Temporal limits of level dominance in a sample discrimination task (L).

Level dominance refers to the effect where attention is automatically directed to the loudest part of an auditory display. In a sample discrimination task, the frequencies of five 50 ms tones were sampled from normal distributions with means of 1000 and 1100 Hz and presented sequentially, with the tones alternating in intensity. Observers decide from which distribution the sample was drawn. The informativeness of the even numbered tones (d' = 2) was greater than the informativeness of the odd numbered tones (d' = 1). Estimates of decision weights and performance levels (d') show that when the more informative tones were less intense, observers attended to the louder tones rather than the more informative tones. This effect extends well beyond the temporal limits expected from forward masking studies.