IQ Part 4: Working Memory
After closely studying our first three components of the IQ (Verbal Comprehension, Visual Spatial, and Fluid Reasoning), today’s post will dive into Working Memory and how it impacts one’s cognitive profile.
Once again, I am using the WISC-V as the basis for this breakdown. The WISC-V is administered to children ages 6-16. However, the WAIS-IV, which is used to assess adults, also contains a Working Memory index score. Thus, the following information pertains to pretty much all age ranges.
What is Working Memory?
When I write my reports, I describe Working Memory as:
the ability to take in, retain, and immediately recall small pieces of visual and/or auditory information.
When I explain working memory to parents and students, I often tell them it is the ability to hear someone give you a phone number and then immediately dial that number on the phone. For many of us we may hear that number only to forget the last couple of numbers as we are dialing. Others may remember that number and dial it successfully. Not surprisingly, phone numbers were assigned seven digits because this is about the maximum amount of numbers we can hold in our working memory. It is important to note that working memory can also include visual information, as we will see below.
How is it Calculated?
The Working Memory subtest is calculated using two primary subtests: Digit Span and Picture Span. By using these two subtests, we can evaluate one’s working memory in relation to both auditory and visual stimuli.
There is a supplemental subtest called Letter-Number Sequencing that can replace one of the other subtests if necessary. However, I rarely use this particular subtest when evaluating students.
The Digit Span subtest requires the examinee to listen to a list of numbers and then immediately repeat them back to the examiner. The lists start off with two numbers and increase in length as the items become more difficult. There are also three variations of the lists. In the first, the examinee must repeat the numbers exactly as he heard them. In the second, the examinee must repeat the numbers backward. And in the third, the examinee must repeat them in numerical order, smallest to biggest.
The Picture Span subtest allows the examinee to view a series of pictures for five seconds. The examiner then presents a random list of pictures that includes the previous pictures as well as several others. The examiner must then correctly pick out the items he saw previously and put them in proper order. The number of pictures included on each item increases as the subtest progresses.
Once these two subtests are completed, an index score for Working Memory can be calculated. Similar to the other index scores on the WISC-V, the Working Memory index score can be interpreted by the following:
130 or above: Very Superior
120-129: Superior
110-119: High Average
90-109: Average
80-89: Low Average
70-79: Borderline
Below 70: Extremely Low
The majority of students across the country score between 80-120, with a score of 100 falling exactly in the middle.
What Does the Score Tell Us?
As mentioned above, working memory measures one’s ability to take in, retain, and immediately recall small pieces of auditory and/or visual information. Working memory is highly correlated with other areas of cognition, including processing speed (which we will examine in depth in the next post). It makes sense that students with high working memory are able to process information quicker, since they are able to store and retrieve it efficiently.
Additionally, working memory is also highly correlated with other behavioral domains. For instance, students with low working memory tend to struggle with various aspects of executive functioning. Executive functioning refers to self-regulation skills, including time management, organization, and planning. Often times students with low working memory require additional executive function support, as they simply struggle to keep track of their work.
And finally, students with ADHD typically experience working memory deficits, as remaining sufficiently engaged and alert to retain information can be difficult. It is important to note, however, that not all students with ADHD experience low working memory. Conversely, not all students with low working memory experience significant attention deficits indicative of ADHD. Unfortunately, I have seen too many students with low working memory labelled as ADHD despite a lack of other ADHD symptoms. Though the signs of both are similar, there are distinct differences in how they manifest and how they are remediated.
In our next post we will examine the final component of the IQ: Processing Speed.