The short answer
Short-term memory is about holding: keeping a few items available for a few seconds. Working memory is about holding and using: keeping items available while you reorder, combine or calculate with them.
Researchers use the two terms in this way, for maintaining information and for maintaining plus manipulating it, although the research literature does not always use them strictly [1].
An everyday test: if you only need to give the information back as you received it, that is short-term memory. If you have to change it while you hold it, that is working memory.
- Hearing a door code and typing it in: short-term memory.
- Hearing a door code and adding up its digits while you hold it: working memory.
Simple span vs complex span
The distinction shows most clearly in how each is measured. Short-term memory is typically measured with simple span tasks and working memory with complex span tasks [1].
A simple span task shows you a sequence (digits, letters, words or locations) and asks you to repeat it. Digit span and the Corsi block task are classic examples [1]. A complex span task adds a demanding second job between the items: in an operation span task, for example, you solve a short sum between the words you must remember [1]. So you have to keep the list in mind while your attention is on something else.
N-back is usually listed with the working-memory tasks [1], because the item you compare against changes at every step. You are not storing one list; you are updating it constantly.
Are they really two different things?
Partly. The evidence pulls in two directions.
In a 1999 study, 133 participants completed 11 memory tasks, some thought to reflect short-term memory and some working memory, plus two tests of general fluid intelligence. Statistical modelling (structural equation modelling) suggested that short-term and working memory were separate but highly related [2]. Working memory was strongly connected to fluid intelligence; short-term memory was not [2]. The authors argued that working-memory capacity reflects the ability to keep information active, particularly in the face of interference and distraction [2].
Randall Engle later summarised this view: working-memory capacity is separable from short-term memory and reflects a general limit on the ability to control attention, which shows up most when distraction or conflicting habits get in the way [3].
A 2012 review was more cautious. Correlational studies have not been able to separate the two consistently, and some evidence points to a large or even complete overlap [1]. The tasks used to measure each, and how much attention and processing speed they demand, play a crucial role in what studies find [1].
The fair summary: the two ideas are different on paper, the tasks used to measure them overlap, and many researchers assume that every working-memory task includes a short-term storage component [1].
Forward and backward span: an everyday illustration
LaserMind's Digit Span has a Forward and a Backward mode. Digits appear one at a time, about a second each, and you type them back with no time limit. In Forward you repeat them in order; in Backward you type them in reverse. The sequence starts at 3 digits, you get two tries at each length, and your span is the longest length you got right at least once.
Forward span is a simple span task: hold and repeat [1]. Backward span adds a step, because you have to reverse the order before you answer. Some researchers think that step brings in executive control, which is why backward span is often treated as a working-memory measure; others think it mainly brings in visuospatial resources [4]. The sources are not settled:
- Aben and colleagues note that there is no consensus about the processes involved in backward span [1]. Reversing the order can be seen as the extra job of a complex span task, but some researchers have classed backward span as a simple span task [1].
- In five experiments, St Clair-Thompson and Allen found that an extra task done while the digits were being presented did not disrupt backward recall more than forward recall [4]. An extra task done during recall did, and the extra resources backward recall needed seemed to be visuospatial, with evidence of a role for visual imagery [4].
The same exercise shows another difference. A review of order-recall studies found that, for digits and other verbal material, recalling backwards is usually harder than recalling forwards [5]. For spatial sequences such as the Corsi task, backward recall is not always harder, although it is for people with weaker visuospatial abilities [5]. LaserMind's Light Path has a Backward mode too, so you can compare the two patterns in your own results.
If your backward digit span is lower than your forward span, that is the usual pattern for digits [5], not a warning sign. And if you want a task that is clearly about updating rather than holding, try N-Back.
