By Betsy Hill and Roger Stark
The distinction between “cognitive ability” and “cognitive capacity” has become increasingly common in discussions about learning. Cognitive ability describes the potential a person has to develop thinking skills, while cognitive capacity describes how well those skills have actually been developed and how much information the brain can handle at a given moment.
Dr. Olenka Bilash at the University of Alberta defines cognitive capacity as “the total amount of information the brain is capable of retaining at any particular moment.” This framing helps explain why some tasks feel manageable while others overwhelm us: the demands placed on our mental resources—known as cognitive load—can exceed our available capacity.
These concepts are often misunderstood. For example, a webinar hosted by EdWeb titled “Lies the System Teaches School Leaders about Struggling Readers” challenged the idea that struggling readers have lower cognitive capacity than typical readers. While the presenter used the term in a particular way, for many struggling readers the evidence points to real differences in cognitive capacity and in the brain systems that support reading.
Brain imaging and cognitive research show that the neural pathways supporting decoding, speech production, and other cognitive skills can differ between proficient and struggling readers. Reading is not a single skill but a complex set of processes that rely on many underlying cognitive abilities. Weaknesses in any of these areas—or poor coordination among them—make reading difficult.
Different students struggle with different aspects of reading. Some have trouble decoding—translating letters into sounds and recognizing words—while others can read words aloud but fail to understand or retain what they read. Comprehension difficulties are very common among struggling readers and often reflect underlying limitations in cognitive capacity.
Successful decoding depends on several automatic cognitive skills: focused attention, visual discrimination, visual sequential processing, immediate memory, and working memory. If attention wanders while a student is sounding out a word, they may need to restart and lose track of what they were processing. Visual sequential processing keeps letters and sounds in order, while visual discrimination allows the brain to distinguish similar-looking letters—critical for recognizing words quickly.
Comprehension requires a different mix of cognitive skills, notably working memory, visualization, and planning. Working memory allows a reader to hold and manipulate information—keeping the current sentence in mind while integrating it with previous sentences and background knowledge. Because working memory capacity varies among individuals, some readers have less mental space to build meaning from text.
Visualization—forming mental images or conceptual maps of content—strengthens understanding and improves the chances that information will be encoded into long-term memory. Planning helps readers choose an appropriate reading strategy: scanning for a single fact, reading for emotional tone, or reading slowly to master new concepts. Skilled readers adapt their approach to fit their purpose and the text.
When cognitive skills are weak or poorly integrated, reading struggles are likely. The EdWeb presenter used the term “cognitive capacity” in reference to a student’s interest level or subject knowledge rather than to underlying brain-based skills. From that angle, providing age-appropriate content and avoiding “dumbed down” material makes sense. Tools like audiobooks can give struggling readers access to richer content than they might decode independently, and audiobooks are an effective accommodation when decoding limits access to ideas.
However, accommodations do not remove the need to address the root causes of reading difficulty. Cognitive capacity—the degree to which the brain’s cognitive skills are developed—affects all areas of learning. Yet teachers often lack clear information about an individual student’s cognitive strengths and weaknesses. Cognitive screening and assessment tools, such as Mindprint and other validated instruments, can reveal specific areas to target. With that information, educators and families can use personalized strategies and cognitive training to build capacity and reduce the cognitive load that interferes with reading and learning.
About the authors
Betsy Hill is President of BrainWare Learning Company, an organization that applies neuroscience to improve learning capacity. An experienced educator, she has studied the links between neuroscience and education and has served on the board of trustees at Chicago State University. She also teaches strategic thinking in the MBA program at Lake Forest Graduate School of Management and holds a Master of Arts in Teaching and an MBA from Northwestern University.
Roger Stark is Co-founder and CEO of BrainWare Learning Company. He has spent years promoting accessible cognitive literacy training and assessment and led development of BrainWare SAFARI, a comprehensive online cognitive training program aimed at strengthening the foundational skills that support reading and learning.
This article was originally published by The Learning Counsel, a research institute and news media hub focused on the transition to digital curriculum in education.