Jacob spoke first.
“I want to know if my hair is just like yours,” he told Mr. Obama, but so quietly that the president asked him to speak again.
Jacob did, and Mr. Obama replied, “Why don’t you touch it and see for yourself?” He brought his head level with Jacob, who hesitated.
“Touch it, dude!” Mr. Obama said.
As Jacob, who was 5, patted the presidential crown, Mr. Souza snapped.
“So, what do you think?” Mr. Obama asked.