Definition of Learning:

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PSYCHOLOGY 2250 LEARNING
Definition of Learning In defining learning we
could refer simply to overt behavior. For ex.,
if I see you riding a bicycle I can assume that
youve learned that skill.
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Definition of Learning In defining learning we
could also refer to an internal state of
knowledge. For ex., you all know the 10
provinces (but I cant tell that just by looking
at you). So, behavior, or performance, is
important.
A good definition of learning should have both
components Overt behavior and internal state of
knowledge
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Learning as knowledge acquisition Animals learn
about stimuli in their environment Such stimuli
serve as signals for some important outcome for
ex., a particular odor could indicate that there
is food or a predator nearby. Animals also
learn about their own behavior A certain action
will produce a particular outcome for ex.,
running to escape from a predator Usually both
types of knowledge occur together. For ex., an
animal detects a certain odor that tells it a
predator is nearby and this odor evokes an escape
response, namely running, to avoid being attacked
by the predator.
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Learning is an inferred change in the organisms
mental state which results from experience and
which influences in a relatively permanent
fashion the organisms potential for subsequent
adaptive behavior.
Why is learning defined this way?
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Key components to definition of Learning

• Learning is inferred from performance.
• If there is no behavior to observe then we
  cant say for sure
• whether or not learning has occurred.
• 2. Learning involves a change in the mental
  state of an organism
• We cant see the neurological structures that
  underlie this
• mental state but, in theory, they must exist.
  Acquired knowledge
• must somehow be coded or represented in the
  brain.
• 3. Learning stems from experience
• This distinguishes learning from instinct,
  which refers to
• behaviors present at birth (i.e., imprinting in
  certain species of birds)

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Key components to definition of Learning
4. Learning is relatively permanent Learning
persists through time. This part of the
definition guards against mistaking a temporary
change in behavior, due to fatigue for example,
for real learning. 5. Learning is a change in
the potential to behave. An animal could
acquire knowledge and yet not perform in such a
way as to demonstrate that knowledge. The
organism could have the potential to behave even
though the behavior is not occurring.
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Other points Learning is assessed as a change
in behavior this could mean an increase or
decrease in behavior For ex., In presence of
light barpress for food In presence of tone
barpress for shock
What other things could influence behavior or
performance (other than learning)?
Fatigue temporary change so not
learning Motivation maze example learning
occurs but rat not motivated to
perform Maturation could also affect
performance but wouldnt call it learning (i.e.,
kid reaching cookie jar on top of counter)
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Domjans definition of Learning Learning is an
enduring change in the mechanisms of behavior
involving specific stimuli and/or responses that
results from prior experience with those or
similar stimuli and responses (p. 14) Emphasize
distinction between learning and
performance fatigue maturation motivation
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Habituation and Sensitization
Much of behavior occurs in response to stimuli,
that is, it is elicited, as opposed to
spontaneously produced.
The simplest form of elicited behavior is
reflexive behavior. -knee-jerk reflex -a
loud noise causes a startle response -puff of
air at the cornea makes the eye blink These are
all reflexes.
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A reflex involves 2 closely related
events -eliciting stimulus -corresponding
response The response and stimulus are
linked -presentation of the stimulus leads to
the response and the response rarely occurs in
the absence of the stimulus (i.e., you dont go
around kicking your leg out unless someone taps
you on the knee).
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The specificity of the relation between stimulus
and response is a consequence of the
organization of the nervous system. Simple
reflexes involve three neurons (1). Sensory
afferent to spinal cord (2). Motor efferent
to muscles (3). Interneuron sensory and motor
neurons often dont communicate directly. This
is known as the reflex arc (see Fig. 2.1)
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Other forms of elicited behavior
Two of the simplest and most common forms of
behavioral change are (1). Habituationdefined
as a progressive decrease in the vigor of an
elicited response that may occur with repeated
presentations of the eliciting stimulus. (2).
Sensitization defined as an increase in the
vigor of elicited behavior that may result from
repeated presentations of the eliciting
stimulus.
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Habituation and Sensitization occur in a wide
variety of response systems and are therefore
fundamental properties of behavior. Because
elicited behavior involves a very close
relationship between the eliciting stimulus and
the resulting response, people often think that
the behavior is invariant, or fixed. The common
assumption is that elicited behavior will occur
the same way every time the stimulus is
presented--not true! Behavior is plastic it
changes it does not occur the same way every
time.
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Procedures used to study Habituation and
Sensitization (examples of repeated stimulation)
1. Visual attention in human infants In babies,
visual cues elicit a looking response which can
be measured by how long an infant keeps her eye
on one object before shifting her gaze. A study
by Bashinski, Werner Rudy (1985)-described on
p. 37 of Domjan. 2. Startle response in rats A
study by Davis (1974)-described on p.38 of
Domjan The startle response is a defensive
response in many species (i.e., present loud
noise, you jump).
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In rats, we can measure startle in a stabilimeter
chamber
Rat jumps, chamber bounces and sensors detect the
amount of movement
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Davis investigated startle in rats by presenting
a loud tone. 2 groups of rats -each received
100 tones at 30 sec intervals (110-dB) -noise
generator that provided background noise Group
1 Group 2 soft background noise loud
background noise (60-dB) (80-dB not as
intense as the tone)
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Results

• Repeated presentations of the tone did not always
  elicit the
• same response
• With soft background noise, repetitions of the
  tone resulted in
• weaker startle response (i.e., habituation)
• In contrast, when the background noise was
  louder, repetitions
• of the tone resulted in a bigger startle response
  (i.e., sensitization)
• With the same tone, see 2 different patterns
  depending on other
• circumstances.

