Technology doesn't just advance on its own. Somebody has to try new things, experiment, innovate, and test it all again and again.

The same was true 1,500 years ago when the bow and arrow was introduced to North America, a new study suggests.

University of Missouri archaeologists have discovered that early man, on the way to perfecting the performance of this new weapon, engaged in experimental research, producing a great variety of projectile points in the quest for the best, most effective system. The resulting new technology replaced the atlatl (spear thrower) and the dart and changed hunting and warfare forever.

"The introduction of the bow and arrow, a different weapon delivery system, demanded some innovative thinking and technology," said R. Lee Lyman, professor and chair of the University of Missouri Department of Anthropology. "In other words, one could not just shoot a dart from a bow. Components like the shaft and arrow point needed to be reinvented."

The bow and arrow has been around for perhaps 40,000 years and developed differently in various times and cultures.

Because flight dynamics and mechanics of the arrow wouldn't have been fully understood, the indigenous people of North America, when they began using the bow and arrow, would have tried all sorts of points with different types of shafts, attempting to discover the best combinations, Lyman figures. In fact, this reinvention process can be seen archaeologically through an increase in the number and variation of projectile points, indicating the transition period between the atlatl and the bow and arrow.

"Once a change is made in one variable, it may prompt changes in another variable because the two are mechanically linked," Lyman explained. "For example, if something gets longer, generally, it will get heavier. This is called a cascade effect. This, in combination with experimentation, resulted in the tremendous variation in projectile points."

Lyman said there is evidence of an initial burst of variation in projectile points at the time bow-and-arrow technology was introduced and that prehistoric artisans experimentally sought arrow points that worked effectively. Following that initial burst, less-effective projectile models were discarded, causing archaeologists to see a reduction in variation.

The results will be published this fall in the Journal of Archaeological Science.