Subject: Re: Instruction for subjects From: Bruno Repp <repp(at)HASKINS.YALE.EDU> Date: Thu, 27 Oct 2005 11:17:58 -0400Dear Fatima: I found your observations interesting, although I am not really an expert on this phenomenon. Nevertheless, the task reminds me of some work on phoneme restoration that I did long ago. I suspect that the reported continuity of the disrupted/masked sound is not really auditory, or only partially so. Rather, it is a figural completion achieved at a higher level of processing. It may be analogous to the completition of partially hidden objects in vision. If part of an object is obscured by another object, people don't really "see" the obscured part, even though they perceive the obscured object to be intact. Similarly, the disrupted/masked sound may be perceived as a continuous auditory "object", even though people really don't "hear" it during the masked portion. You are asking your subjects to compare a sound which is heard in its entirety to one that is heard only partially, and that may be the reason for the confusion. The empirical question is what is actually heard during the /disrupted/masked segment: Do people only hear the masking noise, or do they also hear the masked sound? You could try to address that question by asking subjects to compare the disrupted test sounds with standards that have their central segment attenuated by varying degrees. Perhaps there is a certain degree of attenuation that best matches what subjects actually hear. Best, Bruno >Dear List > >I am running some pilot behavioral studies of auditory continuity illusion >(aka temporal induction). >The sounds are FM sweeps with gaps or noise-inserted gaps. >For various reasons I am running them as "same/different" trials, >wth the first sound of the trial being a regular FM sweep and the >second one being >the modified FM sweep. > >When I ask the subjects, "Is the second sound as continuous as the >first sound?" they become confused. > >Even FM sweeps with much-louder noise inserted in the gap are >considered by some subjects to be not very continuous. (contrary to >literature) > >How do I change my instructions (basically, the confusion is around the >word 'continuous')? Or change the task? > >Any ideas? > >Thanks > >Fatima T. Husain, Ph.D. >NIDCD/NIH >Bldg. 10/ Room 8S-235D >Phone: 301-594-7758 -- Bruno H. Repp Haskins Laboratories 300 George Street New Haven, CT 06511-6624 Tel. (203) 865-6163, ext. 236 Fax (203) 865-8963 NOTE: I am at Rutgers University, Newark, two days per week, usually Tuesday and Wednesday, and don't read my Haskins e-mail on those days. To reach me at Rutgers, send e-mail to <repp(at)psychology.rutgers.edu>.