Thanks for your comments. If temporal resolution does, under the right conditions, track the subjective experience of time, I expect it will be the temporal resolution of whichever sensory modality exerts the biggest selection pressure due to differences in the subjective experience of time. In many cases that will probably be the sensory modality with the best (fastest) temporal resolution, but that need not always be the case. As I say in the post, temporal resolution only plausibly tracks the subjective experience of time for animals in which the fitness-improving actions that the greater temporal resolution enables require conscious processing. It may be the case that for certain animals, improvements in temporal resolution in one sense enable actions that increase fitness without conscious processing, while improvements in temporal resolution in a different sense enable actions that increase fitness only with additional conscious processing.
In short, I unfortunately don’t expect there to be any simple rule that will show which measures of temporal resolution are best at tracking differences in the subjective experience of time in all circumstances. In determining whether and to what degree a particular measure of temporal resolution might track differences in the subjective experience of time within a group of species, we’ll need to pay attention to the context in which evolutionary pressures were likely to exert an influence on temporal resolution and temporal experience for the species in the group.
It seems like there’s a simple and plausible argument for a lower bound on the maximum frequency of conscious experience that doesn’t depend so much on evolutionary pressures, although maybe only having one bound isn’t good enough for comparisons between species.
Premise 1: If an individual X can consciously recognize that a stimulus is changing when it’s changing at some frequency f, then X can (sometimes) have experiences at a frequency at least f. In other words, X’s maximum frequency of conscious experience fmax satisfies fmax≥f.
Premise 2: Individual X can consciously recognize that some stimulus is changing at frequency f1, that some stimulus (possibly the same, or even a different modality) is changing at frequency f2, …, and that some stimulus is changing at frequency fn, n≥1.
Conclusion: X’s maximum frequency of conscious experience fmax is such that fmax≥f1,fmax≥f2,…fmax≥fn, and hence fmax≥max{f1,f2,…,fn}.
I think that the truth or falsity of Premise 1 for a given individual X shouldn’t depend so finely on the evolutionary pressures their species faced, and it should be the same across species for which conscious perception works the same way in their brains, but possibly with different emphases/prioritization, i.e. differences in degree, not kind. So, if the brains of individuals X and Y differ only in number of neurons doing similar jobs or the frequency with which their neurons fire, Premise 1 should be true for both, or false for both. Enough functional and structural homology (together) would preserve the truth value of Premise 1.
For example, I’d expect Premise 1 to be true for both moles and hedgehogs, or false for both, even though moles have poor vision. I’d even guess that Premise 1 is true for (almost?) all mammals or false for (almost?) all mammals, because high-level structures like the cerebral cortex, occipital lobe, visual cortex, etc. are common to us. This is not a particularly informed guess, though.
Is Premise 1 too strong? I think one reason to doubt it is that if you subsample a periodic signal at some regular period, it’s very rare that the subsample will be constant. For example, a periodic discrete subsample of sin(x) will only be constant if its period is an integer multiple of π.
Is it the case that CFF and similar measures often can’t be used for the frequencies in Premise 2, say, because the recognition often isn’t conscious?
Thanks for the interesting argument. Before I can evaluate it, however, I’d need you to clarify your terms a bit for me. In particular, I’d need to know more about what you mean by “frequency of conscious experience.” Based on my best reconstruction of the argument, it can’t mean temporal resolution or rate of subjective experience.
I’ll try clarify my position a bit, in case it’s helpful to you or other readers. I don’t think there’s an a priori connection between temporal resolution (as measured by CFF or any other method) and rate of subjective experience. If there’s a correlation between the two, that’s a contingent empirical fact. There is no conceptual tension between the claim that a creature consciously perceives the flicker-to-steady-glow transition at some high threshold (200 Hz vs 60 Hz for humans, say) and the claim that the creature has the same rate of subjective experience as a typical human. (Similarly, there is no conceptual tension between the claim that some creature consciously perceives the transition at the same threshold as humans but has a different rate of subjective experience.) It’s tempting to think that temporal resolution is like the frame rate of a video, and as the temporal resolution goes up or down, so too must the rate of subjective experience. But the mechanisms that govern the intake and processing of perceptual information are a lot more complicated than that, and the mechanisms that govern the subjective experience of time appear to be more complicated still.
One analogy that is sometimes helpful to me is to think of (visual) temporal resolution as a measure of motion blur. As one’s temporal resolution improves, motion blur is reduced. But changes in motion blur need not have any connection to temporal experience. When I’m drunk, my motion blur greatly increases, but my rate of subjective experience doesn’t change.
(Also, apologies if in elaborating my position I’ve missed the point of your argument. Like I said, it looks interesting, I just need to understand the terms better to evaluate it.)
Thanks for the interesting argument. Before I can evaluate it, however, I’d need you to clarify your terms a bit for me. In particular, I’d need to know more about what you mean by “frequency of conscious experience.” Based on my best reconstruction of the argument, it can’t mean temporal resolution or rate of subjective experience.
