work­ing or “scratch pad” mem­o­ry. What we know, stored in reg­u­lar mem­o­ry, is brought onto the scratch pad in suc­ces­sive stages, each involv­ing sub­ject­ing the knowl­edge to analy­sis, inte­gra­tion into the cur­rent con­text, and cre­ative re-orga­ni­za­tion via our think­ing process­es (“thought engine”). The ani­mat­ed ver­sion of this graph­ic shows item 1 mov­ing on to the scratch pad and then sent on to the “thought engine.” This is fol­lowed by item 2, then 3, etc.

Con­scious think­ing thus requires the abil­i­ty to hold infor­ma­tion “on line” long enough to use it in think­ing. Con­scious thought thus seems to be a seri­al­ly ordered process of mov­ing thought bites on to and off of the scratch pad.

Uncon­scious Think­ing

What about uncon­scious thought … the kind that occurs when you are not pay­ing atten­tion? We know that the sub­con­scious mind is pro­cess­ing infor­ma­tion (i.e. “think­ing”) all the time, even while we sleep. The evi­dence for this kind of “sleep learn­ing” is incon­tro­vert­ible and sum­ma­rized in my mem­o­ry improve­ment book (see http://thankyoubrain.com). Sub­con­scious think­ing and its relat­ed mem­o­ries may not involve a scratch pad of work­ing mem­o­ry. Sub­con­scious think­ing could occur as mul­ti­ple par­al­lel process­es and may be more non-lin­ear than con­scious thought. How­ev­er, in the case of dream sleep, which I regard as a form of con­scious­ness, those dreams that I hap­pen to remem­ber do seem to be based on seri­al­ly ordered “thought bites.”

A recent study, not explic­it­ly con­cern­ing mem­o­ry, sheds some impor­tant light both on how we think and on the role of work­ing mem­o­ry in thought. In this study, the researchers exam­ined how peo­ple make a cor­rect choice. Researchers com­pared the qual­i­ty of deci­sions formed from con­scious ver­sus uncon­scious think­ing with that result­ing from uncon­scious think­ing. Here is how they stud­ied this issue. In one study, sub­jects were giv­en infor­ma­tion about the attrib­ut­es of four hypo­thet­i­cal cars, and they were to decide which was the best car, based on the attrib­ut­es assigned to each car. Analy­sis con­di­tions were either sim­ple (based on only four attrib­ut­es) or com­plex (based on 12 attrib­ut­es). After read­ing about the attrib­ut­es, sub­jects were assigned to one of two groups: con­scious analy­sis or to an uncon­scious thought con­di­tion. In the con­scious con­di­tion, they thought about the attrib­ut­es for four min­utes before mak­ing a choice. In the uncon­scious con­di­tion, sub­jects were told they would have to make a choice in four min­utes, but they were dis­tract­ed dur­ing that time by being required to solve ana­grams.

Their “think­ing” about the prob­lem was thus not allowed to be con­scious.

Not sur­pris­ing­ly, when only four attrib­ut­es were involved, sub­jects in the con­scious-thought con­di­tion made the best choice of car. But when the com­plex con­di­tion of 12 attrib­ut­es, results reversed. The best car was cho­sen most reli­ably in the uncon­scious-thought con­di­tion.

In a sec­ond study, one change was made. Instead of choos­ing the best car, sub­jects were asked about their atti­tudes toward the four cars. Again, con­scious thinkers made the clear­est dis­tinc­tions among the cars when only four attrib­ut­es were con­sid­ered, but the oppo­site occurred when 12 attrib­ut­es had to be con­sid­ered.

In anoth­er exper­i­ment, two stores were select­ed, one that sold com­pli­cat­ed items like fur­ni­ture and the oth­er a depart­ment store that sold sim­ple prod­ucts. As peo­ple left the store, peo­ple were asked ques­tions about what they bought, why they bought it, how cost­ly was it, and how much they thought about mak­ing the choice. The buy­ers were cat­e­go­rized as either “thinkers” (those who spent a lot of time con­scious­ly mak­ing a deci­sion) and “impulse buy­ers” (who did not spend much time con­scious­ly think­ing about their choice). Sev­er­al weeks lat­er, these same peo­ple were called to check on how sat­is­fied they were with the pur­chase. As expect­ed, more post-choice sat­is­fac­tion was found in the con­scious thinker group, but only for the sim­ple items in the depart­ment store. For the com­plex choic­es in the fur­ni­ture store, the uncon­scious thinkers expressed the most sat­is­fac­tion with their pur­chas­es.

What all this says is that sim­ple deci­sions are best made by care­ful con­scious thought. But for com­pli­cat­ed deci­sions, the best choic­es may result from “delib­er­a­tion with­out pay­ing atten­tion,” that is let­ting the think­ing be done by the uncon­scious mind. I inter­pret these results to reflect the depen­dence of con­scious thought on scratch-pad mem­o­ry and the rel­a­tive inde­pen­dence of sub­con­scious thought on scratch-pad mem­o­ry. Con­scious thought is very effec­tive as long as it can work on infor­ma­tion that it can hold on-line in work­ing mem­o­ry. But work­ing mem­o­ry has lim­it­ed capac­i­ty. There­fore it can­not be very effec­tive when the amount of infor­ma­tion need­ed for high-qual­i­ty thought exceeds the car­ry­ing capac­i­ty of work­ing mem­o­ry.

