How Do AI Detectors Work? | GPTZero
Vivienne Chen

By 2026, it’s estimated that a whopping 90% of online content could be AI-generated. It’s never been more important to be able to differentiate between human-generated and AI-generated content – but how do AI content detectors actually work? Here, we uncover the science behind these sophisticated systems.
What are AI content detectors?

AI content detectors are tools that analyze text to figure out if it was written by a human or an AI system. The tools use algorithms to look at how words are used, how sentences are put together, and what the text actually means – and compare the text to large collections of known AI-generated and human-written content. This helps them spot telltale signs of AI.
AI Detection GPTZero Advanced Scan
An example from GPTZero of advanced AI detection.
Why do AI detectors matter

As AI tools become more user-friendly and more of the world starts to engage with them, there has been a growing flood of AI-generated content, prompting concern over content integrity and quality. AI content detectors have become more popular recently across industries for several key reasons around maintaining standards around authenticity and trust: 

    Education institutions: Schools, colleges and universities use AI detectors to uphold academic integrity. They help educators find out whether students have used certain AI tools too heavily, which makes sure that submitted work is an honest reflection of a student’s understanding of the subject area.
    Businesses: In professional settings, AI tools are being used to create content at scale for websites, blogs and social media – as well as for general marketing materials and internal communications. AI content detectors help to make sure companies keep their brand voice and identity, as well as remaining an original and genuine reflection of the company.  
    Politics and journalism: With the rise of deepfakes and the spread of misinformation, AI detectors are used to grade the integrity of news and make sure false content is not mistaken for genuine information. This is particularly crucial during election cycles, when content can influence public opinion and threaten the democratic process. 

How does AI content detection work?

Many AI content detectors rely on the same techniques AI models like ChatGPT use to create language, including machine learning (ML) and natural language processing (NLP). 
Machine learning (ML)

Machine learning is about recognizing patterns – the more text is analyzed, the more easily the tools can pick up the subtle differences between AI-generated and human-generated content. Machine learning drives predictive analysis, which is critical for measuring perplexity (which we’ll get to later) – a key indicator of AI-generated text. 
Natural language processing (NLP)

Natural language processing is about the nuances of language, and helps AI detectors gauge the context and syntax of the text it is analyzing. AI can create grammatically correct sentences but tends to struggle with being creative, subtle, and adding depth of meaning (which humans naturally use in their writing). 
Classifiers and Embeddings

Within these broad categories of ML and NLP, classifiers and embeddings play important roles in the detection process. Classifiers place text into groups depending on the patterns they have learned: much like teaching someone to sort fruits based on characteristics they’ve learned, but applied to language. 

Embeddings represent words or phrases as vectors, which create a ‘map’ of language – this allows AI detectors to analyze semantic coherence. 
Key techniques in AI content detection

GPTZero was one of the first AI detectors to pioneer the idea of using "perplexity" and "burstiness" to evaluate writing. Since then, we have evolved our model beyond just these two factors, into a multilayered system with seven components to determine if text was written by AI – but it’s worth looking at where the model began. 
Perplexity

Perplexity is like a surprise meter when it comes to AI content detectors. The higher the perplexity, the more ‘surprised’ the detector is by the text it is seeing – as unexpected or unusual words or sentence structures tend to raise the perplexity score. If the text is ranked to have higher perplexity, it is more likely to be created by a human. If the text is too predictable, it’s likely to be AI authorship. 
Burstiness

Burstiness is a measure of how much the perplexity varies over the entire document – and is more about how the text flows. While human writing has a rhythm of short and long phrases, mixing up both simple and complex sentences, AI can often be a lot more predictable. Which means its sentences tend to be fairly uniform. 

This means AI generators often veer towards lower burstiness and create more monotonous text – repeating certain words or phrases too frequently because they've seen them appear often in their training data.
The interaction between perplexity and burstiness  

While perplexity is about the individual surprises of specific words and phrases, burstiness is more about the overall rhythm of a piece. 

A text with high burstiness can lead to higher perplexity as this is like a curveball to AI, with sudden shifts in sentence length making it harder for the AI to predict what comes next. But low burstiness often means lower perplexity – uniform sentences mean that AI has an easier time spotting the pattern and predicting the next words. 

