286:
percentage of individuals exhibit an accuracy of between a quarter and a half ST. Although JND varies as a function of the frequency band being tested, it has been shown that JND for the best performers at around 1 kHz is well below 1 Hz, (i.e. less than a tenth of a percent). It is, however, important to be aware of the role played by critical bandwidth when performing this kind of analysis.
318:
their products. Less than the JND is wasted effort because the improvement will not be perceived; more than the JND is again wasteful because it reduces the level of repeat sales. On the other hand, when it comes to price increases, less than the JND is desirable because consumers are unlikely to notice it.
289:
When analysing speech melody, rather than musical tones, accuracy decreases. This is not surprising given that speech does not stay at fixed intervals in the way that tones in music do. Johan 't Hart (1981) found that JND for speech averaged between 1 and 2 STs but concluded that "only differences of
317:
When it comes to product improvements, marketers very much want to meet or exceed the consumer's differential threshold; that is, they want consumers to readily perceive any improvements made in the original products. Marketers use the JND to determine the amount of improvement they should make in
230:
The JND is a statistical, rather than an exact quantity: from trial to trial, the difference that a given person notices will vary somewhat, and it is therefore necessary to conduct many trials in order to determine the threshold. The JND usually reported is the difference that a person notices on
285:
JND analysis is frequently occurring in both music and speech, the two being related and overlapping in the analysis of speech prosody (i.e. speech melody). While several studies have shown that JND for tones (not necessarily sine waves) might normally lie between 5 and 9 semitones (STs), a small
246:
of the level of a feature in an object or situation and an internal standard of comparison in memory, such as the 'template' for a category or the 'norm' of recognition. The JND-scaled distances from norm can be combined among observed and inferred psychophysical functions to generate diagnostics
238:, imply that the observed JND, even in this statistical sense, is not an absolute quantity, but will depend on situational and motivational as well as perceptual factors. For example, when a researcher flashes a very dim light, a participant may report seeing it on some trials but not on others.
293:
Note that, given the logarithmic characteristics of Hz, for both music and speech perception results should not be reported in Hz but either as percentages or in STs (5 Hz between 20 and 25 Hz is very different from 5 Hz between 2000 and 2005 Hz, but an ~18.9% or 3 semitone
241:
The JND formula has an objective interpretation (implied at the start of this entry) as the disparity between levels of the presented stimulus that is detected on 50% of occasions by a particular observed response, rather than what is subjectively "noticed" or as a difference in magnitudes of
82:
For many sensory modalities, over a wide range of stimulus magnitudes sufficiently far from the upper and lower limits of perception, the 'JND' is a fixed proportion of the reference sensory level, and so the ratio of the JND/reference is roughly constant (that is the JND is a constant
333:
devices and robotic applications. Exerting the proper amount of force to human operator is a critical aspects in human robot interactions and tele operation scenarios. It can highly improve the performance of the user in accomplishing a task.
671:
Feyzabadi, Seyedshams; Straube, Sirko; Folgheraiter, Michele; Kirchner, Elsa Andrea; Kim, Su Kyoung; Albiez, Jan
Christian (2013). "Human Force Discrimination during Active Arm Motion for Force Feedback Design".
313:
so that product improvements (e.g. improved or updated packaging, larger size or lower price) are very apparent to consumers without being wastefully extravagant (i.e. they are at or just above the JND).
262:
The JND for tone is dependent on the tone's frequency content. Below 500 Hz, the JND is about 3 Hz for sine waves; above 1000 Hz, the JND for sine waves is about 0.6% (about 10
185:(1795–1878), an anatomist and physiologist, in experiments on the thresholds of perception of lifted weights. A theoretical rationale (not universally accepted) was subsequently provided by
269:
The JND is typically tested by playing two tones in quick succession with the listener asked if there was a difference in their pitches. The JND becomes smaller if the two tones are played
124:
277:. The total number of perceptible pitch steps in the range of human hearing is about 1,400; the total number of notes in the equal-tempered scale, from 16 to 16,000 Hz, is 120.
