Literacy refers to the ability to read and write. Literacy is fundamental to many aspects of modern life, but it is not a capacity that humans develop naturally. Instead, children need to be taught to read, and as a result, a large proportion of the world’s population never becomes literate. Yet, reading and reading acquisition are among the most well-studied topics in the cognitive sciences. This body of research shows that reading is a multidimensional skill involving the perception of visual symbols, the analysis of linguistic information, and the coordination of eye movements. Learning to read requires the repurposing of these visual, language, and motor systems, none of which evolved specifically for reading, and therefore takes years to master. 

History

The use of visual symbols to represent language is a cultural invention that is over 5,400 years old, and the phenomenon of mass public literacy has arisen within the last 200 to 300 years. These cultural milestones are far too recent for human evolution to have engineered a dedicated cognitive capacity for reading. Moreover, although literacy has become a basic prerequisite for human flourishing in high-income countries, most children in low- and middle-income countries do not learn to read (Crawford et al., 2025). Yet, despite the fact that literacy is not a universal part of human experience, it has been a substantive topic of research for well over 100 years.  

Three strands of inquiry shaped the development of research on literacy in the late 19th century and the years that followed. The first strand was an interest in measuring the speed of mental processes, or mental chronometry. One early pioneer was James Cattell (1886), who measured reaction times to visually presented stimuli such as letters and words to draw inferences about underlying processes. The second strand focused on how to teach children to read, with Edmund B. Huey (1908) among the first to unite psychology and education, arguing that findings from the psychology of reading should inform reading pedagogy. Finally, a long-standing interest in reforming English spelling, aimed at making it easier and less expensive to teach children to read, gained momentum around the turn of the 20th century, propelled by influential organizations such as the Simplified Spelling Board in the United States and the Simplified Spelling Society in the United Kingdom.  

Core concepts

Skilled behavior

Reading and writing are learned skills, acquired over many years through instruction and text experience. Instruction is essential for helping children understand how to interpret the arbitrary lines, squiggles, and dots that constitute writing (Rastle et al., 2021). Text experience allows readers to memorize the orthographic forms of frequent words and to discover nuanced regularities in how visual symbols map onto the sounds and meanings of their language. The latter process of discovery is known as statistical learning (Treiman & Kessler, 2022) [see Statistical Learning]. The outcome of these years of instruction and text experience is an interface that allows literate individuals to access spoken language through the visual system.  

Writing systems

Writing systems all represent spoken language, but they do so in different ways. These differences have important consequences for instruction: for example, whether children are taught meaningful characters (as in Chinese) or symbol–sound mappings (as in English) or even the relationship between spoken language and tactile symbols (as in Braille). Likewise, the characteristics of a writing system may come to influence the nature of the skilled system through the process of statistical learning (Harm & Seidenberg, 2004). For instance, although skilled English readers tolerate letter transpositions (e.g., raed tihs jubmled txet), Hebrew readers do not. One reason may be that although anagrams like lion and loin are relatively rare in English, they occur frequently in Hebrew, and readers develop particularly rigid orthographic representations to ensure accurate word recognition (Frost, 2012). 

Written language

Written language differs from spoken language in several important ways that affect learning and processing. It lacks characteristics such as prosody, intonation, gesture, and audiovisual cues that support comprehension. Yet, its vocabulary is more sophisticated, and its syntax is more complex than spoken language (Nation et al., 2022). The average silent reading rate of literate adults—around 240 to 260 words per minute in English (Brysbaert, 2019)—is impressive given these characteristics. This remarkable speed reflects not only highly efficient recognition of individual words but also an eye-movement system tuned through reading experience to deliver visual information to the linguistic processing system at the right time (Rayner, 2009). 

Questions, controversies, and new developments

The cognitive science of literacy has profound implications for the teaching of literacy. However, this field has been plagued by the so-called reading wars—debates about the relevance of cognitive science research in classroom settings (Castles et al., 2018). These debates partially stemmed from the mistaken impression that reading develops naturally (and thus does not require instruction) and that children read like miniature adults (for example, by using sophisticated predictive processes; Goodman, 1967). However, the evidence base also has important gaps, particularly around understanding why some children struggle to learn to read despite having high-quality instruction. The journey to becoming a skilled reader is a long and multidimensional one, and formulating a robust understanding of how individual differences across these dimensions contribute to reading outcomes is a critical area for future research (Perfetti & Stafura, 2014; Snowling & Hulme, 2021). 

It is also important to recognize that the vast majority of research on literacy has been conducted in English or in related European languages (e.g., French, Spanish, Dutch). This bias has led to theoretical constructs focusing on the differences between alphabets; for example, much attention has been given to the less-regular relationship between spelling and sound in English than in other European languages (Share, 2008). However, major world languages such as Chinese, Arabic, Hindi, and Bangla use non-alphabetic scripts and employ morphological systems that build words differently from English. These differences have important implications for both reading acquisition and skilled reading. Widening the evidence base is vital, not only to enhance the theoretical richness of the field but also to ensure that all children receive instruction grounded in evidence that reflects their language and writing system.   

Broader connections

Literacy is a learned skill, but it shapes more primary cognitive capabilities. Learning to read sharpens spoken language representations, likely because invariant visual symbols bind together sounds that vary widely across different word and speaker contexts (Huettig & Pickering, 2019) [see Speech Recognition]. Similarly, the sophistication of written language exposes readers to nuanced vocabulary in a manner that arguably deepens conceptual knowledge and supports the development of fine-grained emotion and mental state categories (Nation et al., 2022). Finally, one intriguing philosophical proposal is that writing allows the mind to extend into the environment (Clark & Chalmers, 1998) to allow information processing loops that transform human reasoning (Lock & Gers, 2012) [see Cultural Evolution]. 

Acknowledgments

The author received funding from the Economic and Social Research Council (ES/W002310/1). The author thanks Maria Korochkina and Anastasiya Lopukhina for valuable comments on this entry.  

Further reading 

References