Connectionists: FW: AI at 50 videos...

Fri Aug 21 13:52:33 EDT 2026

Yup some bright lights are going out way  too often now.

I meant Larry at Oxford when  I was on the McDonnell-PEW CNS advisory board.   Very kind fellow.

Charlie was also a great Historian and loved to put things in their proper context.

Best

Stephen

On 8/21/26 13:46, KENTRIDGE, ROBERT W. wrote:
Hi Stephen,

Your recollections and mine of Charlie’s views seem very similar - Charlie did not believe his face cells and the like were grandmother cells - they were part of a population code rather than being cells whose activity could be read out as unambiguous evidence for the presence of ‘x’s. So, his concept must have been closer to my ‘hardline’ definition than to Reddy and Thorpe’s conception.

I knew that Charlie had died in 2019. I think the last time I saw him was at a meeting in Oxford, I don’t remember the date, with Alan Cowey (alas another great, and great friend, we have lost, along with Larry Weiskrantz who was one of my closest friends in visual neuroscience - I published a lot with both of them). At that meeting Charlie was clearly far from well - so sad.

cheers,

Bob

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From: Stephen José Hanson <jose at rubic.rutgers.edu><mailto:jose at rubic.rutgers.edu>
Date: Friday, 21 August 2026 at 17:28
To: KENTRIDGE, ROBERT W. <robert.kentridge at durham.ac.uk><mailto:robert.kentridge at durham.ac.uk>; Asim Roy <ASIM.ROY at asu.edu><mailto:ASIM.ROY at asu.edu>; Gary Marcus <gary.marcus at nyu.edu><mailto:gary.marcus at nyu.edu>; Hava Siegelmann (hava.siegelmann at gmail.com<mailto:hava.siegelmann at gmail.com>) <hava.siegelmann at gmail.com><mailto:hava.siegelmann at gmail.com>; Juergen Schmidhuber <juergen.schmidhuber at kaust.edu.sa><mailto:juergen.schmidhuber at kaust.edu.sa>; Ali Minai <minaiaa at gmail.com><mailto:minaiaa at gmail.com>
Cc: director at inc.ucsd.edu<mailto:director at inc.ucsd.edu> <director at inc.ucsd.edu><mailto:director at inc.ucsd.edu>; connectionists at mailman.srv.cs.cmu.edu<mailto:connectionists at mailman.srv.cs.cmu.edu> <connectionists at mailman.srv.cs.cmu.edu><mailto:connectionists at mailman.srv.cs.cmu.edu>
Subject: Re: Connectionists: FW: AI at 50 videos...

[EXTERNAL EMAIL]

Hi Robert,

I was a friend of Charlies in princeton from the 80s.  Charlie died in 2019.

And we had many dinners together.. occasionally with his most recent wife, Joyce Carol Oats.

Charlie argued  his face cells (and hand cells0  were not grandmother cells: they were coarsely tuned, responded to many faces, and fit an ensemble/population code.

Its hard to fight a counterfactual, as there are too many ways a concept or category intension could be false.   How many control conditions do you need before it is categorical response to a specific stimulus?  Is an equivalence class enough for it to be categorical?     Same problem with so called fuisform face area..

A relevant paper to this is something I wrote a few years ago  in Frontiers, Human Neuroscience..  The

The Failure of Blobology: fMRI Misinterpretation, Maleficience and Muddle

https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2022.870091/full

On 8/21/26 12:14, KENTRIDGE, ROBERT W. wrote:
I don’t think there is much I disagree with in Asim’s comment. I does go to show, though, how important the details of one’s definition of a grandmother cell is.

If you take the hardline definition that a grandmother cell must respond to one concept and one concept alone, so that you can read off the presence of an ‘x’ from the response of a grandmother cell tuned to ‘x’s then the Jennifer Aniston cell is not a grandmother cell.

If you take Asim’s definition that they are cells which respond to a complex concept across a range of modalities etc., without any proviso that they must respond exclusively to ‘x’s then the Jennifer Aniston cell is indeed a grandmother cell.

Reddy and Thorpe certainly describe an interesting class of cell, I’m just not sure if they correspond to Lettvin’s view.

