The latest paper from our lab by Imran Razik, Bridget Brown, and I can be found here at Biology Letters.
This plot shows the experimental design. Imran let female vampire bats groom each other (network on left), then randomly selected bats to house together in a small cage for one week (middle), and then let them freely associate and groom each other again (network on right).
Below is a plot from the supplementary materials showing the raw data. The dots shows the mean grooming rate (log-transformed) for the test group (blue) and control group (red) after the test group was forced into close proximity during the period of time between the two vertical bars. As you can see, the forced-proximity period elevated the social grooming rates in the test group, even after several weeks.
This effect was only evident in the test pairs: