Cyclists and motorists behave EXACTLY the same
Considering they are all people and very often the same people, it would be very strange if it wasn't so. And the way people behave isn't specific to road transport, it applies very generally.
They will mostly break rules when convenient if (a) they don't themselves think it will do much harm to themselves or others that they consider important, (b) there isn't much chance of getting caught and (c) they think their mates do the same thing. But which rules they break varies with the circumstances. Cyclists can't break all the same rules as motorists and vice versa.
In many cases people will seek to justify their rule-breaking with spurious arguments or minimise the extent of their rule-breaking: I was only going x over the limit, speed limits cause motorists to bunch up and increase danger, it's safer to jump lights and/or cycle on the pavement, data should be free, I pay too much tax anyway (for the huge VAT-free cash payment brigade).
I have my share of horror stories about motorists cyclists and bikers but I won't bore you with them.
I am not a professional psychologist but I base these comments on 60 years of observing people on the road and in other places.
If this is true, you would expect that the way to change behaviour is with a combination of enforcement and campaigns to alter public perception of acceptability. This worked to a large expent with drunken driving. But enforcement had to come first because people rely on their peer group to judge their behaviour and this is very hard to change from outside.