AI content detectors look for a balance of perplexity and burstiness that mimic the way humans naturally write and speak. Too much of either perplexity or burstiness can be a red flag.  
Building a custom AI model to detect AI

As AI evolves rapidly to learn how to sound more human, AI detectors like GPTZero are also evolving to keep up with the new models. We’ve built a custom model that trains on human and AI text from the latest models to constantly evaluate for key differences between AI and human text beyond just perplexity and burstiness.

These days, our model also includes features like our Advanced scan, a sentence-by-sentence classification model; Internet Text Search, which checks if text has been found to exist in text and internet archives; and a shield that defends against other tools looking to exploit AI detectors. We combine these methods with even more dynamic ways to keep up with AI and the latest attempts to bypass AI detection.
How effective are AI detectors?

No tool can legitimately claim to be 100% accurate. Instead, the goal for any good AI tool should be to have the highest accuracy rate with the lowest rate of false positives and false negatives. GPTZero has a 99% accuracy rate and 1% false positive rate when detecting AI versus human samples. 

The real challenge is in detecting mixed documents that contain both AI-generated and human-written content. GPTZero is much better than our competitors at detecting mixed documents, with a 96.5% accuracy rate. 

GPTZero is trained on millions of documents spanning various domains of writing including creating writing, scientific writing, blogs, news articles, and more. We test our models on a never-before-seen set of human and AI articles from a section of our large-scale dataset, in addition to a smaller set of challenging articles that are outside its training distribution.
AI detectors vs. plagiarism checkers

While both AI detectors and plagiarism detection tools exist to verify the authenticity of content, they operate differently. AI detectors look at the text’s structure and word choice and overall style to see whether it was created by artificial intelligence or a human – and involves advanced algorithms and linguistic analysis. 

Meanwhile, plagiarism checkers are more straightforward and are essentially looking to match the text – and compare the writing against a broad data set of existing writing. When they spot similarities or matches, they will flag this as potential plagiarism. 

AI detectors exist to make sure the content is genuinely written by a human, while plagiarism checkers exist to confirm it is not copied from existing sources. However, neither type of tool is perfect – and it is important to review results critically and use them as input sources rather than singular and definitive judges. 
Limitations to watch out for
False positives or negatives

AI detectors work on probabilities, not absolutes – and can sometimes produce false positives or false negatives. This is because the systems are relying on algorithms which analyze patterns, and work by judging the likelihood of any given piece of content being produced by AI. Sometimes, human-written content can be mistakenly flagged as AI-generated. And similarly, AI-generated content can be mistakenly flagged as human-written. At GPTZero, we dive more into how our benchmarking works and how we arrive at our accuracy rates.
Trained on English language

Most AI detectors are trained on English language content, and can recognize structures and patterns that are commonly found in English. An AI detector might be less (or not at all) effective when analyzing multilingual content, or text in other languages. For non-English content, an AI detector might not be able to recognize specific characteristics it has been trained on, because it differs from what it is trained to recognize – making it less reliable. 

Here at GPTZero, we’ve made a lot of progress in addressing language-based limitations by using a more rigorous evaluation dataset. Through refining model training and bringing in de-biasing techniques, we’ve improved GPTZero’s reliability across different language contexts.   
Writing aids that increasingly use AI 

Many AI detectors usually cannot tell the difference between ethically used AI assistance (with grammar tools such as Grammarly) and completely AI-generated content. Some systems cannot always differentiate between someone using AI for minor edits like grammar corrections, or leaning on AI to generate the entire text. GPTZero has trained our models to account for this.   
How to use AI detectors responsibly

With all of the above in mind, AI content detectors should be treated as tools in a broader strategy when it comes to gauging content integrity – as opposed to standalone judges of content quality. To use AI detectors effectively, we need to recognize their limitations and bring in human judgment for the specific context in which the content is being created. 

The bottom line is that these tools are not ultimate authorities. They should complement human judgment, especially in situations where false positives or negatives can have long-reaching consequences. The central way to use AI detectors responsibly is to take a balanced approach that prioritizes fairness above convenience. 


5 Common Types of Plagiarism (And How to Avoid Them)

Everyone knows that copying and pasting text is plagiarism – but what about all the other kinds? These days, new  forms of plagiarism are becoming more and more common. Understanding these subtler forms of cheating and the different types of plagiarism help to protect academic integrity in your institution. 
What is Plagiarism?

