How a group of people behave, their views, opinions, and perceptions based on language, ethnicity and race is culture. Culture affects virtually all human behaviour.
Marketing communications are heavily dependent on a particular groups culture. Culture affects not just what is communicated but how it is communicated as well. Depending on how industrialized and advanced a country or region might be affects the medium through which marketing communications are rolled out. A marketeers success is largely dependant on how well he understands cultural preferences, ideologies and behaviours of target consumers.
