Could you narrow down your question slightly? Britain has had colonies all over the world, so there are quite a few possible answers.

It very much depends on each individual colony. India, for example, was socio-economically very different from North America, or South Africa. Your question is much too broad, unfortunately. The British colonized territories inhabited by people living a hunter-gatherer lifestyle (like Australia), to people with a very "advanced" civilization (ie, own alphabet, historical records, urbanized and comparatively quite "modern"... like India or China).

But very broadly, European colonies, before European settlement, were at "best" at a medieval level in terms of technology. Through Industrial Revolution and the invention of the scientific method, Britain, and Europe, jumped a huge step and were basically overpowered.

Now, you spoke of the "sociological" difference. This is an interesting subject, because in a sense it's quite controversial. What I'll say may actually be quite controversial. Europeans may have fed the slave trade initially, but eventually, the Enlightenment, Human Rights, and whatnot, are European ideals. The British notably forced India to end the ritual slaughter of widows, and imposed the end of slavery in some parts of Africa. This last point is a subject of shame amongst current African intellectuals. The fact that institutionalized slavery ended in Africa, not by Africans, but by the Europeans who at some point philosophically and morally evolved to consider slavery was wrong.

You mean.. before any Europeans arrived? Or before the British got there? Are you asking what was the socio-economic status of various indigenous people?