Operation Span test online: memory under load
Check a sum, see a letter, check another sum, see another letter. After 3 to 7 of these pairs you pick the letters back in the order they came. Letters from sets you get exactly right add up to your score, out of 75.
Start Operation SpanAfter the last set you see your span score and can keep it with a free account.
Works best on a computer.
How it works
Practice comes first: 3 sums on their own, then 1 short set with 2 letters. After that come 15 scored sets. About 9 minutes in all.
- 1 · Each pair
Check the sum
A sum such as (3 × 2) + 1 = 7 appears. Choose TRUE if the answer shown is right and FALSE if it is not. You have 6 seconds, and a bar shows the time left.
- 2 · Each pair
Keep the letter
A letter then shows for 1 second, followed by a half-second pause before the next sum. No letter repeats within a set.
- 3 · End of each set
Pick the letters in order
A grid of 12 letters appears. Tap them in the order you saw them; each fades once used. Clear empties your answer, and Submit works once you have picked as many letters as the set held.
- 4 · 15 sets
3 to 7 letters
There are 3 sets of each length, from 3 to 7 letters, in a random order. A line above each sum gives the set number and how many items that set has.
The practice sums allow 8 seconds and have no time bar, so you can learn the format first. During the scored sets nothing tells you whether a recall was right, and a sum left unanswered when the bar runs out counts as wrong.
Tasks like this are called complex span tasks: a memory list with a second job between the items. Unsworth and colleagues published an automated version in 2005 that is mouse driven and scores itself, and it proved reliable, with a test-retest correlation of .83 (Unsworth et al., 2005). This version follows the same plan of sums, letters and recall in order.
What it measures
The sums take up your attention between letters, so the list cannot simply be repeated to yourself. What you recall shows how much you can hold while doing something else.
The letters
- Working memory capacity: how many letters you keep while your attention is pulled away.
- Serial order: each letter has to go back in its own place.
- Getting the list back after every sum interrupts it.
The sums
- Fast arithmetic checking within a 6-second limit.
- Shifting attention between the sum and the letter list, again and again.
- Effort on both jobs: the result is read with caution if sum accuracy falls below 85%.
Simple span tasks, such as repeating digits, measure how much you can hold when nothing else is going on. Complex span tasks add the second job. In Unsworth's study, the automated operation span loaded on the same factor as other working memory tasks, and that factor was linked to a factor of fluid reasoning measures (Unsworth et al., 2005).
The 85% rule exists because the sums only work as a distraction if you really solve them. Skipping them to rehearse the letters would turn the task back into a simple span task.
A test, not a diagnosis.
One span score describes one attempt under one kind of load. It cannot confirm or exclude a diagnosis.
What you get
Your scores appear after the 15th set.
On the result screen
- Your span score out of 75, with sum accuracy and recall accuracy as percentages.
- A verdict line from fixed bands on the span score, 45 or more, 20 to 44 and under 20, or a caution in its place if sum accuracy was under 85%.
- Short notes on the sums and on the letters, with how many of the 15 sets you recalled perfectly.
- A clinician panel with the absolute and partial scores, a table by set length and a note that college samples average about 40.
- A CSV file with the trial data.
When you keep it
- A free account holds on to your span score so you can look at it from any device.
- It is filed under working memory in your results, beside Digit Span, Corsi Blocks and N-Back as you take them.
- The Continue button leads on to another test, so you can build a wider picture.
How this version is scored
Each sum answer and each recall is stored. Scores come from the 15 scored sets only; practice is left out.
- Perfect set
- Every letter recalled in its exact position. One letter out of place makes the whole set imperfect.
- Span score
- The total length of your perfect sets, from 0 to 75. A perfect set of 6 adds 6; an imperfect set adds nothing. Researchers call this the absolute score.
- Partial score
- Every letter recalled in its right position, perfect set or not, out of 75. Recall accuracy is this count as a percentage.
- Sum accuracy
- Correct TRUE or FALSE answers as a share of all scored sums, including those left unanswered.
- 85% check
- Below 85% sum accuracy the verdict is replaced by a caution, because the letters may have had your attention at the expense of the sums.
Why the sums have a clock. Without a limit you could pause on each sum and rehearse the letters. The 6-second window keeps the sums working as a distraction.
Absolute and partial. The span score gives credit only for whole sets, which is strict. The partial score counts every letter in its place, so it separates near misses from sets you lost entirely.
Lab numbers, browser task. Published scores come from lab versions with their own timing and setting. Web studies can match lab results on many tasks (Germine et al., 2012), but treat any outside number as context. The result screen does not convert your score into a percentile.
Before you start
This is the longest of the memory tests, so plan for a quiet stretch.
For a cleaner attempt
- A computer with a mouse is easiest; on a phone, hold it steady and keep the whole letter grid in view.
- Set aside about 9 minutes without calls or messages.
- Give each sum a real answer: rushing them to protect the letters lowers sum accuracy.
- Use the practice to settle on a way to keep the letters, such as saying them silently.
Interpret cautiously when
- You were tired, unwell, rushed or interrupted between sets.
- Mental arithmetic is hard for you, or you need extra time for reading or maths, since the sums then take more of your attention.
- You use motor-access tools or a very small screen, which make the timed buttons and the grid harder to use.
- You have taken this task before and know the format well.
Questions
What does the Operation Span task measure?
Working memory capacity: how much you can keep in mind while your attention is busy with something else. The sums interrupt the letter list after every item, so the score reflects storage plus the control needed to protect it, not a plain memory span.
What is a good Operation Span score?
In a pooled sample of 6,236 young adults aged 17 to 35, the absolute score averaged about 42 out of 75, with a standard deviation near 18 (Redick et al., 2012). Those data come from a lab version with its own timing, so treat them as context. The result screen reads your score against fixed bands rather than age norms.
Can I do Operation Span on my phone?
Yes, but it works best on a computer. The sums have a 6-second limit and the letter grid needs accurate taps, which are easier with a larger screen and a mouse. On a phone, hold it steady and keep the grid in view.
Does practising Operation Span improve working memory?
Your score will usually rise as the task becomes familiar. A meta-analysis of working memory training found no improvement on measures of intelligence or other far transfer tests (Melby-Lervåg et al., 2016). A retake is useful to check a result, not as training.
Sources
- Unsworth et al. (2005): An automated version of the operation span task
- Redick et al. (2012): Measuring working memory capacity with automated complex span tasks
- Melby-Lervåg, Redick and Hulme (2016): Working memory training does not improve performance on measures of intelligence or other measures of far transfer
- Germine et al. (2012): Is the Web as good as the lab? Web and lab performance compared