My intention was rate of subjective experience. I can rephrase Premise 1:
Premise 1: Any observed conscious temporal resolution frequency for an individual X (within some set of possible conditions C) is a lower bound for the maximum frequency of subjective experience for X (within C).
Does it make sense to interpret the rate of subjective experience as a frequency, the number of subjective experiences per second? Maybe our conscious experiences are not sufficiently synchronized across our brains for such an interpretation?
Even if it does make sense, Premise 1 could still be false. Or, even if Premise 1 is true, it could be that the actual maximum frequency of subjective experience isn’t well correlated with the observed maximum temporal resolution frequency (say as measured by CFF). Maybe the gap is huge, and our max frequency of subjective experiences is millions of times faster than our max temporal resolution frequency.
It’s tempting to think that temporal resolution is like the frame rate of a video, and as the temporal resolution goes up or down, so too must the rate of subjective experience. But the mechanisms that govern the intake and processing of perceptual information are a lot more complicated than that, and the mechanisms that govern the subjective experience of time appear to be more complicated still.
Premise 1 depends on interpreting temporal resolution like a lower bound for the frame rate of the video which is our subjective experience, although it isn’t committed to the claim about correlation between temporal resolution and the rate of subjective experience.
There is no conceptual tension between the claim that a creature consciously perceives the flicker-to-steady-glow transition at some high threshold (200 Hz vs 60 Hz for humans, say) and the claim that the creature has the same rate of subjective experience as a typical human. (Similarly, there is no conceptual tension between the claim that some creature consciously perceives the transition at the same threshold as humans but has a different rate of subjective experience.)
How this could look is that the 60 Hz max CFF for humans is a bad lower bound for our frequency of subjective experience, which is actually much faster, but to match an individual with a CFF of 200 Hz, our maximum frequency of subjective experience would have to be at least 200 Hz.
Great, thanks Michael—that clarifies the argument for me.
Premise 1: Any observed conscious temporal resolution frequency for an individual X (within some set of possible conditions C) is a lower bound for the maximum frequency of subjective experience for X (within C).
While I think it’s plausible that one’s temporal resolution sets some sort of bound on one’s rate of subjective experience, I just want to reiterate that I believe this is an empirical claim, not a conceptual claim. I’m open to the possibility that temporal resolution is just totally irrelevant to the subjective experience of time.
(As an aside, I think we have to be a bit careful how we (myself included) use the word ‘conscious’ in this context. In the post I distinguish behavioral methods for determining CFF from ERG methods for determining CFF. But even bees can be trained on the behavioral paradigm. This of course doesn’t settle the question of whether they’re conscious.)
Does it make sense to interpret the rate of subjective experience as a frequency, the number of subjective experiences per second? Maybe our conscious experiences are not sufficiently synchronized across our brains for such an interpretation?
This is another good question for which I don’t have the answer. A related issue is whether experiences are discrete (countable) in the relevant sense. There are arguments that pull in either direction here. But, just to clarify, even if experiences are countable in the relevant sense, it would be an astounding coincidence if our experience frequency exactly matched our critical flicker-fusion frequency (i.e., 60 experiences per second).
Hi Michael,
Thanks for your comments. If temporal resolution does, under the right conditions, track the subjective experience of time, I expect it will be the temporal resolution of whichever sensory modality exerts the biggest selection pressure due to differences in the subjective experience of time. In many cases that will probably be the sensory modality with the best (fastest) temporal resolution, but that need not always be the case. As I say in the post, temporal resolution only plausibly tracks the subjective experience of time for animals in which the fitness-improving actions that the greater temporal resolution enables require conscious processing. It may be the case that for certain animals, improvements in temporal resolution in one sense enable actions that increase fitness without conscious processing, while improvements in temporal resolution in a different sense enable actions that increase fitness only with additional conscious processing.
In short, I unfortunately don’t expect there to be any simple rule that will show which measures of temporal resolution are best at tracking differences in the subjective experience of time in all circumstances. In determining whether and to what degree a particular measure of temporal resolution might track differences in the subjective experience of time within a group of species, we’ll need to pay attention to the context in which evolutionary pressures were likely to exert an influence on temporal resolution and temporal experience for the species in the group.
It seems like there’s a simple and plausible argument for a lower bound on the maximum frequency of conscious experience that doesn’t depend so much on evolutionary pressures, although maybe only having one bound isn’t good enough for comparisons between species.
Premise 1: If an individual X can consciously recognize that a stimulus is changing when it’s changing at some frequency f, then X can (sometimes) have experiences at a frequency at least f. In other words, X’s maximum frequency of conscious experience fmax satisfies fmax≥f.
Premise 2: Individual X can consciously recognize that some stimulus is changing at frequency f1, that some stimulus (possibly the same, or even a different modality) is changing at frequency f2, …, and that some stimulus is changing at frequency fn, n≥1.
Conclusion: X’s maximum frequency of conscious experience fmax is such that fmax≥f1,fmax≥f2,…fmax≥fn, and hence fmax≥max{f1,f2,…,fn}.
