In discussing the ubiquity of human violence in history and the suspicion of strangers, I recalled that I had long ago posted on an Indo-European word root that revealed the ambiguity of the situation nicely. The root *ghosti is the root of both guest and host in English, host in both senses: "one who receives a visitor" and "multitude." It is also the root of hostile, hostel, hospital, hospitality, hostage, and similar words in other Indo-European languages. It described a mutual relationship, an association cemented by an exchange of gifts. Or, er, children. The giving in marriage, surety, or apprenticeship as a pledge between families is not that different from hostage. Ruling families would send sons to be in another's army or daughters to be brides, and whether this was friendship, appeasement, or tribute might be difficult to sort out. The biblical covenant had similarities, but was not quite the same thing. Still, as Christianity came to places settled by descendants of the Indo-Europeans, the concept was familiar to them.
Many cultures have something like this, but the idea of such gift-exchanges had attenuated by the time of European colonisation of the New World. Native Americans would give gifts to settlers as an indication that they wished to start a formal relationship between tribes. They expected that if the gift was accepted, a reciprocal gift would follow. If it did not, the bestowing tribe was to conclude that an alliance was not desired. This was not necessarily an insult - everyone knew that alliances have positive and negative effects, and a repeat offer might be initiated by either party at a later time. Yet if the gift was not reciprocated, the original giver was entitled to his original gift back. The Europeans, unfortunately, just thought "hey, a gift!" and felt no obligation. Thus when the Natives reclaimed their gift, it looked like theft to the Europeans, or at best, a sort of falseness in giving. Hence the term "Indian-giver," which illustrates how poorly the English understood a custom their ancestors would have known better. Had the Mayflower settlers left any kind of gift behind when they came upon the Indian stash of food, things would have gone better thereafter.
Side note: The word ghost meaning "spirit" may be more distantly related.
Side note: In my entry on this root written in 2006, I referred to myself as a "psychblogger" then. I had completely forgotten that in the ensuing years. While I wrote on many subjects right from the start, I wrote much more often on mental health topics then, and associated myself with a small circle which included Dr. Sanity, Gaghdad Bob at One Cosmos, G M Roper, Shrinkwrapped, and others. They all tended to write at great length, and I think I was influenced by them as I also wrote some very long pieces in the first few years. As I grew less interested in reading beyond a few paragraphs of their work, I concluded that readers might feel similarly about my writing, even if they agreed with me. Moral: Memory of the self is unreliable.