The Logic of Expressive Collective Action: When will Individuals ‘Nail their Colours to the Mast’?

Individuals do not act collectively simply because they recognise common interests; collective interests can be defined as collective goods and collective goods are non-excludable. In ‘large’ groups instrumental individuals have no incentive to act because individual action is imperceptible. But are individuals always this instrumental? If it is a mistake to assume that collective action occurs ‘naturally’ when common interests are recognised, it is a mistake to ignore awareness of common interests. Individuals derive satisfaction from expressing identity with common interests but when will individuals choose to ‘nail their colours to the mast’?