Human–animal communication
Human–animal communication is the communication observed between humans and other animals, from non-verbal cues and vocalizations through to the use of language.
Introduction
Human–animal communication may be observed in everyday life. The interactions between pets and their owners, for example, reflect a form of spoken, while not necessarily verbal dialogue. A dog being scolded is able to grasp the message by interpreting cues such as the owner's stance, tone of voice, and body language. This communication is two-way, as owners can learn to discern the subtle differences between barks and meows, and there is a clear difference between the bark of an angry dog defending its home and the happy bark of the same animal while playing. Communication (often nonverbal) is also significant in equestrian activities such as dressage.
One scientific study has found that 30 bird species and 29 mammal species share the same pattern of pitch and speed in basic messages, so humans and those 59 species can understand each other when they express "aggression, hostility, appeasement, approachability, submission and fear.[1][2]
Birds
Parrots are able to use words meaningfully in linguistic tasks.[3] In particular, the grey parrot Alex learned 100 words,[4] and after training used English words to answer questions about color, shapes, size and numbers correctly about 80% of the time.[5] He also, without training, said where he wanted to be taken, such as his cage or the back of a chair, and protested when taken elsewhere, or when hidden objects were not where he thought they were.[6] He asked a question, what color he himself was,[6] which has been called the only question so far asked by a non-human animal.[7] Scientific American editor Madhusree Mukerjee described these abilities as creativity and reasoning comparable to nonhuman primates or cetaceans,[8] while expressing concern that extensive language use resulted in feather-plucking behavior, a possible sign of stress.
Most bird species have at least six calls which humans can learn to understand, for situations including danger, distress, hunger, and the presence of food.[9]
Pigeons can identify different artists.[10] Pigeons can learn to recognize up to 58 four-letter English words, with an average of 43, though they were not taught any meanings to associate with the words.[11]
Java Sparrows chose music 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.[12]
The greater honeyguide has a specific call to alert humans that it can lead them to honey, and also responds to a specific human call requesting such a lead, by leading humans to honeybee hives so it can eat the discarded honeycomb wax after humans collect the honey. The human call varies regionally, so the honeyguide's response is learned in each area, not instinctive.[13]
Crows identify and respond differently to different human faces.[14]
Fictional portrayals of sentient talking parrots and similar birds are common in children's fiction,[15] such as the talking, loud-mouth parrot Iago of Disney's Aladdin.
Primates
Chimpanzees can make at least 32 sounds with distinct meanings for humans.[9]
Chimpanzees, bonobos, gorillas and orangutans have used sign language, physical tokens, keyboards and touch screens to communicate with humans in numerous research studies. The research showed that they understood multiple signals and produced them to communicate with humans. There is some disagreement whether they can re-order them to create distinct meanings.
Baboons can learn to recognize an average of 139 4-letter English words (maximum of 308), though they were not taught any meanings to associate with the words.[16]
Primates also have been trained to use touch screens to tell a researcher their musical preferences. In Toronto, for hundreds of songs in random order, orangutans were given one 30-second segment of a song, and then chose between repeating that segment or 30 seconds of silence.[17] Different orangutans chose to replay from 8% to 48% of the segments, and all exhibited stress throughout the trials. There was no pattern of selections by genre, and the researchers did not look for other attributes which were shared by the orangutans' chosen segments. No comparison was available of how many 30-second segments humans would repeat in the same situation. In another experiment the orangutans did not distinguish between music played in its original order and music sliced into half-second intervals which were played in random order. Chimpanzees can hear higher frequencies than humans; if orangutans can too, and if these overtones are present in the recordings, the overtones would affect their choices.[17]
Cetaceans
Lilly
In the 1960s, John C. Lilly sponsored English lessons for one bottlenose dolphin (Tursiops truncatus). The teacher, Margaret Howe Lovatt, lived with the dolphin for 2 1⁄2 months in a house on the shore of the Virgin Islands. The house was partially flooded and allowed them to be together for meals, play, language lessons, and sleep.[18][19][20][21] Lilly thought of this as a mother-child dyad, though the dolphin was 5–6 years old.[22] Lilly said that he had heard other dolphins repeating his own English words,[23] and believed that an intelligent animal would want to mimic the language of its captors, to communicate.[24][25] The experiment ended in the third month and did not restart, because Howe found the two-room lab and constant bumping from the dolphin too constricting.[26]
After several weeks, a concerted effort by the dolphin to imitate the instructor's speech was evident, and human-like sounds were apparent, and recorded. It was able to perform tasks such as retrieval of aurally indicated objects without fail. Later in the project the dolphin's ability to process linguistic syntax was made apparent, in that it could distinguish between commands such as "Bring the ball to the doll," and "Bring the doll to the ball." This ability not only demonstrates the bottlenose dolphin's grasp of basic grammar, but also implies the dolphins' own language might include syntactical rules. The correlation between length and 'syllables' (bursts of the dolphin's sound) with the instructor's speech also went from essentially zero at the beginning of the session to almost a perfect correlation by its completion, so that when the human spoke 5 or 10 syllables, the dolphin also spoke 5 or 10 'syllables' or bursts of sound.[27]
Two experiments of this sort are explained in detail in Lilly's book, Mind of the Dolphin. The first experiment was more of a test run to check psychological and other strains on the human and cetacean participants, determining the extent of the need for other human contact, dry clothing, time alone, and so on. Despite tensions after several weeks, Howe Lovatt agreed to the 2 1⁄2 months isolated with the dolphin.
