Evidence for Your learning state #

Every substantive claim on the Your learning state page is checked against current research. Here is each claim, how well today’s evidence supports it, and the sources. The full, de-duplicated source list lives on the references page.

Supported · moderate evidence — Your physical and mental condition while learning—hydration, energy, fitness, rest, focus and mood—substantially affects how much you learn and remember, independent of which study technique you use.

The broad principle that bodily and cognitive state (sleep, stress, attention, fitness, nutrition) modulates learning is well established across cognitive neuroscience and education by 2026; no single source proves the umbrella claim, but the converging literatures on each factor support it. Effect sizes vary by factor and population.

Sources: Diamond, A. (2013), Executive functions, Annual Review of Psychology, 64, 135-168 — https://doi.org/10.1146/annurev-psych-113011-143750 · full reference ›

Supported · strong evidence — Sleep after learning actively strengthens memory: the brain replays and consolidates the day’s material during sleep, so the hours after study are part of the learning, not merely rest.

Rasch & Born’s authoritative Physiological Reviews synthesis documents sleep-dependent consolidation and active systems consolidation (hippocampal replay); the role of post-learning sleep in stabilising and integrating memories is well established in 2026, though magnitude varies by memory type and the active-systems mechanism is still being refined.

Sources: Rasch, B. & Born, J. (2013), About sleep’s role in memory, Physiological Reviews, 93(2), 681-766 — https://doi.org/10.1152/physrev.00032.2012 · full reference ›

Supported · strong evidence — Inadequate sleep before learning impairs the attention and encoding needed to take new material in, so last-minute late-night cramming can cost more than it gains.

Sleep deprivation degrading attention, working memory and hippocampal encoding of new information is robustly demonstrated (e.g. Walker; Yoo et al. 2007 showed reduced hippocampal encoding after sleep loss); well supported in 2026. The cramming trade-off is a reasonable practical inference from this and the consolidation literature.

Sources: Walker, M. P. (2009), The role of sleep in cognition and emotion, Annals of the New York Academy of Sciences, 1156, 168-197 — https://doi.org/10.1111/j.1749-6632.2009.04416.x · full reference ›

Mixed · moderate evidence — The mere presence of one’s own smartphone—even silenced and not in use—reduces available cognitive capacity, because suppressing the urge to attend to it consumes limited attentional resources.

Ward et al. reported the ‘brain drain’ effect, and the broader finding that phone presence/notifications harm sustained attention and task performance has substantial support by 2026 (e.g. Stothart et al. 2015 on notifications). However, direct replications of the specific cognitive-capacity effect have been mixed, so it is best stated as a real but modest and not-fully-settled effect rather than a strong law.

Sources: Ward, A. F., Duke, K., Gneezy, A. & Bos, M. W. (2017), Brain drain: the mere presence of one’s own smartphone reduces available cognitive capacity, Journal of the Association for Consumer Research, 2(2), 140-154 — https://doi.org/10.1086/691462 · Stothart, C., Mitchum, A. & Yehnert, C. (2015), The attentional cost of receiving a cell phone notification, Journal of Experimental Psychology: Human Perception and Performance, 41(4), 893-897 — https://doi.org/10.1037/xhp0000100 · full reference ›

Supported · strong evidence — Attention is the gateway to memory: material you do not attend to is unlikely to be encoded, so divided attention and distraction degrade learning.

That attention at encoding is necessary for durable memory, and that divided attention sharply reduces later recall, is a foundational and well-replicated finding (Craik et al.; broad attention-and-memory literature); firmly established in 2026.

Sources: Craik, F. I. M., Govoni, R., Naveh-Benjamin, M. & Anderson, N. D. (1996), The effects of divided attention on encoding and retrieval processes in human memory, Journal of Experimental Psychology: General, 125(2), 159-180 — https://doi.org/10.1037/0096-3445.125.2.159 · full reference ›

Supported · strong evidence — Emotion influences learning and memory at every stage—attention, encoding and long-term retention—so how a learner feels shapes what they remember.

Tyng et al.’s widely cited review synthesises a large literature showing emotion modulates attention, encoding and consolidation; the broad claim is well established in 2026, even though specific effects are valence- and arousal-dependent.

Sources: Tyng, C. M., Amin, H. U., Saad, M. N. M. & Malik, A. S. (2017), The influences of emotion on learning and memory, Frontiers in Psychology, 8, 1454 — https://doi.org/10.3389/fpsyg.2017.01454 · full reference ›

Supported · strong evidence — Anxiety impairs learning and performance partly by consuming limited working-memory capacity with worry and intrusive thoughts.

Attentional control theory (Eysenck et al.) and the test-anxiety literature consistently show worry consumes working-memory resources and reduces processing efficiency; a mainstream, well-supported account in 2026.

Sources: Eysenck, M. W., Derakshan, N., Santos, R. & Calvo, M. G. (2007), Anxiety and cognitive performance: attentional control theory, Emotion, 7(2), 336-353 — https://doi.org/10.1037/1528-3542.7.2.336 · full reference ›

Supported · moderate evidence — Cardiovascular fitness and physical exercise benefit cognition and learning, including memory, partly via improved blood flow and brain health.

The link between aerobic fitness/exercise and improved cognition and hippocampal/memory function is well supported by 2026 (Hillman et al.; Erickson et al. 2011 showed exercise-induced hippocampal growth), though effect sizes are modest and vary by age, dose and outcome.

Sources: Hillman, C. H., Erickson, K. I. & Kramer, A. F. (2008), Be smart, exercise your heart: exercise effects on brain and cognition, Nature Reviews Neuroscience, 9(1), 58-65 — https://doi.org/10.1038/nrn2298 · full reference ›

Supported · moderate evidence — Cognitive performance, including alertness and learning-relevant functions, varies across the day with circadian rhythm.

Time-of-day modulation of attention, alertness and some cognitive performance via the circadian system is well documented (Schmidt et al. review); established in 2026, while the size and direction of effects depend on task, chronotype and sleep pressure.

Sources: Schmidt, C., Collette, F., Cajochen, C. & Peigneux, P. (2007), A time to think: circadian rhythms in human cognition, Cognitive Neuropsychology, 24(7), 755-789 — https://doi.org/10.1080/02643290701754158 · full reference ›

Mixed · moderate evidence — Dehydration measurably impairs cognitive functions such as attention and short-term memory.

Mild dehydration impairing attention, mood and some memory tasks is supported by reviews (Adan), but the literature is heterogeneous and effects are small and task-dependent; the practical ‘stay hydrated’ advice is sound, while strong claims should be qualified.

Sources: Adan, A. (2012), Cognitive performance and dehydration, Journal of the American College of Nutrition, 31(2), 71-78 — https://doi.org/10.1080/07315724.2012.10720011 · full reference ›