First, let’s review the basics: complete or direct plagiarism, which most people associate with the P-word. Both of these – as we know – are serious academic offenses, and they are also the simplest to detect. 
Complete Plagiarism

Complete plagiarism is when someone submits a whole piece of work that definitely is not their own, even if they edit a few words here and there. This type of plagiarism could involve buying an essay online, getting someone else to write it, or copying and pasting entire documents. 
Direct Plagiarism

Direct plagiarism is copying and pasting exact passages or sentences from another source without providing proper citations or even quotation marks.  It could involve taking paragraphs from websites and putting them into an essay. Even if it’s only a minor part of the overall work, it’s still plagiarism.  
Different Types of Plagiarism

While you might think the above is where plagiarism stops, the reality is that they are just the start. There are other types of plagiarism that are less obvious, and lesser known, but just as serious and damaging. Even though they are harder to detect, they can be just as destructive as complete or direct plagiarism. 

Here are five surprisingly common types of plagiarism that exist:
Self-Plagiarism

Self-plagiarism is what it sounds like: when you copy your own work. Maybe you recycle your own previously submitted work without the right citation – the equivalent of turning in the same essay for two different classes or reusing chunks of your old research paper in a new one without acknowledging it. 

While it could seem harmless – since it's your work – in academic settings, each assignment is meant to be original. The key is to remember that just because you wrote something, that doesn't mean you can reuse it freely without citing it properly. 
Paraphrasing Plagiarism

Paraphrasing plagiarism is when you use someone else's ideas without giving them credit, even if you've changed the words. It’s taking someone else’s ideas and then spinning them in your own vocabulary. Just because you’ve altered the words, that doesn’t mean you can skip citing where you found the core concept or idea. 

If you are paraphrasing someone else’s work in your own words, you need to attribute them properly to your sources. Otherwise – even if you are swapping out some of the words – you’re still trying to pass off someone else’s work as your own.
Mosaic Plagiarism

Mosaic plagiarism (also known as “patchwork” plagiarism) is what it sounds like: taking different parts from different sources and then collating them together. It is a sneakier form of copying and pasting which results in a mosaic (or patchwork) of plagiarism that can be tricky for human eyes to detect but is still detectable by AI plagiarism checkers. 

This type of plagiarism can arise from failing to take notes properly or not really understanding how to credit sources properly.  
Accidental Plagiarism

Accidental plagiarism is when you inadvertently take another person’s ideas without citation. Maybe you forget where you got your information from, get confused when it comes to citations, or imitate someone else’s words too closely when trying to explain them in your own voice. 

Even if it was genuinely a mistake made with innocent intentions, accidental plagiarism still counts as plagiarism. 
AI Plagiarism

AI plagiarism is using artificial intelligence tools to create content and then pretending it’s your own original work. It can come from the ease of using AI tools as well as a general lack of awareness around citation practices around such new technology. 

This type of plagiarism is a fast-growing concern in education circles as AI tools become more popular. 

AI Plagiarism – like the other forms mentioned above – can be hard for humans to detect, but is easily spotted by AI content detection tools like GPTZero. A unique feature of GPTZero is its Chrome Extension: Origin by GPTZero allows users to scan text to check whether it was written by an AI or a human.
Consequences of Plagiarism

Plagiarism is a serious offense that can have long-ranging impacts on your life, depending on how severe the plagiarism is and the policies of your institution. Not only can it affect your academic record and reputation, but internally, the guilt and damage to your self-respect can affect your personal confidence for years to come. 

More specifically, here are some of the consequences you might have to face: 

    Academic probation: This is like a warning, during which your academic progress is likely to be closely monitored. It could also go on your academic record. 
    Failing the assignment: This could mean getting a zero on the plagiarized assignment, which could massively impact your overall grade. 
    Failing the entire course: This could lead to having to repeat the course, which could delay expected graduation times and potentially increase education costs. 
    Suspension or expulsion: These are the most serious academic penalties and have the potential to severely disrupt your academic progress.  
    Reputational damage: Plagiarism can hurt the relationship you have with teachers and peers by damaging your reputation in the long term.  

