Four days after the bombings at the Boston Marathon… we are still getting details about the nature of the attacks.   While much is yet to be know… the effects–especially the psychological toll-- of the bombing are widespread. Many of you–our listeners-- have expressed discomfort around gathering in large groups in the aftermath of the attack. While that may be a natural response to such a horrific event… there are others who say that acting on our fears this way is to capitulate to the perpetrators. Listen to President Obama at a press conference on Tuesday: TERRORISM 1 OBAMA — 12s Pres. Obama at press conference 4/16/13 "The American people refuse to be terrorized... because what the world saw yesterday in the aftermath of the explosions were stories of heroism, and kindness, and generosity, and love." Another such voice is Bruce Schneier. He is a security expert… and wrote an op-ed in The Atlantic… arguing we should "empathize… but refuse to be terrorized." Also with us for an update on the latest in Boston is Phillip Martin. He is Senior Investigative Reporter for our partner WGBH… and will be with us the rest of the hour.   A manhunt is underway for the surviving Boston Marathon shooting suspect, who has been identified as 19-year-old Dzhokhar Tsarnaev. The other suspect, Tsarnaev's brother, was killed in a shootout with police after an extended chase that resulted in the death of an MIT police officer. Charlie Sennott, executive editor of GlobalPost, describes the scene in Boston-- and his feelings on covering a story like this in his home.  Anne Speckhard, author of "Talking to Terrorists" and a professor of psychiatry who has studied Chechens intensively describes how their early years in that region may have influenced them.