Welfare-aligned Sentience: Enhanced Capacities to Experience, Interact, Anticipate, Choose and Survive

Abstract

The focus of this opinion is on the key features of sentience in animals which can experience different states of welfare, encapsulated by the new term ‘welfare-aligned sentience’. This term is intended to exclude potential forms of sentience that do not enable animals in some taxa to have the subjective experiences which underlie different welfare states. As the scientific understanding of key features of sentience has increased markedly during the last 10 to 15 years, a major purpose here is to provide up-to-date information regarding those features. Eleven interconnected statements about sentience-associated body functions and behaviour are therefore presented and explained briefly. These statements are sequenced to provide progressively more information about key scientifically-supported attributes of welfare-aligned sentience, leading, in their entirety, to a more comprehensive understanding of those attributes. They are as follows: (1) Internal structure–function interactions and integration are the foundations of sentience; (2) animals posess a capacity to respond behaviourally to a range of sensory inputs; (3) the more sophisticated nervous systems can generate subjective experiences, that is, affects; (4) sentience means that animals perceive or experience different affects consciously; (5) within a species, the stage of neurobiological development is significant; (6) during development the onset of cortically-based consciousness is accompanied by cognitively-enhanced capacities to respond behaviourally to unpredictable postnatal environments; (7) sentience includes capacities to communicate with others and to interact with the environment; (8) sentience incorporates experiences of negative and positive affects; (9) negative and positive affective experiences ‘matter’ to animals for various reasons; (10) acknowledged obstacles inherent in anthropomorphism are largely circumvented by new scientific knowledge, but caution is still required; and (11) there is increasing evidence for sentience among a wider range of invertebrates. The science-based explanations of these statements provide the foundation for a brief definition of ‘welfare-aligned sentience’, which is offered for consideration. Finally, it is recommended that when assessing key features of sentience the same emphasis should be given to positive and negative affective experiences in the context of their roles in, or potential impacts on, animal welfare.

Mouth Pain in Horses: Physiological Foundations, Behavioural Indices, Welfare Implications, and a Suggested Solution

“…However, such views are not widely accepted by animal welfare and other scientists [15,20,30]. Instead, the majority hold that animals would consciously experience pain when it can be shown that coincident physiological and behavioural responses are indeed due to nociceptive inputs from areas of the body subject to noxious stimulation [13][14][15]20,21,30]. Such arguments rely on the cautious application of scientifically informed best judgement, which underlies conclusions that recognise a legitimate role for what has come to be known as "critical anthropomorphism" [30,31].…”

“…Instead, the majority hold that animals would consciously experience pain when it can be shown that coincident physiological and behavioural responses are indeed due to nociceptive inputs from areas of the body subject to noxious stimulation [13][14][15]20,21,30]. Such arguments rely on the cautious application of scientifically informed best judgement, which underlies conclusions that recognise a legitimate role for what has come to be known as "critical anthropomorphism" [30,31]. Moreover, evidence that the cerebral cortex of mammals has an integral role in the conscious experience of pain [32][33][34] further supports this reasoned approach.…”

“…In addition to the many varieties of pain [22], there are numerous other subjective sensations, feelings, and emotions, collectively known as 'affects' [66], which animals may experience consciously. Evidence for this has been provided during the last 15-20 years by numerous studies of the brain processing of specific sensory inputs that lead to the generation of different affects (for references, see [30,[67][68][69][70][71][72][73]. There are affects related mainly to the internal state of the animal, which include breathlessness, thirst, hunger, nausea, dizziness, debility, weakness, and sickness, as well as pain.…”

“…There are other physiological changes elicited by potentially painful stimuli in mammals, many of which involve the sympathetic nervous system (SNS) and the hypothalamic-pituitary-adrenocortical axis (the HPA axis). Detailed descriptions of these responses and of their usefulness as indirect indices of pain and the effectiveness of analgesics have been provided elsewhere (e.g., [14,[17][18][19][20][21]28,30,[74][75][76][77][78][79][80][81]). Briefly, SNS responses include changes in the circulating concentrations of adrenaline and noradrenaline, as well as related changes in heart rate, blood pressure, respiratory rate, and whole body or regional temperature; HPA responses have usually focused on elevations in circulating glucocorticoid concentrations.…”

“…It is suggested here that anxiety in anticipation of pain, and fear whilst experiencing it, especially if the pain is intense, may be additional emotional constituents of conflict behaviours. Moreover, anxiety may also accompany the experience of suffocating breathlessness in circumstances when it is anticipated, and fear when it actually occurs [30,171].…”