The Neuroscience of Lying (feat. Dr. Christopher Sundby)The Neuroscience of Lying (feat. Dr. Christopher Sundby)
Lobes and Robes
Dr Christopher Sundby talks with Colin Saldanha and Gustavo Ribeiro about how neuroscience research on lying challenges traditional evidence rules and hearsay exceptions. The conversation also examines neurointerventions in criminal justice, balancing rehabilitation, autonomy and the risk of medicalising crime.
35:21•30 Apr 2026
Brains, Lies and Justice: Dr Christopher Sundby on Neurolaw and Evidence
Episode Overview
- Neuroscience can be used to test psychological assumptions built into procedural rules, especially hearsay exceptions like the present sense impression.
- Experimental data suggest people lie less when speaking immediately, and that within about three seconds the brain may drop truthful details from working memory to support a lie.
- Sundby argues for limiting the present sense impression rule to truly contemporaneous statements to improve consistency and reliability in courts.
- He proposes a personality integrity test to assess when neurointerventions, such as medications or brain stimulation, are acceptable in criminal justice.
- The discussion stresses humility: scientific findings should inform but not dictate legal change, given the dangers of over-medicalising crime and expanding state power.
“People lied about 9% less when responding in the moment compared to after a delay.”
Gain insights from experts and survivors on how science and law try to make sense of something as everyday – and slippery – as lying. Lobes and Robes brings together neuroscience and the courtroom, with Dr Christopher Sundby explaining how tiny shifts in brain activity can change what counts as reliable evidence. This conversation centres on hearsay rules, especially the present sense impression rule – yes, it sounds dry, but stick with it.
Sundby shows how long-standing legal assumptions about honesty can actually be tested in the lab. He reports that people “lied about 9% less when responding in the moment compared to after a delay,” and that within as little as three seconds the brain appears to drop the truth from working memory, making it easier to stick to a lie.
You’ll hear a fun back-and-forth about judges wrestling with what “substantially contemporaneous” really means, and why Sundby thinks the rule should be tightened to cover only truly immediate statements. Along the way, he highlights the wider challenge of basing legal rules on “folk psychology” rather than data, while still respecting that law also reflects values, not just brain scans.
The second half shifts to neurointerventions in criminal justice, including chemical castration, deep brain stimulation and medications that might reduce aggression or support people with substance use issues. Sundby lays out his “personality integrity” test, aimed at protecting autonomy while still leaving space for genuinely rehabilitative interventions. He stresses the risk of turning crime into a purely medical problem and warns about “problematic social engineering” if the state gains too much power over people’s brains.
Anyone curious about how neuroscience could influence sentencing, mandatory treatment, or evidence rules will find plenty to mull over. It’s a thoughtful mix of lab results, legal doctrine and cautionary humour that might make you rethink what honesty and responsibility really mean in court. How might these ideas change the way we think about responsibility and rehabilitation in justice systems?
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