HOME ~ SMAD.INFO and Animals'
Enrichment
Animals
Choosing their Music
Many
places have let animals choose music to hear. A 2009 survey of 238 staff at 60 zoos worldwide found that 93%
of staff think auditory enrichment is "Important" for mammals,
but 74% never provide it, because of staff time constraints.
PRIMATES
Studies
vary on how much primates like music, and there are different ways to interpret
the studies. The researchers did important work to help animals choose, but it
is challenging. Humans gradually discover music we like over many years. We
vary a lot, get suggestions from others, and we have private spaces to enjoy
our choices without disturbing others. Most of us like some music and dislike
some, even within a genre.
Responses
of female rhesus macaques to an environmental enrichment apparatus
S.
W. Line, A. S. Clarke, H. Markowitz, G. Ellman
Laboratory Animals (1990) 24, 213-220
http://journals.sagepub.com/doi/pdf/10.1258/002367790780866245
Line
et al. mounted a radio on the cages of five single adult female rhesus
macaques. The radio was available for a 14-week period and was preset to a soft
rock music station; the animals could turn the radio on and off by touching two
different bars. Individual animals turned on the radio for 0–24 hours on
different days. Different animals averaged 3-15 hours per day over the
experiment as a whole, with the overall average of the 5 animals greater than
12 hours per day. Authors graph the total hours played by each animal each
week. The monkeys showed no signs of losing interest in listening to the music.
Chimpanzees
Prefer African and Indian Music Over Silence
Morgan
E. Mingle, Timothy M. Eppley, Matthew W. Campbell,
Katie Hall, Victoria Horner, and Frans B. M. de Waal,
Journal of Experimental Psychology: Animal Learning and Cognition
emory.edu/LIVING_LINKS/publications/articles/Mingle%20et%20al%202014.pdf
A
2014 study found that 16 chimpanzees in Georgia stayed close to the loudspeaker
during irregular rhythms in some Akan music (Ghana) and Indian ragas more than
Japanese taiko, which has regular rhythms like the
western music used in Edinburgh. Each type of music was played 40 minutes on 3
different days. The first three days were controls, with a silent stereo,
followed by 9 days of music in random order. The researchers suggested regular
rhythms may be unpleasant, since chimpanzees use regular rhythms in dominance
displays, "stomping, clapping, and banging objects".
Music
as enrichment for Sumatran orangutans (Pongo abelii)
Sarah E. Ritvo and Suzanne
E. MacDonald, Journal of Zoo and Aquarium
Research 4(3) 2016
Toronto
researchers chose 210 pieces of music, from among the most popular on iTunes as
well as Tuvan throat singing, which is similar to orangutan long calls. They
played the first 30 seconds of each to 3 orangutans (separately), and after
each snippet, let the orangutan choose between a repeat, or 30 seconds of
silence, by touching the coloured half of a
touchscreen to repeat, or the grey half for silence. The 3 individuals chose to
repeat snippet of music 8%, 37% and 48% of the time. They had no chance to hear
the rest of the tune, or go back to a tune they liked a lot, as humans do.
It
would be interesting to give humans the same opportunity, and see how often
they ask for repeats, when listening to 30-second snippets of someone else's
choice of 210 tunes. All 3 orangutans "consistently displayed behaviours associated with orangutan distress"
throughout the touchscreen sessions, not unreasonably, given the frustrations
of hearing 30 seconds of random music 1,100 times. They pressed grey (silence)
more when especially stressed or distracted.
This
30-second approach may be an effective way to race through a lot of tunes to
find some tunes each orangutan likes. Whichever tunes they do like, there are
hundreds of similar ones which a service like Pandora or Slacker could offer,
to see how many of those they like. The researchers did not find any
consistency by genre, which is similar to humans, who may like some classical
tunes, or jazz or rock or folk, but not others. Even people who say they
"like classical music" often have preferences for romantic, baroque,
opera, modern, etc.
Is music enriching
for group-housed captive chimpanzees (Pan troglodytes)?
Wallace,et al, PLOS ONE, March 2017
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172672
PMID:
28355212, PMCID: PMC5371285,
DOI: 10.1371/journal.pone.0172672
Another
group of researchers let chimpanzees in Edinburgh come and go from an area
where they played either silence or a rotation of 7 classical tunes, or 7
pop/rock tunes, which were very familiar, having been played more than 50 times
each in experiments in the previous two years. Chimpanzees varied widely in how
long they stayed in the small outdoor area where music played:
- 5
chimpanzees spent under 15 minutes where the music was playing.
- 3 spent
over 2 hours, out of about 4 hours when the music was playing.
- The other
10 ranged from 20 to 110 minutes, for a total of 18 chimpanzees.
The
wide range of time may mean the chimpanzees varied this much in how long they
wanted to hear these familiar tunes. On the other hand the chimpanzees who
listened the longest to music, also stayed longest during silence. They may
have liked the area or they may have hoped for the music to start again.
The
researchers tried to train the chimpanzees to choose for themselves whether to
have music or silence in the research area, by pressing symbols on a
touchscreen. However researchers were not sure the chimpanzees understood what
the symbols meant, since training only gave them 3-second bursts of music plus
half a grape each time they pressed any symbol. The 3-second bursts and grapes
may have squelched any intrinsic pleasure in the music.
Chimpanzees
could press symbols to turn music on or off, or switch between classical and
pop/rock, but could not pick individual tunes and could not select new music.
The researchers had removed dynamic range from each tune, "by reducing the
volume of loud passages and increasing the volume of quieter ones."
The
symbols were always in different locations on the screen, and symbols in the
final sessions were much smaller and squarer than they had been in training.
