1. Signal coding Definitions Types of coding schemes Inferring sender and receiver coding Signal function and coding

2. Conflict resolution example

3. Signal definitions

4. Assumptions Senders produce signals in order to provide honest (accurate) information to receivers –Dishonest signalling will be considered in the third section of the course Communication involves signal production, transmission, and reception. All three processes influence the accuracy of any coding scheme

5. Coding matrix Probability of giving a signal in each condition. Sender matrix must be similar to Receiver matrix for communication to occur.

6. Coding conventions None - all probabilities equal Perfect - each signal coocurs with each condition Imperfect –Specific - one signal per condition, but conditions may not be discriminable –Unique - one or more signals per condition

7. Reasons for imperfect coding Sender –Errs in assessment of condition –Mistakenly assigns signals to conditions Receiver –Signal is modified by transmission –Errs in identifying signal –Has not yet learned correct signal

8. Coding schemes Codes require signal diversity Variation can be created by –Modifying signal element attributes Sound: amplitude, frequency, duration Light: color, size, location –Combining signal elements in series Signal elements must be perceptually distinct

9. Hierarchical syntax

10. Stereotypy Stereotypic signals may represent constraints on senders

11. Coding options

12. Coding scheme examples

13. Iconic aggressive signals

14. Inferring sender coding schemes For discrete conditions and discrete signals, use contingency table analysis For discrete conditions and continuous signals, use discriminant function analysis For continuous signals and uncertain conditions, use clustering or principle component analysis

15. Phyllostomus hastatus

16. Females form stable groups

17. Departing bats give screech calls Bouts of screech calling often coincide with group departures

18. Calling rate and diet varies with season

19. Calling females recruit group mates

20. Groups have distinct calls

21. Inferring receiver coding schemes Determine how receiver categorizes the set of signal variants –In captivity, present alternative forms to determine which are perceived as same or different using habituation-dishabituation expt or operant conditioning paradigm Determine which condition is associated with each category by the receiver

22. Females can discriminate group mates by call

23. Compound coding schemes Combination mapping –Combining information into a single signal can save energy and reduce exposure Parameter mapping –Body size covaries with pitch, energy reserves covaries with calling rate Hierarchical mapping –Mean differences denote group, individual differences denote individual

24. Tamarin group calls

25. Signal ontogeny Heritable Favored when coding scheme is predictable, e.g. individual or kinship differences Learned –Individual or trial-and-error –Social Critical period vs. open-ended Believed to be faster and avoids costly errors

26. Females learn to match calls Group 1 Group 2 Before 5 months after move

27. Signal function and coding Binary assignment –E.g. sex labels –need only 2 signals, can be heritable Binary recognition –need many signals –decide own vs other

28. Signal function and coding Binary comparison - often continuous signals –opponent fighting ability, threshold mate choice, best-of-n mate choice Manifold decisions –Iconic rule - Honeybee language –pairwise associations