La science économique au service de la société

Colloque « Welfare across species » | 8-9 juin

Paris School of Economics a le plaisir de vous inviter au colloque « Welfare across species » organisé par la Chaire Ouvrir la science économique.



Ce colloque est organisé conjointement à Paris School of Economics par les deux équipes qui développent des collaborations et des activités interdisciplinaires avec la philosophie et les sciences de l’environnement.

Il se concentrera sur la question de l’évaluation de la biodiversité du point de vue du bien-être. Chaque discipline est confrontée à des défis importants à cet égard.

L’évaluation des politiques environnementales ne peut plus se faire uniquement en termes de services écosystémiques pour l’humanité et ce point est fermement exprimé par la Plateforme intergouvernementale scientifique et politique sur la biodiversité et les services écosystémiques (IPBES).

  • Pour les économistes, cela signifie que la mesure du « bien-être social » doit être élargie pour tenir compte du bien-être des espèces non-humaines.
  • Pour les philosophes, conceptualiser la nouvelle relation entre les humains et les non-humains en termes de similitude dans la sensibilité, ou en termes de droits et de personnalité, soulève de nombreuses questions.
  • Pour les éthologues et les zoologistes, une nouvelle compréhension de la vision spécifique du monde et de la qualité de vie d’autres espèces remet en question les anciennes hypothèses.
  • Pour les biologistes de la conservation, la préservation du statu quo entre les espèces est contestée par des perspectives alternatives reconnaissant la valeur des organismes individuels.

Le colloque réunit des chercheurs des trois domaines (économie, philosophie, environnement et sciences naturelles) pour partager les progrès récents dans leurs domaines respectifs et, surtout, exposer ouvertement les défis et les questions ouvertes auxquels chacun d’entre eux fait face dans les domaines liés au bien-être de diverses espèces.

Une attention particulière est mise sur les travaux qui mettent en lumière l’évaluation des compromis entre les intérêts conflictuels des diverses espèces mais aussi les synergies possibles entre les espèces pour définir des politiques responsables en matière de biodiversité.


Jeudi 8 juin

Stéphane Zuber (PSE, CNRS)
Separable social welfare functions for multi-species populations
If non-human animals experience wellbeing and suffering, such welfare consequences arguably should be included in a social welfare evaluation. Yet economic evaluations almost universally ignore non-human animals, in part because axiomatic social choice theory has failed to propose and characterize multi-species social welfare functions. Here we propose axioms and functional forms to fill this gap. We provide a range of alternative representations, characterizing a broad range of possibilities for multi-species social welfare. Among these, we identify a new characterization of additively-separable generalized (multi-species) total utilitarianism. The multispecies setting permits a novel, weak species-level separability axiom with important consequences. We provide examples to illustrate that non-separability across species is implausible in a multi-species setting

Audrey Maille (MNHN)
Co-existing with other primates : welfare issues in captivity and in the wild
Nowadays, most nonhuman primates live in a world that is full of humans. More than 60% of the 500 (currently described) primate species are threatened with extinction by the end of the 21st century, and this number is increasing at each census. In the hope of reinforcing the remaining populations, many species of primates are the subject of breeding programs in zoos. It is therefore urgent to better understand how anthropogenic activities affect the well-being of individual primates, both in captivity and in the wild. I will present some case studies in various contexts, highlighting the contributions of animal behaviour sciences (ethology and behavioural ecology) to the study of primate welfare.

Walter Veit (University of Bristol)
From Life History Complexity to Welfare Comparisons
While differences in moral status in humans are considered to be highly controversial, it appears to be an inevitable conclusion when it comes to welfare comparisons across species.
From a bee to a blue whale, there appears to be a need to recognize distinct levels of sentience with different capacities for suffering (or for that matter pleasure).
In this talk, I will introduce a theoretical framework based in life history theory to assess how complex the strategies are that natural selection has implemented to maximize fitness and relate them to welfare.
As I shall argue, sentience evolved as a common currency to deal with complex economic decision problems involving trade-offs and understanding this capacity through comparative neuroeconomics research across the animal branch of life will enable us to make better inter-species welfare comparisons.

