What Is an AI Detector?

The Definition of an AI Detector

An AI content detector is a type of software that usually uses machine learning models and sometimes other approaches to determine whether a piece of content—such as text, images, or videos—was generated by artificial intelligence or created by a human.

AI text detectors, also called AI text checkers or AI writing detectors, analyze written content to determine its origin. These tools are often available as online software and are sometimes bundled with plagiarism checkers, though many exist as standalone products.

How Do AI Detectors Work?

Unlike plagiarism detection tools, which match text exactly to sources for verification, AI detectors work on probabilities. Determining whether text was AI-generated can be challenging, especially when paraphrasing is involved.

It's similar to detecting AI-generated images. Some AI images are easily identifiable due to visible flaws, like unnatural hand shapes or distorted facial features. However, if an advanced AI model was used, the prompt was carefully crafted, and post-editing was applied, it can be nearly impossible to distinguish between an AI-generated and a human-made image. The same applies to text—when well-structured and proofread, even the best AI detectors may struggle to determine its origin.

AI detection software employs various techniques, often combining multiple approaches to improve accuracy. Some key methods include:

Perplexity

Perplexity measures how predictable a text is. If a text is very predictable, it likely follows patterns that AI models use, making it more likely to be AI-generated. Lower perplexity means the text is easier for an AI to predict.

Burstiness

In human writing, sentence lengths are mixed—some are short, and some are long. AI-generated text, however, tends to have sentences that are all about the same length, making it sound more uniform.

Probability Analysis

AI-generated text often uses very common and predictable words. This makes it easier to detect because human writing usually includes more variety and unexpected word choices.

Token Patterns

AI-generated text often repeats certain words, phrases, or sentence structures in a predictable way. These patterns can help detect if a text was written by AI.

Stylistic Analysis

AI-generated text often sounds very formal and has a strict structure. Not much of creativity, personal touch, and natural variations that human writing usually has.

Deep Learning Classification

Some AI detectors use large datasets of AI and human text, training deep learning models to classify content.

Watermarking

Just like some images have hidden watermarks, some AI-generated text includes special markers—hidden patterns in the words—that help identify if AI created it.

If you want to learn more about how AI detectors work, we have written a more detailed article here. The English version of the article includes examples of AI detection algorithms:

How Do AI Detectors Work?

AI Detection in Schools: Challenges and Considerations

AI detectors are tools designed to identify whether a piece of writing was created by a human or artificial intelligence. While useful, they are not 100% reliable. These tools sometimes misidentify human-written content as AI-generated (false positives) or fail to detect AI-generated text (false negatives). As AI technology advances, detection tools may struggle to keep up, making evaluation even more complex.

Many schools and universities use AI detectors alongside plagiarism checkers to assess student work. However, these tools only provide an estimate of how "AI-like" a text appears. For example, a student using AI for minor grammar corrections might receive a high AI score, even though the ideas are their own. Educators should use these tools carefully, ensuring they do not unfairly penalize students based on AI-generated results alone.

AI detection should be just one part of the student evaluation process. Since these tools can vary in accuracy, they should be used thoughtfully, especially in important decisions like grading. Over-reliance on AI detectors can lead to mistakes and unnecessary stress for students.

These challenges have been widely discussed in media:

The software says my student cheated using AI. They say they’re innocent. Who do I believe?

The Guardian

Professors are using ChatGPT detector tools to accuse students of cheating. But what if the software is wrong?

USA Today

Detecting AI may be impossible. That's a big problem for teachers.

The Washington Post (Paywall)

We tested a new ChatGPT-detector for teachers. It flagged an innocent student.

The Washington Post (Paywall)

While AI detectors can be helpful, they should not be the only factor in determining academic integrity. A balanced approach, including teacher judgment and multiple evaluation methods, is crucial in ensuring fairness in education.

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