I recommend research on the welfare of soil invertebrates, and welfare comparisons across species. I do not recommend pursuing whatever land use changes seem to increase the welfare of soil invertebrates the most cost-effectively.
Part 3: Welfare Biology and AI: What We Can Do Now turns to interventions. I unpack Vasco Griloâs finding that the effects of GiveWellâs top charities on soil animals are ~90,000Ă larger than their effects on humans
This does not describe my current views well. I can see effects on soil invertebrates being anything from negligible to all that matters in terms of changes in welfare. Below are some numbers illustrating this.
For individual welfare per fully-healthy-animal-year proportional to âindividual number of neuronsâ^âexponentâ, and âexponentâ from 0 to 2, which covers the best guesses that I consider reasonable, I estimatethat GiveWellâs top charities change the welfare of soil ants, termites, springtails, mites, and nematodes 1.08*10^-5 to 10.9 billion times as much as they increase the welfare of humans. For my preferred exponent of 1, the change in the welfare on those soil invertebrates is 41.5 times as large as the increase in the welfare of humans (much less than the ratio of 90 k you mention in the quote above).
In addition, I have no idea about whether interventions targeting invertebrates increase the welfare of their target beneficiaries more or less cost-effectively than ones targeting humans. For individual welfare per fully-healthy-animal-year proportional to âindividual number of neuronsâ^âexponentâ, and âexponentâ from 0 to 2, which covers the best guesses that I consider reasonable, I estimatethat the Shrimp Welfare Projectâs (SWPâs) Humane Slaughter Initiative (HSI) has increased the welfare of shrimps 1.68*10^-6 to 1.68 M times as cost-effectively as GiveWellâs top charities increase the welfare of humans.
Rethink Priorities (RP) has done rigorous work on invertebrate sentience and moral weights, estimating welfare ranges for various species based on neuroscientific evidence. Their moral weight project produced estimates that are widely used in EA cost-effectiveness analyses â including the welfare range of 6.68 Ă 10âťâś (relative to humans) that Vasco Grilo extrapolated for nematodes. He deferred the caculation to Gemini 2.5, so the derivation is opaque, and the result should not be taken literally.
To clarify, RP did not get welfare ranges for nematodes, and Geminiâs guess that a modal soil nematode has 240 neurons has a negligible impact on my estimate for the expected welfare range of nematodes. Adult caenorhabditis elegans have 302 neurons, and the modal soil nematode has fewer neurons than this because new neurons are formed until adulthood. I do not know what is the exact number of neurons of random soil nematodes. However, the conclusions I would take from the calculations would be the same regardless of whether I used 302 or 30 neurons. So I just went with a guess from Gemini.
Thanks! Yes, small invertebrates have been on my mind ever since Brian Tomasik wrote about them 10+ years ago and cautioned against walking on grass. Iâm sort of reducitarian about grass⌠Iâve also donated to the âinvertsâ project of RP! Itâs a cause area Iâm quite excited about, though Iâm not sure whether Iâm more excited about helping arthropods or nematodes.
Your updated estimates have huge credible intervals! What is the main source of the uncertainty in the model, or the main sources?
Iâll compress some of my summaries of your articles to remove the older numbers and clarify your updated views in the second article by quoting from the comment. Ty!
The 90k (or 90.3k) figure is based on this sentence from this article:
Nonetheless, I calculate GiveWellâs top charities increase the welfare of soil animals 90.3 k times as much as they increase the welfare of humans, which is a way higher ratio than the ones I just mentioned.
Iâve also donated to the âinvertsâ project of RP!
Great. You may also be interested in donating to Arthropoda Foundation. I donated a few k$ to them last year. You are most likely aware of them. If relevant to readers, here is the post announcing their launch, and here is their post during the last Marginal Funding Week. They have been funding research informing how to increase the welfare of farmed arthropods, and âare particularly interested in research with a clear path to impact, whether by shaping future science or informing real-world decision-makingâ.
Your updated estimates have huge credible intervals! What is the main source of the uncertainty in the model, or the main sources?
