Thursday, April 30, 2020

Outline of Pavlov's lectures on Conditioned Reflexes 1927

What follows is my outline for Pavlov's Lectures Conditioned Reflexes (1927). Bracketed numbers refer to page numbers according Anrep's translation as found in the Classics in the History of Psychology page. The rest are my sparce notes. 
 

Lecture I

 

Recent physiological investigations

Investigative options

Through (then actual) psychology

Brand-new path of physiology stemming by the reflex as described by Descartes

A necessary reaction to an external stimulus through a definite nervous path

Objective and experimental

Thorndike

Pavlov's own frustrations in subjective methods

25 years of investigations and systematization (at the time of the lectures) with collaborators

Description of reflexes in general

These are for the survival of the organism (through adaptability)

Inhibitory and excitatory

Instincts

Chains of reflexes

Identification of reflexes [12]

Example of freedom reflex

Investigatory reflex

Dynamic balance of reflexes in the organism

Signalization

 

Lecture II

 

Methodology

Choice of secretory reflex

Hookup

Isolation from other stimuli [20]

Defense of isolation

 

Demonstration #1 [22]

Plain vanilla with metronome

 

Demonstration #2 [22]

Conditioned reflex. Signalization through sight . Food, conditioned itself

 

Demonstration #3 [23]

Food as an unconditional stimulus

 

Nomenclature of unconditioned and conditioned reflexes

Conditioning as learning

 

Conditions for successful conditioning [26, 392]

  1. It must overlap in time with the unconditioned stimulus;

The conditioned stimulus has to have some lead time;

The reverse doesn't generate a bond

  1. The organism has to be alert;

And free from any other nervous activity (as that arising from competing stimuli)

  1. A good state of health;
  2. The stimulus has to be mild or not overbearing.

 

Transformation of an unconditioned reflex into a conditioned one

 

Threshold of stimulus intensity

 

Lecture III

 

Second order conditioning

Third order conditioning found to be impossible

 

Conditioning through rituals [35]

Demonstration #4 [36]

Speculation on nervous connections

 

Characteristics of stimuli

Individual fluctuations in internal or external environment of the organism may, singly or collectively, acquire the properties of a conditioned stimulus

Changes

Interruption

Trace conditioned reflex

Time lapse

 

Inhibition [43]

Types

Direct/internal

Indirect/external

Description of external stimuli disrupting the conditioning of the dog [44]

Lasting effects

Old, established reflexes are more difficult to inhibit

Strength or unusualness of the stimulus has a proportional effect [46] !?

However, if not reinforced, they eventually lose their inhibitory powers !? Hence, they may be termed temporary inhibitory stimuli

Permanent external inhibition

 

Lecture IV

 

Internal inhibition

Develops progressively, often with difficulty, as opposed to external inhibition

 

Extinction (primary)

Weakening of the conditioned reflex by repeated application of the conditioned stimulus without reinforcement

Demonstration #5a

Fluctuations in the curve of extinction

External influences

Internal

Rate of extinction [51]

Peculiarities of each organism

Strength of previous conditioning

Number of trials

Intensity of the unconditioned reflex

Length of pause between successive repetitions

Secondary extinction

When primary extinction is happeningother conditioned reflexes are also affected notwithstanding if these are:

Homogeneous conditioned reflexes

Based on the same unconditioned reflex

Heterogeneous conditioned reflexes

On a different unconditioned reflex

After several extinctions even the unconditioned reflex might weaken [54]

The permanency of the secondary reflex also depends on

Its own reinforcement and extinction

If it's weaker than the primary reflex acted upon

When the stimulus is compound, the individual stimuli also suffer from secondary extinction

Similarly, the stronger the stimulus, the more effect it will have on the weaker and viceversa

Recovery

Extinction beyond zero [58]

Measured by its effects on the secondary reflex

Spontaneous recovery

Demonstration #5b

Recovery by a few pairings

Extinction is regarded (by Pavlov) as a special case of inhibition and thus it cannot be completely destroyed. (Hence, nervous connections are rendered latent and subject to reestablishment)

