This recent breakthrough allowed researchers at the University of Texas at Austin to "read" someone's thoughts as a continuous flow of text, based on what they were listening to, imagining or watching.

It raises significant concerns for privacy, freedom of thought, and even the freedom to dream without interference. Our laws are not equipped to deal with the widespread commercial use of mind-reading technology – freedom of speech law does not extend to the protection of our thoughts.

Participants in the Texas study were asked to listen to audiobooks for 16 hours while inside an MRI scanner. At the same time, a computer "learnt" how to associate their brain activity from the MRI with what they were listening to. Once trained, the decoder could generate text from someone's thoughts while they listened to a new story, or imagined a story of their own.

According to the researchers, the process was labour intensive and the computer only managed to get the gist of what someone was thinking. However, the findings still represent a significant breakthrough in the field of brain-machine interfaces that, up to now, have relied on invasive medical implants. Previous non-invasive devices could only decipher a handful of words or images.