I think that the truth or falsity of Premise 1 for a given individual X shouldn’t depend so finely on the evolutionary pressures their species faced, and it should be the same across species for which conscious perception works the same way in their brains, but possibly with different emphases/prioritization, i.e. differences in degree, not kind. So, if the brains of individuals X and Y differ only in number of neurons doing similar jobs or the frequency with which their neurons fire, Premise 1 should be true for both, or false for both. Enough functional and structural homology (together) would preserve the truth value of Premise 1.
For example, I’d expect Premise 1 to be true for both moles and hedgehogs, or false for both, even though moles have poor vision. I’d even guess that Premise 1 is true for (almost?) all mammals or false for (almost?) all mammals, because high-level structures like the cerebral cortex, occipital lobe, visual cortex, etc. are common to us. This is not a particularly informed guess, though.
Is Premise 1 too strong? I think one reason to doubt it is that if you subsample a periodic signal at some regular period, it’s very rare that the subsample will be constant. For example, a periodic discrete subsample of sin(x) will only be constant if its period is an integer multiple of π.
Is it the case that CFF and similar measures often can’t be used for the frequencies in Premise 2, say, because the recognition often isn’t conscious?
Hi Michael,
Thanks for the interesting argument. Before I can evaluate it, however, I’d need you to clarify your terms a bit for me. In particular, I’d need to know more about what you mean by “frequency of conscious experience.” Based on my best reconstruction of the argument, it can’t mean temporal resolution or rate of subjective experience.
I’ll try clarify my position a bit, in case it’s helpful to you or other readers. I don’t think there’s an a priori connection between temporal resolution (as measured by CFF or any other method) and rate of subjective experience. If there’s a correlation between the two, that’s a contingent empirical fact. There is no conceptual tension between the claim that a creature consciously perceives the flicker-to-steady-glow transition at some high threshold (200 Hz vs 60 Hz for humans, say) and the claim that the creature has the same rate of subjective experience as a typical human. (Similarly, there is no conceptual tension between the claim that some creature consciously perceives the transition at the same threshold as humans but has a different rate of subjective experience.) It’s tempting to think that temporal resolution is like the frame rate of a video, and as the temporal resolution goes up or down, so too must the rate of subjective experience. But the mechanisms that govern the intake and processing of perceptual information are a lot more complicated than that, and the mechanisms that govern the subjective experience of time appear to be more complicated still.
One analogy that is sometimes helpful to me is to think of (visual) temporal resolution as a measure of motion blur. As one’s temporal resolution improves, motion blur is reduced. But changes in motion blur need not have any connection to temporal experience. When I’m drunk, my motion blur greatly increases, but my rate of subjective experience doesn’t change.
(Also, apologies if in elaborating my position I’ve missed the point of your argument. Like I said, it looks interesting, I just need to understand the terms better to evaluate it.)
My intention was rate of subjective experience. I can rephrase Premise 1:
Premise 1: Any observed conscious temporal resolution frequency for an individual X (within some set of possible conditions C) is a lower bound for the maximum frequency of subjective experience for X (within C).
Does it make sense to interpret the rate of subjective experience as a frequency, the number of subjective experiences per second? Maybe our conscious experiences are not sufficiently synchronized across our brains for such an interpretation?
Even if it does make sense, Premise 1 could still be false. Or, even if Premise 1 is true, it could be that the actual maximum frequency of subjective experience isn’t well correlated with the observed maximum temporal resolution frequency (say as measured by CFF). Maybe the gap is huge, and our max frequency of subjective experiences is millions of times faster than our max temporal resolution frequency.
Premise 1 depends on interpreting temporal resolution like a lower bound for the frame rate of the video which is our subjective experience, although it isn’t committed to the claim about correlation between temporal resolution and the rate of subjective experience.
How this could look is that the 60 Hz max CFF for humans is a bad lower bound for our frequency of subjective experience, which is actually much faster, but to match an individual with a CFF of 200 Hz, our maximum frequency of subjective experience would have to be at least 200 Hz.
Great, thanks Michael—that clarifies the argument for me.
While I think it’s plausible that one’s temporal resolution sets some sort of bound on one’s rate of subjective experience, I just want to reiterate that I believe this is an empirical claim, not a conceptual claim. I’m open to the possibility that temporal resolution is just totally irrelevant to the subjective experience of time.
(As an aside, I think we have to be a bit careful how we (myself included) use the word ‘conscious’ in this context. In the post I distinguish behavioral methods for determining CFF from ERG methods for determining CFF. But even bees can be trained on the behavioral paradigm. This of course doesn’t settle the question of whether they’re conscious.)
This is another good question for which I don’t have the answer. A related issue is whether experiences are discrete (countable) in the relevant sense. There are arguments that pull in either direction here. But, just to clarify, even if experiences are countable in the relevant sense, it would be an astounding coincidence if our experience frequency exactly matched our critical flicker-fusion frequency (i.e., 60 experiences per second).