Barn owls can be trained to report acoustic motion direction changes

Evidence

Barn owls are keen hunters of moving prey. They have evolved an auditory system with impressive anatomical and physiological specializations for localizing their prey. Here we present behavioural data on the owl’s sensitivity for discriminating acoustic motion direction in azimuth that, for the first time, allow a direct comparison of neuronal and perceptual sensitivity for acoustic motion in the same model species. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3178

We trained two barn owls to report a change in auditory motion within a series of repeating band-pass noise stimuli (500–6000 Hz) presented in the horizontal plane. Motion was simulated by sequentially activating up to eight loudspeakers (Vifa XT25TG30-04), fading in and out the sound between adjacent loudspeakers (spacing 12°; Fig. 1 ). The experiments were performed in a sound-attenuating echo-reduced chamber (IAC 1203-A, walls with sound absorbing foam). Signals were generated by a 24-bit sound card (Hammerfall DSP Multiface II, RME, Germany) and the loudspeakers were driven by a multichannel amplifier (RMB-1048, Rotel, Japan). — Dijk, Pim van, Physiology, Psychoacoustics and…, 3187

Responses to inward and outward sweeps were equally frequent: the owls had relative hit rates of between about 35 and 43 % for each of the two directions (Χ2 tests n.s., Table 1 ). The owls responded more often to stimuli with a change in direction moving in the frontal range compared to those moving in the lateral range (Table 2 ): Owl “ba” had a relative Hit rate of about 67 % in the frontal space and of only 38 % in the lateral space (Χ2 = 15.7, P < 0.01) while owl “we” had relative hit rates of about 52 and 39 % for the frontal and lateral range, respectively (Χ2 = 3.1, P = 0.077). — Dijk, Pim van, Physiology, Psychoacoustics and…, 3207

Categorization

• corroborated: 4 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 3178; Dijk, Pim van, Physiology, Psychoacoustics and…, 3187; Dijk, Pim van, Physiology, Psychoacoustics and…, 3207
• XREF: connects to: Angular range, not velocity, dominates barn owl auditory motion discrimination sensitivity — Dijk, Pim van, Physiology, Psychoacoustics and…, 3178; Barn owls judge sound direction via dedicated motion circuits, not endpoint comparison.; Angular range dominates hearing-driven motion detection over speed and duration. (+2 more)

Broader Connections

• Barn owls judge sound direction via dedicated motion circuits, not endpoint comparison. #expands (0.88)
• Angular range, not velocity, dominates barn owl auditory motion discrimination sensitivity #qualifies (0.85) — Dijk, Pim van, Physiology, Psychoacoustics and…, 3178
• Angular range dominates hearing-driven motion detection over speed and duration. #qualifies (0.82)
• Auditory motion perception is not computed from endpoint comparisons #expands (0.80)
• Controlled experiments trace sound-feature variables against listeners’ behavioral responses #corroborates (0.75)