Can an fMRI machine read your thoughts?

It is symptomatic of some mental health disorders that sufferers believe their minds are being controlled by external forces. This has now been induced in participants experimentally. Olsen et al (2016) deceived participants into thinking that an fMRI machine could read their thoughts and control their minds.

Participants were then asked to complete what they thought were "mind reading" and "mind influencing" experiments in what was actually a mock “scanner”.

In the "mind reading" stage, researchers asked each participant to lie in the "scanner", silently think of any two-digit number and press a button when they were done. The fMRI machine then produced a number on screen and the researcher could be seen writing the result onto a clipboard.

Next, the participant was asked to name the number they had silently thought of. The researcher turned the clipboard, stunning the participant by showing exactly their number – seemingly "read" from their mind by the power of fMRI.

In the second, "mind influencing" condition, the participant was told that the machine was programmed to put a number into their mind. This time the researcher "wrote down" the number the machine had chosen to "transmit". As before, the participant was asked to silently think of any two-digit number and after the "scan" the researcher seemed to show that the participant had thought of exactly the number the machine had ‘transmitted’ to them.

Both of these numbers were produced through tricks – the “scanner” had obviously not influenced the participant nor managed to read their mind. However, when the researchers asked the participants to rate how much control they felt they had over their choice of numbers those in the second stage of the experiment believed they had less control and that the machine had influenced their thinking.

In some types of mental health problems, people start to experience their thoughts and actions being controlled by what seem like outside forces. However, Olsen et al’s experiment showed that people can be deceived into believing that outside forces can control their minds.

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