Suggestibility, looking for research or general information

I’ve been thinking for a while now that the human ability to be suggestible, i.e. being inclined to accept and act on the suggestions of others, is a pretty major factor in the world from advertising to elections.

I’m wondering if any reasons have been found for those who are very suggestible and those who aren’t, and I’m wondering what percentages of people are very suggestible.

I’m interested in what effects suggestibiliy has on culture, and on a person’s life.

Can anyone point me to anything that provides more information without being too technical. Something on the internet would be great, or a book (that’s not too expensive :)).

Thanks for any help!