Animal welfare research has been criticized for being anthropocentric, emotionally driven rather than scientific. It is argued that there is a need to take an allostasis view (stability through change), instead of a homeostasis view (maintained at a set point) of animal wellbeing which could potentially be achieved through improved cognitive enrichment. It is also argued that the success of enrichment is too often measured by observing a decrease in negative behaviour, for instance aggression, and that it should be measured by indication of good wellbeing and positive emotion. Others emphasize that it is crucial that there be benefits to the animal’s welfare in order for the process to be considered cognitive enrichment.