“Mindreading” often sounds like science fiction. However, new research shows that you only need to take a quick video.
Researchers at the Champalimaud Foundation in Portugal found that mouse facial movements reveal their internal thinking strategies. This finding could open up non-invasive ways to study brain activity, raising new concerns about mental privacy.
In previous work, the team set up a mouse puzzle. The animals had to figure out which of the two water gush served the sweet drink.
The reward was switched between spouts, so the mouse had to adjust its strategy to get it right.
“We knew that mice could use a variety of strategies to solve this task. We were able to identify the strategies they were using according to their actions,” said van Deir Cazetz, who is now at the Centre National de La Lechesche Scienfic and the University of Ax Marseille.
Researchers expected that neurons would only reflect active strategies. Instead, they found all the strategies that were represented in their brains at once, regardless of the choice they chose.
This prompted new questions. Can these strategies also appear in the face of animals?
The face reflects brain activity
The team recorded both facial movements and brain activity. Next, we analyzed the data using machine learning. The results surprised them. Subtle facial cues have proven to be as beneficial as neuronal populations.
“To our surprise, we discovered that mice can get a lot of information about what they're thinking from recording the activity of dozens of neurons,” said Zachary Mainen, chief investigator at the Champalimaud Foundation.
“Having such simple access to hidden content in the mind can provide an important boost to brain research.”
What's even more impressive was the consistency of the entire animal. “Similar face patterns represent the same strategy in different mice,” says Davide Leat, now co-author of the University of Marseille and the Mines Saint-Etienne.
“This suggests that reflections of certain patterns of thought at the level of facial movement can be stereotyped like emotions.”
Promise and privacy concerns
According to the author, this work provides a way to study brain function without invasive tools.
This helps researchers to better understand health and illness. However, ease of access also raises ethical issues.
“The extremely easy access to hidden content in our minds underscores the need to start thinking about regulations to protect our mental privacy,” Mainen said.
Alfonso Renart, who is also the lead researcher at the Champalimaud Foundation, emphasized the broader meaning.
“Our research shows that videos aren't just about recording behavior, they also show that they can provide a detailed window into brain activity. This is exciting from a scientific perspective, but also raises questions about the need to protect privacy.”
The author argues that facial videos can be a powerful scientific tool.
At the same time, they urge policymakers to consider safeguards before such technology moves beyond the lab.
This study is published in the journal Natural Neuroscience.
