zipf’s slope
DESCRIPTION
Kenna Lehmann. Zipf’s Slope. Investigating the southern residents’ repertoire with Information Theory. Beam Reach Marine Science and Sustainability School - beamreach.org/071. Communication. The passing of information from one individual (the sender) to another (the receiver). Information. - PowerPoint PPT PresentationTRANSCRIPT
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Zipf’s Slope
Investigating the southern residents’
repertoire with Information
Theory
Kenna Lehmann
Beam Reach Marine Science and Sustainability School - beamreach.org/071
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Communication
• The passing of information from one individual (the sender) to another (the receiver)
Sender Receiver
Information
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Communication Channels
• Different senses (i.e. sight, sound, smell)
• Different environments (i.e. the ocean, the forest, the savanna)
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Background
• Orcas are highly social and vocal– Communication is key in maintaining social
interactions
• Call meanings have never been determined– No correlation between behavior and call-type
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Questions
• What information do orcas send in their calls?
• How much information do orcas send in their calls?
• How is that information organized?
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Information Theory• Quantitative way to analyze a
communication system
• As designed by Shannon and Weaver (1949) – Determines how a communication system is
internally organized
• Zipf’s slope: indication of a repertoire’s potential to contain information
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Calculating Zipf’s slope
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Zipf’s Slope
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Balance between
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Too diverse
Y=-.5+B
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Too unified
Y=-1.5x+B
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Methods
Additional recordings
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Call Types
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Ford (1991)
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What?
• The southern residents’ repertoire has a Zipf’s slope that is steeper than optimum
• Decreased from 1979-1983 to 2006-2007
• Repertoire is too unified (i.e. repetition)
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Why?
• Too much background noise in the communication channel?
• Contact calls?
• Have Soundwatch guidelines decreased boat noise in recent years?
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Further Research
• Comparing different populations and species
• Use Shannon and Weaver’s Information Theory to evaluate the internal organization of the repertoire
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Acknowledgments
John Burt for Syrinx, Scott and Val Veirs for Call Tutor and guidance, FHL computer team for helping with the many computer glitches, team VaTo, Leslie Veirs for the goodies, Mike for not crashing the boat (oh wait), my parents for obvious reasons, Shannon Fowler for the excellent feedback on my papers and life, Jason Wood for the support, feedback, brainstorming and putting up with us
And to my favorite whales: Liz, Heather, Elise, and WesFor the good times