Jean Laurens
@jeanlaurens.bsky.social
Neuroscientist - Vestibular system, Spatial navigation - Group leader at the Ernst Strüngmann Institute for Neuroscience, Frankfurt, Germany.
And in doing so, we can also re-center the debate on solid scientific arguments, which benefits the scientific community in general and animal research in particular.
November 12, 2025 at 10:17 AM
And in doing so, we can also re-center the debate on solid scientific arguments, which benefits the scientific community in general and animal research in particular.
This is a very sensible point. The goal here isn’t to dismiss rodent research, but to emphasize the indispensability of work with NHP.
But let's keep in mind that research in NHPs is only ethical and legal when it cannot be done in rodents; therefore we must highlight this indispensability.
But let's keep in mind that research in NHPs is only ethical and legal when it cannot be done in rodents; therefore we must highlight this indispensability.
November 12, 2025 at 10:15 AM
This is a very sensible point. The goal here isn’t to dismiss rodent research, but to emphasize the indispensability of work with NHP.
But let's keep in mind that research in NHPs is only ethical and legal when it cannot be done in rodents; therefore we must highlight this indispensability.
But let's keep in mind that research in NHPs is only ethical and legal when it cannot be done in rodents; therefore we must highlight this indispensability.
Maybe the pattern is that transformative discoveries are made in NHPs first, and then, with some effort, we figure out how to translate them to rodents. 😅
November 12, 2025 at 10:08 AM
Maybe the pattern is that transformative discoveries are made in NHPs first, and then, with some effort, we figure out how to translate them to rodents. 😅
So to conclude: monkeys are not “uniquely intelligent.”
Depending on the species, their intelligence is on par with pigs, cats, dogs, many birds, etc. Maybe even rats. And nowhere near humans (except apes).
What is crucial for neuroscience is their evolutionary and anatomical proximity.
Depending on the species, their intelligence is on par with pigs, cats, dogs, many birds, etc. Maybe even rats. And nowhere near humans (except apes).
What is crucial for neuroscience is their evolutionary and anatomical proximity.
November 12, 2025 at 7:36 AM
So to conclude: monkeys are not “uniquely intelligent.”
Depending on the species, their intelligence is on par with pigs, cats, dogs, many birds, etc. Maybe even rats. And nowhere near humans (except apes).
What is crucial for neuroscience is their evolutionary and anatomical proximity.
Depending on the species, their intelligence is on par with pigs, cats, dogs, many birds, etc. Maybe even rats. And nowhere near humans (except apes).
What is crucial for neuroscience is their evolutionary and anatomical proximity.
In my view, it is not intelligence in the absolute that makes monkeys human-relevant in neuroscience.
What truly matters is intelligence embedded in a human-like body, sensors and effectors, and brain structure.
That is what shapes how brains work.
What truly matters is intelligence embedded in a human-like body, sensors and effectors, and brain structure.
That is what shapes how brains work.
November 12, 2025 at 7:36 AM
In my view, it is not intelligence in the absolute that makes monkeys human-relevant in neuroscience.
What truly matters is intelligence embedded in a human-like body, sensors and effectors, and brain structure.
That is what shapes how brains work.
What truly matters is intelligence embedded in a human-like body, sensors and effectors, and brain structure.
That is what shapes how brains work.
A rat may be almost “marmoset-smart,” but it is essentially blind compared to a primate.
It can grasp food with its forepaws, but it lacks the fine motor control of a monkey: their corticospinal pathways are fundamentally different.
And that's the difference.
It can grasp food with its forepaws, but it lacks the fine motor control of a monkey: their corticospinal pathways are fundamentally different.
And that's the difference.
November 12, 2025 at 7:36 AM
A rat may be almost “marmoset-smart,” but it is essentially blind compared to a primate.
It can grasp food with its forepaws, but it lacks the fine motor control of a monkey: their corticospinal pathways are fundamentally different.
And that's the difference.
It can grasp food with its forepaws, but it lacks the fine motor control of a monkey: their corticospinal pathways are fundamentally different.
And that's the difference.
So what’s the real difference between a marmoset and a rat?
Are marmosets perhaps “twice as smart”? Would that make rats “almost as good as marmosets”?
In my view, the fundamental distinction is not their degree of intelligence, but their body.
Are marmosets perhaps “twice as smart”? Would that make rats “almost as good as marmosets”?
In my view, the fundamental distinction is not their degree of intelligence, but their body.
November 12, 2025 at 7:36 AM
So what’s the real difference between a marmoset and a rat?
Are marmosets perhaps “twice as smart”? Would that make rats “almost as good as marmosets”?
In my view, the fundamental distinction is not their degree of intelligence, but their body.
Are marmosets perhaps “twice as smart”? Would that make rats “almost as good as marmosets”?
