Animal Pain and Ethical Implications

Question 1

what are the views of animal pain

Answer 1

1. obvious similarities between humans and other animals –> feel pain like we do
2. don’t experience pain consciously at all, or in anything like the same way we do

Question 2

what is the UK legislation

Answer 2

wider inclusion

protection to all mammals, birds, reptiles, fish, amphibia and cephalopods –> capable of suffering

Question 3

what are the yes and no arguments to can animals experience conscious pain and their objections

Answer 3

1. yes: argument by analogy –> inference from behavioural and neurological similarity and evolutionary continuity –>

objection: similarities are of unknown significance, also many dissimilarities present in mammals but even more so in distant species

2. no: higher order definition of consciousness –> phenomenal consciousness (and conscious perception of pain) requires capacity to think about ones own thoughts and to have a theory of mind

objection: some animals have self awareness and evidence of a theory of mind, weak evidence that this higher order definition of consciousness is necessary for pain perception

Question 4

what are the components of pain

Answer 4

1. sensory-discriminative: component that refers to the capacity to analyze location, intensity and duration of nociceptive stimulus
2. motivational and affective: component that gives rise to the unpleasant character of pain perception and modifies behaviour
3. cognitive and evaluative: involved in phenomena of anticipation, attention, suggestion and past experiences

Question 5

why do we feel pain

Answer 5

an adaptive response

detection and avoidance of noxious stimuli, prevention of further injury obviously adaptive

Question 6

what are the arguments against conscious pain perception in inverts

Answer 6

1. reduced evolutionary advantage (short life span)
2. limited neural capacity
3. lack of pain related behavioural responses

Question 7

what is the zimmermann definition of animal pain

Answer 7

pain in animals is an aversive sensory experience caused by actual or potential injury that elicits protective motor and vegetative reactions, results in learned avoidance behaviour and may modify species specific behaviour including social behaviour

Question 8

what is the molony definition of animal pain 4

Answer 8

Question 9

what are the approaches to the study of animal pain

Answer 9

1. sensory discriminative component (histology of nerves involved –> fibre types electrophysiology of peripheral afferents)
2. somatic/reflex response: (physiological responses –> heart rate and blood pressure)
3. motivational component (behavioural studies, pain models)
4. cognitive component (behavioural/psychological studies, pain models)

Question 10

what are the anatomy of the rainbow trout nocicpetive nerves

Answer 10

A-delta and C fibres

sections of trigeminal nerve studied –> innervates head and mouth

Question 11

what are the axon types in the trigeminal nerve in the rainbow trout

Answer 11

a-alpha

a-beta

c fibre

a delta

Question 12

what is the function of nociceptors

Answer 12

respond to noxious stimuli in a graded manner

mechanical, thermal, chemical

Question 13

what is the evidence for pain in fish

Answer 13

1. sensory-discriminative: fish posses A-delta and C fibres and electrophysiological recordings confirm the responses of these fibres to noxious stimulation
2. motivational: application of noxious stimuli has physiological consequence and has an adverse effect on behaviour
3. recent evidence suggests that trout can experience fear and that they can learn to avoid frightening stimuli

Question 14

what are behavioural signalling of pain

Answer 14

noxious stimulation frequently results in either quantitatively or qualitatively abnormal behaviour which may or may not be adaptive

some animals –> prey anaimals have evolved ways of disguising responses to pain

Question 15

what are behavioural responses to acute pain

Answer 15

1. escape + avoidance
2. vocalization
3. defensive

may direct attention towards site of pain (licking, scratching)

Question 16

what are behavioural responses to tonic/chronic pain

Answer 16

1. protective or guarding behaviours (where animal protects a sensitive body part from environmental stimulation)
2. posture may change
3. chronic pain: depression and learned helplessness

Question 17

how can behaviour be used as an indicator of pain and measured

Answer 17

1. continuum from subjective to objective
2. more objective assessments involved detailed quantification of clearly defined behaviours

Question 18

what are the physiological responses to pain

Answer 18

1. sympatho-adrenal catecholamine release: changes in blood pressure, increased heart rate, changes in resp., muscle tone, defecation, urination
2. activation of HPA –> glucocorticoid release

Question 19

what are the ethical implications of animal pain

Answer 19

ethical responsibility to recognize and treat pain to improve welfare in animals (where capacity to feel pain is not in doubt)