There is a lot of misunderstanding out there about how well dogs hear. It’s true that their hearing is better than that of humans in a couple ways. They can hear higher-pitched sounds than humans can, and they can hear quieter sounds than we can in some frequency ranges. Because of this, they have a reputation of superb hearing. But their hearing capabilities are not better across the board. Our capabilities are superior to theirs in a few important ways as well.
Here is what the experimental literature tells us about dogs’ hearing compared to that of humans. First, we’ll cover a couple of things we need to know about the characteristics of sound.
Measuring and Defining Sounds
There are two aspects of sound that are most important to understand and identify: frequency (pitch) and sound pressure level. Sound pressure level (SPL) is a physically measurable quantity that corresponds very roughly to what we subjectively experience as volume.
There are other qualities that are essential to sound, such as timbre and duration. But frequency and SPL are the most important to understand.
Frequency is how high or low the sound is in pitch. It is measured in cycles per second or Hertz. Low, rumbly sounds have low frequencies, that is, fewer cycles per second. High sounds such as digital beeps, children singing, and most birdsong have more cycles per second. Some frequencies of well-known sounds are:
- The lowest note on an 88-key piano: 28 Hz
- The highest note on an 88-key piano: 4,186 Hz
- The low rumbles of thunder: 5–220 Hz (Holmes, 1971)
- The typical range of human conversation: 80–8,000 Hz (Fant, 2006, p. 218). The fundamental frequencies of speech are on the low end; fricative consonants like f and s are on the high end.
- Typical digital beeps and whistles: 1,500–5,000 Hz (measurements by author)
- The high range of hummingbird vocalizations: 12,000 Hz (Rusch, Pytte, & Ficken, 1996)
Sound pressure level is measured in decibels, a logarithmic unit. The decibel scale is used because the range of detectable sound is so wide. A linear scale would have to go from 0 to greater than 100 million units to cover the range of sounds we can respond to. But SPL doesn’t exactly correspond to how loud we perceive a sound to be. That is termed “apparent loudness” and differs from person to person, organism to organism. It can’t be objectively measured in a practical way. But SPL can be objectively measured, and those measurements are what we have available to tell us roughly how “loud” we will experience a sound to be.
Logarithmic scales are counterintuitive and a bit difficult to understand. But you can get the idea of the range of sounds we can hear and how loud they are on the image below. You can also consult this article by the U.S. Centers for Disease Control to help you get your bearings with decibels.
Dogs’ Hearing vs. Human Hearing
OK, so now we are ready to compare dogs’ hearing to humans’.
Dogs can hear much higher frequencies than humans can. A young human with normal hearing can typically hear up to about 20,000 Hz (Gelfand, 2010, p. 166). As humans age, that upper limit decreases to about 12,000 Hz. Dogs can hear to 45,000 Hz (Heffner, 1983).
Humans can hear slightly lower frequencies than dogs can. We can hear pitches down to about 20 Hz. We can hear lower than this, down to about 2 Hz, but we don’t perceive these notes as pitches (Gelfand, 2010, p. 166). Sound lower than 20 Hz is called the infrasound range. Dogs can hear down to about 67 Hz (Heffner, 1983). There was speculation in the past that large dogs such St. Bernards can hear low frequencies better. But this was not born out by Heffner’s research. The dog that could hear the lowest frequencies best was a poodle, and the St. Bernard came in last(Heffner, 1983).
Humans can locate sounds more precisely than dogs can. For humans, the so-called minimum audible angle is 1° or less in our strongest zone and frequency (Mills, 1958). The minimal audible angle for dogs is 4° (Fay and Wilber, 1989, p. 519).
Psychologist Dr. Stanley Coren (2005, p. 47) points out that sound location is one of the first capabilities that dogs lose if they go deaf.