 

Deviations in the curve of extinction

 

Temporary restoration of the condition reflects is regarded as a dis-inhibition [66] or inhibition of a inhibition

 

Lecture V

 

Internal inhibition (continued)

Combinations of stimuli

Conditioned inhibition/differential inhibition

An unreinforced combination will render an otherwise positive stimulus inactive

Temporal considerations

Overlap of a few seconds in the stimuli is of the essence for inhibition

A clear temporal separation of the stimuli renders the additional one as positive (of the second order) rather than inhibitory (provided it is not very intense, in which case it would work as an external inhibition)

Curve behavior [72]

Other factors

Character of the individual

Intensity of the stimulus

First establishment of an inhibitory process or a succeeding one

Details

Summation or repetition of an inhibitory process [79]

Shortening of its effects

Dis-inhibition [82]

By the introduction of just another external stimuli the inhibition is partially lifted

 

Lecture VI

 

Internal inhibition (continued)

Delay

Interval between stimulus and reinforcement of the unconditioned reflex

Simultaneous

Delayed

Establishment

By retarding a simultaneous reflex gradually

By jumping from a simultaneous reflects to a delayed one

There's an initial disappearance of the reflex, however, it gradually strengthens with enough trials and moves into intermediate position between the stimulus and the reinforcement

It is difficult to establish a delayed reflex without a previous application of a simultaneous regime

Intervening factors

Character of the individual

Type of conditioned stimulus used [90]

Trials during the preliminary stage

Whether the stimulus is continued or intermittent

Nature of the delay inhibition

Initially strong and not a gradual summation of the excitatory processes nor fatigue

Other stimuli acting on the delay phase

These may disrupt or not the inhibition depending on their type (strength)[94] or their repetition [98]

Initial excitatory behavior versus posterior inhibitory in the delay phase from one stimulus [103]

A compound stimulus is formed with the lapse of time experienced

Latent period

Brief recapitulation [106]

Experimental extinction

Conditioned inhibition

Inhibition of delay

 

Second order inhibition

 

Lecture VII

 

Reflex mechanisms

Analyzing mechanism

By which it selects out of the whole complexity of the environment those units which are of significance

Synthesizing mechanism

By which individual units can be integrated into an excitatory complex

 

Previous investigations of the analyzing mechanism

The superiority of the scope of the conditioned reflex

Contrasts

Generalization

Initially, all the characteristics of the environment serve as a generalized stimulus and after some trials, the relevant stimulus from it come to the foreground, while those that are not, fall back [115]

Not based on dis-inhibition

Establishment of differentiations

Through repeated reinforcement

Not as effective if at all

By contrast [118, 122]

First, establish a reflex;

Present a similar, though contrasting in some aspect, stimuli without reinforcement;

Work from there to even finer contrasts

 

The non-reinforced stimuli lose their excitatory processes through inhibition […, 125]

Though not without fluctuations [120]

Can work with either positive or negative conditioned stimuli

Differential inhibition is the fourth type of internal inhibition

Disturbances

Intensity of the stimulus

Intensity of the unconditioned reflex

Excitability

 

Lecture VIII

 

Instrumentation recap

 

Sense (analyzers) sensibility

Visual

Auditory [134]

Tone, pitch, rhythm

Instrument limits

Tactile [137]

Smell

Taste

Nutritive substances

Rejectable substances

Synthesis [141]

Compound stimuli

Overshadowing of different stimuli in type

Cutaneous is stronger than auditory; stronger than auditory; stronger than visual

Nevertheless, the weaker stimulus is necessary for the production of the conditioned reflects a when it has been compounded with a stronger one. Also on the weaker element can bring down a compound stimulus if it is not singly reinforced (inhibition).

If single stimuli already have served on conditioning, there is no overshadowing when compounded [IX]

Successive stimuli [145]

With same or different analyzers

Modifications of patterns

A set pattern can be differentiated from unreinforced ones although this, takes time

Individual stimuli lose their excitatory properties

Elementary and higher forms of analysis and synthesis [148]

Sense limits

Hemispheres

 

Lecture IX

 

Irradiation and concentration

Internal inhibition initiated in a single definite point of an analyzer, rapidly irradiates over the whole analyzer, after which it is slowly concentrated upon its initial point. This can be traced.

