Lecture 3: Non-associative Learning Learning, Psychology 3510 Spring, 2015 Professor Delamater

Lecture 3: Non-associative Learning

Learning, Psychology 3510

Spring, 2015

Professor Delamater

Non-associative Learning

Three Types1. Habituation2. Dishabituation3. Sensitization

Or, for the most part, changes in responsiveness to a single stimulus

Non-associative Learning: Habituation

Habituation – Decline in responsiveness to a stimulus with repeatedexposures, but arising from “central” changes.

• Learning to “tune” out the radio, or the siren, etc• Used to study sensory capacities in human infants, and, more generally,• Simple learning processes in other organisms.• Major headway in understanding the neural mechanisms in memory.



• Learning to “tune” out the radio, or the siren, or background noise, etc• Used to study sensory capacities in human infants, and, more generally,• Simple learning processes in other organisms.• Major headway in understanding the neural mechanisms in memory.



• Learning to “tune” out the radio, or the siren, or background noise, etc• Used to study sensory capacities in human infants, and, more generally,• Simple learning processes in other organisms.• Major headway in understanding the neural mechanisms in memory.

Women asked to rate thePleasantness of a specificTaste stimulus.

Also, the amount ofSalivation was measured.

Steady decreases with repeatedexposures suggests habituation.



How do we know this is due to a “central” change?



Need to rule out sensory adaptation and motor fatigue (two “peripheral” change mechanisms).



Need to rule out sensory adaptation and motor fatigue (two “peripheral” change mechanisms).

But notice that Habituation is Stimulus-Specific!!!This rules out Motor Fatigue as an explanation of the decrease in responding.But what about Sensory Adaptation???

Non-associative Learning: Dishabituation

Dishabituation – Recovery in responsiveness to an already habituatedstimulus.

Presenting a Tone stimulus causes the rat to startle.But repeated presentations of this Tone results in progressively less startle responding.

Michael Davis: Studied Startle responding in the rat

1 2 3 4 5 6 7 8 9 10 11 Test05

101520253035404550

Dishabituation of the Startle Response in the Rat

Tone

Light - Tone

Stimulus Presentations ("Trials")

Mea

n St

artle

Res

pons

e

Non-associative Learning: Dishabituation


Is this due to Habituation, Sensory Adaptation, or Motor Fatigue?The Startle response recovers on a test trial when Light is presented just before the Tone.The Light stimulus dishabituates the rats startle response to Tone.This rules out sensory adaptation, as well as motor fatigue.

Michael Davis: Studied Startle responding in the rat

1 2 3 4 5 6 7 8 9 10 11 Test05

101520253035404550

Dishabituation of the Startle Response in the Rat

Tone

Light - Tone

Stimulus Presentations ("Trials")

Mea

n St

artle

Res

pons

e

Non-associative Learning: Short vs Long-Term Habituation


Tones presented once a day produces lasting long term habituation.Tones presented every 3 s produces deeper habituation.But this does not last until the next day – short term habituation (shows spontaneous recovery).Short ISI leads to good short term habituation, but long ISI leads to good long term habituation.

Leaton (1976) Experiment: Studied Startle responding in the rat

FIGURE 2.10Startle response of rats to a tone presented once a day in Phase 1, every 3 seconds in Phase 2, and once a day in Phase 3. (Based on “Long-Term Retention of the Habituation of Lick Suppression and Startle Response Produced by a Single Auditory Stimulus,” by R.N. Leaton, 1976, Journal of Experimental Psychology: Animal Behavior Processes, 2, pp. 248–259.)

Non-associative Learning: Sensitization

Sensitization – Increase in responsiveness to a stimulus when the stimulus is presented in an “arousing” context.

Tones presented in a relatively quite environment undergo habituation.Tones presented in a noisy environment undergoes sensitization.

Davis (1974) Experiment: Studied Startle responding in the rat

FIGURE 2.11Magnitude of the startle response of rats to successive presentations of a tone with a background noise of 60 or 80 dB. (Based on “Sensitization of the Rat Startle Response by Noise,” by M. Davis, 1974, Journal of Comparative and Physiological Psychology, 87, pp. 571–581.)


Sensitization – Increase in responsiveness to a stimulus when the stimulus is presented in an “arousing” context.

The Tone produces more startle responding when it follows a Shockthan when presented alone. The shock “potentiates” the startle response to the Toneprobably because it “arouses” the rat.

Davis: Studied Potentiated Startle responding in the rat

Experimental Procedure: Present Tone and measure startle responding Present Foot Shock, then Tone and measure startle responding


Habituation & Sensitization processes both can affect respondingat the same time.

Habituation in the human infant

Experimental Procedure: Present visual stimuli that vary in complexity and measureLooking time.



Looking time steadily decreases over trials as the infant habituates to the visual stimulus.Looking time first increases to the complex stimulus (sensitization) before it decreases (habituation).

Habituation in the human infant (Bashinski, Werner, & Rudy, 1985)

Experimental Procedure: Present visual stimuli that vary in complexity and measureLooking time.

Non-associative Learning: Dual Process Theory (Groves & Thompson, 1970)


S-R System: Habituation (processing of information from sensory to motor neurons)State System: Sensitization (general process that can influence many neural pathways)

Habituation should be stimulus specificSensitization should be stimulus general because it relies on a general “state” system

Non-associative Learning: Sensitization and Dishabituation Compared

Dishabituation & Sensitization both increase responding.Do they have a common underlying substrate, e.g., arousal?

Hypothesis: If they have a common underlying substrate, then whenever one occurs the other should also occur.

Marcus, Nolen, Rankin, & Carew (1988) Aplysia Study

• Gill Withdrawal Response habituates,Dishabituates, and sensitizes

• But they have different developmentalonsets

• That means dishabituation can occurwithout sensitization, so they must relyon different underlying substrates.




Whitlow (1975) Rabbit Study

• Vasoconstriction measured in response to different tone stimuli• Less responding to Event 2 on Same than Different trials indicates habituation

Trial Type Event 1Event 2

A – A Tone 1Tone 1

B – B Tone 2Tone 2

A – B Tone 1Tone 2

B – A Tone 2Tone 1

} Same Trials

} Different Trials





• Vasoconstriction measured in response to different tone stimuli• Less responding to Event 2 on Same than Different trials indicates habituation• More responding to Event 2 on Same + distractor than Same trials indicates dishabituation• Equal responding to Event 2 on Diff + distractor and Diff trials shows NO sensitization






A-x-A Tone 1 xTone 1

B-x-B Tone 2 xTone 2

A-x-B Tone 1 xTone 2

B-x-A Tone 2 xTone 1

} Same Trials

} Different Trials

} Same Trials + distractor

} Different Trials + distractor





• Results: Dishabituation can occur without Sensitization, indicating that• These two processes must rely on different underlying substrates






A-x-A Tone 1 xTone 1

B-x-B Tone 2 xTone 2

A-x-B Tone 1 xTone 2

B-x-A Tone 2 xTone 1

} Same Trials

} Different Trials

} Same Trials + distractor

} Different Trials + distractor

Non-associative Learning Involving Complex “Emotional” Stimuli

Solomon and Corbit (1974): Opponent Process Theory

Two opposing processes combine to produce an overall emotional effect, but one of theseprocesses (the opponent “b” process) change over time and the other (“a” process) does not.This leads to a decreased emotional response when stimulus occurs, but a lasting opponent response when the stimulus is removed.

Initial Exposure to Drug After Repeated Exposures to Drug

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Lecture 3: Non-associative Learning Learning, Psychology 3510 Spring, 2015 Professor Delamater