What is Sentience? and Why do We Care?

Ian J.H. Duncan University of Guelph Guelph, Ontario, Canada What is Sentience?

Sentience n. The condition or quality of being sentient, consciousness, susceptibility to sensation.

Sentient adj. A. That which feels or is capable of feeling; having the power or function of sensation or of perception by the senses. B. That which has sensation or feeling.

The Oxford English Dictionary Why do we care?

We should care, because being sentient means that what happens to animals MATTERS TO THEM A short history

Dark Ages Evidence that there was some acceptance of sentience in animals. Renaissance Good evidence from the writings of Leonardo, Erasmus, Thomas More, Montaigne, Shakespeare et al., that animal sentience was accepted as part of secular knowledge. A short history

But of course, philosophers did not follow the views of the masses, and there is a clear line of argument for non-sentience :

Aristotle (384-322 BC)

Thomas Aquinas (1224-1274)

René Descartes (1596-1650)

Immanuel Kant (1724-1804) Jeremy Bentham (1748-1832)

Had little to say about animals, but he rejected the claims of Aristotle, Aquinas, Descartes and Kant outright. He said that rationality is not the relevant matter:

“The question is not, Can they reason? nor, Can they talk? But, Can they suffer?” William Youatt (1776-1847)

Influential English veterinarian (who embarked on a veterinary career at the age of 35!).

1830. Canine Madness. 1831. The Horse. With a Treatise on Draught. 1834. Cattle. Their Breeds, Management and Diseases. 1837. Sheep. 1845. The Dog. 1847. The Pig. 1828–1847 Editor of The Veterinarian William Youatt (1776-1847)

1839. The Obligation and Extent of Humanity to Brutes, Principally Considered with Reference to the Domesticated Animals.

Republished in 2004. Edited, introduced and annotated by Rod Preece. Edwin Mellen Press, Lewiston, N.Y. William Youatt (1776-1847)

Youatt writes of animals’ senses, emotions, consciousness, attention, memory, sagacity, docility, association of ideas, imagination, reason, instinct, social affections, the moral qualities, friendship and loyalty.

So he, most definitely knew that animals were sentient! William Youatt (1776-1847)

More than 30 years before Darwin’s ‘The Expression of the Emotions in Man and Animals’, Youatt wrote:-

“We are operating on animals that have, probably, as keen feelings of pleasure and of pain as ourselves” Darwin, C., 1872. The Expression of the Emotions in Man and Animals. John Murray, London.

 Noted the universal nature of human facial emotional expression  Described some commonalities in expression of emotions in animals  Suggested a shared evolution Fig. 5. Dog approaching another dog with hostile intentions Darwin was mainly interested in EMOTIONAL EXPRESSION

So he was interested in:  Underlying anatomy and physiology  Signal value of the expression  The evolution of the emotions

He seemed to accept the SUBJECTIVE EXPERIENCE associated with the emotions, but this was not explored in any depth. George John Romanes (1848-1894)

Born in Kingston, Ontario. Educated at Cambridge. A close friend and disciple of Charles Darwin. He was explicit about subjective experiences of animals. George John Romanes (1883)

“Pleasures and Pains must have been evolved as the subjective accompaniment of processes which are respectively beneficial or injurious to the organism, and so evolved for the purpose or to the end that the organism should seek the one and shun the other.”

Mental Evolution in Animals The Disconnect

So…130 years ago it was commonly accepted by scientists that animals had feelings.

This was also the “commonsense” view held by the community.

But through much of 20th century, scientists eschewed any study of animal feelings.

COMMUNITY SCIENCE How did this disconnect arise?

The answer is that a branch of psychology called “Behaviorism” had a huge effect on the way that behavioural scientists thought about the mind, consciousness and feelings through the first 70 years of the 20th century. William James (1842-1910) established principles on which Behaviorism was founded

J.B. Watson (1878-1958) the founder of Behaviorism

B.F. Skinner (1904-1990) the most famous proponent of Behaviorism. J.B. Watson (1928)

“The behaviorist sweeps aside all medieval conceptions. He drops from his scientific vocabulary all subjective terms such as sensation, perception, image, desire and even thinking and emotion.” • These were powerful scientists.

• Not surprising that the emergence of animal welfare science was delayed.

• But the non-scientific community knew that animals had feelings - and it was feelings that mattered! A short history

1964 Ruth Harrison “Animal Machines” Great emphasis on “suffering”.

1965 “The Brambell Report” “Welfare is a wide term that embraces both the physical and mental well-being of the animal. Any attempt to evaluate welfare, therefore, must take into account the scientific evidence available concerning the feelings of animals that can be derived from their structure and function and also from their behaviour.” A short history

1964 Ruth Harrison “Animal Machines” 1965 “The Brambell Report”

In spite of what Harrison and Brambell said, we early welfare scientists assumed that “welfare” would be best assessed with some measurement of stress. (The legacy of Behaviorism was strong)

A short history

Pattern broken by Donald Griffin at 1975 International Ethology Conference in Parma, Italy.

Griffin, D., 1976. The Question of Animal Awareness. Rockefeller, New York.

Following which there has been a burgeoning literature on sentience. All organisms have certain needs which have to be satisfied in order that the organism: survives grows reproduces As true for a potato as for a pig If needs not met, organism will show symptoms of atrophy, stress, ill health and will eventually die. Lower invertebrate satisfies its needs by simple, hard-wired, stimulus-response behaviour.

(A fly avoids a large shape rushing towards it)

Higher organisms (vertebrates) have evolved ‘feelings’ (subjective affective states) to protect their needs in a flexible way.