Avoiding plagiarism starts with citation, citation, citation. It’s about always giving credit to your sources, using quotation marks for direct quotes, and paraphrasing in your own words when you're not quoting directly (and if you're paraphrasing, you still need to cite the source). Plagiarism is preventable as long as you get into the right habits to make sure your work is original and properly credited. Overall, it’s important to always keep track of your sources as you research, as this will help you do the below more easily. Cite everything that is not common knowledge and remember that too many citations are better than accidental plagiarism. 

The following tips will help you avoid plagiarism and instead create work that is a genuine reflection of your own ideas: 
Proper Citations

There are various citation styles (e.g. APA, MLA, and Chicago) which each have their own twist on the same information: who created the source, what it is called, when it was published, and where to find it. In-text citations indicate your source, while your reference list gives the full details. (You can check out a free citation generator here.) It’s consistency that matters most: that you pick a style of citation and keep it throughout the assignment.
Quoting and Paraphrasing Techniques

You can use other people's ideas in your work as long as you make it clear that their ideas didn’t come from you. With direct quotes, use quotation marks and provide the page number in your citation. If you’re paraphrasing, rewrite the idea in your own words, as changing a word here and there isn't enough. And as always, make sure to cite your source.
Using Plagiarism Checkers

Plagiarism checkers aren’t perfect, but they can be useful tools for catching accidental plagiarism or helping you double-check your paraphrasing. We’ve got our own expert tool here – an industry leading plagiarism check to match your text to millions of documents in our databases and on the internet. You can use it for free. Still, these tools are not meant to substitute good writing practices and are there to be used as a final check.
Why is plagiarism bad?

Without any original thought, there would never be any progress: exploring and developing original thought is how each of us contributes to broader human society. On an individual level, it is also how we build our critical thinking skills and grow as people, and is arguably the very meaning of education. This is why plagiarism can be so severely punished. 

While the consequences of plagiarism can sound scary, the truth is that you can avoid them entirely by making a conscious effort to develop strong academic habits: cite your sources, quote properly, and use plagiarism checkers as a final step. 

Maintaining academic integrity is about respecting the gift of original thought, and contributing meaningfully to a broader conversation. By getting into good habits early on, you set yourself up to succeed in the long run in terms of the quality and credibility of your work.



It’s no secret that the use of artificial intelligence is expanding—quickly. From streamlining workflows to personalizing product recommendations to providing 24/7 customer support, ecommerce companies can use AI to increase productivity across their businesses. One of the simplest ways to use AI technology, however, is to generate written content.

According to 2024 Survey Monkey research, 88% of marketers surveyed currently use AI, and of those using it, 93% use it to create content. While AI can help you conceive ideas and save time, its machine-generated content doesn’t always sound, well, human.

Using a few easy tips, you can learn how to humanize AI content, transforming generic text into compelling messaging that captivates your audience and wins sales. Read on for essential tips to turn AI content into compelling, authentic text.
What is AI content?

AI-generated content, commonly known as AI content, is any written, visual, or auditory material created by artificial intelligence algorithms. AI models like ChatGPT pull from a vast database of existing writing and use natural language processing technology to create text.

Using AI content can save you time, but AI tools can’t always produce accurate and human-sounding text.
Why humanize AI content?

    Improve tone
    Maintain brand voice
    Evade AI detection
    Cater to SEO

It’s worth humanizing AI content for these four reasons:
Improve tone

If you’ve ever read something that sounds a bit “off” but you can’t quite put your finger on why, you might have just read a piece of AI-generated content. The tone of AI-written content often lacks the human touch we expect as readers. AI writing tools might provide good first drafts, but you’ll want to diligently proofread and edit to ensure that the content has the tone of human writing.
Maintain brand voice

A solid brand voice can set you apart from your competitors, but AI writing might struggle to replicate the brand voice you’ve developed for your company. For this reason, make sure to edit AI content so it matches the voice you and your customers have come to expect.
Evade AI detection

As businesses integrate AI into their content, consumers are becoming aware of the generic, bland traits that mark AI-generated material. Customers are less likely to feel engaged with a text they suspect was written by AI, and some customers might think a brand using AI-generated text is impersonal. By humanizing your AI content, you can bypass AI detectors—both human and algorithmic ones.
Cater to SEO

Search engine optimization (SEO) is integral to ensuring your website or ecommerce shop is easy to find in online search results. Search engines like Google do not necessarily penalize businesses for using AI content, but the algorithm that decides which web pages rank the highest in search results favors unique and engaging content. AI creates its text by examining existing writing, limiting its capacity for creating truly original content.

