With the exception of the immediate family, many humans interact more with domesticated animals than they do with other humans. These interactions are often frequent and intense and consequently complex and strong social relationships can be formed between humans and domesticated animals. Results of recent research on the interactions between humans and farm animals indicate some surprising and substantial consequences for the animals and the objective of this paper is to review some of this recent research, particularly that concerned with the biological basis of the response of farm animals to humans. The results of recent research by my colleagues and I, particularly on commercial pigs, will be utilized heavily in this paper.

In intensive animal production the animal frequently has to respond to the presence of humans and to handling by humans. One of the main motivations of the animal which will determine the animal's response to humans is fear. Although there is debate concerning the concept and measurement of fear, we have adopted a functional approach in studying the behavioural responses of farm animals to humans.