2 results
Contrasts and Comparisons of Incentive Situations in Domestic Poultry
- M J Haskell, M Vilarino, N C A Coerse, M Picard
-
- Journal:
- Animal Welfare / Volume 10 / Issue S1 / February 2001
- Published online by Cambridge University Press:
- 11 January 2023, p. S241
-
- Article
- Export citation
-
Understanding the way in which animals perceive important features of their environment, and how this information may be stored and used, underpins the study of the impact of husbandry systems on animal welfare. Research into incentive contrast in laboratory animals has indicated that they can store and use information about stimuli associated with situations or resources. If cognitive processes are used, the relevant stimuli associated with a resource or event are encoded, allowing comparisons to be made when the key stimuli are changed. The presence and quality of this comparison, negative or positive, can be ascertained by assessing the change in the animal's level of appetitive or operant responding in order to gain access to the situation on the subsequent trial. We wished to determine whether the presence of a sudden change in appetitive response, such as speed of approach to an area following a change in incentive features of a resource or event in that area, is shown by the domestic chicken. This would indicate the presence of a cognitive comparison of incentives. The magnitude of such a change may also provide a measure of the welfare impact of the change. In the first experiment, 16 groups of four broiler chicks were trained to run a maze to an area where they received a high quality test diet. After training, the test diet of eight groups was changed to a low quality diet that all groups had been receiving in their home pens. Compared to the control unchanged groups, the experimental birds took increasingly longer to run the maze on successive post-change trials; the decrease reaching significance on the fourth post-change trial (P < 0.05). The behaviour of the chicks on the day of the change was indicative of frustration, with greater activity and redirected foraging shown (P < 0.05). Although there was no definitive evidence of cognitive processing which would have been shown by an immediate decrease in approach speed, this may have been due in part to the testing of groups of chicks. However, the occurrence of a frustration reaction indicated that some cognitive representation of food quality may have been present. In a second experiment, individual adult hens were trained to run a runway for access to food or water, while food- or water-deprived, respectively. Every fourth trial in a total of 16 trials, access to the resource was thwarted by a clear plastic lid on the dish. Time taken to traverse the runway was significantly longer on the two trials following this experience (P < 0.05), with no effect of repetition of thwarting (P > 0.05), indicating that the experience of thwarting was aversive. These results indicated that chickens appear to be able to store and use information on incentives. Additionally, with appropriate experimental design, an incentive contrast paradigm might be used to assess birds’ perception of the quality of changes in incentives.
Incentive Value Learning in Domestic Hens
- N C A Coerse, M J Haskell, B Forkman
-
- Journal:
- Animal Welfare / Volume 10 / Issue S1 / February 2001
- Published online by Cambridge University Press:
- 11 January 2023, p. S237
-
- Article
- Export citation
-
The incentive value learning theory states that the value assigned to a resource depends on the motivational state of an animal when it first encounters that resource. The present experiment investigated whether domestic hens, Gallus domesticus, assign different incentive values to a novel food depending on their deprivation state when they encounter this novel food. Hens were first trained to find a novel food type hidden under wood shavings in a large food dish. Then, after half of the animals were food-deprived and half left not food-deprived, all hens were re-exposed to the novel food in a small food dish in a second test arena. Next, all hens were food-deprived and then given access to the original food dish with wood shavings but no food in the original test arena. Hens that had been food-deprived before re-exposure spent more time looking, pecking or scratching at the wood shavings in the dish and pecked more at the dish than did the hens that were re-exposed while sated. The sated hens also tended to sit down longer in the test arena than did deprived hens. Thus, hens that had been deprived before re-exposure to the novel food searched more actively for the food than hens that had been sated before re-exposure, indicating a higher motivation. These results prove for the first time that incentive value learning occurs in domestic hens.
![](/core/cambridge-core/public/images/lazy-loader.gif)