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Using economic techniques
to assess what animals value: an example using mink (Mustela
vison)
Georgia Mason, Jonathan
Cooper and Catharine Clarebrough
University of Oxford, United Kingdom
In humans, affect functions to
motivate behaviours. If non-human animals are similar, measuring
what they prefer will reveal what gives them pleasure –
a powerful tool for improving animal welfare. How activities
decrease with cost yields several economic measures that indicate
importance: reservation price (the maximum price paid), consumer
surplus (the area under a demand curve); the price elasticity
of demand in response to cost-increases; and the income elasticity
of demand in response to income-cuts.
I present data from a four-year study of mink housed long-term
in individual closed economy set-ups. In these, they could access
resources (e.g. chewable toys, swimming-water) if they pushed
heavily-weighted doors. Door-weights ranged from 0g to beyond
average body-weight (c. 2000g), each weight being imposed for
seven days. Results showed the mink were motivated to perform
several 'natural' activities, despite being raised in barren
farm-style cages; concordance between the four measures of preference
was good, although as in human economics, elasticity measures
were influenced by a resource's baseline costs; and the economic
measures of preference predicted the minks' corticosteroid outputs
in response to deprivation. Our subjects were most motivated
to access swimming-water, suggesting that providing this resource
would cause the greatest welfare improvement on fur farms.
Keywords: economics, value, demand, preference, motivation, utility,
animal welfare |