It's called the Relative Income Hypothesis. James Dusenberry wrote his PhD Thesis on it in 1948.
Most of us here know this type of behaviour as "Keeping up with the Jones's"
In todays terms considering real wages for most people are falling and yet productivity and profits are increasing is it any wonder people are trying to top up their earnings via penalty rates or OT ?
The fun will begin when the financial engineering comes to a halt and workers will no longer be able to spend more than they earn using credit.
That will spell the end to profits and indeed result in a recession the likes of which we have nver seen before.