Nineteen papers, each with a plain summary and an explicit note on what it does not establish. Filter by topic.
Auditory beatsMeta-analysis
Efficacy of binaural auditory beats in cognition, anxiety, and pain perception
Garcia-Argibay, Santed & Reales · 2019 · Psychological Research 83(2), 357–372
Pools 35 effect sizes and reports a medium, significant overall effect on cognition, anxiety and pain perception. Effects varied with beat frequency, with how long people listened, and with whether listening happened before or during a task.
Does not show: that any particular frequency is best, or that the effect holds for hour-long music sessions. Most included studies used short exposures to tones, not music.
PubMed ↗
Auditory beatsReview
Auditory beat stimulation and its effects on cognition and mood states
Chaieb, Wilpert, Reber & Fell · 2015 · Frontiers in Psychiatry 6:70
A review of binaural and monaural beat stimulation across attention, memory and emotional state, and the clearest available account of how the two techniques differ physically.
Does not show: a consistent dose-response relationship. The review notes that findings depend on frequency and protocol and that study designs vary widely.
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Auditory beatsResearch article
The effect of binaural beats on visuospatial working memory and cortical connectivity
Beauchene, Abaid, Moran, Diana & Leonessa · 2016 · PLOS ONE 11(11), e0166630
15 Hz binaural beats during a visuospatial working-memory task were associated with better performance and altered cortical connectivity, compared with other frequencies and with silence.
Does not show: that the effect generalises beyond this task type, or that it persists after the listening session ends.
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Auditory beatsResearch article
The impact of monaural beat stimulation on anxiety and cognition
Chaieb, Wilpert, Hoppe, Axmacher & Fell · 2017 · Frontiers in Human Neuroscience 11:251
Five minutes of monaural beats at 6, 10 and 40 Hz were associated with lower state-anxiety scores than the control condition in healthy participants.
Does not show: any cognitive benefit. The same study found no significant effects on vigilance, working memory or long-term memory. The supported finding is about anxiety only.
PubMed ↗
Auditory beatsResearch article
Effects of binaural and monaural beat stimulation on attention and EEG
Engelbregt et al. · 2021 · Experimental Brain Research 239, 2781–2791
In a Flanker task, 40 Hz binaural beats were associated with fewer incorrect responses than pink noise, while 40 Hz monaural beats were associated with more.
Does not show: entrainment. The EEG analysis did not confirm consistent neural following at 40 or 45 Hz. This is one of the clearest arguments for treating “brainwave entrainment” as a hypothesis rather than a mechanism.
PubMed ↗
Auditory beatsSystematic review
Effects of binaural beats and isochronic tones on brain wave modulation
Aparecido-Kanzler, Cidral-Filho & Prediger · 2021 · Rev Mex Neurocienc 22(6), 238–247
Seventeen studies met the review's quality criteria, reporting potentially useful effects across mood, attention and memory.
Does not show: parity between techniques. The authors note the evidence base for isochronic tones is considerably smaller than for binaural beats, and emphasise methodological variability throughout.
DOI ↗
SleepResearch article
Auditory closed-loop stimulation of the sleep slow oscillation enhances memory
Ngo, Martinetz, Born & Mölle · 2013 · Neuron 78(3), 545–553
Short sounds played in phase with the up-states of the sleep slow oscillation enhanced that oscillation and improved overnight retention of word pairs. A landmark result for how sound and sleeping brain activity interact.
A different technique. Closed-loop stimulation requires live EEG to time each click to the ongoing oscillation. Recorded music with a frequency layer cannot do this. We include it as context for the field, not as support for our sessions.
PubMed ↗
SleepResearch article
Closed-loop acoustic stimulation enhances sleep oscillations but not memory performance
Henin et al. · 2019 · eNeuro 6(5)
Replicated the physiological effect — slow oscillations and spindle activity increased — but found no accompanying improvement in verbal associative memory.
Does not show: that changing a brain rhythm changes behaviour. This is the counterweight to the paper above, and the reason we describe measurable audio rather than promised outcomes.
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SleepRandomised controlled trial
Binaural beat music, sleep quality, heart rate variability and depression in older people
Chen et al. · 2024 · Geriatrics & Gerontology International 24(3)
Fourteen days of binaural beat music in a long-term care setting were associated with improved sleep quality, increased heart rate variability and reduced depression scores versus control. One of the few trials using music rather than bare tones.
Does not show: transfer to the general population. Participants were older adults with poor sleep in institutional care, a group whose baseline sleep environment differs substantially from a bedroom at home.
