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Science, sentience, and animal welfare


I sketch briefly some of the more influential theories concerned with the moral status of nonhuman animals, highlighting their biological/physiological aspects. I then survey the most prominent empirical research on the physiological and cognitive capacities of nonhuman animals, focusing primarily on sentience, but looking also at a few other morally relevant capacities such as self-awareness, memory, and mindreading. Lastly, I discuss two examples of current animal welfare policy, namely, animals used in industrialized food production and in scientific research. I argue that even the most progressive current welfare policies lag behind, are ignorant of, or arbitrarily disregard the science on sentience and cognition.

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  1. I will use the terms ‘animals’ and ‘nonhuman animals’ interchangeably throughout the paper to refer to nonhuman animals.

  2. See Gruen (2011), chapter one, for a clear and thorough discussion and analysis of human exceptionalism.

  3. See, for example (Humphrey 2002).

  4. For a quite forceful defense of the attribution of mental states to nonhuman animals, see Andrews (2009).

  5. Endorphins and encephalins are two of the more common substances—found in many organisms—known to have morphine-like analgesic effects.

  6. Noxious stimuli used in pain research on nonhumans include mechanical (pricking or probing), thermal (heating or freezing), chemical (exposure to acidic irritants), and electrical (shocking).

  7. Dawkins (2006) presents a clear and persuasive analysis of the scientific basis for assessing suffering in animals, highlighting the plurality of mental states that might be properly described as ‘suffering’, and thus somewhat vaguely (and I think, wisely) characterizes suffering as the “experiencing one of a wide range of extremely unpleasant subjective (mental) states,” (2006: 28), a definition I wholly endorse.

  8. For clear discussions of some of the difficulties peculiar to assessing animal pain, see Allen (2004, 2005).

  9. For a nice discussion of the difficulties in finding a unified theory of pain, see Aydede’s Introduction to his (Aydede 2005).

  10. See Grahek (2007) for quite a thorough analysis of the empirical literature on such pain abnormalities and the implications of such data for the “hard problem” of consciousness in the context of pain.

  11. See the World Society for the Protection of Animals (WSPA) website Sentience Mosaic (WSPA 2012) for an exhaustive number of resources on the scientific literature on nonhuman animal sentience and its connection to animal welfare issues.

  12. See, for example (Carruthers 1992 and Rose 2007).

  13. See, for example (Rose 2002).

  14. See, for example (Agger 2009).

  15. See Braithwaite (2010), Utrecht (2010).

  16. Interestingly, Eisemann advises the “experimental biologist\(\ldots\) to follow, whenever feasible, Wigglesworth’s recommendation that insects have their nervous systems inactivated prior to traumatizing manipulation. This procedure not only facilitates handling, but also guards against the remaining possibility of pain infliction and, equally important, helps to preserve in the experimenter an appropriately respectful attitude towards living organisms whose physiology, though different, and perhaps simpler than our own, is as yet far from completely understood” (167).

  17. See, for example (Wallace 2004) and (Sample 2007).

  18. Serving an adaptive function as part of the body’s fight-or-flight response, fear is believed to operate in a more primitive subcortical brain circuit than pain. For example, when the cortex of an animal is removed, it appears no longer to suffer pain, yet still appears capable of learning a conditional fear response (Grandin 2003).

  19. See Huntingford et al. (2006) for a through review of fish welfare issues.

  20. Interestingly, in July of 2012, scientists gathered at the University of Cambridge for the first annual Francis Crick Memorial Conference, “Consciousness in Human and Non-Human Animals,” and produced the The Cambridge Declaration on Consciousness (Low 2012). The declaration concludes that “non-human animals have the neuroanatomical, neurochemical, and neurophysiological substrates of conscious states along with the capacity to exhibit intentional behaviors. Consequently, the weight of evidence indicates that humans are not unique in possessing the neurological substrates that generate consciousness. Non-human animals, including all mammals and birds, and many other creatures, including octopuses, also possess these neurological substrates.”

  21. I use the term ‘unnecessary anthropomorphism’ here to distinguish it from what Mark Bekoff (2000) calls biocentric anthropomorphism, the indispensable use of human terms to explain animals’ mental lives, emotions, or feelings. However, Marian Stamp Dawkins (2012) attacks even this kind of anthropocentrism as too prevalent in the scientific literature, ultimately harming the cause of animal welfare.

  22. For an extensive review of the manifold criteria and arguments for self-awareness in nonhuman animals (a phenomenon (rightly) characterized not as a single but as a complex phenomenon), see DeGrazia (2009).

  23. Bekoff (2001) describes what he calls the “yellow snow” test intended to evaluate a certain level of self/other differentiation in dogs. According to Bekoff, dogs have some of the same aspects of self-awareness that humans have, for example, a kind of “body-ness” (or proprioceptive sense), and a somewhat territorial/ownership sense of “mine-ness.” However, Bekoff does not believe the data yet support in dogs robust self-awareness.

  24. For a novel defense of the view that MSR shows self-awareness see Savanah (2012).

  25. For example, semantic, episodic, and procedural. See Tulving (1985) for a thorough taxonomy.

  26. For a sophisticated and persuasive response to “Povinelli’s challange” see Andrews (2005).

  27. The focus of this section will be on cattle, pigs, and chicken. Other land animals produced in mass numbers for food and clothing include sheep, horses, rabbits, turkeys, fur mammals, and others. Data on this latter group is not as readily available as on the former.

  28. For details on CAFOs see Eisnitz (1997), Imhoff (2010), Kirby (2010).

  29. ‘Sea animals’ includes so-called “finfish” and shellfish, but excludes other kinds of marine species killed for food, e.g., marine mammals, eels, etc.

  30. See Dantzer (2002) for what seems a reasonable and workable research agenda on emotion and cognition in farm animals that would help us understand their welfare requirements.

  31. Since these taxa are not covered under the Act, research facilities are not required to keep numbers on the use of such animals, thus accurate figures for the number used in US research facilities go unreported. See Greek and Greek (2000) for a thorough and insightful analysis of the “animal research-industrial complex.”


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This research was financially supported in part by a Summer Fellowship from the Animal and Society Institute-Wesleyan Animal Studies (ASI-WAS). I would like to thank ASI-WAS and my ASI-WAS Fellows for their helpful input on this work. I would also like to thank Sara Trechter, Alexandra Horowitz, an anonymous referee, and especially Lori Gruen for their thorough and substantive comments, and Aimin Chen for helpful editorial suggestions on an early draft of this paper. Thanks also to Peter Godfrey-Smith and Kim Sterelny.

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Correspondence to Robert C. Jones.

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Jones, R.C. Science, sentience, and animal welfare. Biol Philos 28, 1–30 (2013).

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  • Animal
  • Welfare
  • Ethics
  • Pain
  • Sentience
  • Cognition
  • Agriculture
  • Speciesism
  • Biomedical research