PSYCH 2TT3 Lecture 8: Lecture 8 (March 11) - PSYCH 2TT3
9 Sep 2013
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Document Summary
Why bother: vocal signals are ubiquitous, birds are a classical model system, vocal learning has allowed the evolution of language. Sound pressure waves travelling through a medium. In air and water, molecules are packed together at different densities, depending on the air pressure. Sound pressure waves are relative to the ambient air pressure: height of wave = amplitude (loudness, distance between peaks (or valleys); one cycle = frequency (pitch) Sine waves do not occur in nature: they must be artificially created, naturally occurring sound are complex waveforms, no regular patterns, two people can say the same thing sound wave would be different. Sound fingerprint : represents sound, amplitude change and frequency. Amplitude based on darkness of dots red specks are maximum loudness: use to differentiate species or replicate sound. The syrinx: mtm (medial tympaniform membrane) special membranes (mtm) vibrate when air from the lungs is forced over them; produces sound in birds.