Experiments by the research team of Louis Herman, a former collaborator and student of Lilly's, demonstrated that dolphins could understand human communication in whistles and respond with the same whistles.
A female bottlenose dolphin, Phoenix, understood at least 34 whistles.[28] p.415</ref>
Whistles created a system of 2-way communication. By having separate whistles for object and action, Herman could reorder commands without fresh teaching (take hoop to ball). Successful communication was shown when Herman used new combinations, and the dolphin understood and did what he asked without further training 80-90% of the time.[29]
In 1980, Herman had taught 6 whistles to a female bottle-nose dolphin, Kea, to refer to three objects and three actions, and the dolphin followed his instructions. He wrote, "In addition to mouthing the three familiar training objects in the presence of the mouth name, Kea correctly mouthed on their first appearance a plastic water pipe, a wooden disc, and the experimenter's open hand. The same type of immediate response generalization occurred for touch and fetch."[30]
Richards, Wolz and Herman[31] (1984) trained a dolphin to make distinct whistles for objects, "so that, in effect, the dolphin gave unique vocal labels to those objects."
Herman's later publications do not discuss the whistle communication. Herman started getting US Navy funding in 1985,[32] so further expansion of the 2-way whistle language would have been in the classified United States Navy Marine Mammal Program, a black project.
Herman also studied the crossmodal perceptual ability of dolphins. Dolphins typically perceive their environment through sound waves generated in the melon of their skulls, through a process known as echolocation (similar to that seen in bats, though the mechanism of production is different). The dolphin's eyesight however is also fairly good, even by human standards, and Herman's research found that any object, even of complex and arbitrary shape, identified either by sight or sound by the dolphin, could later be correctly identified by the dolphin with the alternate sense modality with almost 100 per cent accuracy, in what is classically known in psychology and behaviorism as a match-to-sample test. The only errors noted were presumed to have been a misunderstanding of the task during the first few trials, and not an inability of the dolphin's perceptual apparatus. This capacity is strong evidence for abstract and conceptual thought in the dolphin's brain, wherein an idea of the object is stored and understood not merely by its sensory properties; such abstraction may be argued to be of the same kind as complex language, mathematics, and art, and implies a potentially very great intelligence and conceptual understanding within the brains of tursiops and possibly many other cetaceans. Accordingly, Lilly's interest later shifted to whale song and the possibility of high intelligence in the brains of large whales, and Louis Herman's research at the now misnomered Dolphin Institute in Honolulu, Hawaii, focuses exclusively on the Humpback whale.
Other researchers
- Batteau[32] (1964, video) developed machines for the US Navy, which translated human voices to higher frequencies for dolphins to hear and translated dolphin voices to lower frequencies for humans to hear. The work continued at least until 1967 when the Navy classified its dolphin research. Batteau died, also in 1967, before he published results.
