The way we feel about receiving a reward does not just depend on the perceived value of the reward (the absolute value), but also the value of the reward in comparison to what we were expecting to receive (its relative value). So, although dogs would normally be happy to eat dried kibble, we would expect them to show behaviours akin to disappointment if they were anticipating hot dog (a preferred food) but instead received kibble. This sensitivity to the relative contrast of the two foods, known as reward sensitivity, is thought to be common in many animals, and is what helps us make decisions.
Recent findings have shown that the way we are feeling can influence reward sensitivity. Animals in a positive mood have been found to recover more quickly from an unexpected loss of reward than animals in a negative state. It is possible that reward sensitivity could be a quick, effective and non-invasive method to assess moods and emotions, in animals. As moods and emotions are the reflection of how we are feeling about something (e.g. the conditions in which we are currently living), reward sensitivity may be a good way of assessing welfare in animals.
Find out more about how affective state affects reward sensitivity here.
Find out how we assess sensitivity to reward change here.