Cognitive performance
Attention, memory, and processing speed on a named lab task. It is not IQ-as-destiny and not a career score.
Edges here use tasks such as digit span, reaction time, or verbal fluency after a named exposure like iron, sleep, or a supplement. A lab task is not a promotion, and status or income should not ride along inside the score.
Also called attention, working memory.
Connected relationships
Mendelian randomization · Contested
Alcohol intake→Cognitive performance
A rise in Alcohol intake does not identify a change in Cognitive performance.
Almeida 2014 and Campbell 2024 find no Mendelian randomization effect of adult alcohol on cognitive impairment or Alzheimer disease; Cui 2022, with 235 genotyped rural Chinese adults, finds more drinking and more mild cognitive impairment.
Randomized trial · Contested
Bacopa→Cognitive performance
Higher Bacopa moves Cognitive performance only in some conditions. Read the mechanism.
Calabrese 2009 found that 300 mg of standardized Bacopa monnieri a day for twelve weeks improved delayed word recall on the Rey Auditory Verbal Learning Test versus placebo in 48 healthy adults aged 65 or older. Lopresti 2025 saw no between-group change on primary learning, attention, or working memory in 87 completers aged 40 to 70.
Observational · Low
Breastfeeding duration→Cognitive performance
Higher Breastfeeding duration increases Cognitive performance.
In three European birth cohorts, longer breastfeeding tracked with higher child IQ on crude models. After maternal IQ, education, and class, Generation R's 0.32 IQ points per month fell to 0.09 and crossed zero. Sabadell's full breastfeeding past six months still sat 7.4 McCarthy points higher. Nobody randomized the feed.
Randomized trial · Contested
Creatine supplementation→Cognitive performance
Higher Creatine supplementation moves Cognitive performance only in some conditions. Read the mechanism.
McMorris 2008 found that 20 g a day of creatine for one week, after a placebo week, improved random-number, recall, and long-term memory tasks versus continued placebo in 32 older adults, except backward number recall. Toniolo 2018 then found that 6 g a day as an adjunct in 18 people with bipolar depression moved only verbal fluency.
Randomized trial · Moderate
DHEA-S→Cognitive performance
A rise in DHEA-S does not identify a change in Cognitive performance.
A year of 50 mg DHEA did not move six cognitive tests against placebo in 225 healthy adults aged 55 to 85. A Cochrane review of earlier RCTs and a 13-week crossover in 46 older men also found no cognitive benefit.
Randomized trial · Moderate
Ferritin→Cognitive performance
Higher Ferritin increases Cognitive performance.
Treating iron deficiency in young women can move attention and memory on named tasks. Murray-Kolb and Beard (2007) showed that in a blinded 16-week trial. Two later trials in the same age band again find the gain where ferritin rose. Berglund's infant trial found no WISC-IV difference at age 7.
Randomized trial · Contested
Green tea / EGCG→Cognitive performance
Higher Green tea / EGCG moves Cognitive performance only in some conditions. Read the mechanism.
Wightman 2012 found that 135 or 270 mg of epigallocatechin gallate did not change computerised cognitive tasks or mood versus placebo in 27 healthy adults, though frontal blood flow fell at the lower dose. Dietz 2019 saw a small attention and psychomotor-speed rise after a matcha drink in 23 people.
Randomized trial · Contested
Hearing loss→Cognitive performance
Higher Hearing loss moves Cognitive performance only in some conditions. Read the mechanism.
In 977 older adults with untreated hearing loss, three years of hearing aids did not slow a global cognition score versus health education; a prespecified ARIC slice of 238 people at higher risk did.
Observational · Low
Blood lead→Cognitive performance
Higher Blood lead decreases Cognitive performance.
Higher childhood blood lead tracked lower IQ in Rochester, the Lanphear pool, and Dunedin at age 38 after maternal IQ was in the model. Nobody randomized lead.
Randomized trial · Contested
Lion's mane→Cognitive performance
Higher Lion's mane moves Cognitive performance only in some conditions. Read the mechanism.