- Reiss + McCowan (1993) taught dolphins 3 whistles (ball, ring, rub), which the 2 dolphins produced, and even combined, when playing with the ball and/or ring, or getting a rub.[33]
- Delfour and Marten (2005) gave dolphins a touchscreen to show they recognized a musical note[34]
- Kuczaj (2006) used an underwater keyboard, which humans and dolphins can touch to signal an action.[35]
- Amundin et al. (2008) had dolphins point narrow echolocation beams onto an array of hydrophones which acted like a touchscreen to communicate with the researchers[36] (video)
- Reiss (2011) used an underwater keyboard which dolphins could press.[37] A dolphin defined a key as "I want a small fish" and Reiss (2011, p. 100) understood, but ignored it.[38]
- Herzing (2013) used an underwater keyboard in the open ocean which dolphins and humans could press to choose a plaything.[39]
- Herzing (2014) created 3 whistles for "play objects (Sargassum... scarf, and rope)", and found that wild dolphins understand them, but has not found if dolphins produce the whistles.[40]
Historical
From Roman times to modern Brazil, dolphins have been known to drive fish toward fishermen waiting on shore, and signal to the fishermen when to throw their nets, even when water is too murky for the fishermen to see the arrival of the fish. The dolphins catch unnetted fish disoriented by the net.[41][42]
From about 1840-1920 orcas smacked the water off Twofold Bay in New South Wales to signal to human whalers that the orcas were herding large baleen whales nearby, so the humans would send boats to harpoon the whales, killing them faster and more assuredly than the orcas could. The orcas ate the tongues and lips, leaving the blubber and bones for the humans.[43][44]
Dogs
Dogs communicating to humans
Bonnie Bergin trained dogs to go to specific text on the wall to ask clearly for "water, treat or pet me." Dogs were able to learn English or Japanese text. She says service dogs can learn to find EXIT signs, bathroom gender signs, and report what disease they smell in a urine sample by going to a sign on the wall naming that disease.[45]
Police and private dogs can be trained to "alert" when they find certain scents, including drugs, explosives, mines, scent of a suspect, fire accelerants, bed bugs. The alert can be a specific bark or position, and can be accepted as evidence in court.[46]
Stanley Coren identifies 56 signals which untrained dogs make and people can understand, including 10 barks, 5 growls, 8 other vocalizations, 11 tail signals, 5 ear and eye positions, 5 mouth signals and 12 body positions.[47] Faragó et al. describe research that humans can accurately categorize barks from unseen dogs as aggressive, playful, or stressed, even if they do not own a dog.[48] This recognizability has led to machine learning algorithms to categorize barks,[49] and commercial products and apps such as Bow Lingual, Talk With Your Dog, and Talk Dog.
Humans communicating to dogs
Dogs can be trained to understand hundreds of spoken words, including Chaser (1,022 words),[50] Betsy (340 words),[51] Rico (200 words),[52] and others.[9] [47] They can react appropriately when a human uses verbs and nouns in new combinations, such as "fetch ball" or "paw frisbee."[50]
Bergin trained dogs to obey 20 written commands on flashcards, in Roman or Japanese characters, including 🚫 to keep them away from an area.[45]
Shepherds and others have developed detailed commands to tell herding dogs when to move, stop, collect or separate herd animals.[53][54]
Other animal training
Humans teach animals specific responses for specific conditions or stimuli. Training may be for purposes such as companionship, detection, protection, research and entertainment. During training humans communicate their wishes with positive or negative reinforcement. After training is finished the human communicates by giving signals with words, whistles, gestures, body language, etc.[55]
APOPO has trained Southern giant pouched rats to communicate to humans the presence of land mines, by scratching the ground, and tuberculosis in medical samples. They identify 40% more cases of tuberculosis than clinics do, an extra 12,000 cases from 2007-2017. They have identified 100,000 mines from 2003-2017, certifying 2,200 hectares (5,400 acres) as mine-free. They are accurate enough that the human trainers run on the land after removing the mines which rats have identified.[56]
Rats (Wistar, Rattus norvegicus) have been taught to distinguish and respond differently to different human faces.[57]
Patricia McConnell found that handlers around the world, speaking 16 languages, working with camels, dogs, donkeys, horses and water buffalo, all use long sounds with a steady pitch to tell animals to go more slowly (whoa, euuuuuu), and they use short repeated sounds, often rising in pitch, to speed them up or bring them to the handler (Go, Go, Go, claps, clicks). Chimpanzees, dogs, gulls, horses, rats, roosters, sheep and sparrows all use similar short repeated sounds to tell others of the same species to come closer.[58]
Even fish, which lack a neocortex, have been taught to distinguish and respond differently to different human faces (archerfish[59]) or styles of music (goldfish[60] and koi[61]).