 

Supposition that there is a correspondence between the analyzers and that of the cortex in regards of neighboring areas [154, 214]

 

Investigation of the nature of the phenomena [156]

Places of secondary and primary extinction

 

Auditory specific

 

Lecture X

 

Secondary inhibition of the other analyzers

Inhibition initiated in one analyzer reveals itself in other analyzers as well in the form of inhibitory aftereffect

Dependent on inhibition strength

Nonetheless the effect is weaker than in the primary analyzer

Variations

Experimental methodology [171]

Difficulties [175]

 

Aftereffects of the excitatory processes

 

Generalization of any recently established conditioned stimulus [185]

 

Lecture XI

 

Mutual induction

 

Positive induction

Inhibition leading to increased excitation

Following the extinction in some other area of stimulus within the analyzer

Not the form of dis-inhibition [190]

Depends on

The intensity of inhibition

Coarseness (or just how fine) of differentiation [194]

Coarser differentiation loses its induction when followed by finer training

Represents a temporary, phasic phenomenon in the establishment of inhibition

There are exceptions

Negative induction [196]

Excitation leading to increased inhibition

Difficulties in its investigation

Lecture XII

 

Interaction of irradiation and concentration with induction

These processes interact with one another

Sensitivity [208]

Of single non-reinforcement

Delicacy

Small influences over extended periods

Undulation (waves) in time and distribution of inhibition

Correspondence [214]

 

Positive induction applied to a definite place limits the spread of the inhibitory process

 

The interaction between expectation and mediation is determined either by the face of establishing new relations in the cortex or by the type of nervous system in different animals

 

Lecture XIII

 

The cortex as a mosaic of functions

Some cells respond to excitation while others to inhibition in a localized manner

Suggested problems (unresolved)

Functional demarcation

Its mechanism

Examples

Variability and stability [227]

Dynamic system [232]

 

Lecture XIV

 

Second kind of inhibition: inhibition in the cortex

Under the influence of conditioned stimuli that cortex sooner or later (sometimes very slowly) develops inhibition. This happens in a progressive manner

Frequent repetitions accelerates this process [237, 242]

This is attributed to the sensibility of the cortical elements which become functionally exhausted [244]

In other words, it is a protective mechanism

Countermeasures

Main:

Shortening of the reinforcement delay

Avoiding many repetitions in one session

Interruption of the trials

Subsidiary:

Increase in the strength of the conditioned stimulus

Increase of the number of the conditioned stimuli (positive induction)

Increasing the strength of the unconditioned stimulus

 

When the inhibition has taken hold even the conditioned stimulus fails

A new conditioned stimulus restores the subject [239-241]

 

Lecture XV

 

A general spreading of this inhibition is possible: sleep or internal inhibition

 

Development of inhibitions

Prolonged action of a conditioned stimulus

Perhaps even more so with extinction

In differentiation it is clearer

Happens also with delayed reflexes

 

Starts with drowsiness and develops into deep sleep

The unconditioned stimulus even loses efficacy

With non-reinforcement

Reinforcement delays the progression of the secondary inhibition

 

Powerful stimuli (such as electric shocks) can also be found to develop internal and secondary inhibition

 

Some analyzers (senses) lend themselves more readily to inhibitions than others

 

Internal inhibition is explained as a scattered sleep [253] and functional fatigue [259]

 

Avoidance tactics [254]

The addition of other stimuli [255]

Even add to the sleep [258]

Monotonous stimuli on humans

 

Surgical investigations [259]

 

From sleep to inhibition [260]

With delays

Summation of inhibitions (cf. 256)

 

Excitation preceding drowsiness [263]

 

Final considerations

 

Lecture XVI

 

