close
Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2009 Jan 22;276(1655):247-54.
doi: 10.1098/rspb.2008.1107.

Do new caledonian crows solve physical problems through causal reasoning?

A H Taylor  1 , G R Hunt, F S Medina, R D Gray
Affiliations

Do new caledonian crows solve physical problems through causal reasoning?

A H Taylor et al. Proc Biol Sci. .

Abstract

The extent to which animals other than humans can reason about physical problems is contentious. The benchmark test for this ability has been the trap-tube task. We presented New Caledonian crows with a series of two-trap versions of this problem. Three out of six crows solved the initial trap-tube. These crows continued to avoid the trap when the arbitrary features that had previously been associated with successful performances were removed. However, they did not avoid the trap when a hole and a functional trap were in the tube. In contrast to a recent primate study, the three crows then solved a causally equivalent but visually distinct problem--the trap-table task. The performance of the three crows across the four transfers made explanations based on chance, associative learning, visual and tactile generalization, and previous dispositions unlikely. Our findings suggest that New Caledonian crows can solve complex physical problems by reasoning both causally and analogically about causal relations. Causal and analogical reasoning may form the basis of the New Caledonian crow's exceptional tool skills.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Drawing of the experimental apparatus. (a) The trap-tube. (b) The trap-table.
Figure 2
Figure 2
The trap-tube apparatus. (a) The initial trap-tube. (b–d) The three transfer trap-tubes. The coloured discs represent actual colours and solid surfaces. The left trap in transfer 1 was non-functional with a transparent solid surface. Transfer 1 was placed on a wooden base. The other three trap-tubes were suspended above the wooden base. The arrows show the direction in which the food must be extracted to avoid the trap.
Figure 3
Figure 3
The performance of the crows with the initial trap-tube. (a) Successful crows (solid line, Obo; dotted line, Tiga; dashed line, Slevin) and (b) unsuccessful crows (solid line, Espanol; dotted line, Batou; dashed line, Egg). The x-axis gives the block number.
Figure 4
Figure 4
Results of the four transfer tasks. (a) Transfer 1: the only visual cue retained from the initial tube is the blue rim (circle, Obo; down triangle, Tiga; square, Slevin). (b) Transfer 2: the disc positions are the same as in the initial tube, but the discs are coloured black, and the blue rim is absent (circle, Obo; down triangle, Tiga; square, Slevin). (c) Transfer 3: the tube contains two holes, one with a base, making it a functional trap, and one without a base, making it a non-functional trap. Food can only be retrieved once it falls through the non-functional trap (circle, Obo; down triangle, Tiga; square, Slevin). (d) Transfer 4: the trap-table (circle, Obo; down triangle, Tiga; square, Slevin; diamond, Espanol; hexagon, Batou; up triangle, Egg).
Figure 5
Figure 5
Comparison of latencies and switching rates (±s.e.) in four tasks with the trap-tube. (a) Comparison of latencies for the three successful crows in the initial trap-tube (final block only) and transfers 1–3 (first block only) (filled circle, Obo; open circle, Slevin; down triangle, Tiga). (b) Comparison of side-switching for the three successful crows in the initial trap-tube (final block only) and transfers 1–3 (first block only) (filled circle, Obo; open circle, Slevin; down triangle, Tiga).
See this image and copyright information in PMC

References

    1. Blaisdell A.P., Sawa K., Leising K.J., Waldmann M.R. Causal reasoning in rats. Science. 2006;311:1020–1022. doi:10.1126/science.1121872 - DOI - PubMed
    1. Boysen S.T., Mukobi K.L., Berntson G.G. Overcoming response bias using symbolic representations of number by chimpanzees (Pan troglodytes) Anim. Learn. Behav. 1999;27:229–235.
    1. Boysen S.T., Berntson G.G., Mukobi K.L. Size matters: impact of item size and quantity on array choice by chimpanzees (Pan troglodytes) J. Comp. Psychol. 2001;115:106–110. doi:10.1037/0735-7036.115.1.106 - DOI - PubMed
    1. Call J. Inferences about the location of food in the great apes (Pan paniscus, Pan troglodytes, Gorilla gorilla, and Pongo pygmaeus) J. Comp. Psychol. 2004;118:231–242. doi:10.1037/0735-7036.118.2.232 - DOI - PubMed
    1. Cunningham C.L., Anderson J.R., Mootnick A.R. Object manipulation to obtain a food reward in hoolock gibbons, Bunopithecus hoolock. Anim. Behav. 2006;71:621–629. doi:10.1016/j.anbehav.2005.05.013 - DOI

Publication types