How we write can reveal lies – new research could be a tool for the judicial system
Source: https://www.lunduniversity.lu.se/article/how-we-write-can-reveal-lies-new-research-could-be-tool-judicial-system Parent: https://www.lunduniversity.lu.se/news
By gisela [dot] lindberg [at] kansliht [dot] lu [dot] se (Gisela Lindberg) - published 11 February 2026
Efforts to understand whether someone is lying often focus on how the person talks. New research suggests it could be promising to also examine how someone writes. This is according to Kajsa Gullberg, researcher in general linguistics, who hopes that her thesis can provide insights into people’s complex language skills.
Kajsa Gullberg’s research shows that the degree of truth in what you write can affect the writing process itself. It is possible to discern patterns in how long the writing process takes, the number of edits, and the length and number of pauses that are taken.
The writing process reveals more than we think
Research on deception is a long-established field in psychology with the aim of finding indications that a person is lying, for example in word choice, body language and by monitoring pulse. In speech, the traditional approach has been to try to detect linguistic markers for lies such as repetitions, gestures and pauses, whereas in writing the main focus has been on the finished text.
Within psycholinguistics, Kajsa Gullberg’s field of research, the path from thought to speech or writing is key in understanding language skills, and in Kajsa Gullberg’s thesis, the focus is on examining whether the degree of truth in what is produced affects this path, i.e. the speech and writing process.
“Research that examines linguistic markers is important, but it can be supplemented with more knowledge on the writing process itself in real time. And here my study suggests that the writing process is affected when someone is lying ,” says Kajsa Gullberg.
Her results show that:
- If a person writes a long lie, more pauses are taken than when writing a long truthful narrative.
- If a person takes a long time to write a lie, fewer pauses are taken than when taking a long time to write the truth.
- The text is edited less when a person writes a lie – regardless of the length of the text and how long the writing takes.
“I was surprised that people did not edit their text as much. It could be the case that when we lie, we plan more before we write, especially if we spend a long time on writing our narrative. If we write a long lie we pause more often, because we are thinking about it and constructing the lie before we write it down and therefore don’t need to edit as much later,” says Kajsa Gullberg.
It is faster to repeat the truth
In a follow-up study, the participants wrote the same truthful or untruthful narratives several times. The results showed that:
- The writer makes fewer edits when truths are repeated, whereas the number of edits for lies remains the same or increases when repeated.
The reasons for this seem to be that:
- It is easier to retell something truthful, as the person is only recreating the sequence of events they remember and that becomes even easier after further repetitions. \
- Lies require that the person remember both the actual sequence of events and how they lied about it, so the lying is consistent. This makes it more difficult, requires more control and therefore takes longer.
The speech process differs from the writing process
Most people have a lot of experience of hearing others talk and know how people sound when they talk, but the majority are not aware of what someone’s writing process is like – not even their own.
The study showed that lies in speech had:
- fewer “hesitant” pauses such as “er”
- an increased number of filled pauses if a person talks for a long time, however, regarding repetitions the differences between lies and truth diminished.
“A lie requires more energy and control, and this may be evident when we pause,” says Kajsa Gullberg. “The hesitation may be perceived as uncertainty, so perhaps it feels better to keep talking when you are lying,” she continues.
Even though her research shows visible deviations, Kajsa Gullberg adds that it is often very difficult to determine whether a person is lying. This applies even among those trained to watch for certain markers in speech, who only categorise around 50-60% of the lies correctly.
“However, knowledge about what writing processes are like could nonetheless help in forensic contexts by providing an extra tool for identifying if someone is deviating from the norm in their language production. Overall, my thesis points to the writing process as a promising area for continued exploration regarding deception,” says Kajsa Gullberg.
Publications:
Link to the thesis:
Link to the latest published study:
Contact:
\ Kajsa Gullberg\ Researcher, General Linguistics\ Lund University\ kajsa [dot] gullberg [at] ling [dot] lu [dot] se (kajsa[dot]gullberg[at]ling[dot]lu[dot]se)
A unique study:
Kajsa Gullberg collected over 800 narratives in speech and writing by Swedish native speakers from people who retold a long sequence of events in both speech and writing – both truthful and untruthful.\ As all language production is affected by its context, the recording situation was refined as far as possible to prevent external influences.
Indications that someone is perhaps being deceptive
\ During the writing process
- More pauses in long narratives
- Fewer edits than in truthful writing
- More need for control in repetitions – the edits increase and take longer.
In speech
- Fewer hesitant pauses (“er”) in untruthful narratives
- More filled pauses in long lies, i.e. the liar prefers to talk rather than remaining silent.
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Last updated: 11 Feb 2026 | editors-news [at] kommunikation [dot] lu [dot] se