Homelessness in the Valley / Surviving Day by Day : Advocates for Homeless Urge More Compassion : Poverty: Psychologists offer explanations for the often fickle reactions that passersby show toward those in need.

There he is again. That shaggy-looking guy who hangs around your favorite grocery store.

Do you say hello? Walk quickly past, looking at your shoes? Or figure out a way to help? Under different circumstances, after all, that could be you.

Psychologists say our often fickle reactions to the homeless are partly based on whether we feel they are similar to us or blame them for their situation.

“When you see someone who is like yourself, you may be more willing to help them,” said Michele Wittig, a psychology professor at Cal State Northridge and a Santa Monica homeless advocate. “But you may also want to distance yourself from them, because that is usually easier.”

Many people, Wittig said, make a split-second distinction when they see someone camped on the sidewalk or pushing a shopping cart: that the person is either a victim of society--and therefore worth helping--or crazy, drunk or on drugs and, therefore, deserving of homelessness.

Too often, experts say, people have the latter reaction.

In their 1993 book “Malign Neglect,” Los Angeles-based homeless researchers Jennifer Wolch and Michael Dear describe a general loss of compassion for the homeless during the past decade.

“Homeless people,” according to Wolch and Dear, “tend to become tainted with the characteristics of the ‘worst case’ homeless subgroups: substance abusers, the chronically mentally unstable, those who are dangerous and unpredictable and those who are perceived as creating their own difficulties.”

Ambivalence toward such people has even led to an anti-homeless attitude among some of their more fortunate counterparts.

Last September, a Van Nuys man shot and killed a panhandler who had asked for money, according to witnesses. The man, who claimed self-defense, was not prosecuted for murder.

A month earlier, a Winnetka resident shot two homeless men rummaging through his bedroom, killing one. Deputy Police Chief Mark Kroeker called the shooting “characteristic of the tension and frustrations” between the housed and the homeless.

Walking along Van Nuys Boulevard near Victory Boulevard last week, Viola and Arthur Hernandez passed within two feet of a man slumped on the sidewalk. Arthur Hernandez made a little wave and smiled.

“We were homeless four months ago,” explained Viola Hernandez. “The wave is both to say, ‘Hello,’ and, ‘I understand.’ I always promised myself that if I got off the street, I wouldn’t start thinking I was better than other people.”

Other passersby were less friendly. Minutes later, the better-dressed Grant Kowalski walks by without seeming to notice the man.

“You can’t look at everybody,” Kowalski said. “You can’t help everybody. What are you supposed to do? It’s a problem. It’s not going away.”

It’s that feeling of helplessness and alienation that can lead people to lose their sense of responsibility for the homeless, said Richard Lamb, professor of psychiatry at USC.

“A lot of people learn to just step over someone lying on the ground,” Lamb said. “It’s distressing.

“What you really want is for people to see the problem and want to do something about it badly enough that they go home and make some phone calls, contribute to an organization and become part of the solution,” Lamb said. “We are a great country that loves a challenge, and this is a problem that can be remedied.”