20 min readInteractive

Images, voices & deepfakes

Seeing and hearing are no longer enough. Learn what to check instead.

What this lesson assumesNothing. Start anywhere.

Your phone rings. It is your son’s voice. He sounds stressed and says his phone was stolen. He needs you to transfer money quickly.

The number is unfamiliar, but the voice sounds exactly like him.

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What is your first move?

What do you do?

What synthetic media is

Generative AI does not only create text. Models can also generate or alter images, voices, music, and video.

A generated face may belong to nobody. A voice can be made to sound like a real person. A video can make someone appear to say or do something they never did.

The term deepfake is commonly used for convincing AI-generated or AI-manipulated media that imitates a real person. Deepfakes can be used to deceive people, but deception is not required for the technology itself to exist.

The important question is not simply whether something was generated with AI. It is what it is being used for, whether the people involved consented, and whether someone is being misled.

Your eyes and ears are not proof

You might spot some bad fakes. Strange hands, unnatural movement, odd lighting, or a voice that sounds slightly wrong can still give something away.

The problem is that you cannot rely on those signs.

In one study, people could not reliably distinguish a set of AI-generated faces from photographs of real people, and the generated faces were rated slightly more trustworthy. Other experiments have found that people struggle to reliably identify deepfake videos, even when they know deepfakes may be present.

A 2024 review combined results from 56 studies. On average, people judged correctly about 55% of the time, where guessing would get 50%, and that gap was too small to show they were reliably doing better than chance. Performance also depended on the kind and quality of the fake and the conditions of the experiment.

So the lesson is not “you can never spot a fake.” It is that looking real is no longer enough evidence that something is real.

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What actually helps?

For each action, decide whether it gives you weak or stronger evidence.

1 of 6

Look closely at the person’s hands.

The liar’s dividend

Synthetic media creates another problem. If fake evidence can look real, real evidence can also be dismissed as fake.

Someone confronted with a genuine recording can now respond: “that was AI generated.” Researchers have called this the liar’s dividend: the existence of convincing fakes can give dishonest people a new way to deny real evidence.

So there are two mistakes to avoid: believing something because it looks real, and rejecting something just because it could have been faked. The answer to both is the same: look for evidence beyond the media itself.

Where did this come from?

Another way to judge media is to look at its history.

Content Credentials are an open standard designed to attach verifiable information about the origin and editing history of digital content. A credential can record information such as which tool created or edited a file and whether AI was involved. Cryptography helps make changes to that recorded history detectable. Think of it as a kind of history label for digital media.

But there are two important limits. A valid credential can tell you information about where a file came from and what happened to it. It does not prove that everything shown or claimed in the content is true. And if a file has no Content Credential, that does not mean it is fake: not every camera, platform, or editing tool uses them, and credentials can also be removed.

Provenance can give you useful evidence. It is not a truth button.

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What does the label prove?

A photo comes with a valid Content Credential. It says the picture was taken on a camera and not edited with AI. What does that tell you?

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The viral video test

A shocking video appears on your feed from an account you do not recognize. What gives you the best information first?

One habit worth setting up today

For urgent calls involving money, passwords, or personal information, agree on one rule with the people close to you: verify the request through a contact method you already know.

If someone calls claiming to be a family member and urgently needs money, hang up and call their normal number yourself.

The urgency is exactly why the extra check matters. Consumer protection agencies recommend this approach for scams involving cloned voices.

You can add a second check: a code word or phrase that only your family knows, agreed in person and never posted anywhere. The FBI recommends exactly this. A cloned voice can copy how someone sounds, but it can’t know a word that was never said online.

How we know this

The checkable claims in this lesson are backed by sources you can open yourself. Where a statement is our judgment or practical advice rather than an established finding, the text says so. Spot an error? See our corrections policy.

  • Participants struggled to distinguish the AI-generated faces tested in the study from photographs of real faces, and rated the synthetic faces as slightly more trustworthy.

    Research paper Sophie J. Nightingale & Hany Farid (2022). AI-synthesized faces are indistinguishable from real faces and more trustworthy, Proceedings of the National Academy of Sciences

  • Participants could not reliably detect the tested deepfake videos. Warning people about deepfakes or offering financial incentives did not reliably solve the problem.

    Research paper Nils C. Köbis, Barbora Doležalová & Ivan Soraperra (2021). Fooled twice: People cannot detect deepfakes but think they can, iScience

  • “In one large study, people and a leading detection model were about as accurate as each other”: across two experiments with over 15,000 participants, people and the model made different kinds of mistakes. People shown the model’s prediction were more accurate overall, but inaccurate predictions often lowered their accuracy.

    Research paper Matthew Groh, Ziv Epstein, Chaz Firestone & Rosalind Picard (2022). Deepfake detection by human crowds, machines, and machine-informed crowds, Proceedings of the National Academy of Sciences

  • Pooled across 56 papers, human deepfake detection accuracy was 55.54%, and its 95% confidence interval crossed 50%: not significantly better than chance, overall or for any single kind of media.

    Research paper Alexander Diel, Tania Lalgi, Isabel Carolin Schröter, Karl F. MacDorman, Martin Teufel & Alexander Bäuerle (2024). Human performance in detecting deepfakes: A systematic review and meta-analysis of 56 papers, Computers in Human Behavior Reports

  • “Performance also depended on the kind and quality of the fake”: in experiments with real and fabricated political speeches, how well people told them apart varied with whether they read a transcript, heard audio, or watched video.

    Research paper Matthew Groh, Aruna Sankaranarayanan, Nikhil Singh, Dong Young Kim, Andrew Lippman & Rosalind Picard (2024). Human detection of political speech deepfakes across transcripts, audio, and video, Nature Communications

  • The existence of convincing synthetic media can make it easier for people to dismiss genuine evidence as fake.

    Research paper Robert Chesney & Danielle K. Citron (2019). Deep Fakes: A Looming Challenge for Privacy, Democracy, and National Security, California Law Review

  • Content Credentials use cryptographically bound provenance information to record claims about the history of digital media. They help establish provenance, but do not themselves prove that the content is true, and the absence of a credential should not be treated as evidence that something is fake.

    Explainer Coalition for Content Provenance and Authenticity (2024). C2PA and Content Credentials Explainer

  • “Consumer protection agencies recommend this approach for scams involving cloned voices”: the FTC’s advice for a voice-cloned family emergency call is not to trust the voice, and to call the person back on a phone number you know is theirs.

    Guidance U.S. Federal Trade Commission (2023). Scammers use AI to enhance their family emergency schemes, FTC consumer alert

  • “The FBI recommends exactly this”: its advice on AI-enabled fraud includes creating a secret word or phrase with your family to verify their identity.

    Guidance U.S. Federal Bureau of Investigation (2024). Criminals Use Generative Artificial Intelligence to Facilitate Financial Fraud, Public service announcement I-120324-PSA

Last reviewed . AI changes fast; anything here that has gone stale is a mistake worth reporting.

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20 min · Interactive