Excerpt from The Sociopath Next Door by Martha Stout, plus links to reviews, author biography & more

Sometimes when there is a business trip, like today, Joe is gone from home for a day and a half, or even a little longer, and each time he comes back, Reebok greets him at the door with bounding joy and instantaneous forgiveness. Before he takes one of these trips, Joe always leaves large mixing bowls full of food and water for Reebok to consume in his absence, which Reebok does easily. But this time, between the furnace problem and his panic about the 8:00 meeting, Joe forgot. The dog has no food and maybe even no water, and no way to get any until tomorrow evening, when Joe returns from his trip.

Maybe I can call someone to help out, Joe thinks desperately. But no. He is between girlfriends at present, and so no one has a key to his house.

The impossibility of his situation begins to dawn on him, and he grips the steering wheel even harder. He absolutely must make this meeting, and he can be there on time if he just keeps going. But what about Reebok? He will not starve to death in a day and a half, Joe knows, but he will be miserable—and the water—how long does it take an animal to die of dehydration? Joe has no idea. Still driving as fast as the traffic will bear, he tries to think about his options. The available choices tumble over one another in a rush. He can attend the 8:00 meeting and then go home and feed the dog, but that will make him miss his 10:15 flight, and the trip is even more important than the meeting. He can go to the meeting and leave in the middle. No, that would be seen as offensive. He can try to get a later flight, but then he will be very late for his appointment in New York, may even miss it entirely, which could cost him his job. He can ignore the dog until tomorrow. He can turn around now, miss the 8:00 meeting at the firm, take care of the dog, and still make it to the airport for his 10:15 flight.

Like a man in pain, Joe moans loudly and slumps in his seat. Just a few blocks from work, he pulls the car into a spot marked construction only, dials the office on his cell phone, and tells a secretary to inform those at the morning meeting that he will not be attending. He turns the car around and goes home to feed Reebok.

What Is Conscience?

Amazingly, from a certain point of view, the human being we are calling Joe decides to be absent from an important meeting with some wealthy clients, an event he has spent several days planning for, and where his personal interests quite clearly reside. At first, he does everything he can to get to the meeting on time, risking all the possessions in his town house to a repairman he has never met before, and his own physical safety in his car. And then, at the very last minute, he turns around and goes home to feed a dog, a guileless, wordless creature who could not even so much as reprove Joe for ignoring him. Joe sacrifices a high-stakes desire of his own in favor of an action that no one will witness (except maybe the repairman), a choice that will not enrich him by even one penny. What could possibly cause a young, ambitious lawyer to do such a thing?

Most readers will smile a little when Joe turns his car around. We feel pleased with him for going back to feed his dog. But why are we pleased? Is Joe acting out of conscience? Is this what we mean when we make an approving remark about someone's behavior, such as "His conscience stopped him"?

What is this invisible, inescapable, frustratingly incorruptible part of us we call "conscience," anyway?

The question is a complicated one, even as it pertains to the simple vignette about Joe and Reebok, because, surprisingly, there are a number of motivations other than conscience that, separately or together, might cause Joe—might cause any of us—to make an apparently self-sacrificing choice. For example, perhaps Joe simply cannot stomach the thought of returning from his New York trip to find a Labrador retriever dehydrated and dead on his kitchen floor. Not knowing how long a dog can survive without water, he is unwilling to take the risk, but his aversion to the horrifying scenario is not exactly conscience. It is something more like revulsion or fear.

Excerpted from The Sociopath Next Door by Martha Stout, Ph.D. Copyright © 2005 by Martha Stout, Ph.D.. Excerpted by permission of Broadway, a division of Random House, Inc. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.