An economist asked about the AD-AS model featured in Krugman

An economist asked about the AD-AS model featured in Krugman et. al.s textbook says that the model has no value in the real world, as business cycles can be better explained by analysing the animal spirits driving peoples behaviour. Evaluate the statement, using the UK experience from 2008 to February 2015.
Instructions:
You need to discuss the model itself, the relevant animal spirits arguments and the relationship between the two (for example the effect of fairness on the short-run aggregate supply curve or the effect of confidence on the ad curve). You then need to apply both to the data and to events during the specified time. You should then be able to come to an overall conclusion. For example, did nominal and real wages behave as suggested by the ad-as model?