Pre-class assignment due Thursday, February 25:
Studying pair bonding
To study pair bonding, populations of wild voles are brought into the laboratory from the wild and bred to make large colonies. Every so often new, wild-caught voles are bred into these colonies to ensure that natural genetic variation is maintained in the colony (this prevents them from slowly becoming inbred clones over time). At 21 days of age, male and female pups are separated into cages where they are housed with sibling males and sibling females, and they remain in those “group-housed” cages until they are tested during adulthood (60+ days). All cages come with standard laboratory bedding, nesting material, ventilation, and unlimited access to food and water.
To test for pair bond formation, a male and a female vole are placed into a cage and they live together for 24 hours. They are video recorded, and mating during the first 3-6 hours of this 24 hour “cohabitation” is typically required for inclusion in the study. The vast majority of male-female pairs mate during this period. After 24 hours, the male and female are separated into cages where they are housed alone overnight.
The following day, these animals are subjected to a “partner preference test.” In this test, the familiar “partner” (from the 24 hour cohabitation the day before) is tethered with a small collar in one end chamber. A novel, unfamiliar “stranger” is tethered with a small collar in the other, opposite end chamber. The partner and the stranger are the same sex. After being tethered, the partner and the stranger are allowed to habituate to their tethers and the new cage for 10 minutes, and finally the subject is introduced into the center, “neutral” chamber. All animals are video recorded and their exact positions and movements are tracked using software. The time the subject spends in direct social contact with the partner vs. stranger is measured. After 3 hours the test is over and the animals are returned to their cages.
A laboratory test for pair bonding is valuable, because it allows us to investigate the role of specific biological systems in the formation of social bonds. With the partner preference test, we can block, boost, or manipulate different biological systems and investigate how it impacts partner preference formation (partner vs. stranger social contact).
Your assignment
We want to develop the best laboratory test possible to study pair bond formation. Think about the partner preference test, its design, and what it is intended to measure. Is this really the best laboratory test to measure pair bonding, or could there be better alternatives? Based on the information provided above, bring two original criticisms of the partner preference testing paradigm to class. The criticisms can be minor or major, and only need to be 1-3 sentences long (they can be longer if you need, but it’s not necessary). If applicable, briefly state an alternative/improvement that could be made to the partner preference test that would address your criticism.
You will turn in your criticisms, so please write/print your criticisms along with your name onto a sheet of paper and I will collect them at the beginning of class.