The most famous cognitive obstacle to innovation is functional fixedness — an idea first articulated in the 1930s by Karl Duncker — in which people tend to fixate on the common use of an object. For example, the people on the Titanic overlooked the possibility that the iceberg could have been their lifeboat. Newspapers from the time estimated the size of the iceberg to be between 50-100 feet high and 200-400 feet long. Titanic was navigable for awhile and could have pulled aside the iceberg. Many people could have climbed aboard it to find flat places to stay out of the water for the four hours before help arrived. Fixated on the fact that icebergs sink ships, people overlooked the size and shape of the iceberg (plus the fact that it would not sink).