Side by side
| Short-term memory | Working memory | |
|---|---|---|
| What it does | Holds information briefly | Holds information and works with it |
| Typical task | Simple span: repeat digits, words or a path in order | Complex span (remember items while doing another task); n-back |
| Everyday example | Repeating a door code as you type it | Adding up prices while remembering what is in your basket |
| On LaserMind | Digit Span and Light Path, Forward mode | N-Back; Backward span sits in between, and is debated |
| Link to fluid intelligence (1999 study above) | Not strongly linked | Strongly linked |
Why the difference matters for practice
Knowing which kind of task you are practising tells you what your score reflects. A meta-analysis of working-memory training found reliable short-term gains on working-memory tasks but no convincing transfer to other skills, such as verbal and nonverbal ability, word decoding or arithmetic [6]. In plain terms, practising forward span makes you better at forward span, and practising n-back makes you better at n-back.
That is still useful. A rising span on LaserMind is a fair record of your practice on that exercise. It is not a measure of your everyday memory, and LaserMind compares it only with your own history. For the bigger picture, read What is working memory?, or see the method pages for Digit Span, Backward Digit Span and N-back.
Try it on LaserMind
▶ Number SpanDo one round Forward and one Backward, and note the difference in your own spans.
Try it on LaserMind
▶ N-BackTry a task built around updating rather than holding.
What research has not established
- Whether short-term and working memory are separate systems is not settled. Correlational studies have not separated them consistently, and results depend on the tasks used [1].
- The 1999 study that separated them tested 133 participants on one set of tasks; it shows how the measures relate, not how memory works in everyday life [2].
- What backward span measures is still debated. The dual-task evidence comes from laboratory experiments [4].
- LaserMind's Digit Span and Light Path are practice versions of these tasks. They are not standardised clinical tests, and scores vary with device, attention and practice.
Frequently asked questions
Is short-term memory part of working memory? Many researchers think short-term storage is one component of working memory; the debate is about how much the two overlap [1].
Which LaserMind exercise is closest to a working-memory task? N-Back, because the comparison item changes at every step. Digit Span and Light Path in Forward mode are simple span tasks, closer to short-term memory [1], and Backward mode adds a reordering step.
Does a low backward span mean my working memory is poor? No single score shows that. On average, people recall digits less well backwards than forwards [5], and LaserMind's scores are for tracking your own practice, not for diagnosis. If memory problems are affecting your daily life, talk to a doctor or another qualified professional.
What the research says
Last evidence check 2026-10-11Span tasks are classic measures of short-term memory: how many items you can hold briefly and repeat. A later model (1974) describes working memory as a limited system that holds information while you work with it. Trained task [7]
A meta-analysis of working-memory training found reliable short-term gains on working-memory tasks, which did not last well, and no convincing transfer to verbal or nonverbal ability, word decoding or arithmetic. Trained & similar tasks [6]
References
- Aben, B., Stapert, S., & Blokland, A. (2012). About the Distinction between Working Memory and Short-Term Memory. Frontiers in Psychology, 3, 301. https://doi.org/10.3389/fpsyg.2012.00301
- Engle, R. W., Tuholski, S. W., Laughlin, J. E., & Conway, A. R. A. (1999). Working memory, short-term memory, and general fluid intelligence: A latent-variable approach. Journal of Experimental Psychology: General, 128(3), 309–331. https://doi.org/10.1037/0096-3445.128.3.309
- Engle, R. W. (2002). Working Memory Capacity as Executive Attention. Current Directions in Psychological Science, 11(1), 19–23. https://doi.org/10.1111/1467-8721.00160
- St Clair-Thompson, H. L., & Allen, R. J. (2013). Are forward and backward recall the same? A dual-task study of digit recall. Memory & Cognition, 41(4), 519–532. https://doi.org/10.3758/s13421-012-0277-2
- Donolato, E., Giofrè, D., & Mammarella, I. C. (2017). Differences in Verbal and Visuospatial Forward and Backward Order Recall: A Review of the Literature. Frontiers in Psychology, 8, 663. https://doi.org/10.3389/fpsyg.2017.00663
- Melby-Lervåg, M., & Hulme, C. (2013). Is working memory training effective? A meta-analytic review. Developmental Psychology, 49(2), 270–291. https://doi.org/10.1037/a0028228
- Baddeley, A. D., & Hitch, G. (1974). Working memory. Psychology of Learning and Motivation, 8, 47–89. https://doi.org/10.1016/S0079-7421(08)60452-1