Threshold of Hearing
The threshold of hearing is the sound pressure level at which a sound becomes audible. In the lower frequency range (125–500 Hz), dogs’ and humans’ thresholds of hearing are about the same. At higher pitches, though, dogs have a lower threshold. That is, they can hear sounds at a lower volume than we can. This is true in the range of 500–8,000 Hz, where they can hear noises that are from 13–19 decibels lower (quieter) than we can (Lipman & Grassi, 1942). This is a significant difference. At frequencies higher than 8,000 Hz, the discrepancy grows wider. Then comes the range where we can’t hear at all, but dogs can (20,000–45,000 Hz).
There is a widespread claim that dogs can hear things at “four times the distance” humans can. I haven’t found the source for this and the information above shows that it isn’t a general rule. There are many variables in play when sounds travel over a distance. The range in which dogs’ hearing really excels is the high-frequency range. But this is also the range where sounds don’t travel over long distances. The claim may be related to Lipman and Grassi’s above data point that some dogs can hear noises that are up to 19 dB lower than humans in some ranges. That 19 dB difference would correspond to a factor of four in loudness (but not sound pressure level, sorry). But it’s at a specific frequency, 4,000 Hz (Lipman & Grassi, 1942). If that’s the case, the “four times the distance” claim is an overgeneralization and an impractical comparison. In other words, it’s false.
Summary: Comparing the Hearing of Humans and Dogs
The qualities listed above have to do with the physiological capabilities of hearing. Dogs’ abilities to classify and discriminate sounds have been studied as well. The following are not characteristics of hearing, per se, but of the brain’s processing of an auditory stimulus.
Dogs can discriminate between pitches. They have been tested using both operant and respondent methods. Dogs can discriminate up to 1/3 tone, for instance, between 2,820 and 2,900 Hz (Dworkin, 1935). This is a bit finer than the scale of notes used in most Western music, which progresses by 1/2 tones. They can likely perform even better. In one experiment, a single dog was able to discriminate between tones of 29,500 and 30,000 Hz (Andreyev, 1934). This is far above the range of human hearing, and a smaller increment than 1/3 tone.
I’m not sure what to call this one, but experiments have been performed to test dogs’ response to different metronome settings. A musician would call these settings differences in tempo. Tempo is measured in beats per minute. For instance, in a tempo of 60 beats per minute, the beats are exactly one second apart. Dogs can discriminate between 118 beats per minute and 120 beats per minute (Andreyev, 1934). To understand, try this online metronome. Enter the setting of 118 beats per minute, listen, then change it to 120 beats per minute. Could you tell which one it was if someone played one of them for you out of the blue?
Sound Source Categorization
Dogs can learn to categorize sounds. In one study, they were able to differentiate between “sounds that dogs make” and “other sounds.” The other sounds included mechanical sounds and sounds made by other animals (Heffner, 1975).
Timbre is defined as:
a sensory attribute of sound that enables one to judge differences between sounds having the same pitch, loudness, and duration (Gelfand 2010, p. 227).
We witness dogs’ ability to discriminate timbre empirically all the time. Does your dog discriminate the sound of your car from others? Your voice from your best friend’s? Sure! but the research on it seems pretty limited. Some studies were performed in the early 20th century that showed that dogs could discriminate the difference between the same note played on a tuning fork or a keyboard instrument, and also between different chords (Razran & Warden, 1959).
A different kind of evidence of timbre discrimination was shown in Adachi et al’s study (2007). They demonstrated that dogs could match their owner’s face to the owner’s voice (contrasted with another voice and face) calling their name. Ratcliffe et al (2014) similarly showed that dogs could likely discriminate voices by human gender, which may involve timbre discrimination.
Since a lot of what comprises timbre is the overtone structure of a sound, timbre discrimination could be a subset of pitch discrimination.
Human Speech Sound Discrimination
There are also studies that investigate dogs’ abilities to discriminate between aspects of human speech. These are not about dogs’ comprehension of language, which is a different issue. These are tests to see if dogs can hear the difference between certain human-spoken consonant and vowel sounds.
