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Department of Psychology

Audiogram of the De Brazza’s monkey (Cercopithecus neglectus)

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Data from: Owren, M.J., Hopp, S.L., Sinnott, J.M., and Petersen, M.R. (1988) Absolute auditory thresholds in three old world monkey species (Cercopithecus aethiops, C. neglectus, Macaca fuscata)and humans (Homo sapiens). Journal of Comparative Psychology, 102, 99-107.


Average absolute thresholds (in dB re 20 µN/m2) for five de Brazza monkeys

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Frequency

(in kHz)

Average Threshold

(in dB)

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.063

59

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.088

55

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.125

43

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.176

34

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.250

27

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.353

16

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.500

11

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.707

7

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1

4

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1.4

3

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2

15

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2.8

12

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4

9

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5.7

2

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8

4

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11.3

7

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16

6

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22.6

18

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32

22

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34.9

24

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38

29

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40

47

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42

57

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45

>72

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Lowest and highest frequencies audible at sound

pressure levels (SPL) ranging from 30 to 70 dB SPL

SPL

(in dB)

Lowest audible frequency (in kHz)

Highest audible frequency (in kHz)

70

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43

60

.063

43

50

.100

40

40

.140

39

30

.215

38.1

*Extrapolated value

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Additional Parameters:

Body weight = 7 kg

Functional interaural distance= (420) µs

(Time required for sound to travel around the head from one auditory meatus to the other.)

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Comments: Threshold values taken from table in Owren et al.,1988. Tones were presented via headphones.