Detection of 60‐Hertz vertical electric fields by rats

Rats were trained to press levers to indicate the presence or absence of 60‐Hz vertical electric fields at intensities from 0 to 27 kV/m (rms). The probability of detecting the field increased as the strength of the field increased. The shape of the detection curve (psychometric function) for most subjects ( Ss ) was similar whether the discriminative stimulus was the electric field or a tone. Two protocols were used to estimate the minimum field intensity necessary to detect the field ( Reiz Limen, RL ). The RL was estimated to be 13.3 kV/m (rms) when using one protocol (the staircase method) and 7.9 kV/m (rms) when using another protocol (the method of constant stimuli).