In saying that the value of a commodity is determined by the quantity of labour worked up or crystallised in it, we mean the quantity of labour necessary for its production in a given state of society, under certain social average conditions of production, with a given social average intensity, and average skill of the labour employed. The poor hand-loom weaver now worked seventeen or eighteen hours daily, instead of the nine or ten hours that he worked before. Still the product of twenty hours of his labour represented now only ten social hours of labour, or ten hours of labour socially necessary for the conversion of a certain amount of yarn into textile stuffs. His product of twenty hours had, therefore, no more value than his former product of ten hours. As less developed economies are opened up to competition with developed ones, this process repeats itself.
Labour performed in pre-state of the art conditions, is devalued.
But this is an inevitable effect of the exchange process. For in exchange, the social status of private labours, is established by equating use values, and this presupposes self-identity. With the devaluation of labour goes a devaluation of labour power - a decline in wages. Because of inflation, this actually represent a fall in real wages for the US worker, and was thus a still greater fall for the Mexican worker. The devaluation of the labour of countries with a slower development of productivity is reflected too in the repeated devaluations of their currencies - something all too evident with the peso.