BTW, I talked to Charlie Gross about all this in the 1980s or 90s - I haven’t talked to him about this more recently so his views might have changed. I also knew Horace Barlow a bit, but my conversations with him were about artificial neural nets and computation (again in the 80s and 90s), not neurophysiology. At the first talk I ever gave I notice Horace in the audience and shuddered - he was a bit terrifying to a young neophyte. He did ask a question at the end of my talk, but it wasn’t one that stumped me, and he was very gracious about the whole thing.

cheers,

Bob

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From: Asim Roy <ASIM.ROY at asu.edu><mailto:ASIM.ROY at asu.edu>
Date: Friday, 21 August 2026 at 05:16
To: KENTRIDGE, ROBERT W. <robert.kentridge at durham.ac.uk><mailto:robert.kentridge at durham.ac.uk>; Gary Marcus <gary.marcus at nyu.edu><mailto:gary.marcus at nyu.edu>; Stephen José Hanson <jose at rubic.rutgers.edu><mailto:jose at rubic.rutgers.edu>; Hava Siegelmann (hava.siegelmann at gmail.com<mailto:hava.siegelmann at gmail.com>) <hava.siegelmann at gmail.com><mailto:hava.siegelmann at gmail.com>; Juergen Schmidhuber <juergen.schmidhuber at kaust.edu.sa><mailto:juergen.schmidhuber at kaust.edu.sa>; Ali Minai <minaiaa at gmail.com><mailto:minaiaa at gmail.com>
Cc: director at inc.ucsd.edu<mailto:director at inc.ucsd.edu> <director at inc.ucsd.edu><mailto:director at inc.ucsd.edu>; connectionists at mailman.srv.cs.cmu.edu<mailto:connectionists at mailman.srv.cs.cmu.edu> <connectionists at mailman.srv.cs.cmu.edu><mailto:connectionists at mailman.srv.cs.cmu.edu>
Subject: RE: Connectionists: FW: AI at 50 videos...

[EXTERNAL EMAIL]
Charlie Gross was in that discussion with Horace Barlow. So was Itzhak Fried and Christof Koch. The referenced Jennifer Aniston experiments were conducted under their guidance at UCLA. And so was Walter Freeman and many other prominent neuro and cognitive scientists involved in that discussion.

Gross (2002) characterized grandmother cells as “multimodal.” Reddy and Thorpe (2014) also define concepts cells as “invariant, multimodal.” Thus, the fundamental characterization of these two concepts is identical. “Multimodal invariance” implies associative learning across modalities. They also state that concept cells have “meaning of a given stimulus in a manner that is invariant to different representations of that stimulus.”

“Selectivity or specificity,” “complex concept,” “meaning,” “multimodal invariance” and “abstractness” (Reddy and Thorpe, 2014) are all integral properties of both concept cells and grandmother cells.

Reddy and Thorpe (2014) categorically state that “abstract, invariant representations” is “a hallmark of MTL concept cells.” Quiroga (2012) also admit that concept cells are abstract: “These and many other examples suggest that MTL neurons encode an abstract representation of the concept triggered by the stimulus.”

Unfortunately, Barwich (2019) is completely flawed in its arguments against grandmother cells as argued in Roy’s commentary on the article (Roy (2020)).

The neurophysiological evidence for purely abstract single cell representation in the brain points to symbolic representation in the brain. Quiroga et al. (2008) estimate that 40% of MTL cells are abstract. Thus, there is extensive use of abstractions at the single cell level in the brain. This is the neurophysiological evidence for the neurosymbolic approach and what Gary Marcus has been arguing for all along. In a way, both approaches win and need each other.

  1.  Barlow H. B. (2009). Grandmother cells, symmetry, and invariance: how the term arose and what the facts suggest, in The Cognitive Neurosciences, 4th Edn., ed GazzanigaM. (Cambridge, MA: MIT Press), 309–320.
  2.  Gross C. G. (2002). Genealogy of the “grandmother cell”. Neuroscientist8, 512–518. 10.1016/j.meegid.2016.04.006
3.            Reddy L. Thorpe S. J. (2014). Concept cells through associative learning of high-level representations. Neuron84, 248–251. 10.1016/j.neuron.2014.10.004
4.            Barwich A-S (2019) The Value of Failure in Science: The Story of Grandmother Cells in Neuroscience. Front. Neurosci. 13:1121. doi: 10.3389/fnins.2019.01121
5.            Roy A (2020) Commentary: The Value of Failure in Science: The Story of Grandmother Cells in Neuroscience. Front. Neurosci. 14:59. doi: 10.3389/fnins.2020.00059
6.            Quiroga R. Q. Kreiman G. Koch C.FriedI. (2008). Sparse but not ‘grandmother-cell’ coding in the medial temporal lobe. Trends Cogn. Sci.12, 87–91. 10.1016/j.tics.2007.12.003

Asim Roy
Professor, Information Systems
Arizona State University
Lifeboat Foundation Bios: Professor Asim Roy<https://urldefense.com/v3/__https:/lifeboat.com/ex/bios.asim.roy__;!!IKRxdwAv5BmarQ!NHg1P4byXZZmMFLMgr8A4dQNxSlqyvsqWef4wrPXtCXR0f0bo0eMm-rIF8G6ZV0$>
Asim Roy | iSearch (asu.edu)<https://isearch.asu.edu/profile/9973>

From: KENTRIDGE, ROBERT W. <robert.kentridge at durham.ac.uk><mailto:robert.kentridge at durham.ac.uk>
Sent: Thursday, August 20, 2026 3:53 AM
To: Asim Roy <ASIM.ROY at asu.edu><mailto:ASIM.ROY at asu.edu>; Gary Marcus <gary.marcus at nyu.edu><mailto:gary.marcus at nyu.edu>; Stephen José Hanson <jose at rubic.rutgers.edu><mailto:jose at rubic.rutgers.edu>
Cc: director at inc.ucsd.edu<mailto:director at inc.ucsd.edu>; connectionists at mailman.srv.cs.cmu.edu<mailto:connectionists at mailman.srv.cs.cmu.edu>
Subject: Re: Connectionists: FW: AI at 50 videos...

It is worth pointing out that in Jerry Lettvin’s original paper on the grandmother cell the concept was presented as a joke. Lettvin certainly believed in the notion that one might identify cells in the frog’s brain as ‘bug detectors’, but he appeared to be sceptical about the idea that such cells might exist in the human brain representing complex concepts like ‘my grandmother’. There are a couple of great papers on the history of the grandmother cell:

Ann-Sophie Barwich (2019) The Value of Failure in Science: The Story of Grandmother Cells in Neuroscience. Front. Neurosci. 13:1121. doi: 10.3389/fnins.2019.01121

Charles C Gross (2002) Genealogy of the "grandmother cell”. Neuroscientist 8(5):512-8. doi: 10.1177/107385802237175.

I remember chatting to Charlie Gross about this around that time (he also reminisced about his part-time job mowing BF Skinner’s lawn).

People often assume that the Quiroga et al (2005 Nature, 435. 1102 - 1107) paper on the Jennifer Aniston cell was positive evidence for the existence of grandmother cells in the human brain. This is far from the truth. The Jennifer Aniston cell does not only respond to Jennifer Aniston, but also to related concepts like ‘Lisa Kudow’ (another actress in ‘Friends’), so activity in that cell does not uniquely code ‘Jennifer Aniston’ and cannot be used to read out the presence of Jennifer Aniston. Quiroga et al make this clear in the discussion of their findings.

Bob Kentridge

Psychology Department
University of Durham

Canadian Institute for Advanced Research
Programme on Brain, Mind and Consciousness

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From: Connectionists <connectionists-bounces at mailman.srv.cs.cmu.edu<mailto:connectionists-bounces at mailman.srv.cs.cmu.edu>> on behalf of Asim Roy <ASIM.ROY at asu.edu<mailto:ASIM.ROY at asu.edu>>
Date: Thursday, 20 August 2026 at 06:51
To: Gary Marcus <gary.marcus at nyu.edu<mailto:gary.marcus at nyu.edu>>; Stephen José Hanson <jose at rubic.rutgers.edu<mailto:jose at rubic.rutgers.edu>>
Cc: director at inc.ucsd.edu<mailto:director at inc.ucsd.edu> <director at inc.ucsd.edu<mailto:director at inc.ucsd.edu>>; connectionists at mailman.srv.cs.cmu.edu<mailto:connectionists at mailman.srv.cs.cmu.edu> <connectionists at mailman.srv.cs.cmu.edu<mailto:connectionists at mailman.srv.cs.cmu.edu>>
Subject: Re: Connectionists: FW: AI at 50 videos...
[EXTERNAL EMAIL]
The Horace Barlow note was after a furious private debate with some eminent neuro and cognitive scientists regarding Jennifer Aniston cells being evidence for grandmother cells. And this was at age 93 when he visited me after defending his theory. At that stage of his career, his insights were profound.