255:
In music production, a single change in a property of sound which is below the JND does not affect perception of the sound. For amplitude, the JND for humans is around 1
171:
147:
310:
so that negative changes (e.g. reductions in product size or quality, or increase in product price) are not discernible to the public (i.e. remain below JND) and
231:
50% of trials. If a different proportion is used, this should be included in the description—for example one might report the value of the "75% JND".
201:. It is true, at least to a good approximation, of many but not all sensory dimensions, for example the brightness of lights, and the intensity and the
227:, that raises the stimulus to a constant power while, like Weber, also multiplying it by a constant factor in order to achieve the perceived stimulus.
223:
continua, where change of input produces a qualitative rather than a quantitative change of the percept. Stevens developed his own law, called
17:
363:
88:
757:
242:
consciously experienced 'sensations'. This 50%-discriminated disparity can be used as a universal unit of measurement of the
58:
is the amount something must be changed in order for a difference to be noticeable, detectable at least half the time. This
919:
Richardson, N.; Booth, D.A. (1993), "Multiple physical patterns in judgements of the creamy texture of milks and creams",
306:. Manufacturers and marketers endeavor to determine the relevant JND for their products for two very different reasons:
217:, where change of input takes the form of increase in intensity or something obviously analogous; it would not hold for
900:
294:
increase is perceptually the same size difference, regardless of whether one starts at 20Hz or at 2000Hz).
247:
among hypothesised information-transforming (mental) processes mediating observed quantitative judgments.
219:
235:
31:
152:
1027:
243:
39:
956:'t Hart, Johan (1981). "Differential sensitivity to pitch distance, particularly in speech".
745:
388:
373:
224:
206:
190:
965:
850:
813:
615:
270:
182:
643:
Booth, D.A.; Freeman, R.P.J. (1993), "Discriminative measurement of feature integration",
8:
1022:
131:
969:
854:
817:
780:
767:
Middlebrooks, John C.; Green, David M. (1991). "Sound
Localization by Human Listeners".
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343:
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989:
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83:
proportion/percentage of the reference level). Measured in physical units, we have:
973:
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821:
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732:
681:
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623:
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1002:
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1016:
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202:
47:
413:
947:
Ritsma, R. J. (1965), "Pitch discrimination and frequency discrimination",
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263:
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378:
910:
Rakowski, A. (1971), "Pitch discrimination at the threshold of hearing",
685:
43:
862:
825:
627:
977:
303:
670:
588:
841:
Nordmark, Jan O. (1968). "Mechanisms of
Frequency Discrimination".
348:
189:, so the rule is therefore known either as the Weber Law or as the
173:
is the addition to it required for the change to be perceived (the
256:
205:
of sounds. It is not true, however, for the wavelength of light.
492:
290:
more than 3 semitones play a part in communicative situations".
804:
Mills, A. W. (1960). "Lateralization of High‐Frequency Tones".
509:
507:
912:
Proceedings of the
Seventh International Congress on Acoustics
358:
59:
35:
949:
504:
468:
723:
748:. In Jacob Benesty; M. Mohan Sondhi; Yiteng Huang (eds.).
570:
456:
149:
is the original intensity of the particular stimulation,
548:
546:
444:
606:
Bachem, A. (1937). "Various Types of
Absolute Pitch".
420:
155:
134:
91:
558:
543:
432:
743:
498:
719:"Chromaticity sensibility to stimulus differences"
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209:argued that it would hold only for what he called
165:
141:
118:
766:
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181:is a constant. This rule was first discovered by
162:
138:
1014:
958:The Journal of the Acoustical Society of America
843:The Journal of the Acoustical Society of America
806:The Journal of the Acoustical Society of America
608:The Journal of the Acoustical Society of America
480:
250:
234:Modern approaches to psychophysics, for example
27:Amount a stimulus must be changed to be detected
918:
462:
744:Kollmeier, B.; Brand, T.; Meyer, B. (2008).
