Re-reading and highlighting remain two of the most widely used study strategies across schools and universities. They are simple, familiar, and feel productive.
However, large-scale reviews in cognitive science consistently show that these methods produce weak long-term retention and poor knowledge transfer. More importantly, they fail for predictable cognitive reasons.
This article goes beyond surface-level advice and explains how memory encoding, retrieval, and illusion of competence interact, using findings from experimental psychology and neuroscience.
How Memory Is Actually Formed: Encoding vs. Retrieval
To understand why re-reading fails, we must distinguish between encoding strength and retrieval strength.
Psychologist Robert Bjork proposed that learning involves two separate processes:
Encoding: How information is stored
Retrieval: How easily information can be accessed later
Re-reading primarily increases perceptual fluency but does very little to strengthen retrieval pathways.
This is why students often say:
“I understand it when I look at it, but I can’t recall it during exams.”
The Fluency Trap: Why Familiarity Is Misleading
When learners re-read material, neural processing becomes faster and smoother. This creates a sense of mastery — a phenomenon known as fluency illusion.
However, brain imaging studies show that fluency reflects reduced cognitive effort, not deeper learning.
In short:
The brain mistakes ease for mastery
Familiar text feels “known” but remains fragile in memory
Why Highlighting Rarely Improves Learning
Highlighting fails for a structural reason:
It does not require generative processing.
Most learners highlight:
Without deciding why something is important
Without reprocessing highlighted content later
Experimental studies show that excessive highlighting can even reduce comprehension, as it encourages surface scanning instead of meaning construction.
Experimental Evidence: What the Data Shows
In the influential meta-analysis by Dunlosky et al. (2013):
Re-reading and highlighting ranked among the lowest-performing strategies
Retrieval practice and spaced learning produced significantly higher retention gains
Participants who used retrieval-based methods consistently outperformed those who relied on passive review — even when total study time was lower.
Why Ineffective Strategies Persist
These methods survive because they satisfy three psychological biases:
Effort avoidance – The brain prefers low-cost strategies
Immediate confidence – Fluency feels reassuring
Poor metacognition – Learners misjudge what causes learning
Ironically, strategies that feel harder are usually the ones that work.
What Works Better: Mechanism-Based Alternatives
Effective strategies share one principle:
They force the brain to reconstruct information.
Retrieval Practice
Actively recalling material strengthens retrieval routes and exposes gaps.
Spaced Learning
Time gaps introduce forgetting, which paradoxically strengthens memory reconsolidation.
Elaboration
Explaining why and how integrates new knowledge with existing schemas.
Conclusion
Re-reading and highlighting fail not because students use them incorrectly, but because they rely on the wrong cognitive mechanisms.
Learning is not reinforced by exposure, but by reconstruction. Understanding this distinction allows learners to replace comforting habits with strategies that produce durable knowledge.
References
Dunlosky, J., et al. (2013). Psychological Science in the Public Interest
Bjork, R. A. (2011). Desirable Difficulties in Learning