Molluscs, with totally different brain designs, have been taught to distinguish and respond to symbols (cuttlefish[62] and octopus[63]), and have been taught that food behind a clear barrier cannot be eaten (squid[64]).
A harbor seal, Hoover learned to speak several phrases in understandable English as a pup from his human foster parent and used these in appropriate circumstances during his later life at the New England Aquarium until he died in 1985.[65] Other talking animals have been studied, though they did not always use their phrases in meaningful contexts.
Animal communication as entertainment
Though animal communication has always been a topic of public comment and attention, for a period in history it surpassed this and became sensational popular entertainment. From the late 18th century through the mid 19th century, a succession of "learned pigs" and various other animals were displayed to the public in for-profit performances, boasting the ability to communicate with their owners (often in more than one language), write, solve math problems, and the like. One poster dated 1817 shows a group of "Java sparrows" who are advertised as knowing seven languages, including Chinese and Russian.
See also
Bibliography
- Sebeok, Thomas – Essays in Zoosemiotics (1990) ISSN 0838-5858
- Myers, Arthur – Communicating With Animals: The Spiritual Connection Between People and Animals (1997) ISBN 0-8092-3149-2
- Boehner, Bruce Thomas – Parrot Culture: Our 2,500-Year-Long Fascination with the World's Most Talkative Bird (2004) ISBN 0-8122-3793-5
- Summers, Patty – Talking With the Animals (1998) ISBN 1-57174-108-9
- Jay, Ricky – Learned Pigs and Fireproof Women (1987) ISBN 0-446-38590-5
- Gurney, Carol – The Language of Animals: 7 Steps to Communicating with Animals (2001) ISBN 0-440-50912-2
- Grandin, Temple – Animals in Translation: Using the Mysteries of Autism to Decode Animal Behavior (2004) ISBN 0-7432-4769-8
References
- Morton, Eugene, and Donald Henry Owings (1998). Animal vocal communication : a new approach. Cambridge: Cambridge University Press. ISBN 978-0521324687. OCLC 37239014.
- Friend, Tim (2004). Animal talk : breaking the codes of animal language. New York: Free Press. pp. 90. ISBN 978-0743201575. OCLC 53144532.
- Parrot Intelligence
- Carey, Benedict (2007-09-10). "Alex, a Parrot Who Had a Way With Words, Dies". The New York Times. ISSN 0362-4331. Retrieved 2018-02-23.
- "Ask the Scientists: Irene Pepperberg Q&A". Archived from the original on 18 October 2007. Retrieved 11 September 2007.
- Wise, Steven M. (2002). Drawing the Line. Cambridge, MA: Perseus Books. pp. 101–102, 107. ISBN 978-0-7382-0340-9.
- Jordania, Joseph (2006). Who Asked the First Question? The Origins of Human Choral Singing, Intelligence, Language and Speech. Tbilisi: Logos. ISBN 978-99940-31-81-8.
- Mukerjee, Madhusree (1996). "An interview with Alex, the African grey parrot". Scientific American Blog Network.
- Scott, John Paul (1972). Animal behavior. Chicago: University of Chicago Press. pp. 190, 197. ISBN 978-0226743363.
- Watanabe, Shigeru (2001-11-01). "Van Gogh, Chagall and pigeons: picture discrimination in pigeons and humans". Animal Cognition. 4 (3–4): 147–151. doi:10.1007/s100710100112. ISSN 1435-9448. PMID 24777504.
- Scarf, Damian; Boy, Karoline; Reinert, Anelisie Uber; Devine, Jack; Güntürkün, Onur; Colombo, Michael (2016-10-04). "Orthographic processing in pigeons (Columba livia)". Proceedings of the National Academy of Sciences. 113 (40): 11272–11276. doi:10.1073/pnas.1607870113. ISSN 0027-8424. PMC 5056114. PMID 27638211.
