The Dynamics of Reading Speed: Age-Related Changes and the Role of Working Memory

Reading is a fundamental cognitive skill that underpins academic achievement, professional success, and everyday functioning in literate societies. Among its many dimensions, reading speed, the rate at which individuals can process written text, has received considerable research attention as both a measure of reading efficiency and a predictor of reading comprehension. This essay examines two critical questions in reading research: how reading speed varies across the lifespan, and whether individuals with different working memory capacities demonstrate differential reading speeds. Drawing on meta-analytic evidence and recent empirical studies, this review argues that reading speed follows a developmental trajectory across childhood, peaks in young adulthood, and declines in older age, while also being significantly modulated by individual differences in working memory capacity and related executive functions.

Defining and Measuring Reading Speed

Reading speed is typically measured in words per minute and varies depending on text type, reading purpose, and individual characteristics. In a comprehensive meta-analysis of 190 studies encompassing 18,573 participants, Brysbaert (2019) established that the average silent reading rate for adults reading English non-fiction is 238 words per minute, while for fiction, the rate increases to 260 words per minute. This difference is attributable to word length, with non-fiction texts typically containing longer, more complex words than fiction. These estimates are notably lower than the frequently cited figure of 300 words per minute, which Brysbaert attributed to methodological limitations in earlier studies and the persistence of outdated norms in scientific and popular literature.

The distinction between reading speed and reading comprehension is crucial, as these two aspects of reading ability, while correlated, represent separable cognitive skills with different underlying mechanisms. Johann, Könen, and Karbach (2020) demonstrated that reading comprehension and reading speed have distinct relationships with executive functions, supporting the view that they should be considered related but dissociable reading abilities.

Age Differences in Reading Speed

Developmental Trajectories in Childhood and Adolescence

Reading speed develops progressively throughout childhood and adolescence, reflecting both cognitive maturation and educational experience. Taylor (1995, as cited in Brysbaert, 2019) documented steady increases in reading speed across grade levels, with first-grade students averaging approximately 80 words per minute, third-grade students reaching 138 words per minute, and sixth-grade students attaining 185 words per minute. By grades 11 and 12, typical reading speeds approach 195 to 204 words per minute, though still below adult levels.

This developmental progression reflects multiple factors, including increasing automaticity in word recognition, expanding vocabulary, and more efficient eye movement control. As children transition from “learning to read” to “reading to learn,” typically around fourth grade, reading speed becomes increasingly important for academic success, enabling students to process larger volumes of text across content areas.

More recent research has confirmed these developmental patterns. Kail, Lervåg, and Hulme (2012) examined executive function and speed measures across development in participants aged 8 to 16 years. Their latent variable analysis revealed that working memory and general processing speed were unique predictors of both word reading and reading comprehension, with working memory equally important for both reading abilities and processing speed more important for word reading. Notably, inhibition and naming speed for non-alphanumeric stimuli did not uniquely predict reading performance when working memory and processing speed were accounted for.

Peak Performance in Young Adulthood

Young adults, defined in research as approximately 18 to 30 years of age, demonstrate the highest reading speeds across the lifespan. Moreno, León, Arnal, and Botella (2019), in a meta-analysis of 22 experiments comparing eye movements during reading, found that young adults (mean age 21 years) consistently outperformed older adults (mean age 73 years) across multiple measures. Young adults exhibited shorter gaze durations, fewer regressive eye movements (looking back at previously read text), and shorter saccadic movements during reading, all of which contribute to faster overall reading rates.

The effect sizes reported by Moreno and colleagues (2019) ranged from 0.54 to 3.66 in favor of young adults across different eye movement measures, indicating substantial age-related differences in reading efficiency. These findings confirm statistically that young adulthood represents the optimal period for reading speed, supported by peak cognitive efficiency and well-practiced reading skills.

Reading Speed in Older Adulthood

The observed decline in reading speed among older adults raises important questions about underlying mechanisms. Moreno and colleagues (2019) evaluated two competing hypotheses to explain these age differences: the neural degeneration hypothesis, which attributes slower reading to age-related cognitive decline, and the compensatory strategy hypothesis, which suggests that older adults adopt different reading strategies to maintain comprehension despite processing limitations.

The meta-analytic results did not definitively favor either hypothesis, suggesting that both mechanisms may contribute to age-related changes in reading. Older adults may experience genuine slowing in lexical processing and eye movement control, but they may also employ more cautious reading strategies, including more frequent regressions and longer fixation durations, to ensure adequate comprehension. This “risky reading” strategy, as it has been termed, represents a trade-off between speed and accuracy that becomes more pronounced with age.

The practical implications of these age differences are substantial. In a study of postsecondary students, slow reading was identified as the primary basis for requests for extended testing accommodations. Understanding normative age-related changes in reading speed is essential for making appropriate educational and clinical decisions.