Transitional stages into sleep

Partial; localized sleep

Alert posture but unresponsive

Complete inhibition in the cortex; motor centers still free from inhibition

Factors

Time   

Subject's previous conditioning history

Numerous applications

Nature of the neutral stimuli

Weak and/or prolonged

Strong and short

May cause the spread of partial division into other areas of the cortex: "animal hypnotism" [269,312]

Catalepsy

Variation of intensity in compound stimuli as a means of comparing them [269]

What can happen over many days (pathological) can be replicated in a few minutes in the transition to sleep

Paradoxical phase [271]

Strong stimuli do not have an effect while weak ones have a disproportionate one

Equalization phase

All the stimuli become equal in their effect

Intermediate (unnamed) phase

Medium strength stimuli have the greater effect

Return to normal

 

Relation to induction [276]

 

Narcotics [278]

Other transition controls [280]

 

No definite order in the phases can be established

 

Lecture XVII

 

Pathological disturbances arising from function

 

Dependence on types

Equal influences do not have the same effects […, 299]

 

Types

Sanguine

Vivacious, but most likely to fall into drowsiness in the absence of stimuli. Predisposition to excitation […, 293]

Melancholic

Fraidy, but more apt to yield regular results under conditioning.  Predisposition to inhibition (Cf. Introverts).

Intermediate types [288]

Phlegmatic

Choleric

more

 

Conflict between excitation and inhibition [292]

 

Disturbances

There is a breakdown of conditioned reflexes [290, ]. Acute neurosis

Over-generalization

Over-differentiation

 

Treatment

Rest [290,]

Stepping back and starting afresh [291, 319]

Chemical compounds [299]

Companionship [296]

Other stimuli [318]

 

Lecture XVIII

 

Transition from inhibition to excitation

Possibilities [311]

From a single point to the whole cortex

As injurious agent upon the cortex

 

Congenital weaknesses [312]

Definite conditions bring forth abnormalities

Types of stimuli according to intensity

The case of Petrograd 1924

Unusually strong stimulus

Breakdown of conditioned reflexes

Their restoration. Neurotic sequels (PTSD?)

Companionship

Constitutions predisposed to inhibition become even more susceptible to it. Chronic pathological state [, 397]

 

Lecture XIX

 

Physical disturbances or interventions

Methodology and difficulties

Experimenter reflexes are the most likely to disappear well inherent, natural, reflexes are the first to resurface

Usually the greater the lesion, the greater it takes to recover

Recovered reflexes are often stronger [324] while inhibitions weaker

Complications [325]

Peculiar symptoms

Extirpation the whole cortex [328]

Simple reflex machine. Unconditionable

Acoustic analyzer centers [330]

 

Lecture XX

 

Visual analyser

Tactile analyser

Motor analyser

 

Lecture XXI

 

Activity after lesions

Example of reestablishment of conditioned reflexes [374]

 

Lecture XXII

 

Investigatory viewpoints

The one taken: the laws governing a complex system founded on the processes of excitation and inhibition

Determination and tabulation of different phases of the cortical activity

Absence or presence of inhibition or excitation

Their conditions

Their interrelations

 

Difficulties encountered [378]

Exquisiteness and complexity of the system

Interpretations

Observations

Reassessment of the old points of view

Secondary conditions [383]

Stimuli intensity

 

Way forward

Reducing the mass of various separate observations to terms of a progressive diminishing number of general more fundamental units [387]

 

Unknowns

Mechanism of dis-inhibition [390]

Necessary elements of conditioning

 

 

Lecture XXIII

 

Results in application to man

Caveats

Foundations

Habits identified as a chain of conditioned reflexes

Graduality in acquisition

Interruptions as disruptions of performance

Other similarities

Monotonous stimuli inducing drowsiness

Alertness and sleep

Pathological cases

Nervous and psychic disturbances

Violent changes in life, powerful stimuli…

(Petrograd 1924)

Cortex injury

Some individuals remain unaffected [397]

Identification with neurasthenia and hysteria [398]

Sleep disorders

Therapeutic measures [401]

Borderline states [404]

Hypnotic states

Automaticity

The conscious and the unconscious [410]

Synthesis

Final words

Much to explore and to systematize there still is

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