- S Watanabe, M Nemoto (1998-05-01). "Reinforcing property of music in Java sparrows (Padda oryzivora)". Behavioural Processes. 43 (2): 211–218. doi:10.1016/S0376-6357(98)00014-X. ISSN 0376-6357.
- Spottiswoode, Claire N.; Begg, Keith S.; Begg, Colleen M. (2016-07-22). "Reciprocal signaling in honeyguide-human mutualism" (PDF). Science. 353 (6297): 387–389. doi:10.1126/science.aaf4885. ISSN 0036-8075. PMID 27463674.
- "The Crow Paradox". NPR.org. 2009-07-27. Retrieved 2017-12-28.
- Thomas., Boehrer, Bruce (2004). Parrot culture : our 2,500-year-long fascination with the world's most talkative bird. Philadelphia: University of Pennsylvania Press. ISBN 978-0812237931. OCLC 54446320.
- Grainger, Jonathan; Dufau, Stéphane; Montant, Marie; Ziegler, Johannes C.; Fagot, Joël (2012-04-13). "Orthographic Processing in Baboons (Papio papio)" (PDF). Science. 336 (6078): 245–248. doi:10.1126/science.1218152. ISSN 0036-8075. PMID 22499949. Archived from the original (PDF) on 2017-12-29. Retrieved 2017-12-29.
- Ritvo, Sarah and MacDonald, Suzanne (2016). "Music as enrichment for Sumatran orangutans (Pongo abelii)". Journal of Zoo and Aquarium Research.
- Lilly, John Cunningham (1967). The mind of the dolphin : a nonhuman intelligence (1st ed.). Garden City, New York: Doubleday. ISBN 978-0385025430. OCLC 851669.
- Lilly, John Cunningham (1978). Communication between man and dolphin : the possibilities of talking with other species. New York: Crown Publishers. ISBN 978-0517530368. OCLC 4036849.
- Lilly, John (1962). Man and Dolphin. Gollancz.
- Lilly, John (1975). Lilly on Dolphins. Anchor Press.
- Lilly on Dolphins. p. 177.
- Lilly, John C. (1962). "Vocal Behavior of the Bottlenose Dolphin". Proceedings of the American Philosophical Society. 106 (6): 520–529. JSTOR 985258.
- Mind of the Dolphin. p. 218.
- Mind of the Dolphin. p. 196.
- Mind of the Dolphin. pp. 299–300.
- Mind of the Dolphin. pp. 288–295.
-
- 34 whistles with meanings are listed in Herman, "Cognition and Language Competencies of Bottlenosed Dolphins", in Schusterman et al., Dolphin Cognition and Behavior,1986, p.230
- 33 are listed in Herman, Louis M.; Richards, Douglas G.; Wolz, James P. (1984). "Comprehension of sentences by bottlenosed dolphins". Cognition. 16 (2): 129–219. doi:10.1016/0010-0277(84)90003-9. PMID 6540652., p. 144
- 23 are listed in Herman, Louis (1980). Cetacean Behavior. Wiley. pp. 413–418.
- Herman, Louis M.; Richards, Douglas G.; Wolz, James P. (1984). "Comprehension of sentences by bottlenosed dolphins". Cognition. 16 (2): 129–219. doi:10.1016/0010-0277(84)90003-9. PMID 6540652.
- Herman, Louis (1980). Cetacean Behavior. Wiley. pp. 413–418.
- Richards, D. G.; Wolz, J. P.; Herman, L. M. (March 1984). "Vocal mimicry of computer-generated sounds and vocal labeling of objects by a bottlenosed dolphin, Tursiops truncatus". Journal of Comparative Psychology. 98 (1): 10–28. doi:10.1037/0735-7036.98.1.10. ISSN 0735-7036. PMID 6705501.
- LeVasseur, Kenneth. "Dolphin Mental Abilities Paper". whales.org.au. Retrieved 2017-08-21.
- Reiss, Diana, and McCowan, Brenda (1993). "Spontaneous Vocal Mimicry and Production by Bottlenose Dolphins: Tursiops truncatus: Evidence for Vocal Learning" (PDF). Journal of Comparative Psychology. 107 (3): 301–312. doi:10.1037/0735-7036.107.3.301. PMID 8375147. Archived from the original (PDF) on 2017-08-22. Retrieved 2017-08-21.
