Animal decision-making and the 'Concorde fallacy'.

Both animals and humans appear to commit the 'Concorde Fallacy': they seem to gear their investment into a vital task to their past investment, though ideally they should gear it to the net expected future benefits (= benefits minus costs to complete the task)(1,2). By uncoupling past investment from expected benefits, animals have been variously shown to behave in a Concordian way, though in some cases alternative explanations are still possible. While there is no firm evidence that such behaviour is maladaptive, for instance due to cognitive constraints, there are at least two reasons why Concordian behaviour might be adaptive rather than 'fallacious'. One is that past investment lowers the prospects of future reproduction, thereby altering net expected benefits; the other is that past investment is indispensible to gathering the information necessary for deciding the least costly course of action, i.e. to reap the greatest benefit.