The pigs that took part in this study were 36 female and 36 male 8-9 weeks old Yorkshire-Hampshire crossbreeds from 11 litters. The pigs were housed in a integrated pig production unit at the research centre of the Swedish University of Agricultural Sciences.

The study had two parts. First, all pigs took part in an individual behaviour assessment at 8 weeks of age to study their personality. Second, all pigs participated in one treatment on one test occastion in the foam box study. The foam box study was designed to study the effect of familiarity between pairs of pigs in social support.