Discuss the use of animals in research and the ethical issues associated with it?

The question of whether or not it is useful or even necessary to experiment on defenceless animals is the product of a lively debate amongst psychologists. This storm of controversy is mirrored by the ambivalent attitudes of the public towards scientists, who are often seen as cold and objective, deliberately causing pain to innocent animals when this is not necessarily the truth. So why does the issue of animal research stimulate such impassioned opposition?  The represented underlying uneasiness towards science in my opinion is due in part to a classic misconception, which is underlined by Singer (1974,cited in Olen & Barry 1994, p.404) that in all research using animals intolerable pain is caused. However in respect to psychology like all sciences, causing unnecessary pain to animals in research is not always the case….(short extract)