five (surprising) ideas from cognitive and social neuroscience
being idle; social pain ?= physical pain; social GPS; synchrony; unstable memories (and some bonus Alzheimer's treatment news on the way)
Here’s a listicle of interesting ideas from neuroscience that should be more generally known about.
your brain’s “idle” mode is a powerful social and time-travel engine
The idea: When you’re ‘doing nothing,’ a large network of brain regions (the default mode network, DMN) turns on, not off. The DMN supports remembering the past, imagining the future, and simulating other people’s minds — basically running lots of mental ‘what if’ scenarios. You probably spend about 40% of your waking time dropping into this cognitive mode, hence ‘default ‘
Why this surprises people: Most non-neuroscientists assume the brain is most active when you’re focused on an external task and it's idle when you’re daydreaming. In fact, the DMN burns a lot of energy and is tightly linked to mind-wandering, autobiographical memory, social cognition, and planning.
Why we think it’s real (not a fad): The DMN has been replicated across labs, species, and methods (fMRI, fNIRS, intracranial recordings). It is a core brain system for internal mentation and ‘mental time travel,’ - it’s not an artefact.
You can test it for yourself. First reread this paragraph, and count the ‘e's. When you’ve done that, look into the distance, maybe close your eyes. Note the content of your thoughts. Suddenly you're not task-focused, counting the e's, and instead ranging widely across all the important stuff in your life. You might even be indulging in some idle ideas about your nation and your place in it…
social rejection “hurts” because it activates some of the same brain systems as does physical pain
The idea: Being excluded or rejected activates parts of the brain (especially dorsal anterior cingulate cortex and anterior insula – the ‘pain matrix’) also involved in the distress of physical pain.
Why this surprises people: While we might talk about “hurt feelings” as a metaphor, the brain treats social threat as biologically serious. When people relive a painful breakup in the scanner, regions that process the affective and even somatosensory aspects of pain light up in ways similar to physical pain.
Nuance (and why this is good science, not overhype): Newer work shows these regions aren’t only for pain — they encode self-relevant, salient events more broadly. So, the consensus is: social pain and physical pain partly share a survival-relevant alarm system, not that they’re literally identical. This view is supported by careful meta-analyses and newer experiments that tease apart salience from specific ‘pain’ signals. And you remember social slights and insults, long after you’ve forgotten the pain of a stubbed toe.
Read this on the pain of social exclusion and boycotting: Social life: The people around you are inside your head
five (surprising) ideas from cognitive and social neuroscience
your brain uses its spatial GPS system to map abstract ideas and social hierarchies
The idea: The hippocampal–entorhinal system, famous for place cells and grid cells in spatial navigation, also represents conceptual spaces and social hierarchies in a map-like format. People’s brains show grid-like coding when they move through abstract spaces (value, time, social rank) in thought.
Why this surprises people: Most people think ‘the GPS part of the brain’ just helps with physical navigation. It now looks like the brain reuses that circuitry so you can navigate an abstract field: who outranks whom, how concepts relate, where options sit in a value space, even how time is structured.
Why we trust this finding: Multiple high-quality fMRI studies from different groups show grid-like signals in entorhinal cortex and related areas when people infer positions in conceptual or social spaces, not just physical ones; newer work extends this to social “maps” and abstract value spaces.
Read this for lots on the brain’s GPS system: In Praise of Walking: The New Science of how We Walk and why It’s Good for Us
And this for the social and collective purposes of memory: Talking Heads: The New Science of How Conversation Shapes Our Worlds
brains actually synchronise during good interaction (and that predicts learning & cooperation)
The idea: When people cooperate, teach, or even listen to the same story, their brain activity becomes temporally aligned (inter-brain synchrony). Higher synchrony between partners or in classrooms predicts better understanding, rapport, and team performance.
Why this surprises people: We’re used to thinking of brains as isolated in the silent, dark vat of your skull. Hyperscanning (recording multiple brains at once) shows that in real interactions, brains form coupled systems. In students, greater synchrony with peers or the teacher during class predicts test scores and how connected they feel to the group.
Why it’s more than a curiosity: Systematic reviews now argue that inter-brain synchrony is a robust marker of teamwork and social engagement across EEG, fNIRS, and fMRI studies, and that it changes in conditions like autism, depression, and high stress (giving us a new, measurable handle on “group mind” and social impairment).
every time you remember something, your brain partially rewrites it
The idea: Memories aren’t files you “open and close.” When you retrieve a memory, the underlying trace becomes unstable and must be re-stored (reconsolidation). During this window, the memory can be strengthened, updated, or weakened — even selectively disrupted.