The corol­lary of this new evi­dence about work­ing mem­o­ry and think­ing process­es is that if we had a big­ger work­ing mem­o­ry, we might think bet­ter.

Work­ing Mem­o­ry Load Affects Pay­ing Atten­tion

Pay­ing atten­tion is pre-req­ui­site to learn­ing. The abil­i­ty to pay atten­tion seems to be affect­ed by how much infor­ma­tion (load) is being car­ried in work­ing mem­o­ry. These prin­ci­ples have been elu­ci­dat­ed in human exper­i­ments that test­ed the assump­tion that attend­ing to rel­e­vant details in a learn­ing sit­u­a­tion requires that the details be held in work­ing mem­o­ry. Hav­ing oth­er, non-rel­e­vant, infor­ma­tion in work­ing mem­o­ry at the same time serves as a dis­trac­tion, low­er­ing atten­tion and inter­fer­ing with mem­o­ry for­ma­tion.

In this exper­i­ment, par­tic­i­pants per­formed an atten­tion task that required them to ignore pic­tures of dis­tracter faces while hold­ing in work­ing mem­o­ry a string of dig­its that were in the same order (low mem­o­ry load) or dif­fer­ent order (high mem­o­ry order) on every tri­al. The test thus was one of mul­ti-task­ing, one task being hold­ing the dig­its in work­ing mem­o­ry and the oth­er task being iden­ti­fy­ing whether a name flashed on the screen was that of a famous politi­cian or a pop star, while a con­tra­dic­to­ry face was pro­ject­ed. For exam­ple, the name Mick Jag­ger would have the face of Bill Clin­ton super­im­posed, and the task was to know that Mick Jag­ger is a pop star, not a politi­cian.

The atten­tion per­for­mance degrad­ed severe­ly with high work­ing-mem­o­ry load. That is, the dis­tract­ing faces cre­at­ed con­fu­sion when sub­jects were also required to hold mixed-order dig­its in work­ing mem­o­ry at the same time.

The point is sim­ple. It is hard to think about two com­pli­cat­ed things at once. The grow­ing trend, espe­cial­ly among young peo­ple, to mul­ti-task may seem won­der­ful. But actu­al­ly, mul­ti-task­ing is most like­ly to inter­fere with focused atten­tion and, in turn, degrade mem­o­ry for­ma­tion, recall, and think­ing qual­i­ty.

Train­ing Work­ing Mem­o­ry and IQ

Stud­ies have shown that it is pos­si­ble to train ADHD chil­dren to have bet­ter work­ing mem­o­ries. This led researchers in Japan to try to devel­op a sim­ple work­ing mem­o­ry train­ing method and to test whether this method can increase the work­ing mem­o­ry capac­i­ty and whether this has any effect on a child’s IQ. Chil­dren ages 6–8 were trained 10 min­utes a day each day for two months. The train­ing task to expand work­ing mem­o­ry capac­i­ty con­sist­ed of pre­sent­ing a dig­it or a word item for a sec­ond, with one-sec­ond inter­vals between items. For exam­ple, a sequence might be 5, 8, 4, 7, with one-sec­ond inter­vals between each dig­it. Test for recall could take the form of “Where in the sequence was the 4?” or “What was the third item?” Thus stu­dents had to prac­tice hold­ing the item sequence in work­ing mem­o­ry. With prac­tice, the train­ers increased the num­ber of items from 3 to 8.

After train­ing, researchers test­ed the chil­dren on anoth­er work­ing mem­o­ry task. Scores on this test indi­cat­ed that work­ing mem­o­ry cor­re­lat­ed with IQ test scores. That is, chil­dren with bet­ter work­ing mem­o­ry abil­i­ty also had high­er IQs. When first graders were test­ed for intel­li­gence, the data showed that intel­li­gence scores increased dur­ing the year by 6% in con­trols, but increased by 9% in the group that had been giv­en the mem­o­ry train­ing. The mem­o­ry train­ing effect was even more evi­dent in the sec­ond graders, with a 12% gain in intel­li­gence score in the mem­o­ry trained group, com­pared with a 6% gain in con­trols. As might be expect­ed, the low­er IQ chil­dren showed the great­est gain from mem­o­ry train­ing.

So in con­clu­sion, it seems that work­ing mem­o­ry capac­i­ty can be increased by train­ing and that such train­ing can even raise IQ, at least in young chil­dren.