In my view, the fundamental distinction is not their degree of intelligence, but their body.
To extend the argument, let’s consider rats and marmosets.
(Btw, for context: I lead a lab working with both, and I have roughly ten years of experience with macaques.)
Marmosets are much less intelligent than macaques and, from what I hear, probably less intelligent than pigs.
(Btw, for context: I lead a lab working with both, and I have roughly ten years of experience with macaques.)
Marmosets are much less intelligent than macaques and, from what I hear, probably less intelligent than pigs.
November 12, 2025 at 7:36 AM
To extend the argument, let’s consider rats and marmosets.
(Btw, for context: I lead a lab working with both, and I have roughly ten years of experience with macaques.)
Marmosets are much less intelligent than macaques and, from what I hear, probably less intelligent than pigs.
(Btw, for context: I lead a lab working with both, and I have roughly ten years of experience with macaques.)
Marmosets are much less intelligent than macaques and, from what I hear, probably less intelligent than pigs.
So we rightly apply higher ethical standards to highly cognitive animals.
But let's be clear: macaque cognition remains far from human intelligence—no abstract reasoning, language, or symbolic thought.
Even a profoundly impaired human is still far, far smarter than a macaque.
But let's be clear: macaque cognition remains far from human intelligence—no abstract reasoning, language, or symbolic thought.
Even a profoundly impaired human is still far, far smarter than a macaque.
November 12, 2025 at 7:36 AM
So we rightly apply higher ethical standards to highly cognitive animals.
But let's be clear: macaque cognition remains far from human intelligence—no abstract reasoning, language, or symbolic thought.
Even a profoundly impaired human is still far, far smarter than a macaque.
But let's be clear: macaque cognition remains far from human intelligence—no abstract reasoning, language, or symbolic thought.
Even a profoundly impaired human is still far, far smarter than a macaque.
This translates into species-appropriate housing, social enrichment, and the prohibition of social isolation, among other measures.
And the obligation to replace them with species less apt to suffer, e.g. rodents, when possible.
And the obligation to replace them with species less apt to suffer, e.g. rodents, when possible.
November 12, 2025 at 7:36 AM
This translates into species-appropriate housing, social enrichment, and the prohibition of social isolation, among other measures.
And the obligation to replace them with species less apt to suffer, e.g. rodents, when possible.
And the obligation to replace them with species less apt to suffer, e.g. rodents, when possible.
Defining intelligence in animals is not straightforward—there is no objective scale.
In the case of macaques, I would honestly place them somewhere on par with cats and dogs. All of these species receive special ethical consideration because of their cognitive capacities.
In the case of macaques, I would honestly place them somewhere on par with cats and dogs. All of these species receive special ethical consideration because of their cognitive capacities.
November 12, 2025 at 7:36 AM
Defining intelligence in animals is not straightforward—there is no objective scale.
In the case of macaques, I would honestly place them somewhere on par with cats and dogs. All of these species receive special ethical consideration because of their cognitive capacities.
In the case of macaques, I would honestly place them somewhere on par with cats and dogs. All of these species receive special ethical consideration because of their cognitive capacities.
In the case of apes (chimpanzees, gorillas, etc.), we fully acknowledge that they are uniquely intelligent, to the point that we recognize in them something approaching humanity.
This is precisely why experiments on apes are now essentially banned.
This is precisely why experiments on apes are now essentially banned.
November 12, 2025 at 7:36 AM
In the case of apes (chimpanzees, gorillas, etc.), we fully acknowledge that they are uniquely intelligent, to the point that we recognize in them something approaching humanity.
This is precisely why experiments on apes are now essentially banned.
This is precisely why experiments on apes are now essentially banned.
That’s a deep question that I probably can’t answer entirely, but here are a few thoughts.
First, there is indeed a dilemma: to understand the human brain, we need to study animals that are close to humans. The more human-relevant, the greater the ethical implications.
First, there is indeed a dilemma: to understand the human brain, we need to study animals that are close to humans. The more human-relevant, the greater the ethical implications.
November 12, 2025 at 7:36 AM
That’s a deep question that I probably can’t answer entirely, but here are a few thoughts.
First, there is indeed a dilemma: to understand the human brain, we need to study animals that are close to humans. The more human-relevant, the greater the ethical implications.
First, there is indeed a dilemma: to understand the human brain, we need to study animals that are close to humans. The more human-relevant, the greater the ethical implications.
I would argue that 3D rotations are very much a cognitive task, and that hippocampal representations are inherently cognitive in nature.
That said, my own expertise is on the vestibular system and navigation, and I think others have answered this topic better than I can 😁
That said, my own expertise is on the vestibular system and navigation, and I think others have answered this topic better than I can 😁
November 12, 2025 at 6:47 AM
I would argue that 3D rotations are very much a cognitive task, and that hippocampal representations are inherently cognitive in nature.