(A bird avoids a cat moving towards it – but its avoidance is governed by fear) Feelings have evolved to protect “biological fitness” (the ability of genetic material to reproduce itself) So, I am drawing a fine distinction between:

Primary need Secondary feeling having a nutrient feeling hungry deficiency having a fluid feeling thirsty deficiency avoiding predator feeling frightened being ill feeling ill being stressed feeling stressed being injured feeling pain The term:

“TOUCHY-FEELY”

Used (disparagingly) to describe anything non-scientific. “HARD SCIENCE” “TOUCHY- FEELY”

Primary need Secondary feeling having a nutrient feeling hungry deficiency having a fluid feeling thirsty deficiency avoiding predator feeling frightened being ill feeling ill being stressed feeling stressed being injured feeling pain Within the discipline of Animal Welfare Science, two schools of thought emerged:

Biological Feelings School Functioning School (determined to stick (maybe feelings can to hard science) be investigated scientifically) Biological Functioning School

Animal welfare is all to do with good biological functioning :-

• Absence of a stress response (or absence of a large stress response)

• Animal able to ‘cope’

• Animal able to satisfy its biological needs Feelings School

Animal welfare is all to do with what the animals feels :-

• With the absence of negative emotional states (suffering)

• With the presence of positive emotional states (pleasure) (probably) Of course, usually there will be close correspondence between NEED and FEELING (after all, feelings evolved to protect needs) - but not always, particularly in the case of domesticated animals.

WHY NOT? NATURAL SELECTION keeps needs and feelings linked

ARTIFICIAL SELECTION allows needs and feelings to separate

Some examples of a mis-match: Basset Hound – lock up the garbage! Fighting Cocks – extremely aggressive Broiler breeders have huge appetites If allowed to satisfy these appetites, they become obese, ‘unfit’, and they suffer.

If feed-restricted, they function well, their nutritional needs are met, and they appear to be ‘fitter’.

BUT their welfare is severely compromised by the feed restriction.

THEY FEEL HUNGRY ALL THE TIME! You may be misled by the good physical condition and performance of such animals.

But welfare is to do with feelings.

It resides inside the heads of the animals.

And these animals are suffering. POTATO

Can be diseased

Can be water deficient

Can be nutrient deficient

Can be damaged POTATO PIG

Can be diseased Can be diseased and can suffer from malaise Can be water deficient Can be water-deficient and can suffer from thirst Can be nutrient deficient Can be nutrient-deficient and can suffer from hunger Can be damaged Can be injured and can suffer from pain I would argue that it IS possible to be scientific about these feelings. They can be defined operationally and measured.

feeling hungry feeling thirsty feeling frightened feeling ill feeling stressed feeling pain Much of my research career has involved “asking” animals what they feel about the conditions they are kept in and the procedures they are subjected to. The importance of sentience

Gradual acceptance that it is feelings that govern welfare …. …. and therefore feelings that should be measured when assessing welfare.

(With some resistance from stress physiologists!) The importance of sentience

We can now recognize and ‘measure’ some states of suffering in some species: Frustration Fear Pain Discomfort Maternal separation

Loneliness Boredom The importance of sentience

In addition, animals may experience states of suffering not experienced by human beings.

E.g. Fish in water with a low oxygen content or with an abnormal pH value probably suffer.

We should keep out minds open to such possibilities. The importance of sentience

So far, I have only considered states of suffering.

But states of pleasure are also going to affect an animal’s welfare. To date, these have not been investigated in any depth. Primary need Secondary feeling

Learning social graces Play-fighting leads to in a young animal feelings of pleasure

Maintaining social Grooming or being bonds groomed by a herd- or flock-mate leads to feelings of pleasure

Keeping plumage or Bathing leads to pelage in good order feelings of pleasure POSITIVE NEGATIVE FEELINGS FEELINGS POSITIVE NEGATIVE FEELINGS FEELINGS

POSITIVE FEELINGS

NEGATIVE Fraser and FEELINGS Duncan (1998) There are still many important questions

E.g. To what extent can negative feelings be counterbalanced by positive feelings? (A spoonful of sugar to make the medicine go down). Where on the phylogenetic scale does sentience begin?

Not simply restricted to the vertebrates.  The Cephalopods (octopus, etc.) are definitely sentient.  The Decapods (crab, lobster, etc.) are probably sentient.  Great debate over the social insects (bees, ants, etc.) Where on the phylogenetic scale does sentience begin?

A brain or fairly large neural ganglion is required. Seems very likely that there will be a gradation of sentience with species with small neural ganglia having a little sentience. The question “When does it matter to the animal?” has not been adequately answered yet. When during development does sentience begin? Not simply at birth Newborn mouse Newborn guinea pig

Not simply at hatching Newly hatched robins Newly hatched d. chick When during development does sentience begin?

In addition, not all senses develop at the same time or at the same rate.

Therefore, the development of sentience is a gradual process.

The question “When does it matter to the animal?” has not been adequately answered yet. The importance of sentience

I would also urge making a distinction between :

Cognition Consciousness Computational Gives the animal ability – helps the information about animal deal with its internal the external world environment The importance of sentience

I would also urge making a distinction between :

Cognition Consciousness Computational Gives the animal ability – helps the information about animal deal with its internal the external world environment

The question is Can they suffer? The importance of sentience

I would also urge making a distinction between : Cognition Consciousness Computational Gives the animal ability – helps the information about animal deal with its internal the external world environment

The question is Can they suffer? In Conclusion

 Sentience means capable of feeling  It is important because welfare is all to do with what animals feel.  Sentience is not an all-or-none phenomenon.  We do not know exactly where on the phylogenetic scale sentience appears.  We do not know exactly where in ontogenetic development sentience appears.  However, it becomes important when it matters to the animals.