Preference Tests Flashcards
Why are preference tests used?
- Assessing animal welfare
- Giving animals the choice
- Establish their priorities by imposing costs and trade offs
- Humans are not good judges!
Who performed the first preference test?
1977 - Bary Hughes
What are the problems associated with using preference tests?
- preferences are relative to choices given
- preferences are short term (proximate v ultimate)
- animals lack behavioural wisdom
- out of mind is not out of sight
- partial preferences
Give an example of short term v long term preferences differing
Broody hens - trap nesting. May want the nest in the proximate but ultimately do not want to be kept in a small cage
Why may behavioural wisdom appear not to be present?
If presented with an artificial stimulus or environment, innate rules which may be adaptive in the natural environment may appear “stupid”
eg. oystercatcher presented with giant egg will choose over its own as is predisposed to sit on largest egg
eg. animals will not like to go to the vets as there is no evolutionary pressure to do so, but it is a necessary situation to be in.
Why may minority choices be seen by some individuals when the majority of a group opt for another choice?
Interpretation of stimuli Still learning Monitoring alternative choices Genuine individual preference Different motivational state eg. farrowing
What was confused when early work was carried out of preference tests?
Desire to carry out behaviour and desire for outcome
Give two types of preference tests
> T maze - experience both environments then allowed to make choices at the end -> each time they enter an environment they are shut in for a small period of time
Free access test - measure time spent in each environment
How may preference tests be validated?
Incorporate /compare with physiological measures of stress etc.
Give an example of a positive indicator of welfare in hens found by Nicol(?)
Preening associated with most time spent in an environment -> therefore indicator of positive welfare?
Why are preference tests useful?
As a validation tool - cannot be used to directly measure welfare in farmed animals
If group level preference is unclear, what may be the reasons for this?
Individuals making random choices or individuals making consistently different choices
- in chicken study was individual birds making consistent decisions but these were different between birds
What was decision consistency correlated with?
Latency to choose
Were different “types” of hens found to have different preferences?
YES - heavier, v corticosterone, attack novel objects -prefer wire
enjoy feeding and scratching, ^ blood glucose -prefer shavings
Outline a study showing whether chickens are rational
Browne 2010 - transitive preference choices shown in majority of cases (If preferred A>B and B>C, preferred A>C)
