Monocular perception of egocentric distance via optic flow generated by head movement towards a target was investigated using a helmet mounted video camera and display. Ability to perceive target distance was assessed using two response measures, verbal reports and reaches. Systematic and random errors differed as a function of the response measure. Verbal estimates of targets within and beyond reach were obtained before and after the performance of reaches to targets within reach. Systematic errors of verbal estimates changed but did not decrease overall. Random error decreased. Next, verbal estimates and reaches were performed concurrently to targets within reach. Verbal and reaching errors were uncorrelated. Verbal judgments appear to have been anchored using the range of distances experienced while reaching rather than being calibrated to the perceptual information itself. Discussion focused on the advantages of action response measures.