By such a procedure, Lindsley had produced highly stabilized and regular behavior in the dogs, and had conditioned the animals' behavior to certain factors--when the light was on, the dogs would remain idle, when the buzzer sounded, the animals refused to work. With such stability and consistent performance, any changes in the dogs' behavior due to radiation could be observed.

One hour after irradiation, the dogs were placed in the Skinner Box for their usual hour work-period. The canines discriminated the light as before, remaining idue during the 10 minutes it was on. What followed next, though, was singular and unexpected. Not only would the animals refuse to work during the buzzer's blaring, but either stopped work before the buzzer sounded, or did not go to work after it stopped.

Heightened Fear

This shows a heightening of the fear response, both during and beyond the presence of the fear stimulus. In human terms, this would mean that irradiated soldiers would show fear not only during an air raid, for example, but also after the danger had passed.

Of those that continued to work through the buzzer as before, each dog manifested fear in some form. Their hair bristled, their tails went between their legs, or they worked at a decreased rate.

Five days after this first fear reaction, which had never been observed before, came a second stage similar to the first, this time lasting a day or two. Only once before this stage had been observed. It was not until the final, clinical stage, occurring 10 to 15 days after irradiation, that the traditional signs of the illness were evident. In this stage, the animals developed fever, the white corpuscle count went down, they lost appetite and weight.

On the heels of the clinical stage, came death to 30% of the irradiated dogs.

Effect on Soldiers

It is the first stage that interests Lindsley, as psychologist, because of its obvious strategic importance with respect to increased anxiety and fear of combat personnel following even sub-lethal doses of radiation. "The results obtained from these experiments with dogs are based on laws of animal behavior learned through the study of pigeons," says Lindsley. "Most probably a human's reaction to irradiation would be the same as a dog's--for it's a bigger phylogenetic jump from the pigeon to the dog than from the dog to man." Also significant is the fact that many people irradiated in the treatment of cancer have reported nervousness and anxiety in the two-hour period following treatment.

The next step that must be taken, according to Lindsley, is the development of medicine that will counteract the fear following irradiation. Just as important, is the establishment of a predictive correlation between the severity of the anxiety in the first stage, and the severity of the clinical stage. Such a development would afford a means for quick and efficient diagnosis of radiation sickness, and would clear the way for its prompt treatment.

Lindsley notes that his experiments are not classified, in keeping with the Atomic Energy Commission's determination to allow free circulation of results which might benefit humanity. Lindsley hopes his experiments will contribute to that end.