Asim Roy
Professor, Information Systems
Arizona State University
Lifeboat Foundation Bios: Professor Asim Roy<https://urldefense.com/v3/__https:/lifeboat.com/ex/bios.asim.roy__;!!IKRxdwAv5BmarQ!NHg1P4byXZZmMFLMgr8A4dQNxSlqyvsqWef4wrPXtCXR0f0bo0eMm-rIF8G6ZV0$>
Asim Roy | iSearch (asu.edu)<https://isearch.asu.edu/profile/9973>

From: Asim Roy
Sent: Wednesday, August 19, 2026 6:28 PM
To: 'Gary Marcus' <gary.marcus at nyu.edu<mailto:gary.marcus at nyu.edu>>; Stephen José Hanson <jose at rubic.rutgers.edu<mailto:jose at rubic.rutgers.edu>>
Cc: director at inc.ucsd.edu<mailto:director at inc.ucsd.edu>; connectionists at mailman.srv.cs.cmu.edu<mailto:connectionists at mailman.srv.cs.cmu.edu>
Subject: RE: Connectionists: FW: AI at 50 videos...

I had some communication with Marvin Minsky and Jerry Fodor years ago. Here are two quotes from them:

1. Marvin Minsky: "Don’t pay any attention to the critics. Don’t even ignore them.” -By Sam Goldwyn

2. Jerry Fodor: “Arguing with Connectionists is like arguing with zombies; both are dead, but neither has noticed it.”

And here’s a note from a neuroscience pioneer Horace Barlow, Darwin’s great-grandson (Horace Barlow - Wikipedia<https://en.wikipedia.org/wiki/Horace_Barlow>), winner of many neuroscience prizes. Without his pioneering work poking into frog brains with microelectrodes, we would NOT have AI as we see it today. The grandmother cell theory essentially points to where cognition exists in an abstract form. And there is plenty of neurophysiological evidence for such single cell abstractions, starting with line orientation cells.
======================================================================================================================================
Dear Asim
Yes, I would like to join your group, though I would (again) like to make it clear that the grandmother cell theory is not mine, though I still hold that something conforming amazingly well to what was conceptualised by Jerry Lettvin 50 years ago, really does exist!
I am still actively interested in the topic, and have just sent off the final proofs of an essay bearing on it. I shall send you a copy of the final proof as soon as I am allowed to circulate it, and of course the more widely discussed it is the better pleased I shall be, though I fear that what I have written will not be universally accepted, at least at first!
Best regards
Horace
=============================================================================================================

Asim Roy
Professor, Information Systems
Arizona State University
Lifeboat Foundation Bios: Professor Asim Roy<https://urldefense.com/v3/__https:/lifeboat.com/ex/bios.asim.roy__;!!IKRxdwAv5BmarQ!NHg1P4byXZZmMFLMgr8A4dQNxSlqyvsqWef4wrPXtCXR0f0bo0eMm-rIF8G6ZV0$>
Asim Roy | iSearch (asu.edu)<https://isearch.asu.edu/profile/9973>

From: Connectionists <connectionists-bounces at mailman.srv.cs.cmu.edu<mailto:connectionists-bounces at mailman.srv.cs.cmu.edu>> On Behalf Of Gary Marcus
Sent: Wednesday, August 19, 2026 11:23 AM
To: Stephen José Hanson <jose at rubic.rutgers.edu<mailto:jose at rubic.rutgers.edu>>
Cc: director at inc.ucsd.edu<mailto:director at inc.ucsd.edu>; connectionists at mailman.srv.cs.cmu.edu<mailto:connectionists at mailman.srv.cs.cmu.edu>
Subject: Re: Connectionists: FW: AI at 50 videos...

