Truth or lie? Can MRI help scientists read our minds?

 It’s the slogan of a new game show on TV3, but can science help us tell the two apart?

This blog was first posted on the Science Media Centre Sciblogs site. By Dr Donna Rose Addis, Centre for Brain Research, University of Auckland

Mind Reading has always been thought of as a superhuman skill, but fMRI technology is bringing us ever closer to this goal. So-called ‘functional Magnetic Resonance Imaging’ tracks blood oxygen levels across the brain, allowing scientists to visualise what brain regions ‘light up’ during different types of cognition. Of course this is an indirect measure, as we assume that the more oxygen a brain area consumes, the more it is doing – as thinking is hungry work!

Nevertheless the advances in functional MRI (fMRI) since the 1990s have been met with great enthusiasm from the scientific community – in the 16 years between 1991 and 2007, over 19,000 peer-reviewed articles reporting on fMRI research were published (Logothetis, 2008). Coupled with the increasing availability of and access to fMRI technology, this method has come to dominate brain research and led to the emergence of a new field: cognitive neuroscience. fMRI studies have investigated the neural underpinnings of every aspect of thought and emotion, from executing physical movements, language and mathematics, to the more complex and (some would argue) uniquely human abilities of remembering, imagining, and understanding the self.

Despite the exciting technological innovations – and the seductive images of brain regions ‘lighting up’ with activity – there are limits to what we can understand about the brain and cognition from brain imaging. The sin of over-interpreting MRI data usually comes about from a logical fallacy called ‘reverse inference’. Essentially, a reverse inference is when one looks at a pattern of brain activity and from that, makes conclusions about what that brain (or its owner) is thinking or feeling. That is, engaging in a form of mind reading.

The reality is though that in a typical fMRI study, we scan 15–30 different participants and then we put together all their brain scans to get an average picture of brain activity during a particular cognitive task. This averaging is important because everyone’s brain is slightly different in its anatomy and its functioning, and we have to cancel out any idiosyncratic fluctuations (or “noise”). So could MRI ever be used to tell what a single person is actually thinking?

Liars Inc.

The most popular use of this skill would be lie detection tests, and that’s not as futuristic as it sounds. In the US, a company called ‘No Lie MRI Inc.’ is already claiming to “provide unbiased methods for the detection of deception and other information stored in the brain”. However these scans inherently focus on one person – the defendant – making it impossible to know if the defendant’s brain activity shows signs of deception or if it just happens that their brain activates differently from the average. Another issue is that fMRI data can be easily corrupted. In order for lie detection scans to work, the experimenter would have to ensure the defendant is compliant and thinking about the episode in question. It would be easy, however, for a defendant to thwart the lie detection process by just thinking about random things and so ‘scrambling’ their brain activity.

So although fMRI is not a mind reading device, I don’t mean to imply that at its current stage of development, brain imaging cannot provide us with any useful information about the brain. MRI has revolutionised our science and significantly expanded our knowledge about the inner workings of the brain. It has sparked new hypotheses and theories that in turn have changed how we think about the mind and brain.

Furthermore, our methods for human brain mapping are advancing all the time. Not to definitively say what someone is thinking, but to infer statistically what they might be thinking. So if the innovation in the last 20 years of brain imaging is anything to go by, before we know it we may well have mind reading apps on our phones, and scanning tests on daytime TV!

You can find out more about ‘Mind Reading’ in a live scan event during Brain Awareness Week. Dr Donna Rose Addis and colleague Associate Professor Brett Cowan will explore the brain’s inner workings, discovering the origins of imagination and memory. Chaired by journalist Russell Brown, the event will feature live analysis of brain scans at Auckland Museum.

The event will also go online on Thursday 15th March for the rest of New Zealand.

When: Wednesday 14 March 7.00 – 8.30pm

Where: Auckland Museum

Tickets: $10 (plus $3 booking fee)

Book online or phone 09 306 7048. For more details, see or @TeamMRI