Findings in a new study suggest that since 19th century there has been a drastic change in heads of white Americans. It has been proposed that the heads of these native Americans have become larger, taller and narrower.

During the course of the study, forensic anthropologists at University of Tennessee, Knoxville, analyzed skulls of 1,500 people. The heads of people examined dated from mid-1800s to mid-1980s.

It was observed that there was an increase in height of the skull in case of men by approximately by eight millimeters (0.3 inches) and the size increased by 200 cubic centimeters.

However, the team didn’t illustrate reason behind the change in shape and size of the heads, but they suggested that it could have been due to change in lifestyle.

Lee Jantz, coordinator of UT's Forensic Anthropology Center, said “The varieties of changes that have swept American life make determining an exact cause an endlessly complicated proposition”.

Moreover, Jantz asserted that the growth patterns have drastically changed since the past few decades, as a consequence majority proportion gets better nutrition, mortality rates associated with lower infant and maternal issues have declined to a great extent.

Apart from the above mentioned aspects, other factors including less activity and physical work and also old thoughts and barriers regarding marriage, could have been the major contributors.