Umwelt: sensory world of the animal

Merkwelt: our perception of the environment

(Von Uexkull)

Example: A pond is perceived differently by a:

tadpole fish paramecia

hawk duck fisherman

Pavlov's significance:

• First empirical model of associationism.

• Integrated traditions of reflexology and associationism

• Began as a reflexologist by studying reflexes - a skilled surgeon

– studied digestive reflexes– a skilled surgeon, notably for maintained chronic

preparations

• Recognized significance of psychic secretion.

• Provided basis for investigating neuroscience of classical conditioning (Kandel)

• Defined modern concepts of conditioning

The Adventures of the Black Girl in Her Search for God, George Bernard

Shaw (1933)“What am I running away from? I’m not afraid of that dear

noisy old man.”

“Your fears and hopes are only fancies” said a voice close to her, proceeding from a very shortsighted elderly man in spectacles who was sitting on a gnarled log. “In running away you were acting on a conditioned reflex. It is quite simple. Having lived among lions you have from your childhood associated the sound of a roar with deadly danger. Hence your precipitate flight when that superstitious old jackass brayed at you. This remarkable discovery cost me twenty-five years of devoted research, during which I cut out the brains of innumerable dogs, and observed their spittle by making holes in their cheeks for them to salivate through instead of through their tongues. The whole scientific world is prostrate at my feet in admiration of this colossal achievement and gratitude for the light is has shed on the great problems of human conduct.”

The Adventures of the Black Girl in Her Search for God, George Bernard Shaw

(1933) [cont’d.]

“Why didn’t you ask me?” said the black girl. “I could have told you in twenty-five seconds without hurting those poor dogs.”

“Your ignorance and presumption are unspeakable” said the old myop. “The fact was known of course to every child; but it had never been proved experimentally in the laboratory; and therefore it was not scientifically known at all. It reached me as an unskilled conjecture: I handed it on as science. Have you ever performed an experiment, may I ask?”

The Adventures of the Black Girl in Her Search for God, George Bernard

Shaw (1933) [cont’d.]“Several” said the black girl. “I will perform one now.

Do you know what you are sitting on?”

“I am sitting on a log grey with age, and covered with an uncomfortable rugged bark” said the myop.

“You are mistaken” said the black girl. “You are sitting on a sleepy crocodile.”

With a yell which Micah himself might have envied, the myop roe and fled frantically to a neighboring tree, up which he climbed catlike with an agility which in so elderly a gentleman was quite superhuman.

“Come down” said the black girl. “You ought to know that crocodiles are only to be found near rivers. I was only trying an experiment. Come down.”

PAVLOV'S APPARATUS FOR STUDYING

CONDITIONED SALIVARY RESPONSE

CONDITIONING

Trial 1: Later Trials:

CS / /

(Bell)

CR / /

(Salivation)

US / /

(Food)

UR / /

(Salivation)

ACQUISITION OF CONDITIONED SALIVARY RESPONSE

0

10

20

30

40

50

60

70

0 10 20 30 40 50NUMBER OF PAIRINGS OF CS & US

(PAVLOV, 1927)

ACQUISITION OF CONDITIONED RESPONSE

0

5

10

15

20

10 20 30 40 50

NUMBER OF PAIRINGS OF CS AND US

(PAVLOV, 1927)

EXTINCTION

Trial 1: Later Trials:

CS / /

CR / /

US / /

EXTINCTION OF CONDITIONED SALIVARY RESPONSE

0

10

20

30

40

50

60

70

0 10 20 30 40 50

NUMBER OF UNPAIRED PRESENTATIONS OF CS

(PAVLOV, 1927)

GENERALIZATION OF CR

0

10

20

30

40

50

60

70

80

90

400 800 1200 1800 200

FREQUENCY [Hz]

(PAVLOV, 1927)

DISCRIMINATION LEARNING:

CS+ alternates with CS- e.g., Buzzer Food (Acquisition) Light No Food (Extinction)

*Initial generalization from CS+ to CS-*Gradual weakening of response to CS-*Subject responds mainly to CS+ at the

end of discrimination training

Procedure for Establishing “EXPERIMENTAL NEUROSIS”

S+ S-

16:8 Initial

Discrimin.

14:8

12:8

10:8

9:8 Final Discrimination

The Establishment of Higher Order Conditioning

Stage 1 Stage 2 Stage 3

Bell (CS1) Salivation (CR) light (CS2) salivation (CR2)Food (US) Salivation (CR) bell (CS1) salivation (CR1)

Light (CS2) No SalivationBell (CS1) Salivation (CR) buzzer (CS3) no salivation

light (cs2) salivation (CR2)repeated pairingof light + bell

repeated pairings ofbuzzer and light

buzzer (CS3)salivation (CS3)

Classical Conditioning (Basic Phenomena)

• Acquisition

• Extinction

• Spontaneous recovery

• Higher order conditioning

• Discrimination

– Experimental neurosis

• Generalization

– Mediated generalization

Classical Conditioning (Type S)

Signal a reinforcing event (an unconditioned stimulus “US”), e.g., sound a buzzer (a conditioned stimulus) before delivering food.

Buzzer foodCS US

Initially,US URfood salivation

CS orienting (?)buzzer turning towards source

no salivation (or minimal salivation)

After multiple pairings of CS and US:CS CRbuzzer salivation

ACQUISITION OF CONDITIONED RESPONSE

0

5

10

15

20

10 20 30 40 50

NUMBER OF PAIRINGS OF CS AND US

(PAVLOV, 1927)