yep: neural networks ascended, pushed symbols out of the way, and then symbols came back relabeled as harnesses, loops code interpreters, and tools.

neurosymbolic AI, the hybrid of the two approaches, clearly beat either of the two alternatives on their own.

claude code, biggest recent advance, shows that pretty clearly, when you look under the hood.

gary

On Aug 19, 2026, at 10:16 AM, Stephen José Hanson <jose at rubic.rutgers.edu<mailto:jose at rubic.rutgers.edu>> wrote:

Yes, historically this was an important meeting --and indeed the term AI was coined by John McCarthy who with several others put together the 1955 meeting;  McCarthy also invented LISP after this meeting.   Part of the AI meeting at DM was political. McCarthy deliberately chose "Artificial Intelligence" partly to distance the new effort from Wiener's cybernetics and the neural network tradition. Which was thematic in the MACY meetings.. which ended in 1953--2 years before the "AI" meeting.  McCarthy wanted to stake out a separate field with a symbolic/logical emphasis (in contrast to McCulloch and Pitts). So the naming wasn't just descriptive; it was a bit of a territorial move that arguably sidelined neural networks for decades until the connectionist revival in the 1980s (sorry Juergen).  And the more recent revolution associated with DL and LLMs more specifically.  In the 1970s, this fueled the long term debate in Cognitive Science on Symbols/Rules vs Vectors/NN.

Well at least we know how that turned out.

Stephen

On 8/17/26 13:30, Terry Sejnowski wrote:
Jean-Marc -

I was there and gave a talk, the only one on neural networks.  I learned a lot from the other speakers.

I just listened to the questions at the end of my talk.  I pretty much predicted what was going to happen in AI and thought it would take 50 years.  I was wrong, it took less than 20 years.

One of the questions at the end was about intelligent aliens who appear and don't have human brains.
This was a set piece in my recent book on ChatGPT and the Future of AI, where ChatGPT is the alien.

I gave my version of that meeting in my first book on the Deep Learning Revolution.  Every talk that reported progress did so because they had enough data to analyze, including Gene Charniak who was trying to parse sentences and Takeo Kanade working on computer vision (These two talks are not included in the list).  At the end Marvin Minsky accused them for just working on applications, not real AI.

Terry

------
On 8/17/2026 9:18 AM, Fellous, Jean-Marc wrote:
In case you did not see this: Some amazing lectures and (now historical) perspectives… the most interesting parts are when they tried and predicted the future of AI!

From: Connectionists <connectionists-bounces at mailman.srv.cs.cmu.edu><mailto:connectionists-bounces at mailman.srv.cs.cmu.edu> On Behalf Of George Cybenko
Sent: Monday, August 17, 2026 6:00 AM
To: connectionists at mailman.srv.cs.cmu.edu<mailto:connectionists at mailman.srv.cs.cmu.edu>
Subject: Connectionists: AI at 50 videos...

In 2006, we held a 50th anniversary conference at Dartmouth to commemorate
the historic 1956 meeting that coined the term "artificial intelligence."  At that time,
five of the surviving original participants attended.  Today they are all gone.

I just recently posted videos of the talks from the AI at 50 meeting at

https://sites.dartmouth.edu/cybenko/dartmouth-ai50-videos/<https://urldefense.com/v3/__https:/sites.dartmouth.edu/cybenko/dartmouth-ai50-videos/__;!!Mih3wA!HX5M154b9l4fIHZdxakK00FZ4H1IPqVHrV_pC-lh-4XwoZ6CvDp7SyXZ-ObDk5oWYIct3ux47KDlf3KvyIoMq7VLCwxY0JhC$>

INobody foresaw what is happening in AI today and in fact,
there were several digs against neural networks etc.

Enjoy!

Regards
George Cybenko

--

George Cybenko, Dorothy and Walter Gramm Professor of Engineering

Dartmouth College, 8000 Cummings Hall, Hanover NH 03755 USA

email:          gvc at dartmouth.edu<mailto:gvc at dartmouth.edu>

FAX:            603 646-9024

Cell:           603 369-1133

Assistant:      Ellen Wirta, 603 646-9672, Ellen.K.Wirta at Dartmouth.edu<mailto:Ellen.K.Wirta at Dartmouth.edu>

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