Young Australians' working memory and processing speed scores fell about 5% between 2012 and 2024

Each fall is small against its own scale. The working-memory average dropped 0.2 points: 5% of its 2012 level and just under 3% of the 7-point range ^[1][3]. Processing speed dropped 2.7 points, or 4.9% of its starting value and about 2.5% of the 110-point range ^[2][4]. The published account does not report standard deviations or how many 15- to 24-year-olds sat the tasks each year, so it cannot show how far either shift sits outside sampling noise ^[1].

The design is sound. HILDA follows more than 17,000 Australians each year ^[5]. The age band is ten years wide and the comparison spans twelve ^[6], so the 15- to 24-year-olds of 2024 are different people from those of 2012: anyone in the band in 2012 was 27 to 36 by 2024 ^[5]. The survey is setting two cohorts side by side at the same age. That removes ordinary ageing as an explanation. In this survey cognitive ability tends to fall with age, and the slide steepens after 50 ^[6]. The older bands give a rough control as well, because their scores stayed fairly constant over the same years ^[4]. Had the tasks or the way they were administered changed, I'd expect every band to move.

The thing this doesn't tell you is why. The article on phys.org that reported the results asks whether growing screen use is partly responsible, and leaves it as a question ^[7]. The survey's own correlates offer other candidates. Higher education went with higher scores, which the article attributes to better performance on these particular tasks ^[12]. Poor mental health and being out of paid work went with lower scores, the second perhaps because people out of work are often older ^[13]. Weekly exercise, volunteering, club membership and close ties to friends and family went with higher ones ^[14]. Each of those is an association between people at one point in time. A change confined to one age band over 12 years ^[6] needs a test that follows the candidate cause over the same period.

For employers the step from finding to decision is long. The article says cognitive ability shapes whether people find work, how well they do their jobs and their chances of promotion and higher pay ^[8]. A 0.2-point move in a group mean on a 7-point task is a fact about a population ^[2]. A hiring manager assesses one applicant at a time, and a shift that size in the average says little about the person in the room. I think employers should treat the result as a trend to follow through the next waves of the survey.

The money questions are more direct evidence for schools. About 18.9% of 15- to 24-year-olds got only one or two of the five right, almost double the share among 25- to 34-year-olds and people over 65 ^[11]. Four in 10 could not grasp how spreading investments reduces risk ^[16]. The age group also records the lowest financial well-being scores ^[17], while people aged 45 to 64 answered the most questions correctly ^[19]. The article's authors argue for school financial literacy programs combined with parents talking to their children about money ^[18].