- Delfour, Fabienne; Marten, Ken (2005). "Inter-modal learning task in bottlenosed dolphins (Tursiops truncatus): a preliminary study showed that social factors might influence learning strategies". Acta Ethologica. 8 (1): 57–64. doi:10.1007/s10211-005-0110-z.
- Kuczaj (2006). Problem Solving and Behavioral Flexibility, in: Comparative Cognition: Experimental Explorations of Animal Intelligence edited by Edward A. Wasserman, Thomas R. Zentall. Oxford University Press. ISBN 9780195167658. Retrieved 2017-08-22.
- Amundin, Mats; Starkhammar, Josefin; Evander, Mikael; Almqvist, Monica; Lindström, Kjell; Persson, Hans W. (2008-02-01). "An echolocation visualization and interface system for dolphin research" (PDF). The Journal of the Acoustical Society of America. 123 (2): 1188–1194. doi:10.1121/1.2828213. ISSN 0001-4966. PMID 18247918. Archived from the original (PDF) on 2017-08-09. Retrieved 2017-08-22.
- Reiss, Diana (2011). "Dolphin in the Mirror website". Houghton Mifflin. Archived from the original on 2012-01-15. Retrieved 2017-08-22.
- Reiss, Diana (2011). Dolphin in the Mirror book. Houghton Mifflin. ISBN 978-0547445724. Retrieved 2017-08-22.
- Herzing, Denise (February 2013). "Could We Speak the Language of Dolphins?". Retrieved 2017-08-22.
- Herzing, Denise (March 31, 2014). "CHAT: Is It A Dolphin Translator Or An Interface?". wilddolphinproject.org. Retrieved 2017-08-21.
- Pryor, Karen; Lindbergh, Jon (1990-01-01). "A Dolphin-Human Fishing Cooperative in Brazil". Marine Mammal Science. 6 (1): 77–82. doi:10.1111/j.1748-7692.1990.tb00228.x. ISSN 1748-7692.
- Zappes, Camilah Antunes; Andriolo, Artur; Simões-Lopes, Paulo César; Beneditto, Ana Paula Madeira Di (2011-02-22). "'Human-dolphin (Tursiops truncatus Montagu, 1821) cooperative fishery' and its influence on cast net fishing activities in Barra de Imbé/Tramandaí, Southern Brazil". Ocean & Coastal Management. 54 (5): 427–432. doi:10.1016/j.ocecoaman.2011.02.003.
- Clode, Danielle (2002). Killers in Eden : the true story of killer whales and their remarkable partnership with the whalers of Twofold Bay. Crows Nest, N.S.W.: Allen & Unwin. ISBN 978-1865086521. OCLC 52250051.
- "Australia's whaling industry and whales, Twofold Bay – unique teamwork with killer whales". www.australia.gov.au. Archived from the original on 2017-09-07. Retrieved 2017-09-07.
- Bergin, Bonnie (2006). Teach your dog to read : a unique step-by-step program to expand your dog's mind and strengthen the bond between you (1st ed.). New York: Broadway Books. pp. 2, 3, 8, 139, 182–5. ISBN 978-0767922456. OCLC 61211431.
- Ensminger, John (2012). Police and military dogs : criminal detection, forensic evidence, and judicial admissibility (PDF). Boca Raton: CRC Press. ISBN 978-1-4398-7240-6. OCLC 756484228.
- Coren, Stanley (1994). The intelligence of dogs : canine consciousness and capabilities. New York: Free Press. pp. 93–97, 100–109. ISBN 978-0029066836. OCLC 29703107.
- Faragó, Tamás and Townsend, Simon and Range, Friederike (2013-11-18). The information content of wolf (and dog) social communication. Chapter 4 in: Biocommunication of animals. Dordrecht. ISBN 9789400774131. OCLC 865545997.CS1 maint: multiple names: authors list (link)
- Molnár, Csaba; Kaplan, Frédéric; Roy, Pierre; Pachet, François; Pongrácz, Péter; Dóka, Antal; Miklósi, Ádám (2008-07-01). "Classification of dog barks: a machine learning approach". Animal Cognition. 11 (3): 389–400. CiteSeerX 10.1.1.140.9111. doi:10.1007/s10071-007-0129-9. ISSN 1435-9448. PMID 18197442.
