= Playback experiment
A <playback experiment> presents a recorded signal to an animal and measures its response under a specified procedure. In <animal behaviour>, controlled playback can test the effect of an acoustic cue while avoiding the uncontrolled behavior of a live signaler. The recording, loudspeaker position, playback level, timing and response criterion are parts of the experimental manipulation.
A field example compared recordings of one female <lion> roaring with three females roaring together. The recordings simulated unfamiliar intruders in territories of 21 <lion prides>. Defending females were less likely to approach the three-intruder condition and approached it more cautiously; the defenders' own group composition also mattered.<Roaring and numerical assessment in contests between groups of female lions, Panthera leo by K. McComb and others>[Abstract: controlled playback conditions,21prides and approach responses]{ref}
For an original design exercise, imagine testing eight animal groups with one recording, then testing eight groups with eight independently obtained recordings. Both designs observe eight groups, but only the second samples variation among those recordings. Replaying a single recording many times does not make its acoustic details independent examples of a whole signal category. This is one route to <pseudoreplication>.
A <playback experiment> also requires checking that a response difference tracks the intended cue rather than an unintended loudness or position difference. The observed approach or call is a behavioral result; interpreting it as a particular cognitive process requires an argument connecting the manipulation, controls and alternative explanations.
Back to article page
