Question

What fledgling technology was ignored prior to the attack on Pearly Harbor

Answer 1

What fledgling technology was ignored prior to the attack on Pearl Harbor?
Radar
Radar was the fledgling technology that was ignored prior to the attack on Pearl Harbor. Radar was ignored before the attack on Pearl Harbor because it was new, not evolved, and still experimental. 
On the morning of December 7, 1941, it was when the attack on Pearl Harbor occurred.  It was a surprise military strike by the Imperial Japanese Navy Air Service versus the United States naval base at the Pearl Harbor, Hawaii Territory.