Animal Cognition

, Volume 13, Issue 4, pp 641–649 | Cite as

Chimpanzees (Pan troglodytes) accurately compare poured liquid quantities

Original Paper


Although many studies have shown that nonhuman animals can choose the larger of two discrete quantities of items, less emphasis has been given to discrimination of continuous quantity. These studies are necessary to discern the similarities and differences in discrimination performance as a function of the type of quantities that are compared. Chimpanzees made judgments between continuous quantities (liquids) in a series of three experiments. In the first experiment, chimpanzees first chose between two clear containers holding differing amounts of juice. Next, they watched as two liquid quantities were dispensed from opaque syringes held above opaque containers. In the second experiment, one liquid amount was presented by pouring it into an opaque container from an opaque syringe, whereas the other quantity was visible the entire time in a clear container. In the third experiment, the heights at which the opaque syringes were held above opaque containers differed for each set, so that sometimes sets with smaller amounts of juice were dropped from a greater height, providing a possible visual illusion as to the total amount. Chimpanzees succeeded in all tasks and showed many similarities in their continuous quantity estimation to how they performed previously in similar tasks with discrete quantities (for example, performance was constrained by the ratio between sets). Chimpanzees could compare visible sets to nonvisible sets, and they were not distracted by perceptual illusions created through various presentation styles that were not relevant to the actual amount of juice dispensed. This performance demonstrated a similarity in the quantitative discrimination skills of chimpanzees for continuous quantities that matches that previously shown for discrete quantities.


Chimpanzees Pan troglodytes Quantity judgments Continuous quantity Perceptual illusion 



This research was supported by Grant HD-38051 from the National Institute of Child Health and Human Development and by Grants BCS-0924811 and SES-0729244 from the National Science Foundation. All applicable institutional rules and regulations regarding animal care and use were followed in the care and testing of these chimpanzees, and the experiment complied with all laws of the United States of America.


