Clarity in short-term memory shows no link with IQ

November 29, 2010

One person correctly remembers four of eight items just seen but is fuzzy on details. Another person recalls only two of the items but with amazingly precise clarity. So what ability translates to higher IQ?

According to a University of Oregon study, the answer is very clear: More items stored in short-term memory is linked to greater fluid intelligence, as measured in tests. The resolution of those memories, while important in many situations, shows no relationship with fluid intelligence.

The notion that numbers of items is vitally important to short-term memory has been shown in previous studies at the UO. Those studies found that people, generally, have a capacity to temporarily store three to five items in short-term memory. Previous research has shown that capacity in is a reliable predictor of an individual's IQ.

However, the new study, published in the October issue of the journal Psychonomic Bulletin & Review, sought to take a more comprehensive look at the issue to determine which aspects of memory capacity explained the link with fluid intelligence.

Ed Awh on studying working (short-term) memory

"The number of things people can remember is robustly correlated with fluid intelligence -- the larger number remembered, the higher the IQ." said Edward Awh, a psychology professor and a member of the Oregon Visual Working Memory & Attention Lab. "Resolution in memory is not predictive of IQ at all."

"Clarity," said lead author Keisuke Fukuda, a UO doctoral student, "relates to how well a person can detect small changes." This clarity, Fukuda and Awh noted, is indeed important but is a reflection of a person's experience in specific domains of perception. For example, while Japanese characters may appear to be similar to an American's eye, regular Japanese readers will readily see the differences between distinct characters.

Fukuda put 79 undergraduate students through a series of experiments in which either four or eight objects were shown on a screen for an instant. After a one-second blank screen, one item was returned and the subject asked whether that object had been in a location previously.

Ed Awh discusses the value of clarity beyond an IQ measure

By examining the ability to detect large and small changes in the memorized items, Fukuda was able to get estimates of both the number of items maintained in memory, as well as the resolution or clarity of those memories. These aspects of memory were then related to the subjects' scores on tests of fluid intelligence.

The discovery that clarity doesn't factor into a person's IQ score doesn't suggest that resolution is unimportant, the researchers noted. The importance of clarity or resolution of things remembered is indeed vital, for example, to a radiologist studying images of a patient's internal organs with potential disease conditions.

Related Stories

Recommended for you

Self-harm, suicide attempts climb among US girls, study says

November 21, 2017
Attempted suicides, drug overdoses, cutting and other types of self-injury have increased substantially in U.S. girls, a 15-year study of emergency room visits found.

Car, stroller, juice: Babies understand when words are related

November 20, 2017
The meaning behind infants' screeches, squeals and wails may frustrate and confound sleep-deprived new parents. But at an age when babies cannot yet speak to us in words, they are already avid students of language.

Simple EKG can determine whether patient has depression or bipolar disorder

November 20, 2017
A groundbreaking Loyola Medicine study suggests that a simple 15-minute electrocardiogram could help a physician determine whether a patient has major depression or bipolar disorder.

Non-fearful social withdrawal linked positively to creativity

November 20, 2017
Everyone needs an occasional break from the social ramble, though spending too much time alone can be unhealthy and there is growing evidence that the psychosocial effects of too much solitude can last a lifetime.

Cultural values can be a strong predictor of alcohol consumption

November 20, 2017
Countries with populations that value autonomy and harmony tend to have higher average levels of alcohol consumption than countries with more traditional values, such as hierarchy and being part of a collective. This new ...

A walk at the mall or the park? New study shows, for moms and daughters, a walk in the park is best

November 17, 2017
Spending time together with family may help strengthen the family bond, but new research from the University of Illinois shows that specifically spending time outside in nature—even just a 20-minute walk—together can ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

patnclaire
1 / 5 (1) Nov 29, 2010
I thought Miller's Number was seven plus or minus two. I have heard that number repeatedly for 30 years. When was it struck down? By whom?
RobertKarlStonjek
1 / 5 (1) Nov 30, 2010
"...3 to 5 items..."
This is totally wrong. The number of unique items is limited to under 10 but the total number of items may be as high as 1,000 or more (but they must have some logical relationship).

What's the first thing you ask after total memory loss? "Where am I?" Such information is perishable and so is stored in short term memory along with the reasons for your current activity, the previous activity you were engaged in, what you intend to do next, where you are/were/will be etc etc etc.

Apart from orientation information, if you were to suddenly close your eyes and ears and immediately recall everything you have seen and heard in the past few minutes you should be able to list around 1,000 items, though the time it takes to recall these items exceeds the STS footprint. With prompting, 1,000 is easily obtainable eg "mentally look around the room you are in and name every item you see".

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.