Eleftheria Triviza (University of Mannheim)
Eating Habits, Food Consumption, and Health : The Role of Early Life Experiences
This study explores the long-run effects of a temporary scarcity of a consumption good on preferences towards that good once the shock is over. Specifically, we focus on individuals who were children during World War II and assess the consequences of the temporary drop in meat availability they experienced early in life. To this end, we combine new hand-collected historical data on the number of livestock at the local level with microdata on eating habits, health outcomes, and food consumption expenditures. By exploiting cohort and regional variation in a difference-in-differences estimation, we show that individuals who as children were more exposed to meat scarcity tend to consume relatively more meat and spend more on food during late adulthood. Consistent with medical studies on the side effects of meat overconsumption, we also find that these individuals have a higher probability of being overweight and suffering from cardiovascular disease. Our results point towards a behavioral channel, where early-life shocks shape eating habits, food consumption, and adult health.

Matilda Gibbons (University of Pennsylvania)
Can Insects Feel Pain ?
Whether insects feel pain is an important ethical, legal, and scientific question. We tested whether bumblebees (Bombus terrestris) fulfill three indicators of pain. Our first experiment investigated motivational trade-offs. Bees avoided 55 °C feeders when offered differently-coloured, unheated feeders containing high sucrose concentrations. However, when sucrose concentration at unheated feeders decreased, they increasingly fed from noxiously-heated feeders. A memory test revealed that bees’ feeder preference relied on the colour cues, so the motivational trade-off was based on a conditioned memory. Our second experiment explored whether bees groom a noxiously-stimulated body part. We touched bees’ antenna with a 65 ̊C or unheated probe. Bees in the heat-probe treatment groomed their touched antenna more than their other, untouched antenna. Bees in the unheated-probe treatment did not groom their touched antenna more than their untouched antenna. Therefore, bees direct grooming towards a noxiously-stimulated body part. Our third experiment used a similar protocol, but recorded behaviours associated with pain in vertebrates. Bees in the heat-probe treatment exhibited behaviour patterns similar to vertebrates in pain (e.g. increased durations of defensive behaviours and resting), compared to bees in the unheated-probe treatment. Collectively, all three lines of evidence are consistent with insects feeling pain.

Bob Fischer (Texas State University)
A method for making interspecies welfare comparisons
Humans regularly make decisions that involve interspecies welfare comparisons. If we want to make these decisions in a principled way, we need a method for comparing welfare impacts despite significant differences between the individuals whose welfare it is. This talk provides one way to make these comparisons by attempting differences in animals’ respective welfare ranges, understood as the difference between the best and worst welfare states that a given kind of animal can realize. This allows us to convert conventional welfare assessments into a common unit. I also provide some tentative welfare range estimates for several farmed species. Along the way, I discuss the advantages and disadvantages of some other strategies, such as using neuron counts as proxies for animals’ welfare ranges, and I identify some of the limits of my own proposal.

Lynne Sneddon (University of Gothenburg)
Pain and sentience in fishes
Decisions made regarding which species to protect under legislation and recommendations are intrinsically based upon whether that animal is sentient and is capable of suffering. Growing scientific evidence has been gathered to understand whether fishes are sentient and further whether they experience poor welfare states such as pain. The definitions of sentience and pain will be explored and research findings presented to demonstrate the capacity for sentience and the ability to detect, react to and experience the negative affective state of pain in fishes. This has important implications on the treatment and welfare of aquatic animals used by humans

Heather Browning (University of Southampton)
The Underdetermination Problem for Interspecies Welfare Comparisons
Attempts to make welfare comparisons between members of different species are hampered through the problem of underdetermination where the available data cannot decide between multiple possible conclusions. Here, I describe the background similarity assumptions necessary to overcome this problem when making welfare comparisons, and in which contexts they are most likely to be justified.

Gilles Boeuf (Museum National d’Histoire Naturelle, Paris)
How to take animal behavior into account ?

