Subject: Abstract: dolphin object recognition (fwd)

Mike Williamson (
Fri, 2 Oct 1998 11:57:35 -0400 (EDT)

---------- Forwarded message ----------
Date: Fri, 2 Oct 1998 04:40:51 -0700
From: MARMAM Editors <marmamed@UVic.CA>
Reply-To: Marine Mammals Research and Conservation Discussion
Subject: Abstract: dolphin object recognition (fwd)

From: Louis M Herman <>

Seeing through sound:  Dolphins (Tursiops truncatus) perceive the spatial
structure of objects through echolocation.  Herman, L. M.; Pack, A. A.;
Hoffmann-Kuhnt, M. JOURNAL OF COMPARATIVE PSYCHOLOGY, 1998, v112, i 3,

Experiment 1 tested a dolphin (Tursiops truncatus) for cross-modal
recognition of 25 unique pairings of 8 familiar, complexly shaped objects,
using the senses of echolocation and vision.  Cross-modal recognition was
errorless or nearly so for 24 of the 25 pairings under both visual to
echoic (V-E) matching and echoic to visual matching (E-V). First-trial
recognition occurred for 20 pairings under V-E and for 24 under E-V.
Echoic decision time under V-E averaged only 1.88 s.  Experiment 2 tested
4 new pairs of objects for 24 trials of V-E and 24 trials of E-V without
any prior exposure of these objects.  Two pairs yielded performance
significantly above chance in both V-E and E-V.  Also, the dolphin matched
correctly on 7 of 8 1st trials with these pairs.  The results support a
capacity for direct echoic perception of object shape by this species and
demonstrate that prior object exposure is not required for spontaneous
cross-modal recognition.

Herman, L
Kewalo Basin Marine Mammal Laboratory
1129 Ala Moana Blvd.
Honolulu HI 96814

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