What do we know about literacy learning in adulthood?

Despite the rise in adult literacy rates over the past half-century, nearly 1 billion adults still cannot read or write in any language, with the heaviest burden on women and in lower-income countries (UNESCO 2024). This is a far cry from the benchmark set by Sustainable Development Goals (SGDs), which seek to ensure that “all youth and most adults achieve literacy and numeracy by 2030” (UNESCO 2024, SDG Target 4.6). Adult literacy programmes are often used as a policy tool to bridge this gap (UNESCO 2019), yet research has shown that learning acquired during such programmes is either limited or depreciates quickly. This raises the question: why is it difficult for adults to gain literacy skills?  

Learning to read and write is harder as an adult 

While some aspects of (literacy) learning are similar for adults and school-aged children, such as uncertainty regarding the returns to education (Jensen 2010) or the importance of repetition and attendance, adults often face additional and unique barriers to learning. 

The first constraint relates to brain plasticity, or the brain’s ability to respond to stimuli and environmental conditions over time. While all beginner readers start with recognising letters and syllables (“decoding”), and then processing larger units such as words, the initial stage of decoding can be difficult for an adult brain. The task of reading is complex, involving a number of brain areas. Adults typically have lower levels of “brain plasticity” as compared with children. This presents a challenge to sustained literacy acquisition in adulthood because strong decoding skills and word accuracy are critical to being able to read quickly and fluently. In fact, research suggests that adults who learned to read in adulthood read more slowly than those who learned to read as children, even when they were as accurate in their decoding (Dehaene et al. 2010).  

Second, and perhaps unsurprisingly, adult learners often face additional stressors that children and adolescents do not. While all learners must face deadlines and examinations, as well as manage sometimes delicate relationships with teachers and peers, adults must also balance family and work pressures. In addition, since adults typically have a shorter time horizon over which they can observe the potential benefits of increased literacy and numeracy, the degree of uncertainty regarding the economic returns may be more salient for adult learners. 

Designing and implementing adult literacy programmes 

These challenges imply two primary things for the design and implementation of adult literacy programmes. 

First, given the lower brain plasticity of adult learners, moving from phase to phase requires more practice to make things “stick”, which implies critical changes to textbooks and the pedagogical approach for adult education programmes. If insufficient time is spent on early stages of literacy acquisition, then any gains acquired can be easily lost. This approach can also differ by the orthographic transparency of a language - some languages are more transparent (a predictable relationship between letters and sounds), whereas others are more opaque (the match between letters and sounds is less predictable) (Andoni Duñabeitia 2024). In some cases, information technology, such as simple mobile phones, can help practice make perfect (Aker et al. 2012). 

Second, since adults have different opportunity costs, these costs need to be built into the learning curriculum. This can range from extrinsic support, including subsidies or transport, to intrinsic support such as helping learners to identify their own educational needs and highlight their immediate relevance. Technology can also be useful here, enabling adults to immediately practice what they have learned or practice outside of class (see Muralidharan et al. 2019, Aker and Ksoll 2019). This allows for a cycle of continuous learning (Aker et al 2012, Ksoll et al 2023, Angrist et al 2023). 

How effective are adult literacy programmes? 

As for education programmes for school-aged children there is no “one size fits all” when it comes to adult literacy programmes. There is significant variation to the content, delivery method and cost of adult literacy programmes worldwide, ranging from classroom-style programmes taught by volunteer teachers to more comprehensive, IT-focused ones with full-time teachers (Angrist and Meagar 2023, UNESCO 2019). For example, while it is estimated that 400 hours of instructional time is required to achieve basic literacy (Oxenham 2008), programme hours range from 250 hours (in Pakistan) to 450 hours (in Afghanistan) (Hanemann 2015). Focusing on randomised control trials of such programmes, there have been positive and statistically significant impacts of such interventions on reading and maths skills, ranging from 0.07 to 0.37 standard deviations (Banerji et al. 2017, Aker et al. 2012, Aker and Ksoll 2019, Royer et al. 2005). Despite these encouraging results, the magnitudes are not enough to impart functional literacy. For example, Deshpande et al (2017) found that a computer-based literacy program in India increased word reading by 1.7 to 4.8 words per minute on average, but learners were still far below 45 words per minute, the benchmark to be considered literate. As a result of their small effect sizes, these programs may not necessarily translate into improved welfare.  While some studies find that adult literacy programmes are associated with improvements in income and consumption (Blunch and Portner 2011, Aker and Ksoll 2020), self-esteem (Ksoll et al. 2023) and parental involvement in children’s education (Deshpande et al. 2023, Banerji et al. 2017), these are often in specific contexts. 

What explains the low effectiveness of adult education programmes? 

While adult education programmes within sub-Saharan Africa and South Asia can vary substantially both across and within countries, a number of characteristics of adult education programmes can limit learning gains.  

