Animal Cognition

, Volume 15, Issue 4, pp 549–557

Two strings to choose from: do ravens pull the easier one?

Original Paper

Abstract

There are simple co-occurrences as well as functional relationships between events. One may assume that animals detect and use causation rather than mere co-variation. However, understanding causation often requires concepts of hidden forces. In string pulling, obstacles may hamper the access to food. Here, I studied whether ravens have an abstract concept of effort. First, in a competitive situation, ravens (Corvus corax) could choose one out of two strings. The strings differed in whether they were baited with meat and in how far away the meat was. Ravens pulled mainly the string containing meat and where the meat was nearer to the perch, respectively. Second, ravens could choose between two strings that had either a functional obstacle or a non-functional obstacle. Optimal performance required the integration of at least two cues: object and height. In 5 ravens, the model that best matched behaviour took into account only that meat was on a string, ignoring the obstacle. However, 2 ravens’ performance was best explained by a model that took into account both an object’s identity (meat or wood) and its height on the string. Third, one string out of two was loaded with a heavy meat piece. In this overloaded string condition, 5 out of 7 ravens did not try to pull the heavy meat piece but went straight for pulling the smaller piece. The pattern of results indicated that ravens can judge the effort required to pull a string.

Keywords

Physical cognition Causal reasoning Corvids String pulling 

References

  1. Betsch T, Haberstroh S, Molter B, Glockner A (2004) Oops, I did it again—relapse errors in routinized decision making. Organ Behav Hum Decis Process 93:62–74CrossRefGoogle Scholar
  2. Brown MF (1990) The effects of maze-arm length on performance in the radial-arm maze. Anim Learn Behav 18(1):13–22 CrossRefGoogle Scholar
  3. Bugnyar T, Heinrich B (2005) Ravens, Corvus corax, differentiate between knowledgeable and ignorant competitors. Proc R Soc B Biol Sci 272:1641–1646CrossRefGoogle Scholar
  4. Bugnyar T, Kotrschal K (2004) Leading a conspecific away from food in ravens (Corvus corax)? Anim Cogn 7:69–76PubMedCrossRefGoogle Scholar
  5. Chittka L, Dyer AG, Bock F, Dornhaus A (2003) Psychophysics—bees trade off foraging speed for accuracy. Nature 424:388PubMedCrossRefGoogle Scholar
  6. Clayton NS, Dally JM, Emery NJ (2007) Social cognition by food-caching corvids. The western scrub-jay as a natural psychologist. Philos Trans R Soc B 362:507–522CrossRefGoogle Scholar
  7. Emery NJ (2009) Cognitive ornithology: the evolution of avian intelligence. Philos Trans R Soc B 361:23–43CrossRefGoogle Scholar
  8. Emery NJ, Clayton NS (2004) The mentality of crows: convergent evolution of intelligence in corvids and apes. Science 306:1903–1907PubMedCrossRefGoogle Scholar
  9. Halsey LG, Bezerra BM, Souto AS (2006) Can wild common marmosets (Callithrix jacchus) solve the parallel strings task? Anim Cogn 9:229–233PubMedCrossRefGoogle Scholar
  10. Hanus D, Call J (2008) Chimpanzees infer the location of a reward on the basis of the effect of its weight. Curr Biol 18(9):R370–R372PubMedCrossRefGoogle Scholar
  11. Hanus D, Mendes N, Tennie C, Call J (2011) Comparing the performance of apes (Gorilla gorilla, Pan troglodytes, Pongo pygmaeus) and human children (Homo sapiens) in the floating peanut task. PLoS One 6:e19555PubMedCrossRefGoogle Scholar
  12. Hare B, Call J, Tomasello M (2004) Chimpanzees are more skillful in competitive than in cooperative cognitive tasks. Anim Behav 68:571–581CrossRefGoogle Scholar
  13. Heinrich B (1995) An experimental investigation of insight in common ravens (Corvus corax). Auk 112:994–1003Google Scholar
  14. Heinrich B, Bugnyar T (2005) Testing problem solving in ravens: string-pulling to reach food. Ethology 111:962–976CrossRefGoogle Scholar
  15. Hunt GR, Gray RD (2003) Diversification and cumulative evolution in New Caledonian crow tool manufacture. Proc R Soc Lond Ser B Biol Sci 270:867–874CrossRefGoogle Scholar
  16. Jones LV, Fiske DW (1953) Models for testing the significance of combined results. Psychol Bull 50:375–382PubMedCrossRefGoogle Scholar