Mori 2009 found that 3 g a day of Yamabushitake powder for sixteen weeks raised Revised Hasegawa Dementia Scale scores versus placebo in 30 people with mild cognitive impairment; scores fell after the powder stopped. Docherty 2023 saw a faster Stroop after one 1.8 g dose in 41 young adults and little chronic change.
Randomized trial · Moderate
Obstructive sleep apnea→Cognitive performance
A rise in Obstructive sleep apnea does not identify a change in Cognitive performance.
Xu 2025 assigned 148 middle-aged adults with moderate-to-severe obstructive sleep apnea and normal cognition to CPAP plus usual care or usual care alone. At six months the Montreal Cognitive Assessment did not differ (difference -0.04, 95% CI -0.72 to 0.65).
Observational · Low
Ambient air pollution→Cognitive performance
Higher Ambient air pollution decreases Cognitive performance.
Pregnancy-average outdoor PM2.5 tracked 1.79 fewer full-scale IQ points per 3 µg/m³ at age 10.5 in 568 Salinas Valley children, while six European birth cohorts (9,482 children) found no association between pregnancy air pollution and cognition at ages 1 to 6. Nobody randomized the air.
Observational · Low
Screen time→Cognitive performance
Higher Screen time moves Cognitive performance only in some conditions. Read the mechanism.
In 3,625 Pelotas cohort members, more television and games at 11 and more computer time at 11 and 15 tracked with better Digit Span backward scores at 22 in men, and with nothing in women. In 356 Illinois toddlers, more daily screen minutes tracked with worse parent-rated executive function. Nobody assigned the screens.
Meta-analysis · High confidence
Sleep duration and regularity→Cognitive performance
Higher Sleep duration and regularity increases Cognitive performance.
Lim and Dinges's 2010 meta of short-term deprivation shows losses on vigilance and working memory. Santisteban's 2019 adult week and Lo's 2016 adolescent week then lose working memory; Lo also loses vigilance. Zimmerman's 2024 habit trial moves the same tasks.
Randomized trial · Contested
L-theanine→Cognitive performance
Higher L-theanine moves Cognitive performance only in some conditions. Read the mechanism.
Kahathuduwa 2018 found that 200 mg of L-theanine alone sped recognition visual reaction time versus placebo in 20 healthy men. Dassanayake 2023 saw a similar simple-reaction win in 32 young adults and no win on harder attention tasks. Tea-dose theanine alone has often missed.
Randomized trial · Contested
Vitamin / mineral supplementation→Cognitive performance
A rise in Vitamin / mineral supplementation does not identify a change in Cognitive performance.
Chen 2021 found that six months of folic acid plus vitamin B12 moved MoCA total by about one point versus placebo in 120 people with Alzheimer's in Tianjin, while a 2003 Cochrane review of B12 in dementia with low serum B12 found no cognitive effect.
Randomized trial · High confidence
25-hydroxyvitamin D→Cognitive performance
A rise in 25-hydroxyvitamin D does not identify a change in Cognitive performance.
Kang 2022 found that 2000 IU a day of vitamin D3 versus placebo did not slow cognitive decline among 4218 adults aged 60 and older in VITAL (pooled annual global-score difference 0.01, 95% CI -0.01 to 0.02). Corbett 2025 and Pham 2023 then also found no cognitive gain.
Randomized trial · Contested
Zinc→Cognitive performance
Higher Zinc moves Cognitive performance only in some conditions. Read the mechanism.
Maylor 2006 found that 15 or 30 mg of zinc a day for six months had a mixed effect on Cambridge tasks in 387 healthy adults aged 55 to 87: one spatial working-memory score moved at three months, and 15 mg worsened one attention score. de Vargas 2023 saw higher Mini-Mental and Stroop scores on 30 mg in 32 overweight women.
Cases
Sources
- OP Almeida et al. (2014). Alcohol consumption and cognitive impairment in older men: a mendelian randomization study.
- Y Cui et al. (2022). Alcohol Consumption and Mild Cognitive Impairment: A Mendelian Randomization Study from Rural China.
- KA Campbell et al. (2024). Relationship between alcohol consumption and dementia with Mendelian randomization approaches among older adults in the United States.
- C Calabrese et al. (2009). Effects of a standardized Bacopa monnieri extract on cognitive performance, anxiety, and depression in the elderly: a randomized, double-blind, placebo-controlled trial.
- M Delfan et al. (2024). Evaluating the effects of Bacopa monnieri on cognitive performance and sleep quality of patients with mild cognitive impairment: A triple-blinded, randomized, placebo-controlled trial.
- AL Lopresti et al. (2025). The Effects of a Bacopa monnieri Extract (Bacumen®) on Cognition, Stress, and Fatigue in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled Trial.
- A Sajjad et al. (2016). Breastfeeding duration and non-verbal IQ in children.
- J Julvez et al. (2014). A cohort study on full breastfeeding and child neuropsychological development: the role of maternal social, psychological, and nutritional factors.
- JY Bernard et al. (2017). Breastfeeding, Polyunsaturated Fatty Acid Levels in Colostrum and Child Intelligence Quotient at Age 5-6 Years.
- T McMorris et al. (2008). Creatine supplementation and cognitive performance in elderly individuals.
- RA Toniolo et al. (2018). Cognitive effects of creatine monohydrate adjunctive therapy in patients with bipolar depression: Results from a randomized, double-blind, placebo-controlled trial.
- D Kritz-Silverstein et al. (2008). Effects of dehydroepiandrosterone supplementation on cognitive function and quality of life: the DHEA and Well-Ness (DAWN) Trial.
- TD Parsons et al. (2006). Dhea supplementation and cognition in postmenopausal women.
- J Grimley Evans et al. (2007). Dehydroepiandrosterone (DHEA) supplementation for cognitive function in healthy elderly people.
- JK van Niekerk et al. (2001). Salivary cortisol and DHEA: association with measures of cognition and well-being in normal older men, and effects of three months of DHEA supplementation.
- L. E. Murray-Kolb et al. (2007). Iron treatment normalizes cognitive functioning in young women
- C Blanton et al. (2014). Improvements in iron status and cognitive function in young women consuming beef or non-beef lunches.
- AJ Leonard et al. (2015). A study of the effects of latent iron deficiency on measures of cognition: a pilot randomised controlled trial of iron supplementation in young women.
- SK Berglund et al. (2019). Effects of iron supplementation of low-birth-weight infants on cognition and behavior at 7 years: a randomized controlled trial.
- EL Wightman et al. (2012). Epigallocatechin gallate, cerebral blood flow parameters, cognitive performance and mood in healthy humans: a double-blind, placebo-controlled, crossover investigation.
- C Dietz et al. (2019). An intervention study on the effect of matcha tea, in drink and snack bar formats, on mood and cognitive performance.
- FR Lin et al. (2023). Hearing intervention versus health education control to reduce cognitive decline in older adults with hearing loss in the USA (ACHIEVE): a multicentre, randomised controlled trial.
- RC Yu et al. (2024). Adult-onset hearing loss and incident cognitive impairment and dementia - A systematic review and meta-analysis of cohort studies.
- B Grenier et al. (2024). Hearing Loss, Hearing Aids, and Cognition.
- RL Canfield et al. (2003). Intellectual impairment in children with blood lead concentrations below 10 microg per deciliter.
- BP Lanphear et al. (2005). Low-level environmental lead exposure and children's intellectual function: an international pooled analysis.
- TA Jusko et al. (2008). Blood lead concentrations < 10 microg/dL and child intelligence at 6 years of age.
- A Reuben et al. (2021). Association of Childhood Lead Exposure With MRI Measurements of Structural Brain Integrity in Midlife.
- A Reuben et al. (2017). Association of Childhood Blood Lead Levels With Cognitive Function and Socioeconomic Status at Age 38 Years and With IQ Change and Socioeconomic Mobility Between Childhood and Adulthood.
- CM Taylor et al. (2018). Effects of low-level prenatal lead exposure on child IQ at 4 and 8 years in a UK birth cohort study.
