Subject: Re: Sensitivity to increments and decrements From: "Harrington, Ian" <IanHarrington@xxxxxxxx> Date: Sat, 10 Nov 2007 22:17:29 -0600 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>This is a multi-part message in MIME format. ------_=_NextPart_001_01C82419.C5D7487F Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Dear Christian and List, Although not directly relevant to your initial question about the = symmetry of intensity increment and decrement thresholds in humans, I = have some unpublished behavioral data that suggest that the asymmetry in = monkeys may be more modest than was suggested by Sinnott and colleagues = (1985).=20 While working with Henry Heffner I tested three monkeys for the = detection of increments and decrements in the intensity of a 625-Hz tone = (Sinnott et al used 1 kHz tones). Increment thresholds ranged from 1.8 = to 2.7 dB (M =3D 2.2 dB), whereas decrement thresholds ranged from 2.5 = to 3.8 dB (M =3D 3.0 dB). One animal obtained thresholds of 2.7 and 2.6 = dB in the two conditions.=20 Despite the similarity of increment and decrement thresholds in our = =93normal=94 monkeys (a 0.8 dB difference on average), some might be = interested to note that auditory cortex lesions affected the two tasks = differently. First, a monkey with a large bilateral lesion had an = increment threshold of 3.5 dB (near normal), and a decrement threshold = of 9.5 dB (elevated). Second, a monkey with a unilateral lesion had a = decrement threshold of 3.8 dB when the sound was delivered in the free = field or to the ipsilesional ear alone, but was unable to detect a = decrement of even 16 dB in its contralesional ear.=20 These findings are consistent both with an earlier observation hidden in = a paper by Strominger, Oesterreich & Neff (1980) that found a monkey = with a bilateral auditory cortex lesion to have difficulty detecting = even a 40 dB intensity decrement, and with Neff's classic "neural model" = of auditory discrimination (e.g., Neff WD (1961) Neural mechanisms of = auditory discrimination; In, Sensory Communication, W Rosenblith (Ed.), = John Wiley & Sons, NY, NY). Regardless of whether an asymmetry might exist for the detection of = intensity increments and decrements in humans or monkeys, I think it=92s = fair to expect that the processes involved in detecting a barking dog = might differ from those involved in detecting a dog that held its tongue = (or at least barked more quietly).=20 Cheers, IH P.S. I would expect Erick Gallun to weigh in here soon with insights = from some of his human psychophysical data. =20 ______________________ Ian A. Harrington, PhD Department of Psychology Augustana College 639 38th St. Rock Island, IL 61201 email: IanHarrington@xxxxxxxx phone: (309) 794-7243 -----Original Message----- From: Christian Kaernbach [mailto:auditorymail@xxxxxxxx Sent: Sat 11/10/2007 2:42 AM To: AUDITORY@xxxxxxxx Subject: [AUDITORY] Sensitivity to increments and decrements =20 Dear List, Is there anything known about the existence of differences in the=20 sensitivity to intensity increments versus to intensity decrements? Laurent Demany pointed me to a paper by Sinnott et al. (1985) who found=20 no such difference in humans, while they found an advantage for=20 increments in monkeys: Sinnott, J. M., Petersen M. R., Hopp, S. L. (1985). Frequency and intensity discrimination in humans and monkeys. Journal of the Acoustical Society of America, 78, 1977-1985. Is this finding (as to the symmetry of human increment / decrement=20 sensitivity) unchallenged? Best regards, Chris --=20 Prof. Dr. Christian Kaernbach Allgemeine Psychologie Institut f=FCr Psychologie Christian-Albrechts-Universit=E4t zu Kiel Olshausenstr. 62 D-24098 Kiel Germany www.kaernbach.de ------_=_NextPart_001_01C82419.C5D7487F Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> <HTML> <HEAD> <META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; = charset=3Diso-8859-1"> <META NAME=3D"Generator" CONTENT=3D"MS Exchange Server version = 6.5.7651.59"> <TITLE>RE: [AUDITORY] Sensitivity to increments and decrements</TITLE> </HEAD> <BODY> <!