Around AD 800, profound settlement and subsistence changes marked the transition between the periods archaeologists have named Basketmaker III and Pueblo I times. One of these changes was the appearance of cranial deformation. Most archaeologists have assumed that harder cradleboards caused this skeletal feature. Systematic examination of artifacts in their cultural and historical contexts suggest that In fact, the "hardness" of "cradleboards" did not vary over time. Instead, the function of what archaeologists called cradleboards changed dramatically. This functional change can be attributed to the reduction in personal mobility and changes in childcare that accompanied the concomitant adoption of agriculture as a lifeway.