Any symbol preference may be for its appearance (zig-zags, stripes, or
bubbles), not for the 3-second snippets. If chimpanzees do not group genres as
humans do they would not realize there was a pattern where zig-zags gave them
classical music. After training, most button pressing was in the first session,
when they would have expected grape rewards, as they had in training. The
training and observations were in cold weather, January-April 2015, outdoors at
the Edinburgh Zoo.
McDermott
and Hauser:
Nonhuman
primates prefer slow tempos but dislike music overall Cognition
104 (2007) 654–668
Are consonant intervals
music to their ears? Spontaneous acoustic preferences in a nonhuman primate Cognition
94 (2004) B11–B21
The
title of their 2007 article, "Nonhuman primates prefer slow tempos but
dislike music overall", has been much quoted and has led trainers to avoid
playing music to primates. However if monkeys can turn music on and off, all
wanted music part of the time, even after a highly stressful introduction
to a new small cage.
Cotton-top Tamarin and Common Marmoset monkeys used body location to trigger the
researchers to change sound. Monkeys could see researchers, so could have
received unconscious cues ('07,
'04).
Experiments were done with varying numbers of 3 to 8 animals.
- Choosing
between silence versus lullabies or Mozart: individual tamarins and
marmosets spent 54% to 85% of their session with silence (p.663).
All the monkeys chose music some of the time.
- Choosing
between 60dB and 90dB white noise: individual marmosets spent 56%
to 69% of their session with 60dB.
- Choosing
between a flute lullaby and electronic techno at the same volume: on
average tamarins and marmosets spent 63% of their session with flute.
- Choosing
between 60 and 400 clicks per minute, on average tamarins and marmosets
spent 60% of their session with 60 clicks.
- Choosing
between 80 and 160 clicks per minute: on average tamarins and marmosets
spent 55% of their session with 80 clicks.
- Choosing
between recordings of tamarins' feeding chirps versus distress calls: on
average tamarins spent 58% of their time with chirps.
- Choosing
between consonant and dissonant 2-note chords: on average tamarins spent
51% of their time with dissonance (not statistically different from
consonant).
- Choosing
between white noise and steel scratching on glass: both at 80 dB, on
average tamarins spent 53% of their time with the white noise (not
statistically different from scratching steel).
Tamarins and Marmosets were measured when they were
highly stressed.
Researchers carried each animal to the entrance to a small cage with two
branches, left the room, opened the cage remotely, and in the next 5 minutes
the researcher played different sound depending which branch the animal was in.
They do not say how the animals reacted to being carried to the cage, but
"distress calls... screams [are] produced by [tamarins] being held by our
veterinary staff during routine checkups" ('04
p.B15), and, "Primates dislike being handled and are stressed by
it" (AWI
'15 p.176) so carrying them would leave them highly distressed for the next
5 minutes, during the experiment.
Researchers
do not say the cage size, but it appears about 25cm high. Tamarins average 23 cm,
and Marmosets 19 cm,
so they have little room, not "allowing the animals to move up to heights
where they feel secure" (Medical Research Council (2004) of the United
Kingdom, quoted in AWI
'15 p.176).
An
even more sophisticated system would add videos and/or games. Dr. Washburn's
2003 Presidential Address to the Southern Society for Philosophy and Psychology
said,
- "no
intervention has as potent an effect on rhesus monkeys' psychological well-being as does the
computerized test system [with joystick]. Although one can reduce the
symptoms of depression, boredom, and stress with other forms of
environmental enrichment (e.g., social housing, other toys, or manipulanda), the joystick-based apparatus and
game-like tasks have a substantial effect over and above these other
manipulations...
- "Of
course, joystick-based computer games are unlike anything that a rhesus
monkey would naturally encounter in its ecological niche. Rather than
supporting psychological well-being by making the laboratory more like the
wild, we have chosen to employ this highly unnatural technology to address
the basic factors of psychological well-being: comfort, companionship,
challenge, and control." ('03)
NON-PRIMATES
Dolphins used "a movable lever ... at night to turn on or off or
select among various tape-recorded acoustic stimuli, including dolphin sounds,
whale sounds, human voices, music, etc." (Herman, Cetacean Behavior '80)
A
captive Orca was observed to always
want new tunes, and objected to repeats. Orcas are far more acoustically sophisticated
than primates, but primates may have some preference for new tunes too, as
humans do.
Java
Sparrows
triggered a photosensor by sitting on a particular
perch, which determined which music was played. Two birds preferred Bach and
Vivaldi over Schoenberg or silence. The other two birds had varying preferences
among Bach, Schoenberg, white noise and silence. ('98)
Zebra Finches pecked levers
to play music, sometimes for hours, then stopped for hours. It appears each
lever played a short tune, which birds could and did repeat (no date).
Goldfish triggered Rite
of Spring , Bach Toccata and Fugue in
D Minor, or silence by presence in different thirds of a tank. The tank was
painted white to limit visual stimuli, such as experimenters' body language. A
camera and computer recorded fish location and played Bach if at one end,
Stravinsky if at the other end, and silence when in the middle. Only one of the
6 tested showed a preference for one end, where Rite of Spring played. All spent about 2/3 of their
time with music, 1/3 with silence, consistent with the music being in 2/3 of
the tank. ('09)
CONCLUSION
The
research projects here were staff intensive and gave limited times and choices
of music, because of time constraints. It is worth thinking what some ideal
systems might be, so research can see which work best for different animals:
- Quiet
speakers with individual controls so one or a few animals can choose what
to play without imposing it on others
- Buttons or
levers for: off, specific songs, new songs in a wide range of styles, with
a back button to go back to a previous song, and an algorithm or button to
update the specific songs
- Face
recognition or RFID to know which animal is at a speaker and remember what
it plays most, what it interrupts, and suggest new tunes, as Slacker and
Pandora do, with little need for staff maintenance.