A college professor I studied under years ago spoke of a time when he worked as a cop in a large city in South Africa. One night on patrol he heard a baby crying. He was in a warehouse district with no residences nearby. He began searching for the baby and finally found it in a dumpster. He told us (members of the class) he could not have turned away. He felt compelled to search till he found the infant. He gave this as an example of instinctive behaviour which is directed at preserving the species. Searching for a lost member of our "tribe" is as basic as searching for food or water.