  1. Anderson US, Stoinski TS, Bloomsmith MA, Marr MJ, Smith AD, Maple TS (2005) Relative numerousness judgment and summation in young and old Western Lowland gorillas. J Comp Psychol 119:285–295CrossRefPubMedGoogle Scholar
  2. Anderson US, Stoinski TS, Bloomsmith MA, Maple TS (2007) Relative numerousness judgment and summation in young, middle-aged, and old adult orangutans (Pongo pygmaeus abelii and Pongo pygmaeus pygmaeus). J Comp Psychol 121:1–11CrossRefPubMedGoogle Scholar
  3. Beran MJ (2001) Summation and numerousness judgments of sequentially presented sets of items by chimpanzees (Pan troglodytes). J Comp Psychol 115:181–191CrossRefPubMedGoogle Scholar
  4. Beran MJ (2004) Chimpanzees (Pan troglodytes) respond to nonvisible sets after one-by-one addition and removal of items. J Comp Psychol 118:25–36CrossRefPubMedGoogle Scholar
  5. Beran MJ (2006) Quantity perception by adult humans (Homo sapiens), chimpanzees (Pan troglodytes), and rhesus macaques (Macaca mulatta) as a function of stimulus organization. Int J Comp Psychol 19:386–397Google Scholar
  6. Beran MJ (2007a) Rhesus monkeys (Macaca mulatta) enumerate sequentially presented sets of items using analog numerical representations. J Exp Psychol Anim Behav Proc 33:42–54CrossRefGoogle Scholar
  7. Beran MJ (2007b) Rhesus monkeys (Macaca mulatta) succeed on a computerized test designed to assess conservation of discrete quantity. Anim Cogn 10:37–45CrossRefPubMedGoogle Scholar
  8. Beran MJ (2008a) Capuchin monkeys (Cebus apella) succeed in a test of quantity conservation. Anim Cogn 11:109–116CrossRefPubMedGoogle Scholar
  9. Beran MJ (2008b) Monkeys (Macaca mulatta and Cebus apella) track, enumerate, and compare multiple sets of moving items. J Exp Psychol Anim Behav Proc 34:63–74CrossRefGoogle Scholar
  10. Beran MJ, Beran MM (2004) Chimpanzees remember the results of one-by-one addition of food items to sets over extended time periods. Psychol Sci 15:94–99CrossRefPubMedGoogle Scholar
  11. Brannon EM (2006) The representation of numerical magnitude. Curr Opin Neurol 16:222–229CrossRefGoogle Scholar
  12. Brannon EM, Roitman J (2003) Nonverbal representations of time and number in animals and human infants. In: Meck W (ed) Functional and neural mechanisms of interval timing. CRC Press, New York, pp 143–182Google Scholar
  13. Call J (2000) Estimating and operating on discrete quantities in orangutans (Pongo pygmaeus). J Comp Psychol 114:136–147CrossRefPubMedGoogle Scholar
  14. Call J, Rochat P (1997) Perceptual strategies in the estimation of physical quantities by orangutans (Pongo pygmaeus). J Comp Psychol 111:315–329CrossRefPubMedGoogle Scholar
  15. Cantlon JF, Brannon EM (2007) How much does number matter to a monkey (Macaca mulatta)? J Exp Psychol Anim Behav Proc 33:32–41CrossRefGoogle Scholar
  16. Cantlon JF, Platt ML, Brannon EM (2009) Beyond the number domain. Trends Cogn Sci 13:83–91CrossRefPubMedGoogle Scholar
  17. Cheries EW, Mitroff SR, Wynn K, Scholl BJ (2008) Cohesion as a constraint on object persistence in infancy. Dev Sci 11:427–432CrossRefPubMedGoogle Scholar
  18. Chiang WC, Wynn K (2000) Infants’ representation and tracking of multiple objects. Cogn 77:169–195CrossRefGoogle Scholar
  19. Czerny P, Thomas RK (1975) Sameness-difference judgments in Saimiri sciureus based on volumetric cues. Anim Learn Behav 3:375–379Google Scholar
  20. Gallistel CR, Gelman R (2000) Non-verbal numerical cognition: from reals to integers. Trends Cogn Sci 4:59–65CrossRefPubMedGoogle Scholar
  21. Hanus D, Call J (2007) Discrete quantity judgments in the great apes (Pan paniscus, Pan troglodytes, Gorilla gorilla, Pongo pygmaeus): the effect of presenting whole sets versus item-by-item. J Exp Psychol Anim Behav Proc 121:241–249Google Scholar
  22. Hunt GR, Rutledge RB, Gray RD (2006) The right tool for the job: what strategies do wild New Caledonian crows use? Anim Cogn 9:307–316CrossRefPubMedGoogle Scholar
  23. Jordan KE, Brannon EM (2006) A common representational system governed by Weber’s law: nonverbal numerical similarity judgments in 6-year olds and rhesus macaques. J Exp Child Psychol 95:215–229CrossRefPubMedGoogle Scholar
  24. Mahajan N, Barnes JL, Blanco M, Santos LR (2009) Enumeration of objects and substances in non-human primates: experiments with brown lemurs (Eulemur fulvus). Dev Sci 12:920–928CrossRefPubMedGoogle Scholar
  25. McGarrigle J, Donaldson M (1974) Conservation accidents. Cogn 3:341–350CrossRefGoogle Scholar
  26. Meck WH, Church RM (1983) A mode control model of counting and timing processes. J Exp Psychol Anim Behav Proc 9:320–324CrossRefGoogle Scholar
  27. Mehler J, Bever TG (1967) Cognitive capacity of very young children. Science 158:141–142CrossRefPubMedGoogle Scholar
  28. Menzel EW (1961) Perception of food size in the chimpanzee. J Comp Physiol Psychol 54:588–591CrossRefGoogle Scholar
  29. Menzel EW, Draper WA (1965) Primate selection of food by size: visible versus invisible rewards. J Comp Physiol Psychol 59:231–239CrossRefPubMedGoogle Scholar
  30. Muncer SJ (1983) “Conservations” with a chimpanzee. Dev Psychol 16:1–11Google Scholar
  31. Piaget J (1965) The child’s conception of number. Norton, New YorkGoogle Scholar
  32. Piaget J (1969) The mechanisms of perception. Rutledge Kegan Paul, LondonGoogle Scholar
  33. Povinelli DJ (2000) Folk physics for apes: the chimpanzee’s theory of how the world works. Oxford University Press, OxfordGoogle Scholar
  34. Raghubir P, Krishna A (1999) Vital dimensions in volume perception: can the eye fool the stomach? J Marketing Res 36:313–326CrossRefGoogle Scholar
  35. Rumbaugh DM, Savage-Rumbaugh ES, Hegel MT (1987) Summation in the chimpanzee (Pan troglodytes). J Exp Psychol Anim Behav Proc 13:107–115CrossRefGoogle Scholar
  36. Santos LR, Barnes JL, Mahajan N (2005) Expectations about numerical events in four lemur species Eulemur fulvus, Eulemur mongoz, Lemur catta, and Varecia rubra. Anim Cogn 8:253–262CrossRefPubMedGoogle Scholar
  37. Shumaker RW, Palkovich AM, Beck BB, Guagnano GA, Morowitz H (2001) Spontaneous use of magnitude discrimination and ordination by the orangutan (Pongo pygmaeus). J Comp Psychol 115:385–391CrossRefPubMedGoogle Scholar
  38. Silva FJ, Page DM, Silva KM (2005) Methodological-conceptual problems in the study of chimpanzees’ folk physics: how studies with adult humans can help. Learn Behav 33:47–58PubMedGoogle Scholar
  39. Suda C, Call J (2004) Piagetian liquid conservation in the great apes (Pan paniscus, Pan troglodytes, and Pongo pygmaeus). J Comp Psychol 118:265–279CrossRefPubMedGoogle Scholar
  40. Suda C, Call J (2005) Piagetian conservation of discrete quantities in bonobos (Pan paniscus), chimpanzees (Pan troglodytes), and orangutans (Pongo pygaeus). Anim Cogn 8:220–235CrossRefPubMedGoogle Scholar
  41. vanMarle K, Aw J, McCrink K, Santos LA (2006) How capuchin monkeys (Cebus apella) quantify objects and substances. J Comp Psychol 120:416–426CrossRefPubMedGoogle Scholar
  42. Wansink B, Van Ittersum K (2003) Bottoms up! The influence of elongation on pouring and consumption volume. J Consume Res 331:1512–1514Google Scholar
  43. Wansink B, Van Ittersum K (2005) Shape of glass and amount of alcohol poured: comparative study of effect of practice and concentration. Br Med J 331:1512–1514CrossRefGoogle Scholar
  44. Woodruff G, Premack D, Kennel K (1978) Conservation of liquid and solid quantity by the chimpanzee. Science 202:991–994CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Language Research CenterGeorgia State UniversityAtlantaUSA

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