The ABIE study used a combination of observational, behavioral and attitudinal approaches to their research. Teams of researches visited the capital cities of each state and territory. The behavior modes identified varied little from a small, visual study conducted by PRC in center city Philadelphia in the early 80's. Littering remains a common method of disposing of unwanted material. While some people simply leave litter behind, many litterers deliberately place objects in specific locations.
Many people do appear to be consciously aware that they are littering.
There is no such thing as a littering type. People of all ages, races, ethnic background, social classes, and gender were observed littering and also practicing proper disposal habits. Those least likely to litter were those under age 15. People between 16 and 25 were more likely to litter in a group while older people were most likely to litter when they were alone. Students and people not employed had higher than average littering rates.