642:
450:
955:
576:
414:"Weber's Law of Just Noticeable Difference"
302:Weber's law has important applications in
1000:
914:, vol. 3 20H6, Budapest, p. 376
438:
297:
909:
840:
564:
552:
406:
273:as the listener is then able to discern
119:{\displaystyle {\frac {\Delta I}{I}}=k,}
364:Minimal clinically important difference
321:
280:
14:
1015:
946:
750:Springer handbook of speech processing
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885:
803:
513:
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426:
781:10.1146/annurev.ps.42.020191.001031
24:
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25:
1039:
499:Kollmeier, Brand & Meyer 2008
77:
746:"Perception of Speech and Sound"
892:Music, Physics and Engineering
13:
1:
1001:Torgerson, Warren S. (1958).
475:Middlebrooks & Green 1991
416:. University of South Dakota.
394:
251:Music production applications
933:10.1016/0001-6918(93)90075-3
674:IEEE Transactions on Haptics
657:10.1016/0001-6918(93)90068-3
399:
72:least perceptible difference
7:
769:Annual Review of Psychology
463:Richardson & Booth 1993
337:
10:
1044:
598:
166:{\displaystyle \Delta I\!}
52:just-noticeable difference
18:Just noticeable difference
516:, pp. 171, 248–251.
451:Booth & Freeman 1993
717:Judd, Deane B. (1931).
236:signal detection theory
32:experimental psychology
951:, vol. B22, Liège
895:. Dover Publications.
737:10.1364/JOSA.22.000072
298:Marketing applications
244:psychological distance
167:
143:
120:
589:Feyzabadi et al. 2013
374:Psychometric function
207:Stanley Smith Stevens
168:
144:
121:
62:is also known as the
591:, pp. 309, 319.
322:Haptics applications
281:In speech perception
183:Ernst Heinrich Weber
153:
132:
89:
68:difference threshold
970:1981ASAJ...69..811T
855:1968ASAJ...44.1533N
818:1960ASAJ...32..132M
620:1937ASAJ....9..146B
142:{\displaystyle I\!}
1004:Methods of Scaling
686:10.1109/TOH.2013.4
429:, pp. 72–108.
344:Absolute threshold
225:Stevens' Power Law
163:
139:
116:
46:, which is called
921:Acta Psychologica
863:10.1121/1.1911293
826:10.1121/1.1907864
759:978-3-540-49125-5
645:Acta Psychologica
628:10.1121/1.1915919
389:Weber–Fechner law
384:Visual perception
379:Sensor resolution
191:Weber–Fechner law
105:
30:In the branch of
16:(Redirected from
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1008:
997:
978:10.1121/1.385592
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849:(6): 1533–1540.
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369:Mutatis mutandis
354:Color difference
275:beat frequencies
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887:Olson, Harry F.
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964:(3): 811–821.
953:
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907:
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883:
838:
812:(1): 132–134.
801:
775:(1): 135–159.
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680:(3): 309–319.
668:
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614:(2): 146–151.
602:
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579:, p. 811.
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439:Torgerson 1958
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271:simultaneously
252:
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199:Weber constant
197:is called the
187:Gustav Fechner
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109:
104:
100:
97:
79:
78:Quantification
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26:
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1040:
1029:
1028:Psychophysics
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1007:. John Wiley.
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747:
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734:
731:(2): 72–108.
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565:Rakowski 1971
561:
554:
553:Nordmark 1968
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501:, p. 65.
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752:. Springer.
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577:'t Hart 1981
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538:Ritsma 1965
526:Bachem 1937
329:is used in
327:Weber's law
34:focused on
1023:Perception
1017:Categories
514:Olson 1967
487:Mills 1960
395:References
220:metathetic
44:perception
986:0001-4966
871:0001-4966
834:0001-4966
789:0066-4308
694:1939-1412
636:0001-4966
427:Judd 1931
400:Citations
304:marketing
211:prothetic
157:Δ
96:Δ
40:sensation
889:(1967).
710:25749906
702:24808327
349:ABX test
338:See also
215:continua
213:sensory
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966:Bibcode
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128:where
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359:Limen
264:cents
203:pitch
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60:limen
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