Imagine the Martians are looking down at us in the UK. They see large buildings which appear to be factories.
In one factory they observe the workers work a strict 7 hours and then go home in small efficient vehicles.
The other factory contains people who seem to work much longer, even 12 hours or more. The Martians also see that these workers have strange cloth ligatures around their necks, which must be demeaning, they assume.
These workers have much less leisure time and bigger more expensive vehicles, but the road ways are clogged-up so they get home no quicker than the 7 hour factory workers. The Martians listen in and interpret limited amounts of data over the airways.
It seems that the 12 hour + workers have to work there because they have things called degrees. Some have more than one. If the grade of the degree is low e.g. 1st or 2.1 that seems to make it more likely for them to have to work there it seems.
The odd thing is, the Martians wonder why so many people seem to be knocking on the door of the 12 hour factory as if they are trying to get in. Only a few appear to be allowed through the gates each day.
Human Beings are strange creatures, the Martians figure.