That said, my own expertise is on the vestibular system and navigation, and I think others have answered this topic better than I can 😁
That said, my own expertise is on the vestibular system and navigation, and I think others have answered this topic better than I can 😁
In the end, even basic brain connectivity is different between rodents and primates, with primates having more specialized, sparsely connected brain regions.
academic.oup.com/cercor/artic...
academic.oup.com/cercor/artic...
November 11, 2025 at 3:54 PM
In the end, even basic brain connectivity is different between rodents and primates, with primates having more specialized, sparsely connected brain regions.
academic.oup.com/cercor/artic...
academic.oup.com/cercor/artic...
To me, this reveals that most of our subjective experience of the world is driven by accurate, long distance vision.
Which rodents don't have - rats visual acuity is 1/30 to 1/60 of human's.
Which rodents don't have - rats visual acuity is 1/30 to 1/60 of human's.
November 11, 2025 at 3:45 PM
To me, this reveals that most of our subjective experience of the world is driven by accurate, long distance vision.
Which rodents don't have - rats visual acuity is 1/30 to 1/60 of human's.
Which rodents don't have - rats visual acuity is 1/30 to 1/60 of human's.
And then seeing again.
For me, this study of Marmoset hippocampus nails it. Primates don't have 'place cells' like rodents do, instead hippocampal cells encode where the monkeys look.
www.nature.com/articles/s41...
For me, this study of Marmoset hippocampus nails it. Primates don't have 'place cells' like rodents do, instead hippocampal cells encode where the monkeys look.
www.nature.com/articles/s41...
Primacy of vision shapes behavioral strategies and neural substrates of spatial navigation in marmoset hippocampus - Nature Communications
How diurnal primates develop exploration-navigation strategy and how the physiology of primate hippocampus is shaped in navigation are not fully understood. Here authors show that marmosets adapted th...
www.nature.com
November 11, 2025 at 3:42 PM
And then seeing again.
For me, this study of Marmoset hippocampus nails it. Primates don't have 'place cells' like rodents do, instead hippocampal cells encode where the monkeys look.
www.nature.com/articles/s41...
For me, this study of Marmoset hippocampus nails it. Primates don't have 'place cells' like rodents do, instead hippocampal cells encode where the monkeys look.
www.nature.com/articles/s41...
Seeing 😁
Ok, a bit more seriously, here is one example where Marmosets (and primates in general) vastly outperform rats at object recognition, especially when it involves mental rotation:
www.sciencedirect.com/science/arti...
Ok, a bit more seriously, here is one example where Marmosets (and primates in general) vastly outperform rats at object recognition, especially when it involves mental rotation:
www.sciencedirect.com/science/arti...
Marmoset core visual object recognition behavior is comparable to that of macaques and humans
Among the smallest simian primates, the common marmoset offers promise as an experimentally tractable primate model for neuroscience with translationa…
www.sciencedirect.com
November 11, 2025 at 3:38 PM
Seeing 😁
Ok, a bit more seriously, here is one example where Marmosets (and primates in general) vastly outperform rats at object recognition, especially when it involves mental rotation:
www.sciencedirect.com/science/arti...
Ok, a bit more seriously, here is one example where Marmosets (and primates in general) vastly outperform rats at object recognition, especially when it involves mental rotation:
www.sciencedirect.com/science/arti...
I’d be the first to switch from NHPs to humans if I could decide where to record and do it under proper lab conditions.
And I might even see the day when brain electrodes are completely safe, and I can record from healthy volunteers.
But we’re not there yet (and it will take some 🐵s to get there).
And I might even see the day when brain electrodes are completely safe, and I can record from healthy volunteers.
But we’re not there yet (and it will take some 🐵s to get there).
November 3, 2025 at 11:44 AM
I’d be the first to switch from NHPs to humans if I could decide where to record and do it under proper lab conditions.
And I might even see the day when brain electrodes are completely safe, and I can record from healthy volunteers.
But we’re not there yet (and it will take some 🐵s to get there).
And I might even see the day when brain electrodes are completely safe, and I can record from healthy volunteers.
But we’re not there yet (and it will take some 🐵s to get there).
I’m well aware of single-neuron recordings in human patients; but to date, they’ve been very restricted in terms of where you can record and under what conditions (and data quality, although Neuropixels and other electrodes could indeed change that dramatically)...
November 3, 2025 at 11:44 AM
I’m well aware of single-neuron recordings in human patients; but to date, they’ve been very restricted in terms of where you can record and under what conditions (and data quality, although Neuropixels and other electrodes could indeed change that dramatically)...
Such as which ones?
November 3, 2025 at 6:25 AM
Such as which ones?