An easy assessment method for mood is needed to efficiently assess mood states of animals under farm conditions and to conduct more basic research on mood. Such an approach ideally overcomes the limitations of current approaches in that it should be (1) less time consuming, i.e. apart from some habituation to the test situation no training should be necessary, and (2) the test should be repeatable without strong habituation effects.
Alternatives to the cognitive judgement bias test have been sought e.g. in the form of incentive contrasts but were not successful in reducing the necessary amount of training (Burman et al. 2008b, Mitchell et al. 2012). Therefore, a new approach to measuring mood should rely on a simple setting to which animals quickly habituate and to which they need not to be specifically trained. Such an approach should take advantage of a spontaneous reaction of the study animals that does not need to be learnt and is therefore also less likely to be affected by habituation even with repeated testing. It has been suggested that attention could be such a behaviour and that different mood states would introduce attention bias (Paul et al. 2005, Bethell et al. 2012). Indeed, we have shown ourselves that ear postures and movements in sheep that can be related to the attention of the animals are modulated by mood (Reefmann et al. 2012). In respect to attention bias, it is assumed that subjects in a more negative mood will pay relatively more attention towards negative stimuli compared to positive stimuli, specifically when the stimuli are presented simultaneously, than subjects in a more positive mood.
It thus seems that a setting in which attentional reactions are specifically elicited could be a fruitful approach for creating a quick test for mood (see also Winters et al. 2015). Such a test for mood that needs little training can be implemented more easily in a wider variety of circumstances, such as with animals on working farms and animals of a variety of species.
The project has therefore three main objectives:
-
To choose a pair of negative-positive stimuli that are validated for their negativity/positivity and elicit a similar amount of attention (a) to avoid initial bias and (b) to accordingly allow for a relative shift in the focus of the attention either towards the negative or towards the positive stimulus.
-
To conduct a proof of concept of the attention bias test, i.e. to manipulate short-term aspects of the test such as the specific presentation of the stimuli as investigated in part 1 and for which clear hypotheses can be derived under the assumption that, indeed, attention is measured by the experimental set-up.
-
In the end, the main objective of this study for which parts 1 and 2 are only the preparatory steps is to validate the attentive bias test in a setting more closely resembling the intended on-farm use. That is, to experimentally induce different mood states and show that these mood states lead to attentional bias as measured in the proposed attention bias test.
