Love is a Compulsion. The most striking characteristic in the love craving, one which differentiates it sharply from other cravings, is the compulsory exclusiveness of its choice. Hunger drives us to seek a large number of substances which, by filling the stomach, relieve what Cannon describes as a gastric itch.

The person in love, on the other hand, seeks only one single object at a time, which alone seems capable of vouchsafing the desired gratification.

A lovelorn man may be surrounded by many women, all extremely attractive and accessible, and yet pine away for some other woman who perhaps does not compare favorably with those he might conquer. He may, at times, yield to the temporary attraction of a new woman, but in the majority of cases, he will soon return to the woman he actually loves.

Not infrequently his environment will wonder at his choice. "What can he see in her?" Physically or intellectually, anyone but himself would see very little to "admire" in her.

What We See in Our Mate. The many handsome men whom we have met, and who are mated to homely wives, the many wives we have observed, mated to impossible husbands, and whose affection for their unprepossessing life partner is genuine and in no way dictated by sordid considerations, the many triangles we know of, in which a very inferior lover or mistress is preferred to an admittedly superior husband or wife, are evidence of the involuntary, nay compulsory, character of the love choice.

A comparison imposes itself with certain obsessive fears or cravings bearing upon one object which, to any one but the person experiencing such fears or cravings, may appear anything but fearful or desirable. The psychoanalytic investigation of the origin of such obsessions always shows that they can be traced back to childhood impressions which have modified our nervous reactions to certain objects or ideas.

The Meaning of Choice. Applied psychology and laboratory research have in recent years attached a more and more deterministic connotation to the term "choice." The word, which to academic psychologists, implied the exercise of free will and "judgment," will have some day to be accepted as synonymous with "compulsion."

A few examples from animal behavior will illustrate my meaning.

Philosophers have for years wasted breath and ink on the academic consideration of the following puzzle:

A donkey is standing at equal distance from two bales of hay; the two masses of fodder are mathematically alike in size, shape, color, fragrance, quality, etc.

Unless the animal, certain philosophers said, was able to "make a choice" of his own, he would remain motionless between the two bales whose attraction would be perfectly balanced. He would, like some celestial bodies, be held suspended by two forces which would not allow him to turn to the right nor to the left. He would rationally have to starve if attraction were a force exerting itself from the outside exclusively.

Yet no donkey placed in such a situation will fail to make an immediate choice. He will turn to one of the bales and start eating it.

Even if we imagine a philosophising donkey reasoning as follows:

"The two bales are equally attractive. Hence it makes no difference which one I start with. Let us begin with either."

Even then, he will have to "make a choice," altho his selection of one of the bales seems to be due entirely to "chance."

Chance in the Discard. Psychological research has eliminated chance as a factor in human behavior, and whether our donkey starts with the right or with the left bale, an analyst will insist that there are reasons why he picks out that one bale to be eaten first.

Laboratory dogs which have supplied solutions for so many psychological difficulties, have proved of service in this case too.

If the slightest surgical operation has been performed on one side of a dog's brain, he becomes unable to move in a straight line.

He deviates from the straight line toward the side on which his brain has been injured. If the lesion is on the right side he will be compelled to turn to the right and vice versa. This is due to the fact that the injury has weakened that side and the cerebral dynamo which supplies the body with power produces less current on the injured than on the uninjured side.

When you row a boat and slack one oar the boat turns toward the side on which you are expending more effort. Of course the process is reversed in a dog because the nerves of the dog cross over, the right side of his brain supplying the left side of the body, the left side of the brain supplying the right side of the body with power.

Let us repeat on two dogs, the experiment which academic psychologists imagined performed on a mythical jackass.

The Dog's Choice. Offer two pieces of meat to a dog whose brain has been injured on the right side and he will invariably eat the piece of meat nearer that side. Repeat the test on a dog whose brain has suffered a lesion on the left side and you will see him gobble the piece of meat on the left side.

Go even further and place both pieces of meat on the left side of the dog injured on the left side of his brain and he will "pick out" the one farther out. Not that he "prefers" that one. He will aim at the nearest but his injury will cause him to deviate too far to the left and he will be unable to reach the nearest one.

Other experiments on dogs illustrate the purely organic "motives" back of certain lines of conduct.

When both sides of a dog's brain have been injured in the frontal region, the dog refuses to go forward or downstairs but has a tendency to move backwards and to run upstairs.

When the back of a dog's brain has been injured on both sides, the dog has a tendency to keep on running forward all the time and while he is unwilling to climb stairs he will willingly go downstairs.

The Behavior of Copepods. When we pour carbonated water or beer or alcohol into an aquarium, certain crustaceans called copepods will at once swim toward the source of light, as tho they "loved" light, and appear so interested in light that they will "forget," to eat their food, if that food is placed away from the source of light. The same animals when placed in water containing strychnine or caffein, will shun the light as tho they "hated" it, and as tho they "loved" the darkness.

We know that if a galvanic current is sent thru our head we will lean involuntarily against the positive pole. If the current is sent thru an aquarium, a number of the animals swimming in it will be compelled to seek the positive pole and to remain there, others to seek the negative pole.

In the case of the laboratory dogs, a permanent modification of the nervous system caused a permanent modification of the animal's behavior, which could not be "cured," (for brain injuries do not "heal," the cells of the brain being unable to reproduce themselves), but which would probably be compensated for by gradual adaptation. In the case of the "phototropic" or "galvanotropic" animals, the modification of the nervous system was only temporary but might cause a more or less durable modification of the animals' behavior, if allowed to last a considerable length of time.

The love attraction or "erotropism" is likewise due to certain more or less lasting modifications of man's nervous system caused by the fact that his nervous system was for variable periods of time exposed to the influence of certain outside stimuli.