Claim: Does the full moon actually affect human behavior?

First requested: April 25, 2026 at 8:13 AM
36%

IsItCap Score

Truth Potential Meter

Very Low Credibility

AI consensusWeak

Grader consensus is weak.
Range 30%–50% (spread Δ20).
The graders diverge. Treat the combined score as uncertain and read the sources carefully.
Read analysis summary

OpenAI Grade

0%
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30%

Perplexity Grade

0%
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50%

Google Gemini Grade

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50%

Analysis Summary

The claim that the full moon affects human behavior is mostly false. Mainstream scientific sources, such as the Cleveland Clinic and Healthline, indicate that while there may be minor sleep disruptions associated with full moons, there is no strong evidence linking the full moon to increased aggression or other behavioral changes. However, some studies suggest correlations between lunar cycles and various human behaviors, which are often attributed to psychological factors rather than direct effects of the moon itself. This discrepancy highlights the ongoing debate surrounding the topic, with some alternative sources asserting a connection based on astrological beliefs and anecdotal evidence. The graders interpret the evidence differently, so the score range widens. Gemini comes in highest (50%), while OpenAI is lowest (30%). Gemini expresses higher confidence than Perplexity on this claim. While the majority of scientific evidence suggests that the full moon does not significantly affect human behavior, some studies indicate potential correlations with hospital admissions and accidents during lunar cycles. These opposing claims do not fundamentally change the overall verdict, as they often lack robust causal evidence and may be influenced by psychological biases. The presence of anecdotal reports and astrological interpretations further complicates the narrative, but they do not provide strong scientific backing to support the claim that the full moon has a direct impact on behavior.

Source quality

Truth (from sources)3.00 / 10
Source reliability8.00 / 10
Source independence7.00 / 10

Claim checks

Fits established facts4.00 / 10
Logical consistency5.00 / 10
Expert consensus4.00 / 10

Source Analysis

Mainstream Sources

Publication

healthline.com

Title

How Does a Full Moon Affect Our Physical and Mental Well-Being?

Summary

Reviews scientific studies concluding that full moons do not increase aggression, violence, anxiety, or depression, though some evidence shows minor sleep disruptions.

Source details

Publication

health.clevelandclinic.org

Title

Does The Moon Affect Humans?

Summary

Cleveland Clinic explains minor sleep effects from full moons due to light impacting melatonin, but attributes behavioral beliefs to expectation and confirmation bias.

Source details

Publication

youtube.com

Title

Does the Full Moon Affect Human Behavior? - YouTube

Summary

Video debunks myths, noting negligible gravitational pull and only tiny sleep effects, no significant behavioral changes in humans.

Source details

Alternative Sources

Publication

pubmed.ncbi.nlm.nih.gov

Title

The lunar cycle: effects on human and animal behavior and physiology

Summary

2006 study suggests lunar cycles correlate with hospital admissions, accidents, crimes, suicides, and melatonin changes.

Source details

Publication

pureartsgroup.co.uk

Title

How the moon affects your mood

Summary

Astrological view claims full moon heightens emotions, anxiety, irritability due to gravitational pull on body's water content.

Source details

Analysis Breakdown

True/False Spectrum (3.0)Source Credibility (8.0)Bias Assessment (7.0)Contextual Integrity (4.0)Content Coherence (5.0)Expert Consensus (4.0)52%

How to read the breakdown

Weakest areas
Truth3.0/10Context4.0/10
  • Truth: how well sources support the core claim.
  • Source reliability: whether the sources have a strong track record.
  • Independence: whether coverage looks one-sided or recycled.
  • Context: missing details (timeframe, definitions, scope) that change meaning.
  • Tip: if graders disagree, rely more on the summary + sources than the single number.

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Methodology

Fact check: Does the full moon affect human behavior? | IsItCap