Nonhuman primates will not respond to turn off strong 60 Hz electric fields

Using a set of six baboons (Papio cynocephalus), we conducted a series of seven experiments designed to evaluate the potentially aversive character of a 60 Hz electric field (EF). Initially, the subjects were trained, using food rewards as the reinforcer, to respond only when a cue light was illuminated. Next, an EF was presented along with the cue light; responses produced delivery of a food pellet and turned off both the cue light and the EF. Then, stimulus and reward conditions were varied. We determined that 1) presence of a strong EF does not affect operant responding for food rewards, 2) subjects will not respond at normal rates when the only reinforcer is termination of a strong EF, 3) presence of a strong EF can serve as a discriminative stimulus, 4) presence of a strong EF does not affect extinction of an appetite-motivated task, and 5) presentation of an EF can become a secondary reinforcer. The pattern of results was consistent across all experiments, suggesting that an EF of as much 65 kV/m is not aversive to nonhuman primates. Separately, we demonstrated that the average EF detection threshold for baboons in 12 kV/m. Thus, EF exposure at intensities well above the detection threshold and at species-scaled EF strengths greater than those found environmentally does not appear to be aversive.