PubMed ↗
SleepRandomised double-blind trial
Minimal effects of binaural auditory beats for subclinical insomnia
2019 · Journal of Clinical Psychopharmacology 39(5)
A double-blind, sham-controlled randomised trial in people with subclinical insomnia found only minimal effects of binaural beats.
This is the negative result, and it belongs here. Any honest account of binaural beats for sleep has to sit alongside it. We publish sleep sessions because people like listening to them, not because an effect on insomnia is established.
PubMed ↗
SleepRandomised controlled trial
Sound intervention, sleep quality and stress in college students
2026 · Frontiers in Psychology 17
A three-group trial with 66 students with poor sleep compared pink noise plus music, binaural beats plus music, and a control group — a design that tests the beat layer against another sound treatment rather than against silence.
Read it in full before quoting. The sample is small and the population narrow. We list it because the comparison design is unusually informative, not because one arm won.
PMC ↗
40 Hz & gammaResearch article
Single-session gamma sensory stimulation entrains EEG but does not enhance cognition
2025 · Journal of Alzheimer's Disease Reports 9
Real-time EEG confirmed that 40 Hz sensory stimulation entrained cortical activity — and the same session produced no improvement in perception, attention, short-term memory or long-term memory.
The most important paper on this page for anyone selling 40 Hz. Entrainment is measurable. A cognitive benefit from one session is not. We offer 40 Hz sessions as music people find energising, and make no claim beyond that.
PMC ↗
40 Hz & gammaReview
Re-tuning the brain: the promise of 40 Hz sensory stimulation in Alzheimer's disease
2026 · Journal of Alzheimer's Disease
Traces how early findings on 40 Hz stimulation were followed by work reporting absent entrainment, and in some cases increased pathology — with results depending strongly on disease stage, network integrity and the exact stimulation protocol.
Not about healthy listeners or music. This is clinical research in a patient population. We include it because the popular story about “40 Hz” is largely borrowed from it, and the real literature is far more equivocal than that story suggests.
PubMed ↗
Noise & arousalSystematic review & meta-analysis
Do white noise or pink noise help task performance in youth with ADHD?
Lewis et al. · 2024 · Journal of the American Academy of Child & Adolescent Psychiatry 63(8)
Pools thirteen studies of children and young adults with ADHD or elevated attention problems, testing whether broadband noise supports performance.
Does not show: benefit for everyone. Effects in this literature are consistently larger for people with attention difficulties than for neurotypical listeners, who sometimes perform worse with added noise.
PMC ↗
Noise & arousalResearch article
Stochastic resonance is not required for pink noise to have beneficial effects
2024 · Neuropsychologia 202, 108961
Compared pink noise, a pure 100 Hz tone and silence in 60 adults with varying ADHD traits. A plain tone produced effects comparable to random noise, which the stochastic-resonance account does not predict.
Challenges a popular mechanism. If a steady tone works as well as noise, the explanation is more likely arousal than any special property of the noise spectrum — which also applies to claims made for beat frequencies.
PubMed ↗
Noise & arousalResearch article
Pupil-linked arousal does not differ between white, pink and brown noises
2025 · International Journal of Psychophysiology 217
Measured pupil-linked arousal across the three noise colours that dominate popular sleep and focus content, and found no difference between them.
Worth knowing before believing any colour claim — including ours. If the three noise colours are physiologically indistinguishable on this measure, confident statements about which one suits which task are not supported.
PubMed ↗
Music & workResearch article
Effects of music advertised to support focus on mood and processing speed
Orpella, Bowling, Tomaino & Ripollés · 2025 · PLOS ONE 20(2), e0316047
Compared music marketed as “work flow” and “deep focus” against pop hits and office noise. Only the work-flow music produced significant, correlated improvements in mood and processing speed.
Supports an arousal-and-mood account, not a frequency account. The music that helped was designed to be unobtrusive — which is an argument for composition and mixing, not for what is layered underneath.
PLOS ONE ↗
Music & workResearch article
The role of mood and arousal in the effect of background music on attention
Kiss & Linnell · 2024 · Scientific Reports 14, 9485
Preferred background music during a vigilance task decreased mind-wandering, increased task focus and produced faster reactions — with mood and subjective arousal mediating the effect.
“Preferred” is doing real work here. The music people chose themselves outperformed music chosen for them, which is a limit on how much any catalogue can promise.
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Music & workResearch article
The effect of music listening on work performance
Lesiuk · 2005 · Psychology of Music 33(2), 173–191
Across five weeks with 56 software developers, positive mood and perceived work quality were lowest when music was absent and recovered once music returned.
Observational and self-reported. Mood and perceived quality were measured, not output. It describes how work feels with music, which is a reasonable thing to design for.
DOI ↗