volunteer as part of that program. There are concerns about chronic pain studies because the animal is no longer a “volunteer.” In addition, pain caused in other research programs can be addressed using some of the newer long-acting analgesics.

Anxiety and fear are not the same as pain and, unlike pain, there is no obvious organic location associated with anxiety. These states can be treated with anxiolytics and sedatives, but I doubt that many programs do so. One example of the impact of fear in the laboratory was a dog model of anxiety developed by W. G. Reese (1979) out in the Midwest 20 years ago using pointers. In the presence of humans, the pointers would urinate, defecate, and display tonic immobility. If you turned your back on them, you would get bitten. However, in the absence of humans or under anxiolytic therapy, you could not tell which pointers came from the anxious strain and which ones did not.

Discomfort is different from pain and anxiety/fear. It may have an organic location, but we really do not have any sort of good treatment other than palliative care. Disease and malaise may involve discomfort but also include states that are different from those we might characterize typically as discomfort. Distress occurs when any of the states listed above (pain, anxiety, fear, disease) become too great. Distress may be prevented by appropriate psychosocial initiatives. For example, an animal that trusts its handler is far less likely to be distressed than an animal that is fearful.

Finally, we have the overarching concept of suffering. Suffering is a state that requires a certain level of pain, anxiety, or distress before it is experienced. As I discuss later, suffering and distress are not the same concepts. The model that may be used to describe the relation between some of the baseline states like pain, fear, discomfort and disease, and distress and suffering is as follows. The primary baseline states occur at different intensity levels and for different time deviations. Whether or not these baseline states cause distress is a function of intensity and duration. A low stimulus for a long time may cause distress whereas an intense stimulus for a moment may not. Once one has a state of distress, the level of suffering experienced is a function of the cognitive capacity of the being experiencing the distress.

Let us examine the concept of suffering in a little more detail. Some interesting anecdotal data in the literature describe a few humans (not many, it is a very rare syndrome) who cannot feel pain. When you read some of these case studies, you find that some of these individuals report that they are very fearful of surgery or that they just cannot stand going to the hospital. They fear the hospital and report that they suffer in hospitals, and yet they experience no pain whatsoever. This is one of those examples which proves the point that pain and suffering are not the same.

Another side of the suffering question (related to cognition) is the question of whether insects can suffer. A fairly persuasive argument can be made that they do not. Insects have short life spans and there is not a compelling evolutionary reason why pain-induced learning would make much survival sense from an

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement