Echolocation in the blinded rat

The difference threshold for detection of barriers at different distances using a modified method of limits was found, for four blinded rats, to be 9 in. White noise 20 dB above ambient level reduced discrimination performance to chance, indicating that auditory cues were involved in the discrimination. A second determination, utilizing the method of constant stimuli, confirmed the difference threshold to be 9 in. and reduced individual S variation by further training. Evidence with a black and a white barrier indicated the possibility that infrared heat cues do not enter into the discrimination.