Previous research has shown that subjects can respond to the onsets of sinusoidal signals more rapidly than to the offsets of such signals. The difference in the speed of response to onsets and offsets of monaurally presented signals was investigated for three different signal frequencies: 500, 1000, and 4000 Hz. For the two higher signal frequencies it was found that this difference in reaction time to onsets and offsets was greater for signals presented to the right ear than for signals presented to the left eat. This eat difference resulted mainly from slower responses to the offsets of signals presented to the right ear than to the offsets of signals presented to the left ear. This ear difference is unusual in that it was obtained with monaural presentations of simple stimuli: the ear differences most frequently reported are typically found with dichotic presentations of complex (speech) stimuli. Previously reported ear differences have been attributed to differences in hemispheric organization of the brain. The basis of the present results is unclear.