[MARMAM] New publication on gain control in the bottlenose dolphin

Kloepper, Laura laura_kloepper at brown.edu
Thu Aug 28 09:04:04 PDT 2014

Dear Colleagues,

My coauthors and I are pleased to announce our new publication:

Kloepper, L.N., Smith, A.B., Nachtigall, P.E., Buck, J.R., Simmons, J.A.,
and Pacini, A.F. 2014. Cognitive adaptation of sonar gain control in the
bottlenose dolphin. PLoS ONE9(8): e105938. doi: 10.1371/journal.pone.0105938

The paper can be accessed here


Abstract: Echolocating animals adjust the transmit intensity and receive
sensitivity of their sonar in order to regulate the sensation level of
their echoes; this process is often termed automatic gain control. Gain
control is considered not to be under the animal's cognitive control, but
previous investigations studied animals ensonifying targets or hydrophone
arrays at predictable distances. To test whether animals maintain gain
control at a fixed level in uncertain conditions, we measured changes in
signal intensity for a bottlenose dolphin (*Tursiops truncatus*) detecting
a target at three target distances (2.5, 4 and 7 m) in two types of
sessions: predictable and unpredictable. Predictable sessions presented the
target at a constant distance; unpredictable sessions moved the target
randomly between the three target positions. In the predictable sessions
the dolphin demonstrated intensity distance compensation, increasing the
emitted click intensity as the target distance increased. Additionally, as
trials within sessions progressed, the animal adjusted its click intensity
even from the first click in a click train, which is consistent with the
animal expecting a target at a certain range. In the unpredictable sessions
there was no significant difference of intensity with target distance until
after the 7th click in a click train. Together, these results demonstrate
that the bottlenose dolphin uses learning and expectation for sonar gain

Laura N. Kloepper, Ph.D.
Postdoctoral Fellow
Brown University and University of Massachusetts Dartmouth
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