Why is vicarious learning important?

Vicarious learning saves time. Mimicry of an existing behaviour that works sets up patterns of success. This saves calories, risk of injury, risk of attracting predators, risk of death and waste.

It eliminates trial and error. If every monkey had to figure out to use a stick to get termites out of a log, they could starve before they figured it out. If they mimic their mother doing it, they have an instant success and increased survival.

It also eliminates risk in the same way. If there are three colours of berries and 2 colours are poisonous, without vicarious learning 2/3 of all the species risk death at every opportunity to test the berries - that's cumulative. If the mother chimp eats only the red ones and barks when an infant heads for another colour survival is more assured.

If food resources are scarce, a species can ill afford much trial and error at the risk of the food supply.

Factors that affect it are the simplicity of repetition, the ability to communicate the learned behaviour, the criticalness of the behaviour being copies exactly or how much variance is allowable or required, the reasoning ability of the species.

It is observational learning.

Can't cover it in much detail here.

You learn THROUGH other people. If I see a man walking down the road and he trips and falls and a car runs over him, by witnessing this, by seeing what this man did, I now know not to do the same thing he did. I think it is very similar to observational learning. You learn by watching.