New Delhi, March 9 -- On the morning of 26 February, video footage of an Indian Air Force pilot, bleeding, blindfolded, captured by Pakistani forces across the Line of Control, began to circulate on social media. So did unease, doubt and disbelief. Half-truths and falsehoods about the likelihood of war with Pakistan had flooded the internet in previous weeks, produced by partisans enthusiastic about India's prospects in a military confrontation.

These forwards had encouraged strong, simple emotions, such as anger and nationalist pride. In contrast, the video of Wing Commander Abhinandan Varthaman released by Pakistani officials had a disorienting effect on many Indians. Confusion arose on Twitter, and focused, briefly but intensely, on the...