Because of peripheral vision, a young human can see—or at least be aware of—a bit over 180 degrees. You can't really see anything clearly at the extreme edge of your vision, but you are aware of movement.

I know,but I wanted to say in the memory,seem others would have less angle in their memory...Never mind,It's a kind of feeling hard to explain.

thousands of parents have been calling their local city halls asking about what they can do about their hikikomori children, who are almost always male.

Not must be male,is higher chance to be male,this is the reaction of male brain grow up in an unfriendly environment,female brain grow up in an unfriendly environment would become attention whores and bitches(in most people's words),because only the female brain is "forced social",this term is invented by myself. They can be "交" even in horrible environment ,which I feel is horrible.

Hikikomori have the problem to love humans ,their parents have to ask themselves why they rise a child can't love humans rather than use the murder event to ask the city halls,they shirk the fostering responsibility to the society.