Working memory

The research behind "Did I already pack underwear?".

What the essay claims

"Working memory is the mental scratchpad where you hold information while using it — the 'eggs, milk, butter' you repeat on the way to the store. ADHD tends to make that scratchpad smaller and more volatile."

The construct

Working memory is the system that holds a small amount of information available while you operate on it — as distinct from long-term memory, which stores things you are not currently using. The dominant model splits it into a phonological store for verbal material, a visuospatial store, and a central executive that allocates attention between them (Baddeley, 2003).

This is the one construct on this site where the community word and the research word are the same thing. "Working memory" in an ADHD forum means roughly what it means in a journal, and the BRIEF-A even has a scale by that name.

What the research says

• Working memory is among the domains with the strongest and most consistent group differences in the largest meta-analysis of executive function in ADHD, within an overall medium effect-size range of .46–.69. (Willcutt et al., 2005)
• A meta-analysis of 38 studies of working memory in adults with ADHD found what the authors describe as "moderate-magnitude" between-group effect sizes across both the phonological and the visuospatial domain. (Alderson et al., 2013)
• A meta-analysis of 33 studies of adults with ADHD reported notable impairments in attention, behavioral inhibition and memory, alongside normal performance on simple reaction time. (Hervey et al., 2004)
• On self-report, Working Memory was the single most elevated BRIEF-A scale in a sample of treatment-naive adults with newly diagnosed ADHD: mean T = 75.0, against 45.2 in controls. (Grane et al., 2014)
• Reviewing three decades of work on storing intentions in external props rather than in memory, the authors of a review of "intention offloading" conclude the strategy is "highly effective." (Reviewed in Gilbert et al., 2023)

What it doesn't say

It doesn't say the deficit is uniform. Alderson et al.'s stated conclusion is that methodological variability "may explicate why WM deficits have not been uniformly detected in previous experimental studies" — the meta-analysis is partly an explanation of why individual studies disagreed. A group-level effect of moderate size is not a statement about any individual.

The adult effect sizes here are the authors' word, not a number I can show you. Alderson et al.'s abstract characterises the effects as "moderate-magnitude" without publishing the coefficients, and the full text is paywalled; I have not seen the numbers and so do not quote any. The numeric range given above (.46–.69) is Willcutt et al.'s, and that meta-analysis spans childhood and adulthood rather than adults alone.

Self-report is not measurement. The T = 75.0 above is a group of 36 adults rating their own everyday difficulty. In the same study, informant ratings from people who knew them did not reach the clinical cutoff on any scale, and the association between BRIEF-A ratings and laboratory performance was modest.

The offloading research is not ADHD research. Gilbert et al. review intention offloading in the general population and across the lifespan. I could find no study testing whether externalising intentions is more or less effective for adults with ADHD than for anyone else. That it should help more where internal memory is weaker is an inference, and it is labeled as one here.

Nothing here measured packing, a task that runs for an hour or more with interruptions, and no study has tested whether a persistent item library reduces working-memory load across repeated trips.

How this shaped the app

Everything the app could hold for you, it holds: quantities are stored as formulas rather than numbers so the arithmetic is recomputed per trip, notes live on the item rather than in your head, kits travel as a unit, and the same item checked in one place is checked everywhere it appears. The library persists between trips, so knowledge accumulates instead of being rebuilt.

The decisions this shaped — the large library, quantity rules, templates and the split between library and trip — are on Why the app is built this way.

Sources

• Baddeley A (2003). Working memory: looking back and looking forward. Nature Reviews Neuroscience 4:829–863. Cited for the model of working memory used here. doi:10.1038/nrn1201
• Alderson RM, Kasper LJ, Hudec KL, Patros CHG (2013). Attention-deficit/hyperactivity disorder (ADHD) and working memory in adults: a meta-analytic review. Neuropsychology 27(3):287–302. doi:10.1037/a0032371
• Hervey AS, Epstein JN, Curry JF (2004). Neuropsychology of adults with attention-deficit/hyperactivity disorder: a meta-analytic review. Neuropsychology 18(3):485–503. doi:10.1037/0894-4105.18.3.485
• Willcutt EG, Doyle AE, Nigg JT, Faraone SV, Pennington BF (2005). Validity of the executive function theory of attention-deficit/hyperactivity disorder: a meta-analytic review. Biological Psychiatry 57(11):1336–1346. doi:10.1016/j.biopsych.2005.02.006
• Grane VA, Endestad T, Pinto AF, Solbakk A-K (2014). Attentional control and subjective executive function in treatment-naive adults with Attention Deficit Hyperactivity Disorder. PLoS ONE 9(12):e115227. Open access. doi:10.1371/journal.pone.0115227
• Gilbert SJ, Boldt A, Sachdeva C, Scarampi C, Tsai P-C (2023). Outsourcing memory to external tools: a review of "intention offloading." Psychonomic Bulletin & Review 30(1):60–76. Open access. Review article — general population, not ADHD. doi:10.3758/s13423-022-02139-4