1. CATEGORIES OF STIMULI
Releasing (or triggering) stimuli
Orienting stimuli
Priming stimuli
Sign stimuli

2. CATEGORIES OF STIMULI
Sign stimuli - species specific
-release a reaction that is inherited
not learned

3. Sign Stimuli 1. European robin
Red breast releases aggressive behaviour in males

4. Complex Sign Stimuli Cues??
Herring Gull -chick pecks at parent’s beak to obtain regurgitated food
Cues??

5. Two major cues are involved:
1. Yellow bill
2. Red spot on the mandible

6. Male Stickleback (Gasterosteus)
Red Belly
Red Belly +
Head Down
Posture

8. Innate Releasing Mechanisms
SIGN
STIMULUS
receptor
CNS
IRM
Match
Motor pattern
Generated
Motor output
No match
No motor pattern
generated

9. Fixed Action Pattern (FAP)
Egg Rolling in a Greylag Goose

10. A series of FAP’s can be put into a sequence
Female
Male
1. Appears -heads up display
2. Zig-zag swim
3. Swims head up
to male
4. Swim to nest
5. follows
6. Show nest
7. Enters nest
8. Tremble thrust
9. spawn

11. Should look like:
In reality: 1 2 3 4 5 6 7 8 9

12. More Fixed Action Patterns

13. Modal Action Patterns

14. SUPERNORMAL STIMULI

15. SUPERNORMAL STIMULI
Oystercatcher

16. Lorenz’s Hydraulic Model

17. Vacuum activity Time Court rolled up towel Court live female
Court female model
Court corner
of cage

18. Displacement activity