I was reading this article about medieval peasants and the author mentions 14th century England to have particularly high wages. I was under the impression that most peasants were tied down to their land and did mostly farming to pay taxes and subsistence. What were peasant's wages like? Why were they higher in the 14th century? What happened in the 15th to make them lower again?
The Black Death arrived in England in June 1348, and by the end of 1349 had ultimately killed up to 60% of the population. This resulted in a massive shortfall in the labour force, and led to a sudden and rapid increase in the wages and rights of the peasants whose labour was now very much in demand across the country. In England in particular, this increase in wages could be facilitated by the vast amounts of plunder being brought back from France during the Hundred Years War.
To answer the second part of your question, an economic contraction occurred in England from around 1440 to 1480, which is known as "The Great Slump."
One major cause of this depression was the result of a shortage of silver bullion. It has been suggested that this was partially a result of the high amounts of spending on luxury goods flowing into the country that occurred following the Black Death, resulting in a flowing out of precious metals.
With the lack of coinage there was a corresponding shortage of credit, which crippled trade. Those involved in the wool and cloth market were particularly hard hit. Between 1446 and 1450, cloth exports fell by 35%.
As trade began to slow, the recessionary effects rippled through the rest of the economy, resulting in deflation.
For a peasant, they would been hit by falling market prices, grain they were unable to sell, and a decreasing in purchasing power.