- Pilley, John W.; Reid, Alliston K. (2011). "Border collie comprehends object names as verbal referents" (PDF). Behavioural Processes. 86 (2): 184–195. doi:10.1016/j.beproc.2010.11.007. PMID 21145379.
- Grassmann, Susanne; Kaminski, Juliane; Tomasello, Michael (2012-07-01). "How two word-trained dogs integrate pointing and naming". Animal Cognition. 15 (4): 657–665. doi:10.1007/s10071-012-0494-x. ISSN 1435-9448. PMC 3377900. PMID 22526689.
- Kaminski, Juliane; Josep Call; Julia Fischer (11 June 2004). "Word Learning in a Domestic Dog: Evidence for "Fast Mapping"" (PDF). Science. 304 (5677): 1682–3. doi:10.1126/science.1097859. ISSN 0036-8075. PMID 15192233. Archived from the original (PDF) on 8 January 2013. Retrieved January 2, 2013.
- Holland, Vergil (1994). Herding dogs : progressive training. New York: Howell Book House. ISBN 978-0876056448. OCLC 29844283.
- Hartnagle-Taylor, Jeanne Joy (2010). Stockdog savvy. Crawford, CO: Alpine Publications. ISBN 978-1577791065. OCLC 456420606.
- Ramirez, Ken (1999). Animal training : successful animal management through positive reinforcement. Chicago, IL: Shedd Aquarium. ISBN 978-0961107499. OCLC 45076489.
- Lyons, Kate (2017-12-26). "The giant rats that love avocado – and can diagnose deadly TB". The Guardian. Retrieved 2017-12-26.
- Y Otsuka, J Yanagi, S Watanabe (2009-02-01). "Discriminative and reinforcing stimulus properties of music for rats". Behavioural Processes. 80 (2): 121–127. doi:10.1016/j.beproc.2008.10.009. ISSN 0376-6357. PMID 19022358.CS1 maint: multiple names: authors list (link)
- McConnell, Patricia (2002). The other end of the leash : why we do what we do around dogs (1st ed.). New York: Ballantine Books. pp. 57–58, 63. ISBN 978-0345446794. OCLC 49870666.
- Newport, Cait; Wallis, Guy; Reshitnyk, Yarema; Siebeck, Ulrike E. (2016-06-07). "Discrimination of human faces by archerfish (Toxotes chatareus)". Scientific Reports. 6 (1): 27523. doi:10.1038/srep27523. ISSN 2045-2322. PMC 4895153. PMID 27272551.
- Shinozuka, Kazutaka; Ono, Haruka; Watanabe, Shigeru (2013). "Reinforcing and discriminative stimulus properties of music in goldfish". Behavioural Processes. 99: 26–33. doi:10.1016/j.beproc.2013.06.009. PMID 23796771.
- Chase, Ava R. (2001-11-01). "Music discriminations by carp (Cyprinus carpio)". Animal Learning & Behavior. 29 (4): 336–353. doi:10.3758/bf03192900. ISSN 0090-4996.
- Hough, Alexander; Boal, Jean (2014-01-01). "Automation of Discrimination Training for Cuttlefish (Mollusca: Cephalopoda)". Keystone Journal of Undergraduate Research. 2: 15–21 – via Shippensburg University.
- Bublitz, Alexander; Weinhold, Severine R.; Strobel, Sophia; Dehnhardt, Guido; Hanke, Frederike D. (2017). "Reconsideration of Serial Visual Reversal Learning in Octopus (Octopus vulgaris) from a Methodological Perspective". Frontiers in Physiology. 8: 54. doi:10.3389/fphys.2017.00054. ISSN 1664-042X. PMC 5294351. PMID 28223940.
- Zepeda, Emily A.; Veline, Robert J.; Crook, Robyn J. (2017-06-01). "Rapid Associative Learning and Stable Long-Term Memory in the Squid Euprymna scolopes". The Biological Bulletin. 232 (3): 212–218. doi:10.1086/693461. ISSN 0006-3185. PMID 28898600.
- Anthony Hiss (January 3, 1983). "Talk of the Town HOOVER". The New Yorker. Retrieved 2017-12-20.