-- Converted from text/plain format --> <P><FONT SIZE=3D2>Dear Christian and List,<BR> <BR> Although not directly relevant to your initial question about the = symmetry of intensity increment and decrement thresholds in humans, I = have some unpublished behavioral data that suggest that the asymmetry in = monkeys may be more modest than was suggested by Sinnott and colleagues = (1985).<BR> <BR> While working with Henry Heffner I tested three monkeys for the = detection of increments and decrements in the intensity of a 625-Hz tone = (Sinnott et al used 1 kHz tones). Increment thresholds ranged from 1.8 = to 2.7 dB (M =3D 2.2 dB), whereas decrement thresholds ranged from 2.5 = to 3.8 dB (M =3D 3.0 dB). One animal obtained thresholds of 2.7 and 2.6 = dB in the two conditions.<BR> <BR> Despite the similarity of increment and decrement thresholds in our = “normal” monkeys (a 0.8 dB difference on average), some might = be interested to note that auditory cortex lesions affected the two = tasks differently. First, a monkey with a large bilateral lesion had an = increment threshold of 3.5 dB (near normal), and a decrement threshold = of 9.5 dB (elevated). Second, a monkey with a unilateral lesion had a = decrement threshold of 3.8 dB when the sound was delivered in the free = field or to the ipsilesional ear alone, but was unable to detect a = decrement of even 16 dB in its contralesional ear.<BR> <BR> These findings are consistent both with an earlier observation hidden in = a paper by Strominger, Oesterreich & Neff (1980) that found a monkey = with a bilateral auditory cortex lesion to have difficulty detecting = even a 40 dB intensity decrement, and with Neff's classic "neural = model" of auditory discrimination (e.g., Neff WD (1961) Neural = mechanisms of auditory discrimination; In, Sensory Communication, W = Rosenblith (Ed.), John Wiley & Sons, NY, NY).<BR> <BR> Regardless of whether an asymmetry might exist for the detection of = intensity increments and decrements in humans or monkeys, I think = it’s fair to expect that the processes involved in detecting a = barking dog might differ from those involved in detecting a dog that = held its tongue (or at least barked more quietly).<BR> <BR> Cheers,<BR> IH<BR> <BR> P.S. I would expect Erick Gallun to weigh in here soon with insights = from some of his human psychophysical data. <BR> <BR> ______________________<BR> Ian A. Harrington, PhD<BR> <BR> Department of Psychology<BR> Augustana College<BR> 639 38th St.<BR> Rock Island, IL 61201<BR> <BR> email: IanHarrington@xxxxxxxx<BR> phone: (309) 794-7243<BR> <BR> <BR> <BR> -----Original Message-----<BR> From: Christian Kaernbach [<A = HREF=3D"mailto:auditorymail@xxxxxxxx">mailto:auditorymail@xxxxxxxx= E</A>]<BR> Sent: Sat 11/10/2007 2:42 AM<BR> To: AUDITORY@xxxxxxxx<BR> Subject: [AUDITORY] Sensitivity to increments and decrements<BR> <BR> Dear List,<BR> <BR> Is there anything known about the existence of differences in the<BR> sensitivity to intensity increments versus to intensity decrements?<BR> <BR> Laurent Demany pointed me to a paper by Sinnott et al. (1985) who = found<BR> no such difference in humans, while they found an advantage for<BR> increments in monkeys:<BR> Sinnott, J. M., Petersen M. R., Hopp, S. L. = (1985).<BR> Frequency and intensity discrimination in humans and = monkeys.<BR> Journal of the Acoustical Society of America, 78, = 1977-1985.<BR> Is this finding (as to the symmetry of human increment / decrement<BR> sensitivity) unchallenged?<BR> <BR> Best regards,<BR> Chris<BR> <BR> --<BR> Prof. Dr. Christian Kaernbach<BR> Allgemeine Psychologie<BR> Institut f=FCr Psychologie<BR> Christian-Albrechts-Universit=E4t zu Kiel<BR> Olshausenstr. 62<BR> D-24098 Kiel<BR> Germany<BR> www.kaernbach.de<BR> <BR> <BR> </FONT> </P> </BODY> </HTML> ------_=_NextPart_001_01C82419.C5D7487F--