- K Mori et al. (2009). Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial.
- S Docherty et al. (2023). The Acute and Chronic Effects of Lion's Mane Mushroom Supplementation on Cognitive Function, Stress and Mood in Young Adults: A Double-Blind, Parallel Groups, Pilot Study.
- G Surendran et al. (2025). Acute effects of a standardised extract of Hericium erinaceus (Lion's Mane mushroom) on cognition and mood in healthy younger adults: a double-blind randomised placebo-controlled study.
- H Xu et al. (2025). Effects of Continuous Positive Airway Pressure on Neuroimaging Biomarkers and Cognition in Adult Obstructive Sleep Apnea: A Randomized Controlled Trial.
- ML Wang et al. (2021). Cognitive Effects of Treating Obstructive Sleep Apnea: A Meta-Analysis of Randomized Controlled Trials.
- A Durtette et al. (2024). Impact of continuous positive airway pressure on cognitive functions in adult patients with obstructive sleep apnea: A systematic review and meta-analysis.
- M Guxens et al. (2015). Air pollution during pregnancy and childhood cognitive and psychomotor development: six European birth cohorts.
- SM Holm et al. (2023). Cognitive Development and Prenatal Air Pollution Exposure in the CHAMACOS Cohort.
- PSM Soares et al. (2021). Screen time and working memory in adolescents: A longitudinal study.
- AL McMath et al. (2022). Adherence to Screen Time and Physical Activity Guidelines is Associated with Executive Function in US Toddlers Participating in the STRONG Kids 2 Birth Cohort Study.
- J. Lim et al. (2010). A meta-analysis of the impact of short-term sleep deprivation on cognitive variables
- ME Zimmerman et al. (2024). The effects of insufficient sleep and adequate sleep on cognitive function in healthy adults.
- JA Santisteban et al. (2019). Cumulative mild partial sleep deprivation negatively impacts working memory capacity but not sustained attention, response inhibition, or decision making: a randomized controlled trial.
- JC Lo et al. (2016). Cognitive Performance, Sleepiness, and Mood in Partially Sleep Deprived Adolescents: The Need for Sleep Study.
- CN Kahathuduwa et al. (2018). Acute effects of theanine, caffeine and theanine-caffeine combination on attention.
- TL Dassanayake et al. (2023). Dose-response effect of L-theanine on psychomotor speed, sustained attention, and inhibitory control: a double-blind, placebo-controlled, crossover study.
- FL Dodd et al. (2016). A double-blind, placebo-controlled study evaluating the effects of caffeine and L-theanine both alone and in combination on cerebral blood flow, cognition and mood.
- CF Haskell et al. (2008). The effects of L-theanine, caffeine and their combination on cognition and mood.
- T Giesbrecht et al. (2011). The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness.
- SJ Einöther et al. (2010). L-theanine and caffeine improve task switching but not intersensory attention or subjective alertness.
- H Chen et al. (2021). Effects of Folic Acid and Vitamin B12 Supplementation on Cognitive Impairment and Inflammation in Patients with Alzheimer's Disease: A Randomized, Single-Blinded, Placebo-Controlled Trial.
- R Malouf et al. (2003). Vitamin B12 for cognition.
- Z Wang et al. (2022). B vitamins and prevention of cognitive decline and incident dementia: a systematic review and meta-analysis.
- JH Kang et al. (2022). Effect of vitamin D on cognitive decline: results from two ancillary studies of the VITAL randomized trial.
- A Corbett et al. (2025). Impact of Vitamin D Supplementation on Cognition in Adults With Mild to Moderate Vitamin D Deficiency: Outcomes From the VitaMIND Randomized Controlled Trial.
- H Pham et al. (2023). Vitamin D supplementation and cognition-Results from analyses of the D-Health trial.
- EA Maylor et al. (2006). Effects of zinc supplementation on cognitive function in healthy middle-aged and older adults: the ZENITH study.
- LDS de Vargas et al. (2023). Effects of Zinc Supplementation on Inflammatory and Cognitive Parameters in Middle-Aged Women with Overweight or Obesity.