  17. Kirsch JA, Gunturkun O, Rose J (2008) Insight without cortex: lessons from the avian brain. Conscious Cogn 17:475–483PubMedCrossRefGoogle Scholar
  18. Koehler DJ, James G (2009) Probability matching in choice under uncertainty: intuition versus deliberation. Cognition 113:123–127PubMedCrossRefGoogle Scholar
  19. Liedtke J, Werdenich D, Gajdon GK, Huber L, Wanker R (2011) Big brains are not enough: performance of three parrot species in the trap-tube paradigm. Anim Cogn 14:143–149PubMedCrossRefGoogle Scholar
  20. Martin-Ordas G, Call J, Colmenares F (2008) Tubes, tables and traps: great apes solve two functionally equivalent trap tasks but show no evidence of transfer across tasks. Anim Cogn 11:423–430PubMedCrossRefGoogle Scholar
  21. Mendes N, Hanus D, Call J (2007) Raising the level: orangutans use water as a tool. Biol Lett 3:453–455PubMedCrossRefGoogle Scholar
  22. Mulcahy NJ, Call J, Dunbar RIM (2005) Gorillas (Gorilla gorilla) and Orangutans (Pongo pygmaeus) encode relevant problem features in a tool-using task. J Comp Psychol 119(1):23–32 PubMedCrossRefGoogle Scholar
  23. Osthaus B, Lea SEG, Slater AM (2005) Dogs (Canis lupus familiaris) fail to show understanding of means-end connections in a string-pulling task. Anim Cogn 8:37–47PubMedCrossRefGoogle Scholar
  24. Povinelli DJ (2000) Folk physics for apes: the chimpanzee’s theory of how the world works. Oxford University Press, OxfordGoogle Scholar
  25. Schrauf C, Call J (2011) Great apes use weight as a cue to find hidden food. Am J Primatol 73(4):323–334. PubMedCrossRefGoogle Scholar
  26. Schuck-Paim C, Borsari A, Ottoni EB (2009) Means to an end: neotropical parrots manage to pull strings to meet their goals. Anim Cogn 12:287–301PubMedCrossRefGoogle Scholar
  27. Schwab C, Bugnyar T, Schloegl C, Kotrschal K (2008) Enhanced social learning between siblings in common ravens, Corvus corax. Anim Behav 75:501–508CrossRefGoogle Scholar
  28. Seed AM, Tebbich S, Emery NJ, Clayton NS (2006) Investigating physical cognition in rooks, Corvus frugilegus. Curr Biol 16:697–701PubMedCrossRefGoogle Scholar
  29. Sloman SA (2005) Causal models: how we think about the world and its alternatives. Oxford University Press, New YorkGoogle Scholar
  30. Stowe M, Bugnyar T, Loretto M-C, Schloegl C, Range F, Kotrschal K (2006) Novel object exploration in ravens (Corvus corax): effect of social relationships. Behav Process 73:68–75CrossRefGoogle Scholar
  31. Taylor AH, Hunt GR, Holzaider JC, Gray RD (2007) Spontaneous metatool use by New Caledonian crows. Curr Biol 17:1504–1507PubMedCrossRefGoogle Scholar
  32. Taylor AH, Hunt GR, Medina FS, Gray RD (2009) Do New Caledonian crows solve physical problems through causal reasoning? Proc R Soc B Biol Sci 276:247–254CrossRefGoogle Scholar
  33. Taylor AH, Medina FS, Holzaider JC, Hearne LJ, Hunt GR, Gray RD (2010) An investigation into the cognition behind spontaneous string pulling in New Caledonian Crows. PLoS One 5:e9345. doi:10.1371/journal.pone.0009345 PubMedCrossRefGoogle Scholar
  34. Tebbich S, Seed AM, Emery NJ, Clayton NS (2007) Non-tool-using rooks, Corvus frugilegus, solve the trap-tube problem. Anim Cogn 10:225–231PubMedCrossRefGoogle Scholar
  35. Tomasello M (2000) Two hypotheses about primate cognition. In: Heyes CM, Huber L (eds) The evolution of cognition. MIT Press, CambridgeGoogle Scholar
  36. Visalberghi E, Limongelli L (1994) Lack of comprehension of cause-effect relations in tool-using capuchin monkeys (Cebus apella). J Comp Psychol 108:15–22PubMedCrossRefGoogle Scholar
  37. Visalberghi E, Néel C (2003) Tufted capuchins (Cebus apella) use weight and sound to choose between full and empty nuts. Ecol Psychol 15:215–228CrossRefGoogle Scholar
  38. Visalberghi E, Addessi E, Truppa V, Spagnoletti N, Ottoni E, Izar P, Fragaszy D (2009) Selection of effective stone tools by wild capuchin monkeys. Curr Biol 19:213–217PubMedCrossRefGoogle Scholar
  39. Weir AAS, Chappell J, Kacelnik A (2002) Shaping of hooks in new Caledonian crows. Science 297:981PubMedCrossRefGoogle Scholar
  40. Werdenich D, Huber L (2006) A case of quick problem solving in birds: string pulling in keas, Nestor notabilis. Anim Behav 71:855–863CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  1. 1.Department of PsychologyNTNUTrondheimNorway

Personalised recommendations