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These 2 studies show that increases or decreases
in responding can occur with repeated
presentations of stimuli Decreases in
responsiveness by repeated stimulation
Habituation Increases in responsiveness by
repeated stimulation Sensitization
Lots of everyday example grandfather clocks,
trains
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Habituation is a decline in the response that was
initially elicited by a stimulus However,
habituation is not the only effect that can
produce a decrease in response
Must distinguish habituation from response
fatigue sensory adaptation muscles become
incapacitated sense organs become by
fatigue temporarily insensitive
(i.e.,wont respond to visual cues if youre
temporarily blinded by a bright light)
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Habituation is stimulus-specific -if you present
a different stimulus, the animal will make the
response -shows that they are not fatigued if
they can still make the response -rules out
response fatigue Habituation is
response-specific -an animal may stop responding
to a stimulus in one aspect of its behavior but
continue to respond in other ways -e.g.,
orienting response to mothers voice may
habituate but still listen to what she is
saying -rules out sensory adaptation
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Dual-Process Theory
Habituation and Sensitization effects are
changes in behavior or performance But what
factors are responsible for such changes? The
Dual-Process Theory (Groves Thompson, 1970)
was an attempt to get at this issue The DPT
assumes that different types of underlying
neural processes are responsible for increases
and decreases in response to stimuli.
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The habituation process produces decreases in
responding The sensitization process produces
increases in responding
These 2 processes are not mutually exclusive
they may be activated at the same time. The
behavioral outcome depends on which process is
stronger.
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Net effect summation of habituation and
sensitization processes (not to be confused with
habituation and sensitization effects) process
underlying neural process/mechanism effect
behavior (what you actually observe) if you
observe habituation, might still have
sensitization process activated, but its not
very strong
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Groves Thompson suggested that habituation and
sensitization processes occur in different parts
of the nervous system. Habituation processes are
assumed to occur in the S-R system -the shortest
neural path connecting the stimulus and the
response (sense organs and muscles) -similar to
the reflex arc Each presentation of the stimulus
activates the S-R system and causes some build
up of habituation
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Sensitization processes are assumed to occur in
the state system -this system consists of other
parts of the nervous system that determine the
organisms general level of responsiveness or
readiness to respond -only arousing events
activate state system not necessarily activated
with every stimulus presentation.
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The state system determines the animals
readiness to respond, whereas the S-R system
enables the animal to make the specific response
that is elicited by the particular
stimulus Changes in behavior that occur with
repeated presentations of a stimulus reflect the
combined actions of the S-R and state systems
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Back to Startle Response in rats When the rats
were tested with the quiet background
noise, there was little to arouse them the
state system was probably not activated -
repeated presentations of the tone activated only
the S-R system and the result was habituation of
the startle response When the rats were tested
with the loud background noise, the state system
was activated and the result was an increase in
the startle response to the same tone.
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The State and S-R systems are activated
differently by repeated presentations of a
stimulus The S-R system is activated every time
a stimulus elicits a response -it is the neural
circuit that conducts impulses from
sensory input to response output The state
system only becomes involved in special
circumstances -e.g., when stimulus is intense
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Characteristics of Habituation and
Sensitization Time course Sensitization is
usually temporary -sensitization can last for up
to a week but not generally a long-term effect.
-with a stronger stimulus, the effects last
longer. Habituation can be short-term or
long-term, depending on presentation and interval
between stimuli.
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Short-term habituation -rapid presentations of
a stimulus with a short interval between
presentations -results in habituation quickly
but see spontaneous recovery -the degree of
spontaneous recovery depends on length of rest
interval. Long-term habituation -one stimulus
presentation a day -see more long-term
effects -see less spontaneous recovery
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Leaton, 1976 see page 46 of Domjan
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Stimulus specificity Habituation is
stimulus-specific -if you change the stimulus,
see recovery of the response Sensitization is
not highly stimulus-specific -if an animal is
aroused, it is usually aroused to a variety of
cues
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Effects of strong extraneous stimuli If you
change the nature of the eliciting stimulus you
see recovery of the habituated response. Can
also see recovery of the response if the animal
is given a rest period spontaneous
recovery. The response can also be restored by
presenting a strong stimulus this is called
dishabituation. Dishabituation refers to
recovery of the response to the habituated
stimulus following presentation of a different,
novel stimulus.
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