The ranges only account for uncertainty in the individual welfare per fully-healthy-animal-year. I consider this roughly proportional to the expected welfare range. So you can say I am just accounting for uncertainty in the expected welfare range. I believe this the overwhelming driver of the overall uncertainty. Here are the expected welfare ranges as a fraction of that of humans as a function of the exponent of the individual number of neurons.
The 90k (or 90.3k) figure is based on this sentence from this article
Got it. I consider the above ratio reasonable too, but my current best guess is much lower, as I commented above.
Hi Dawn. Thanks for looking into soil invertebrates.
I recommend research on the welfare of soil invertebrates, and welfare comparisons across species. I do not recommend pursuing whatever land use changes seem to increase the welfare of soil invertebrates the most cost-effectively.
This does not describe my current views well. I can see effects on soil invertebrates being anything from negligible to all that matters in terms of changes in welfare. Below are some numbers illustrating this.
For individual welfare per fully-healthy-animal-year proportional to âindividual number of neuronsâ^âexponentâ, and âexponentâ from 0 to 2, which covers the best guesses that I consider reasonable, I estimate that GiveWellâs top charities change the welfare of soil ants, termites, springtails, mites, and nematodes 1.08*10^-5 to 10.9 billion times as much as they increase the welfare of humans. For my preferred exponent of 1, the change in the welfare on those soil invertebrates is 41.5 times as large as the increase in the welfare of humans (much less than the ratio of 90 k you mention in the quote above).
In addition, I have no idea about whether interventions targeting invertebrates increase the welfare of their target beneficiaries more or less cost-effectively than ones targeting humans. For individual welfare per fully-healthy-animal-year proportional to âindividual number of neuronsâ^âexponentâ, and âexponentâ from 0 to 2, which covers the best guesses that I consider reasonable, I estimate that the Shrimp Welfare Projectâs (SWPâs) Humane Slaughter Initiative (HSI) has increased the welfare of shrimps 1.68*10^-6 to 1.68 M times as cost-effectively as GiveWellâs top charities increase the welfare of humans.
To clarify, RP did not get welfare ranges for nematodes, and Geminiâs guess that a modal soil nematode has 240 neurons has a negligible impact on my estimate for the expected welfare range of nematodes. Adult caenorhabditis elegans have 302 neurons, and the modal soil nematode has fewer neurons than this because new neurons are formed until adulthood. I do not know what is the exact number of neurons of random soil nematodes. However, the conclusions I would take from the calculations would be the same regardless of whether I used 302 or 30 neurons. So I just went with a guess from Gemini.
Thanks! Yes, small invertebrates have been on my mind ever since Brian Tomasik wrote about them 10+ years ago and cautioned against walking on grass. Iâm sort of reducitarian about grass⌠Iâve also donated to the âinvertsâ project of RP! Itâs a cause area Iâm quite excited about, though Iâm not sure whether Iâm more excited about helping arthropods or nematodes.
Your updated estimates have huge credible intervals! What is the main source of the uncertainty in the model, or the main sources?
Iâll compress some of my summaries of your articles to remove the older numbers and clarify your updated views in the second article by quoting from the comment. Ty!
The 90k (or 90.3k) figure is based on this sentence from this article:
Iâll avoid citing the precise number.
Great. You may also be interested in donating to Arthropoda Foundation. I donated a few k$ to them last year. You are most likely aware of them. If relevant to readers, here is the post announcing their launch, and here is their post during the last Marginal Funding Week. They have been funding research informing how to increase the welfare of farmed arthropods, and âare particularly interested in research with a clear path to impact, whether by shaping future science or informing real-world decision-makingâ.
The ranges only account for uncertainty in the individual welfare per fully-healthy-animal-year. I consider this roughly proportional to the expected welfare range. So you can say I am just accounting for uncertainty in the expected welfare range. I believe this the overwhelming driver of the overall uncertainty. Here are the expected welfare ranges as a fraction of that of humans as a function of the exponent of the individual number of neurons.
Got it. I consider the above ratio reasonable too, but my current best guess is much lower, as I commented above.