Vendredi 9 juin

Rafael Schütz (PSE, Université Paris 1 Panthéon-Sorbonne)
Does it take a stick to eat a carrot ? Estimating the animal welfare impacts of food consumption and Pigouvian pricing
Combining 35 years of household expenditure surveys and aggregate food supply data from the United Kingdom, I estimate the animal welfare footprint of consumers’ food purchases. Focusing on the extensive margin, I consider three indicators of animal welfare : (1) meat and fish purchase quantities ; (2) the number of slaughtered animals and caught fish ; (3) the second indicator, weighted by species-specific neuron counts. Throughout the whole time frame (1985 to 2020), there is a large dispersion in animal welfare footprints across individuals. The link with income is weak. I simulate the effects of two Pigouvian pricing interventions : carbon pricing of food and an animal welfare levy as envisaged by the German government. Demand system and machine learning estimates coincide in predicting both interventions to reduce greenhouse gas emissions and substantially improve aggregate animal welfare.

Jonathan Birch (LSE)
Animal sentience and interspecies welfare comparisons
When comparing welfare in the human case, we face a serious problem of interpersonal comparison. Two people may not experience the same deprivations in the same way, and there is an inscrutable private element to these experiences. This problem is part of what motivates the « Capabilities Approach », which aims to make comparisons through objectively measurable indices of capabilities relevant for flourishing. In the non-human case, we face even more serious problems of comparison. Can an expanded version of the Capabilities Approach (such as that defended by Nussbaum) help with these ? I think the answer is : maybe, if we can first agree on expanded principles of interspecies justice/fairness analogous to those that underlie the human version of the Capabilities Approach. But agreement on those underlying principles will be hard to achieve.

Romain Espinosa (CIRED) & Nicolas Treich (TSE)
The Animal Welfare Levy
We provide an economic rationale for implementing a meat consumption levy because of animal welfare considerations. This levy operates similarly to a Pigouvian fee by accounting for externalities on animals produced for meat. Under total utilitarianism, the levy per animal is equal to the opposite of the farm animal utility level. As a result, the levy acts as a subsidy when an animal’s life is considered worth living, and as a tax when it is not. Under average utilitarianism, the levy is always a tax when human welfare exceeds animal welfare. To calibrate the appropriate levy rate, we combine the Five-Freedom approach with the quality-adjusted life years. Our findings indicate that the tax per kg of meat is significantly higher for chickens and pigs compared to cows, including both beef and dairy herds. This result stands in contrast with the taxation of other meat externalities (e.g., climate externalities)

Leisha Hewitt (Adelaide University)
Transforming policy into meaningful animal welfare improvements
There is a growing expectation that businesses or organisations which produce or use animal-derived materials must meet their ethical responsibilities by protecting the welfare of animals in their supply chains. An animal welfare policy outlines the measurable and verifiable principles of action intended to deliver animal welfare outcomes that are acceptable to consumers and the wider community. This presentation provides an insight into the transformation of animal welfare policy into meaningful practical welfare improvements.

Kevin Kuruc (University of Texas at Austin)
What should we pay to avert the life of a farmed animal ?
Many observers believe it would be welfare enhancing to reduce the number of animals living in industrial farms, even if the alternative is non-existence. However, there do not at present exist reliable methods to value the gains from averting bad existences, leaving us in the dark about the relative importance of this issue versus other pressing issues. This paper makes progress along two dimensions. First, we show that monetarily valuing this outcome depends on three conceptually distinct values : (i) a neutral utility level for humans, (ii) a human-equivalent utility for animals and (iii) a marginal utility of money for humans. Second, we take advantage of recent work on (i) and (ii)---which can be combined with a well-established literature on (iii)---to generate a range of estimates for the monetary value of averting the life of different animals.

Nicolas Delon (New College of Florida)
Agency and Welfare across Species
In this talk, I will discuss the notion of a welfare subject, its relation to moral status, and the relation between conditions for being a welfare subject and the grounds of moral status. I then argue for the inclusion of agency, construed as flexible goal-directed behavior, as a constituent of welfare and ground of moral status. I explain how my view makes some questions of welfare comparisons more tractable but also complicates most of the current research on these questions. Some of the new questions raised by the approach include : what are proxies for the welfare-relevant dimensions of agency ; how to weigh agency against other constituents of welfare (especially affective experience) ; finally, what we need to know to compare agency across species.


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La chaire Ouvrir la science économique doit permettre aux économistes de répondre de façon originale et efficace aux grands problèmes de notre temps, en intégrant un double constat : les défis actuels, complexes et multiformes, nécessitent une approche dépassant les frontières disciplinaires ; la recherche en économie doit être davantage renouvelée par les avancées dans des disciplines connexes.