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Tips for humanizing AI content

    Use an active voice
    Be concise
    Exude credibility
    Add a personal touch
    Use AI humanization tools
    Be specific with AI prompts
    Use AI for research
    Detect for AI

AI tools can bolster your productivity and improve your ecommerce company’s marketing performance. Make AI work for your business by humanizing AI content using these tips:
Use an active voice

When you use an AI text tool, you might notice that the AI writes in a passive voice. For example, AI may create the phrase, “The product was purchased by the customer” (passive voice) instead of generating the phrase, “The customer purchased the product” (active voice). This might seem like a minor detail, but an active voice sounds more natural and conversational and cuts down on unnecessary words like “was” and “by.” Editing AI-generated text to have an active voice is an easy way to increase readability and ensure human-like text.
Be concise

Using an AI tool to assist with long-form content can save you a considerable amount of time, but you’ll want to watch out for excessive jargon and complex words that don’t add value to the text. Artificial intelligence can produce long-winded explanations peppered with words that your audience might not understand. Replace jargon with easy-to-understand words when you’re editing AI-generated content.
Exude credibility

Credibility is key when building trust with your target audience. Examine AI text with a fine-tooth comb and remove repeated phrases and inaccurate facts that may deter readers from believing the content. Replace outdated statistics with newer sources or, better yet, include your own findings and research.
Add a personal touch

People gravitate toward personal stories. Whether you’re creating web copy or a blog post, add a personal touch and real-life examples to help engage readers. AI doesn’t have human creativity, so adding a personal story or colloquial phrase helps humanize AI content and keeps your readers interested.
Use AI humanization tools

It may sound counterintuitive, but an AI humanizer tool can be a great way to give your content a human touch. You can use software like Undetectable AI or Humbot, which are specifically designed to humanize AI writing. You can also prompt your AI content generator to modify its original response and make it more humanized. To do this, paste your text into the software, then prompt the algorithm to cater the text to your audience.

For example, imagine you’re creating a blog post for your ecommerce jewelry store. After you receive the AI-generated text, you could enter, “Make this web copy more human-like by speaking in a casual tone to an audience of women aged 25 to 65 in the market for fine jewelry.” This instruction will signal to the AI tool that it should simplify verbiage, trim jargon, and include casual phrases that are more accessible to your customers.
Be specific with AI prompts

AI text generators don’t intuitively understand the user's intent, and they need specific instructions to produce content that can benefit your business. When instructing AI, incorporate brand guidelines along with details on the right tone of voice, target audience, word count, and keywords. Linking to similar articles, telling the AI to exclude certain words, and providing specific statistics can also produce better results.
Use AI for research

Consider viewing AI technology as an AI writing assistant in your content creation process rather than as a writer. AI generators can help you formulate blog ideas, overcome writer’s block, and create robust outlines. Try using AI to inspire creativity and new ideas, then take the time to create a fully human version of the generated content. Whether you humanize AI text absolutely or partially, doing so will make a difference in how readers perceive the text. In any use case, it’s crucial to always fact-check results to make sure the AI is using accurate information in the correct context.
Detect for AI

As a last step, scan your text with an AI content detector to see the percentage of content suspected to be AI-generated. You can also use a plagiarism checker to ensure that you’re publishing plagiarism-free content. If your text still contains a large percentage of suspected AI material, follow the above steps until you are confident that your new piece of writing is engaging, unique, and has a human touch.
How to humanize AI content FAQ
How do you humanize AI content for free?

You can feed humanizing prompts into a free tool like ChatGPT, Gemini, or Perplexity to humanize content or use a dedicated AI humanizer. You can also edit text yourself, adding personal anecdotes and real-life examples, simplifying vocabulary, and making sure your writing includes active rather than passive verbs.
Can Google detect AI content?

Google is not explicitly an AI detector, but prior to 2023, the company treated AI content as spam. Google changed this policy in 2023 and now focuses on “rewarding high-quality content, however it is produced,” meaning that the company does not explicitly penalize you for publishing AI-generated writing.
What is the easiest way to humanize AI content?

The easiest way to humanize AI content is by using highly specific prompts, including original research and anecdotes, simplifying language, and using an AI detector to check your material. Publishing text you’ve edited can lead to higher engagement rates than copy-and-pasted AI-generated content.