Why this surprises people: Laypeople usually think of memory like a video archive. In reality, remembering is an act of reconstruction that opens the memory to change. Experiments show that if you reactivate a fear memory and then apply a targeted manipulation (a drug, brain stimulation, or a specific kind of new learning), later expression of that fear can be reduced.
Why neuroscientists take this seriously: Reconsolidation has been demonstrated across species and paradigms, with converging evidence from behavioural work and neuroimaging showing dynamic interactions between hippocampus, amygdala, and prefrontal cortex during retrieval and updating. Recent critical reviews don’t dismiss reconsolidation; they refine when and how it occurs, which is exactly what you’d expect from a maturing, reliable field.
why these ideas belong outside the lab
Taken together, they paint a different portrait of the human brain:
Not wet hardware, but instead a story-driven simulation engine that burns energy contemplating our own inner lives and those of others, even when nothing much is happening in the world at large.
Not an isolated organ, floating in the dark vat of the skull, but part of a coupled network of other brains, physically synchronising when we talk, learn, and cooperate.
Not a reliable video archive, but a constantly revised narrative, rewritten each time we remember.
Cognitive Republic
I’ve recently started a new project with a separate home and a new: The Cognitive Republic - Building Societies That Experiment, Learn, and Evolve - a book published section by section in public. Last time, I described what this endeavour is about:
a book-length project written online, in public - a new and scary experience for me, and I hope an exhilarating experience for you - the reader. Cognitive Republic started life as a book proposal: I have decided instead to release it here piece-by-piece to test the arguments and to engage in thinking in public.
We will examine how we can reinvent democracies as learning, adaptive, systems. You can read the introduction here.
The writing will of course continue here but and will be thematically varied as always!
Alzheimer’s treatment news on the way
Some bonus Alzheimer’s treatment news is on the way here next time - sign-up!
Further reading
Sins of Memory - false memory implantation in adults is easy (bonus: here’s one way to do it)
My book, Talking Heads: The New Science of How Conversation Shapes Our Worlds (go buy it! - the audiobook version is read by me, and is a bargain atm: only £0.99 in the UK; only $0.99 in the US (Amazon.com).
Raichle, M. E., MacLeod, A. M., Snyder, A. Z., Powers, W. J., Gusnard, D. A., & Shulman, G. L. (2001). A default mode of brain function. Proceedings of the National Academy of Sciences, 98(2), 676–682.
Andrews-Hanna, J. R., Smallwood, J., & Spreng, R. N. (2014). The default network and self-generated thought: Component processes, dynamic control, and clinical relevance. Annals of the New York Academy of Sciences, 1316(1), 29–52.
Eisenberger, N. I., Lieberman, M. D., & Williams, K. D. (2003). Does rejection hurt? An fMRI study of social exclusion. Science, 302(5643), 290–292.
Eisenberger, N. I. (2012). The neural bases of social pain: Evidence for shared representations with physical pain. Psychosomatic Medicine, 74(2), 126–135.
Doeller, C. F., Barry, C., & Burgess, N. (2010). Evidence for grid cells in a human memory network. Nature, 463(7281), 657–661. https://doi.org/10.1038/nature08704
Constantinescu, A. O., O’Reilly, J. X., & Behrens, T. E. J. (2016). Organizing conceptual knowledge in humans with a gridlike code. Science, 352(6292), 1464–1468. https://doi.org/10.1126/science.aaf0941
Parkinson, C., Kleinbaum, A. M., & Wheatley, T. (2017). Spontaneous neural encoding of social network position. Nature Human Behaviour, 1(5), 0072.
Dikker, S., Wan, L., Davidesco, I., Kaggen, L., Oostrik, M., McClintock, J., Rowland, J., Michalareas, G., Van Bavel, J. J., Ding, M., & Poeppel, D. (2017). Brain-to-brain synchrony tracks real-world dynamic group interactions in the classroom. Current Biology, 27(9), 1375–1380.
Davidesco, I. (2020). Brain-to-brain synchrony in the STEM classroom. CBE—Life Sciences Education, 19(3), fe2.
Nader, K., Schafe, G. E., & LeDoux, J. E. (2000). Fear memories require protein synthesis in the amygdala for reconsolidation after retrieval. Nature, 406(6797), 722–726.
Nader, K., & Einarsson, E. Ö. (2010). Memory reconsolidation: An update. Annals of the New York Academy of Sciences, 1191(1), 27–41.
Lee, J. L. C., Nader, K., & Schiller, D. (2017). An update on memory reconsolidation updating. Trends in Cognitive Sciences, 21(7), 531–545.