First, many programmes progress through a curriculum that does not allow sufficient time for practice. Even with hundreds of hours of instructional time, the slower speed at which adults learn means that existing programmes can still progress too quickly. This may often be due to good reasons – for example, literacy programmes may be offered at certain times of year, in order to avoid competing with the agricultural cycle. But this, in turn, limits the time for revision, which is needed. 

Second, many programmes focus primarily on decoding, rather than automaticity and reading comprehension. These latter two skills are necessary for adults to achieve a minimum threshold of learning, which in turn, limits adults’ ability to practice their literacy skills in their daily life. 

Third, such programmes are often characterised by high rates of dropout (ranging from 17-58%) and low attendance, in turn affecting learning. Given the competing demands on adults’ time, these programmes may not be seen as valuable relative to work, home production or leisure (Abadzi 2003). While some adult literacy programmes have offered incentives for enrolment and participation, monetary or otherwise, the impacts of different incentive schemes have not been sufficiently studied. 

Implications for adult education policy 

Our review suggests two important directions for design and research of adult literacy programmess. First, adult literacy programmes should be designed to address the unique cognitive needs of adults. Given the slower speed of literacy acquisition of adults, programmes should focus on modest goals in the short-term with the aim of maintaining engagement to achieve higher-level skills in the long-term. This will require more practice, although the precise length of time required for each step remains an important issue for future research. Second, more research and innovation is needed to understand the most effective methods to accommodate adults’ busy schedules and encourage them to learn. Existing research has shown that technology can play a role in providing flexibility and maintaining engagement, but more work could be done to explore further innovations in incentives and curricular design.  

References 

Abadzi, H (2003), Improving adult literacy outcomes: Lessons from cognitive research for developing countries, World Bank Group.

Aker, J C and C Ksoll (2020), “Can ABC lead to sustained 123? The medium-term effects of a technology-enhanced adult education program,” Economic Development and Cultural Change, 68(3).

Aker, J C and C Ksoll (2019), “Call me educated: Evidence from a mobile phone experiment in Niger,” Economics of Education Review, 72: 239–257.

Aker, J C, C Ksoll, and T J Lybbert (2012), “Can mobile phones improve learning? Evidence from a field experiment in Niger,” American Economic Journal: Applied Economics, 4(4): 94-120.

Angrist, N and R Meager (2023), "Implementation matters: Generalizing treatment effects in education," Working Paper.

Banerji, R, J Berry, and M Shotland (2017), “The impact of mother literacy and participation programs on child learning: Evidence from a randomized evaluation in India,” American Economic Journal: Applied Economics, 9(4).

Blunch, N-H and C C Pörtner (2011), “Literacy, skills and welfare: Effects of participation in adult literacy programs,” Economic Development and Cultural Change, 60(1): 17-66.

Blunch, N-H (2017), “Adult literacy programs in developing countries,” IZA Review of Labor.

Dehaene, S (2009), Reading in the brain: The new science of how we read, Penguin Books.

Dehaene, S, F Pegado, L W Braga, P Ventura, G Nunes Filho, A Jobert, G Dehaene-Lambertz, R Kolinsky, J Morais, and L Cohen (2010), “How learning to read changes the cortical networks for vision and language,” Science, 330(6009): 1359-64.

Deshpande, A, C Ksoll, A Maertens, and V Varghese (2023), “The impact of an adult education program for mothers: Evidence from India,” Economic Development and Cultural Change, 71(2): 709-751.

Deshpande, A, A Desrochers, C Ksoll, and A S Shonchoy (2017), “The impact of a computer-based adult literacy program on literacy and numeracy: Evidence from India,” World Development, 96: 451-473.

Duñabeitia, J A (2024), “Why we can read Finnish without understanding it – a look at ‘transparent’ languages,” The Conversation, June. https://theconversation.com/why-we-can-read-finnish-without-understanding-it-a-look-at-transparent-languages-231628.

Hanemann, U (2015), The evolution and impact of literacy campaigns and programmes 2000-2014, UIL Research Series: No.1, Hamburg: UIL. https://files.eric.ed.gov/fulltext/ED564035.pdf.

Ksoll, C, J C Aker, D Miller, K Perez, and S L Smalley (2023), “Learning without teachers? Experimental evidence on the impact of a mobile phone adult literacy program,” Unpublished working paper.

Oxenham, J (2008), Effective literacy programs: Options for policymakers, UNESCO IIEP.

Oxenham, J, A H Diallo, A R Katahoire, A Petkova-Mwangi, and O Sall (2002), Skills and literacy training for better livelihoods: A review of approaches and experiences, World Bank.

Royer, J, H Abadzi, and J Kinda (2004), “The impact of phonological awareness and rapid reading training on the reading skills of adolescent and adult neoliterates,” International Review of Education, 50(1): 53–71.

UNESCO (2019), “Estimating the costs of achieving basic literacy and numeracy targets in the context of SDG4.6 in GAL countries.”