Working Memory and Reading Speed

The Theoretical Connection

Working memory, the cognitive system responsible for temporarily storing and manipulating information during complex tasks, plays a critical role in reading. The influential model proposed by Baddeley (2003) conceptualizes working memory as comprising multiple components, including the phonological loop (which maintains verbal information) and the central executive (which coordinates attention and processing). During reading, working memory must simultaneously maintain previously read text, integrate new information, and construct a coherent mental representation of the material.

Early research by Daneman and Carpenter (1980) established that individual differences in working memory capacity predict reading comprehension. However, the relationship between working memory and reading speed has received comparatively less attention, though recent studies have begun to elucidate this connection.

Empirical Evidence for Working Memory Contributions

Johann and colleagues (2020) provided compelling evidence for the unique contribution of working memory to reading speed in a study of 186 school children with a mean age of 9.31 years. Using structural equation modeling, they examined the simultaneous contributions of working memory, inhibition, cognitive flexibility, and fluid intelligence to both reading comprehension and reading speed.

The results revealed distinct patterns of association for the two reading abilities. Working memory, inhibition, and fluid intelligence were significantly related to reading speed, indicating that children with higher working memory capacity, better inhibitory control, and higher fluid intelligence demonstrated faster reading rates. In contrast, reading comprehension was associated with cognitive flexibility and fluid intelligence, but not directly with working memory or inhibition when all variables were considered simultaneously.

These findings suggest that working memory contributes to reading efficiency by enabling readers to maintain and process information fluidly as they move through text. Readers with larger working memory capacity may be better able to hold recently read words and phrases in mind while processing new input, reducing the need for regressive eye movements and supporting smoother, faster reading.

Working Memory, Intelligence, and Reading Speed

The relationship between working memory, intelligence, and reading speed has been further explored in developmental research. De Jong and van der Leij (1999) investigated these relationships in 280 elementary school children and found that working memory and reasoning both contributed to reading comprehension, but that these constructs differed in their relations to reading speed. This pattern aligns with the findings of Johann and colleagues (2020), reinforcing the conclusion that reading speed and comprehension, while related, have distinct cognitive underpinnings.

The research by Kail and colleagues (2012) extended this work by demonstrating that working memory and general processing speed were unique predictors of both word reading and reading comprehension, with working memory equally important for both reading abilities and processing speed more important for word reading. Their latent variable analysis provided robust evidence for the distinct contributions of different cognitive processes to reading performance.

The Role of Executive Functions in Reading Speed

The differential contributions of executive functions to reading speed versus comprehension merit careful consideration. Johann and colleagues (2020) found that inhibition predicted reading speed but not comprehension, suggesting that the ability to suppress irrelevant information may facilitate faster text processing by reducing interference from competing stimuli. Readers with strong inhibitory control may be better able to maintain focus on the current text, minimizing distractions that would otherwise slow reading.

Cognitive flexibility, conversely, predicted reading comprehension but not speed, indicating that the ability to shift between different mental sets or perspectives may be more important for understanding text meaning than for processing efficiency. This dissociation underscores the multifaceted nature of reading and the importance of considering multiple cognitive processes in reading research.

Further supporting this view, Borella, Ghisletta, and de Ribaupierre (2011) examined age differences in text processing and found that working memory updating predicted reading speed in both younger and older adults, while inhibitory control was more strongly associated with comprehension outcomes. These findings reinforce the pattern of distinct cognitive contributions to different aspects of reading.

Implications and Future Directions

The findings reviewed here have significant implications for education, clinical practice, and research. Understanding normative developmental trajectories in reading speed can help educators set appropriate expectations and identify children who may need additional support. The recognition that working memory contributes uniquely to reading speed suggests that interventions targeting working memory might benefit not only comprehension but also reading efficiency.

For older adults, awareness of age-related changes in reading speed can inform recommendations about reading strategies and accommodations. The debate between neural degeneration and compensatory strategy explanations for age differences remains unresolved, highlighting the need for longitudinal studies that track reading changes within individuals over time.

Future research should continue to explore the interplay between working memory, other executive functions, and reading speed across different text types and reading purposes. The finding that different cognitive abilities predict reading speed versus comprehension underscores the importance of multidimensional assessment in both research and practice. Additionally, research examining reading speed in clinical populations with working memory impairments could provide valuable insights into the causal relationships between these constructs.

Conclusion

Reading speed follows a predictable developmental trajectory, increasing through childhood and adolescence, peaking in young adulthood, and declining in older age. These changes reflect both cognitive maturation and age-related cognitive changes, though the relative contributions of neural degeneration versus compensatory strategy remain to be fully elucidated. Individual differences in working memory capacity significantly predict reading speed, with higher working memory associated with faster reading rates. This relationship appears to be distinct from the contributions of working memory to reading comprehension, highlighting the separable nature of these reading dimensions. Together, these findings paint a complex picture of reading as a cognitive skill shaped by both developmental processes and enduring individual differences in cognitive capacity.