Comparing the welfare of humans, chickens, pigs, octopuses, bees, and more | Bob Fischer

Project Objective: The Moral Weight Project aims to quantify and compare the welfare ranges of different species (humans and non-humans) to enable rational resource allocation between human and animal causes.

• The project defines "moral weight" as a conversion function translating units of animal welfare into human-equivalent units.
• This allows for direct comparison of interventions, such as contrasting malaria bed net distribution with factory cage-free chicken campaigns.

Methodological Framework: The researchers adopted a specific theoretical model to calculate welfare ranges.

• Theory of Welfare: The project assumes hedonism, positing that welfare is determined solely by the intensity of pleasurable and painful experiences (valenced states).
• Capacity Calculation: An individual's total capacity for welfare is calculated as the product of their welfare range (the intensity of peak positive/negative experiences) and their lifespan.
• Proxy Selection: Instead of using flawed proxies like neuron counts, the team identified empirical proxies for hedonic capacity, including:
  • Reversal learning capabilities.
  • Usage of analgesics (pain medication).
  • Numerical cognition.
  • Ability to learn from past experiences (conditioned place preference).
• Aggregation: Results aggregate uncertainty across different philosophical assumptions, including the possibility that invertebrates have faster "clock speeds" (more subjective experience per unit of objective time) or stronger pain signals to compensate for simpler neurology.

Key Findings on Welfare Ranges: The study estimated welfare ranges for 11 species, revealing that non-human animals have significantly higher moral weight than previously assumed under strict anthropocentric views.

• Chickens: Estimated to have a welfare range roughly 33% (one-third) that of humans.
  • This implies the suffering of one human for one hour is roughly equivalent to the suffering of three chickens for one hour.
• Pigs: Estimated to have a welfare range approximately 50% that of humans.
• Octopuses: Estimated to have a welfare range around 20% that of humans, with significant uncertainty allowing for upper bounds exceeding human capacity.
  • Researchers investigated the "nine minds" hypothesis (multiple independent minds in one body) but concluded octopuses should be treated as single moral patients.
• Invertebrates: Contrary to prior skepticism, invertebrates were found to have welfare ranges within two orders of magnitude of vertebrates.
  • Bees: Estimated at roughly 7% of human capacity.
  • Black Soldier Flies & Crustaceans: Found to have substantial capacity, partly due to their use as depression and pain models in human medical research (e.g., Drosophila).
  • Salmon: Estimated at roughly 5-6%, though the team noted this low figure likely reflects a lack of research rather than a true biological deficit.

Decision-Theoretic Implications: The project tested how different risk aversion strategies alter cost-effectiveness rankings between human and animal interventions.

• Expected Value Maximization: Without adjustments, interventions for shrimp and chickens dominate human interventions due to the sheer volume of animals involved.
• Risk Aversion Types:
  • Worst-Case Risk Aversion: Prioritizes avoiding the worst possible outcomes (e.g., billions of sentient shrimp suffering), which further boosts the value of animal interventions.
  • Difference-Making Risk Aversion: Prioritizes interventions with high certainty of impact, penalizing uncertain animal interventions where sentience probabilities are lower.
  • Ambiguity Aversion: Penalizes interventions with highly uncertain probability ranges (typical for invertebrates).
• Robustness of Chicken Interventions: Even when applying modest levels of difference-making or ambiguity aversion, interventions for chickens remain highly cost-effective, often outperforming both shrimp and human interventions.
• Human Interventions: To make human interventions (like malaria prevention) the optimal choice over animal interventions, one would need extreme levels of risk aversion or a belief that chickens have negligible moral weight.

Debates and Objections Addressed:

• Neuron Count Proxy: The team explicitly rejected neuron counts as a proxy, noting they correlate poorly with the intensity of experience and can be confounded by body size; simpler brains may actually require stronger pain signals to regulate behavior.
• Anthropomorphism: The project warns against both "anthropomorphizing" (over-attributing human traits) and "anthropodenial" (denying complex capacities). The methodology relies on observable proxies rather than subjective intuition.
• Hedonism vs. Non-Hedonic Goods: While critics argue welfare includes non-hedonic factors (knowledge, achievement), the project uses the "Tortured Tim" thought experiment to argue that non-hedonic goods cannot outweigh extreme physical pain, capping their potential contribution to total welfare range.
• Subjective Time: The team incorporated a controversial hypothesis (from Jason Truecraft and others) that smaller organisms may perceive time faster, potentially increasing their subjective welfare range relative to humans.

Future Directions and Limitations:

• The results are intended as placeholders that acknowledge high uncertainty rather than definitive truths.
• The methodology is limited by the availability of data; understudied species (like salmon) receive lower estimates not necessarily due to lower capacity but due to lack of evidence.
• The project calls for new empirical research to refine proxies and reduce reliance on expert hunches.

Personal Reflections:

• Host Luis Rodriguez noted a shift in his own perspective, moving from skepticism about invertebrate sentience to recognizing their significant moral weight based on the data.
• Bob Fisher highlighted that intuition regarding animal moral weight is often unreliable and that the mathematical modeling challenges ingrained biases about the "uniqueness" of human suffering.