Attention factors in contralateral threshold shift

Young adults (2 F, 1 M) in a sound room tracked fixed-frequency Bekesy threshold in the L ear to a 3-kc/s tone for 4 min before, and for 4 min after, receiving in the R ear either a 13-min fatiguing .5-kc/s tone at 75 db SPL, or 13 min silence. Half the time S, when receiving the fatiguing tone, read a magazine, and half the time attention was directed to the R ear. In the control condition with no fatiguing tone, S read half the time and half the time counted soft tone pips in the R ear. Only when S's attention was directed to the fatiguing tone did threshold rise. In other cases, threshold dropped. Results are discussed in terms of central-attentional variables and recovery from fatigue.