Ben­e­fits of Increas­ing Work­ing Mem­o­ry

Accu­mu­lat­ing evi­dence seems to indi­cate that work­ing mem­o­ry, with prop­er train­ing, can be improved in any­one, even adults. I recent­ly found a research report in which last­ing improve­ments in brain func­tion were pro­duced in healthy adults by only five weeks of prac­tice on three work­ing-mem­o­ry tasks that involved the loca­tion of objects in space. Sub­jects per­formed 90 tri­als per day on a train­ing reg­i­men (CogMed). MRI scans showed increased activ­i­ty in the cor­ti­cal areas that were involved in pro­cess­ing the visu­al stim­uli. Brain activ­i­ty increas­es in these areas appeared with­in the first week and grew over time.

Sim­i­lar results have been report­ed by oth­er inves­ti­ga­tors. In a few cas­es, where dif­fer­ent kinds of stim­uli were used, mem­o­ry train­ing induced a decrease of brain activ­i­ty in cer­tain areas, which is inter­pret­ed to indi­cate that the trained brain did not have to work as hard. While we clear­ly don’t under­stand things very well, it seems clear that work­ing mem­o­ry train­ing not only improves mem­o­ry capa­bil­i­ty but also caus­es last­ing changes in the brain.

Help Your Work­ing-Mem­o­ry Capac­i­ty

I just read a fas­ci­nat­ing book on increas­ing teacher aware­ness of the impor­tance of work­ing-mem­o­ry capac­i­ty for teach­ing and learn­ing strate­gies. Many young­sters have work­ing mem­o­ry lim­i­ta­tions, and they usu­al­ly do not grow out of them. This is a major and seri­ous cause of low grades, poor learn­ing skills, poor con­fi­dence, and life-long dimin­ished moti­va­tion to learn.

Lim­it­ed work­ing-mem­o­ry capac­i­ty impairs the abil­i­ty to think and solve prob­lems. I was told once by a mid­dle-school teacher that her “spe­cial needs” stu­dents could do the same math as reg­u­lar stu­dents, but they just can’t remem­ber all the steps. This clear­ly reflects a lim­it­ed work­ing-mem­o­ry capac­i­ty. If the demands made on work­ing mem­o­ry could be less­ened, bet­ter think­ing could result.

Cer­tain strate­gies can help to reduce the load on work­ing mem­o­ry. Teach­ers should mod­el and stu­dents should employ the fol­low­ing devices:

• Pro­vide help, cues, mnemon­ics, reminders.
• KISS (Keep It Sim­ple, Stupid!)(example: use short, sim­ple sen­tences, present much of the instruc­tion as pictures/diagrams).
• Don’t present so much infor­ma­tion. Less can be more.
• Facil­i­tate rehearsal, using only rel­e­vant infor­ma­tion and no dis­trac­tors.
• Get engaged, by tak­ing notes, and cre­at­ing dia­grams and con­cept maps.
• Attach mean­ing from what is already known. (The more you know, the more you can know).
• Orga­nize infor­ma­tion in small cat­e­gories.
• Break down tasks into small chunks. Mas­ter each chunk sequen­tial­ly, one at a time.

Doing these things not only helps the think­ing process, but will also pro­mote the for­ma­tion of last­ing mem­o­ries. The process of con­vert­ing work­ing mem­o­ry into per­ma­nent form is called con­sol­i­da­tion, and I will explain that next time.

— W. 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 and Core Ideas in Neu­ro­science.

Relat­ed arti­cles on Work­ing Mem­o­ry Train­ing

- Can Intel­li­gence Be Trained? Mar­tin Buschkuehl shows how

- Work­ing Mem­o­ry Train­ing: Inter­view with Dr. Torkel Kling­berg

- Work­ing Mem­o­ry Train­ing for Adults

Sources

1. Repovs, G and Bres­janac, M. 2006. Cog­ni­tive neu­ro­science of work­ing mem­o­ry: a pro­logue. Neu­ro­science. 139: 1–3.

2. Dijk­ster­huis, A. et al. 2006. On mak­ing the right choice: the delib­er­a­tion-with­out-atten­tion effect. Sci­ence. 311: 1005–1007.

3. Waji­ma, Kayo, and Sawaguchi, T. 2005. The effect of work­ing mem­o­ry train­ing on gen­er­al intel­li­gence in chil­dren. Soci­ety for Neu­ro­science Abstracts. Abstract 772.11.

4. de Fock­ert, J. W. et al. 2001. The role of work­ing mem­o­ry in visu­al selec­tive atten­tion. Sci­ence. 291: 1803–1806.

5. Ole­sen, P. J., West­er­berg, H., and King­berg, T. 2004. Increased pre­frontal and pari­etal activ­i­ty after train­ing of work­ing mem­o­ry. Nature Neu­ro­science. 7: 75–79.

6. Gath­er­cole, Susan E., and Alloway, Tra­cy P. 2008. Work­ing Mem­o­ry and Learn­ing. Sage Pub­li­ca­tions, 124 pages.

7. Gath­er­cole, Susan E., and Alloway, Tra­cy P. 2008. Work­ing mem­o­ry and learn­ing. Sage Pub­li­ca­tions, . 124 pages.