Work out working memory span instantly with clear inputs, formula shown and shareable results.
Span is scored as the longest fully correct sequence plus partial credit for successes at the next length. Six items plus one of three trials at seven gives 6.33. Typical adult digit span is 7 plus or minus 2, but backward and operation spans run lower at around 4-5 because they demand manipulation as well as storage.
Span score
span = longest correct length + (partial successes / trials per length)
Typical values
forward digit span 7 plus or minus 2; backward and operation spans 4-5
Because reversing the sequence requires manipulation as well as storage, consuming the same limited executive resource.
Training improves performance on the trained task, but transfer to general cognitive ability has repeatedly failed to replicate.