In humans, psychological manipulations such as hypnosis, behavioural modifications, relaxation training and cognitive behaviour therapy have all been used to reduce pain intensity. One thing these treatments have in common is selective attention. Work on attention-based cognitive coping strategies has shown that they have potentially useful analgesic qualities in pain therapy. In animals, there have been few studies on the effects of attentional shifts on pain perception. There is extensive literature on stress-induced analgesia and it is likely that, in some of the experiments, attention could be an important variable. This paper will present some of our recent work on selective attention and pain perception using the sodium urate model of gouty arthritis. Birds are naturally prone to articular gout and the model we have developed mimics acute gouty attacks in a single joint. Experimental sodium urate arthritis produces a tonically painful inflammation lasting for at least 3h during which time the animals show pain-related behaviours. Changes in motivation can reduce these pain-related behaviours and it has been hypothesized that these motivational changes act by way of altering the attention of the animal away from pain. The motivational changes investigated included nesting, feeding, exploration and social interactions. The degree of pain suppression ranged from marked hypoalgesia to complete analgesia and as such demonstrates a remarkable ability to suppress tonic pain. These shifts in attention not only reduced pain but also significantly reduced peripheral inflammation. These results are discussed in terms of the limited capacity models of attention.

It is widely agreed that all animals are entitled to some degree of welfare consideration, but that some are entitled to more consideration than others. However, the basis for singling out some animals for special consideration often seems to be mostly a matter of degree of similarity to, or association with, humans. A more reasonable criterion would involve the extent of suffering caused by given events. Two variables that seem likely to be very important in the extent of suffering are the capacity to anticipate and the capacity to recall. Everyday experience tells us that human suffering can be hugely amplified by either anticipation or recall of painful or distressing events. In the past, psychologists have tended to take the view that both these processes depend on the possession of language, and were therefore irrelevant to species other than humans. But comparative psychologists are increasingly making use of concepts from human cognition, including both memory and anticipation, to explain animals’ responses to both past and future events. These processes are invoked to explain the behaviour of a wide range of vertebrate species. Recent work on primate cognition indicates that more elaborate forms of representation may be possible in the great apes. Such evidence should be used as the basis for deciding whether to give special welfare consideration to certain species which have special cognitive capacities — or indeed enhanced welfare consideration to a wider range of species, if their cognitive capacities are found to be more sophisticated than is generally assumed.

The stressful effects that environments have on farm and laboratory animal welfare are likely to depend on how much animals understand of the behaviour and intentions of their conspecifics as well as on their understanding of their physical environment. However, studies on animal social cognition have primarily focused on primates. Here, we report on our work on social cognition in domestic pigs. It focuses on the ability of domestic pigs to assess and use to their advantage the behaviour of conspecifics, and uses approaches pioneered in studies on primates. Our work has shown that dominant pigs use the privileged knowledge of a subordinate to their own advantage in a competitive foraging situation. While such exploitative behaviour is likely to be based on rapid learning about the subordinate ‘s behaviour, it is also possible that ‘higher’ cognitive abilities such as visual perspective taking could be involved. Ongoing work uses an adaptation of the Guesser-Knower paradigm to test whether pigs are indeed capable of visual perspective taking.

We investigated the ability of hooded crows to form transitive inferences. Subjects were trained to discriminate a series of overlapping pairs of stimuli: A+ B-, B+ C-, C+ D-, D+ E, where the letters stood for colour stimuli and plus and minus for rewarded or non-rewarded choices. The stimuli were cards of different colours with a circle of the same colour on the reverse side and diameters decreased from A to E. To preclude an influence of the reinforcement history on choices with the test pair BD, an overcompensation phase was instituted after training. It consisted of the presentation of all training pairs with frequencies selected so that the reward to non-reward ratios for stimulus D would be between 1.5 and 2.0 times greater than for B. If, during the BD test, the bird chose the stimuli according to these ratios they should prefer D. If they chose according to diameter relation they should prefer B. During these tests, the crows strongly preferred B over D (83.1%). In a second experiment, subjects were trained with the same procedure except that the diameters of the circles were all the same. During this test, the performance of two crows was not significantly different from chance level (53.1%), and the other two crows preferred D (80.0%). We conclude that crows can solve transitivity tests using cognitive mechanisms if they are offered additional information (in this case circle diameter) which, presumably, allows them to represent the relevant stimuli in an ordered series.