I wanted to share some particularly interesting research on pigs regarding generalization behaviors. Pigs (and other animals) learn from experiences by either generalizing or by discriminating - generalizing is the ability to learn something in one context and apply it to other situations, discrimination is learning something and only applying it in the narrow context in which it was learned. Often with prey species, generalization is an important ability with regard to fear-responses because it allows the animals to recognize potentially dangerous situations after only a single or very few encounters. If a prey animal narrowly escapes a predator in one context, it is important to be able to generalize out to other contexts so that the prey animal responds appropriately in the future. In this study (Hemsworth et. al.,1994), researchers found that "in situations in which pigs are briefly handled by one of two stockpersons in a predominantly negative manner or in which pigs are briefly handled by stockpersons who differ markedly in the nature of their behaviour towards pigs, pigs are likely to exhibit stimulus generalization as measured by their behavioural responses to humans." In other words, pigs learn to associate rough handling from their specific handler, and subsequently responded to any humans in the same manner, by practicing avoidance or fearful behaviors. This makes sense, because as a prey species, it is important for pigs to recognize and remember when something unpleasant happens and to be able to apply that knowledge to future situations. Keep in mind that an aversive is ANYTHING the pig finds unpleasant - WE might know that a light shove or push doesn't actually hurt the pig, but if the pig finds it unpleasant, it IS classified as an aversive.
If we use aversive techniques like dominance theory, the pig is likely to generalize his rough handling out to all people. There is a strong anecdotal correlation between homes that utilize methods of force or intimidation to manage problem behaviors and the presence of reactive behaviors from those pigs towards guests and unfamiliar people in the home. Have these pigs generalized their rough handling and learned that all people are unpredictable, frightening and perhaps dangerous?
(ETA): Interestingly, studies also show that while pigs generalize bad experiences, they tend to behave discrimanatorially with regard to postive experiences (ei they won't immediately associate all people with good things if one person treats them well - I'll be discussing those studies in more depth in a future post). It seems it is very easy to lose a pig's trust, and much much harder to regain it.
Hemsworth, P.H., Coleman, G.J. Cox, M. and Barnett, J.L., 1994. Stimulus generalisation: the inability of pigs to discriminate between humans on the basis of their previous handling experience. Applied Animal Behaviour Science, 40: 129-142.
Hemsworth, P.H., Barnett, J.L. and Hansen, C., 1981a. The influence of handling by humans on the behaviour, growth and corticosteroids in the juvenile female pig. Hormones and Behaviour, 15: 396-403.
Hemsworth, P.H., Barnett, J.L. and Hansen, C., 1986. The influence of handling by humans on the behaviour, reproduction and corticosteroids of male and female pigs. Applied Animal Behaviour Science, 15: 303-314.
Hemsworth, P.H., Barnett, J.L. and Hansen, C., 1987. The influence of inconsistant handling on the behaviour, growth and corticosteroids of young pigs. Applied Animal Behaviour Science, 17: 245-252.