Research has indicated that competing leaders erected the moai during periods of prosperity. Societies that have developed a degree of political complexity but lack a fully developed state bureaucracy often produce archeological sites that strike us as enigmatic or even mysterious. These sites are frequently characterized by elaborate and well-planned construction, yet yield little evidence of a ruling elite. Central to most hunter-gatherer societies is egalitarian social organization and an ethos of sharing. Northwest coast societies, divided into nobles, commoners, and slaves, lived in settlements of large houses built of wooden planks. Sharing was central to these societies, but took the form of competitive sharing through feasts known as potlatches. The potlatch is a competitive feast described in ethnographic accounts of northwest coast society. Social inequality on the northwest coast stretches over 2,000 years into the past. Within a village, the various households were ranked so that the leader of the highest-ranking household was the village leader.