1. Timing Periodic Timing –Cyclical behaviour controlled by 24 hour clock time or (circadian) Interval Timing –Stopwatch timing

2. 4pm 8pm Midnight 4am 8am Mid-day ACTIVITY Light off Light on Periodic Timing Controlled by daily time or by light off?

3. Roberts (1965) Activity cycle slightly less than 24 hours in constant dim light Restoring visual cues produces a gradual shift back to correct time. Entrainment: light acts as a zeitgeber (resets 24 hour clock)

4. Bolles & Stokes 24 hour19 hour29 hour “Just Right”“Too Hot”“Too Cold”

5. Bolles & Stokes (1965)

6. 4am 8am Mid-day 4pm 8pm Midnight Food Light Dark Periodic Timing 11pm 4am 8amMid-day 4pm8pm Food Light Dark Paris New York

8. Oscillators (Long Intervals)

9. Example RRRRRGGGGGGRGRGGRRRGGRGR

10. Interval Timing

11. Peak Procedure

12. One vs. Two Seconds Absolute Difference = 1 Weber’s Ratio = 1/2 = 0.5 Weber’s Law Prediction: Very Easy

13. Nineteen vs. Twenty Seconds Absolute Difference = 1 Weber’s Ratio = 19/20 = 0.05 Weber’s Law Prediction: Very Hard

14. Long or Short? 4 s 16 s Choose Lever 1 Choose Lever 2 4 s 16 s 10 s? 4 s 16 s 8 s? 8 is twice 4 16 is twice 8 (16 + 4) * ½ = 10 Absolute Ratio ((16)(4)) 1/2 =8

15. Temporal Discrimination

16. Absolute = (8+2) ½ = 5 Relative = ((8)(2)) 1/2 = 4 Bisection Testing

17. Scalar Timing What scale is used to compare times? –Error is relative to stopwatch time error is a constant proportion of the timed interval called scalar timing –Timing curves are identical if data are plotted as a function of the “percentage” of time remaining Step 1: Normalize Y-axis (common maximum) Step 2: X axis expressed as proportion of timed interval

18. Superposition

19. Scalar Timing

20. Learning-to-Time (LET) Behavior Sequence: PMTLC P = Peck M = Move T = Turn L = Look C = Coo StartStop