What is the point of pay rises?

https://www.independent.co.uk/news/uk/politics/tory-mp-salary-peter-bottomley-b1933668.html

Here is one of the great mysteries of the world. What is the use of a pay rise? It's an established psychological fact that money only works to bribe manual labourers. People who work in creative fields that require their brain do not respond to pay rises.

Surely after a pay rise you get the same money for less work, so you are inclined to do less work?

It got me thinking: what is the point of pay rises for non manual labourers. Answer: there is none!

Never-the-less lots of people like pay rises: can they explain why? My best guess goes to the heart of conditional/relative human existence. We only want a pay rise so we can be better than our neighbours, and they the same so it enters into an arms race. One of the oldest pieces of text (~3000BC) is a cuneiform letter from wife to husband complaining that the neighbours have just put up and extension, so where is theirs? That's the real reason for pay rises. But how sad are these people to be defined in relation to their neighbours rather than by what they really want. On that account they should not be given pay rises and the public system should get the money for democratic collective spending to avoid me vs them time wasting.