For instance, Baru (1975) demonstrated that dogs could discriminate between the vowel sounds i and a. The dogs were trained with shock, where wrong answers and “no responses” were punished.
I’m mentioning one study even though it is a master’s thesis. Athanasiadou (2012) tested vowel discrimination in dogs using the preferential looking paradigm. This is a noninvasive method used with human infants. The dogs could discriminate between the Dutch vowel sounds a and e. I hope that future studies of language discrimination follow this method rather than Baru’s.
There are quite a few studies of dogs vis-à-vis words and language, but these veer away from dogs’ discrimination capabilities. The discrimination abilities are taken as a given. If you are interested in speech sound discrimination, there is a review article by Kriengwatana et al that synopsizes a lot of that research for dogs and other animals and is available free online.
This article is a cornerstone for a new section of my blog devoted to dogs and sounds. I will be offering some very practical advice. I hope you stick around for more!
Adachi I., Kuwahata H., Fujita K. (2007). Dogs recall their owner’s face upon hearing the owner’s voice. Animal Cognition 10 17–21
Andreyev, L. A. (1934). Extreme limits of pitch discrimination with higher tones. Journal of Comparative Psychology, 18(3), 315-332.
Athanasiadou, P. (2012). Studying speech sound discrimination in dogs (Master’s thesis).
Baru A. V. (1975). “Discrimination of synthesized vowels [a] and [i] with varying parameters (Fundamental frequency, intensity, duration and number of formants) in dog,” in Auditory Analysis and Perception of Speech, eds Fant G., Tatham M. A. A., editors. (Waltham, MA: Academic Press; ), 91–101.
Coren, S. (2005). How dogs think: understanding the canine mind. Simon and Schuster.
Dworkin, S. (1935). Alimentary motor conditioning and pitch discrimination in dogs. American Journal of Physiology-Legacy Content, 112(2), 323-328.
Fant, G. (2006). Speech acoustics and phonetics: Selected writings (Vol. 24). Springer Science & Business Media.
Fay, R. R., & Wilber, L. A. (1989). Hearing in vertebrates: a psychophysics databook. Hill-Fay Associates.
Gelfand, S. (2010). Hearing: An introduction to psychological and physiological acoustics. Informa Healthcare.
Heffner, H. (1975). Perception of biologically meaningful sounds by dogs. The Journal of the Acoustical Society of America, 58(S1), S124-S124.
Heffner, H. E. (1983). Hearing in large and small dogs: Absolute thresholds and size of the tympanic membrane. Behavioral Neuroscience, 97(2), 310.
Holmes, C. R., Brook, M., Krehbiel, P., & McCrory, R. (1971). On the power spectrum and mechanism of thunder. Journal of Geophysical Research, 76(9), 2106-2115.
Kriengwatana, B., Escudero, P., & ten Cate, C. (2015). Revisiting vocal perception in non-human animals: a review of vowel discrimination, speaker voice recognition, and speaker normalization. Frontiers in Psychology, 5, 1543.
Lipman, E. A., & Grassi, J. R. (1942). Comparative auditory sensitivity of man and dog. The American Journal of Psychology, 55(1), 84-89.
Mills, A. W. (1958). On the minimum audible angle. The Journal of the Acoustical Society of America, 30(4), 237-246.
Ratcliffe, V. F., McComb, K., & Reby, D. (2014). Cross-modal discrimination of human gender by domestic dogs. Animal Behaviour, 91, 127-135.
Razran, H. S., & Warden, C. J. (1929). The sensory capacities of the dog as studied by the conditioned reflex method (Russian schools). Psychological Bulletin, 26(4), 202.
Rusch, K. M., Pytte, C. L., & Ficken, M. S. (1996). Organization of agonistic vocalizations in Black-chinned Hummingbirds. The Condor, 98(3), 557-566.
Copyright 2019 Eileen Anderson