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Studies / Precognition / Two Replication Studies of a Time-Revers…

Precognition Debunked? Expectation Matters

Arnaud Delorme, Etzel Cardeña, Patrizio TressoldiJournal of Scientific Exploration, 2021 Peer-Reviewed
✦ Imagine …

Can future events influence your reactions right now?

Imagine sitting at a computer, quickly deciding whether words match pictures on screen. But here's the twist: researchers wanted to know if your brain could somehow 'sense' a hint that wouldn't appear until after you'd already made your choice. This international team of scientists tested whether people could unconsciously react to future events in a carefully controlled experiment involving reaction times. The results paint a complex picture that challenges our understanding of time and consciousness.

Two large studies failed to replicate evidence for precognitive abilities.

An international team of researchers attempted to replicate one of the most controversial psychology experiments ever published. Daryl Bem's 2011 study claimed to show that people could unconsciously sense future events before they happened. The scientific community was divided, with some calling for immediate replication studies.

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This large-scale replication found mixed results for 'backwards in time' priming effects, with some intriguing patterns emerging only in specific language groups.

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Key Findings

  • The main experiments failed to show any precognitive effects.
  • However, when researchers dug deeper into their data, they found some intriguing patterns: English-speaking participants showed hints of the effect in one experiment, while those taking translated versions didn't.
  • People who were told the study was about psychic abilities also performed slightly differently than those told it wasn't.

What Is This About?

Researchers had participants look at words on a computer screen and press keys to categorize them as quickly as possible. The twist: normally, people react faster when they see a 'prime' word first that's related to the target word. But in this experiment, the prime appeared after the participant had already responded. If precognition exists, people should still react faster to words that would later be primed, even though they hadn't seen the prime yet. The team also tested whether telling people the experiment was about psychic abilities would influence their performance.

Methodology

Participants responded to stimuli before seeing primes that would normally influence their reaction times, testing if future events can affect present responses.

Outcomes

Both experiments failed to replicate the original precognition effect, though some exploratory analyses showed mixed results for different language groups and belief conditions.

How Good Is the Evidence?

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While specific numbers aren't provided in the abstract, the study involved an international collaboration with multiple research sites, making it one of the largest attempted replications of a precognition experiment.

Anecdotal5/100
AnecdotalPreliminarySolidStrongOverwhelming
✓ What supports it?

This study demonstrates good scientific practice with preregistered hypotheses and international collaboration for replication. The sample size appears large given the international scope, though specific numbers aren't provided. The main hypotheses were clearly not supported, with effect sizes presumably near zero. However, the study lacks information about blinding procedures and data availability. The research was published in a specialized parapsychology journal rather than a mainstream psychology journal. The exploratory analyses, while interesting, carry the risk of multiple comparisons and data mining.

✗ What are the concerns?

The failure to replicate the main preregistered hypothesis significantly undermines the original claims. The positive effects found only in exploratory analyses and specific subgroups raise concerns about selective reporting and multiple comparisons without proper correction. The lack of reported sample sizes and effect sizes limits proper evaluation.

↔ Interpretation Spectrum

Mainstream: Failed replications confirm that precognition claims were statistical artifacts and the exploratory findings are meaningless data mining. Moderate: The study shows how difficult it is to replicate subtle effects, and the language/belief differences warrant further investigation with better controls. Frontier: The partial replications and moderating factors suggest genuine psi effects that are sensitive to experimental conditions and participant beliefs.

Common Misconception

Many people think precognition research is about predicting specific future events like lottery numbers. Actually, these studies test for tiny, unconscious influences that only show up statistically across many trials.

Convincing Checklist
2 of 5 criteria met
Met2/5
Large sample (N>100)
Peer-reviewed journal
Replicated
Significant effect
DOI available

To settle the precognition question would require multiple large-scale, preregistered replications by independent teams, with identical protocols and transparent data sharing. This study meets some criteria (preregistration, large scale, independent replication) but the negative results actually strengthen the case against precognition rather than supporting it.

The confirmatory hypothesis for Experiment 1 was not supported... The results did not support the primary psi hypothesis and there was no effect in the English-language sample.

Stance: Skeptical

What Does It Mean?

The idea that your brain might somehow 'know' about events that haven't happened yet challenges everything we think we know about time flowing in one direction. Even the mixed results spark fascinating questions about consciousness, expectation, and the mysterious nature of time itself.

This is like testing whether you can sense who's calling before you look at your phone, or whether you slow down just before seeing a speed trap you couldn't have known about.

Wonder Score
3/5
Fascinating
💭 If this is true — what does it mean for us?
If precognitive abilities were real and measurable, it would fundamentally challenge our understanding of causality and the nature of time itself. However, the failure to replicate these effects in rigorous conditions suggests such phenomena may not exist or are too weak/inconsistent to be scientifically meaningful.
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Science Literacy Tip

This study shows the importance of preregistration in research - by stating their hypotheses in advance, the researchers couldn't later cherry-pick favorable results from their data.

Understanding Terms

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Precognition
The claimed ability to unconsciously sense or respond to future events before they happen
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Priming
A psychology technique where exposure to one stimulus influences response to a later stimulus
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Preregistration
Publicly recording research hypotheses and methods before collecting data to prevent bias

What This Study Claims

Findings

English-language participants showed a significant effect in exploratory analyses, while non-English translations did not

weak

Participants who received pro-psi statements had greater psi scores than those who received anti-psi statements

weak

Experiment 2 found no support for the primary psi hypothesis and no effect in the English-language sample

strong

The preregistered confirmatory hypothesis was not supported in Experiment 1

strong

Methodology

The study used preregistered confirmatory hypotheses to test time-reversed priming effects

strong

This summary is for general information about current research. It does not constitute medical advice. The scientific interpretation of these results is debated among researchers. If personally affected, please consult qualified professionals.