Download Intro to course and What is learning?

A Brief History of
Learning Theory
What is learning?
 Definition of learning:
 Dictionary definition: To gain knowledge, comprehension, or mastery
through experience or study.
 Psychology definition: A relatively permanent change in behavioral
potentiality that is not due to maturation or typical physical growth, but is
due to (reinforced) practice or experience.
 Which is better description? Why?
 Behavioral potentiality:
 Obviously, must be measurable behavior change
 But when must behavior occur?
Immediately after learning? Within 1 year?
 Issue of learning vs. performance- is this an important distinction?
Must learning result in behavioral change?
 Define permanent and define behavior
 Instinct- may emerge at different time periods
 Importance of critical periods
 Walking- learned or instinct?
 Memory issues
 How much cognition is necessary? Can bacteria learn?
 Definition of behavior: If a dead man can’t do it…….
Definitions of learning?
 Learning: experience, practice or performance?
 Reflexes: Are they important for learning?
 Instincts: imprinting and critical periods
 Practice vs. Experience
 Performance as an issue
 Modified definition of learning: learning is
 a relatively permanent change in behavior or behavioral
potentiality
 that results from experience and
 cannot be attributed to temporary body states (e.g., fatigue,
altered states of consciousness)
Definitions of learning?
 “Types” of learning:
 Classical conditioning
 Instrumental or operant
 Social learning
 Latent learning
 Cognition
 Learning = survival or our strongest instinct
Early history of learning theory
 Plato:
 Socrates was his teacher, Aristotle was his student
 Nativism: Knowledge is
 inherited and a natural component of the human mind
 a matter of recollection, and not of learning, observation, or study
 not empirical, and that it comes from divine insight.
 Every object in physical world has corresponding abstract idea or
form that causes it
 We experience a “tree” but not “treeness”
 Rationalism: One gains knowledge by reflecting on the
contents of one’s mind:
 The mind’s eye: gaining insight
 Turn inward to ponder what is innately available
 Believes in a soul
 Reminiscence: recollection of our experience that our
soul had in heaven which is beyond heaven
 Plato’s Cave analogy
Early history of Learning Theory
 Aristotle: Plato’s student
 Empiricism: Knowledge derived from sensory experiences;
was NOT inherited
 Rationalism: Mind is actively involved in attainment of
knowledge- must integrate sensory experiences with own
knowledge
 Nativism: Mind must actively ponder the information
provided by the senses to discover the knowledge contained
within the information
 Described in detail the human senses
 Laws of association: Experience or recall of one object will
elicit recall of things
 Similar to that object (similarity)
 Opposite that object (contrast)
 That were once originally experienced with that object
(contiguity)
Early History of Learning Theories
 Rene DesCartes: 1596-1650
 Gentleman Soldier
 Knowledge is innate
 Mind versus body problem
 Separate laws govern each
 Only humans have souls (mind)
 Body has “animal spirits”
 Two do influence one another
 Reflex arc:
 Why important? Showed
mechanisms of body
Early History of Learning Theories
 The British Empiricist (including, but not limited to):
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Thomas Hobbes (1651)
John Locke (1690)
James Mill (1829)
John Stuart Mill (1843)
 Source of all knowledge was sensory experience
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People are born knowing nothing
Gradually we gather knowledge via experience
Tabula rasa or blank slate idea (Locke)
Opposite of Kant's Nativism
 Embraced phenomenalism, rational empiricism, pragmatism
 Extreme position = Empiricist position
Set hypotheses for Associationism:
 Empiricists first outlined:
 How old concepts become associated in memory
 How new concepts are formed
 Hypothesized a direct correspondence between experience and memory
 Proposed a 1:1 correspondence between simple sensations and
simple ideas
 experience = sensations
 memory = ideas
 idea = form of a sensation
 Complex ideas: James Mill
 2 or more simple sensations repeatedly presented together,
product of union may be complex idea
 once complex idea formed, can also be evoked by process of
association from simple sensations or ideas
Set hypotheses for Associationism:
 Thomas Browne (1605-1682): Secondary Principles of
association:
 Attempt to make Mills theory more complete
 No data yet…just assumptions and hypotheses
 Several hypotheses
 The length of time 2 sentences coexist determines the strength of association
 The liveliness or vividness of sensations also affects strength of association
 The frequency of pairings: more frequent = stronger association
 Recency of pairings: more recent = stronger association
 Freedom from other strong associations
 Constitutional differences
 current emotional states
 momentary state of body
 individual prior habits
Variations on Associationism
 John Stuart Mill: (1806-1873) Complex associations
 Most important contribution: The whole is different from the sum of its parts
 (Wait, didn’t the Gestaltists say this!?!!?)
 George Berkely: (1685-1753): We can experience only
secondary qualities
 Nothing exists unless it is percevied
 To be is to be perceived
 David Hume: (1711-1776): We know nothing for sure about
ideas
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We can be sure of nothing
Mind = stream of ideas, memories, imaginings, associations, feelings
We experience empirical world only indirectly through our own ideas
“Habitual order of ideas” give rise to general concepts like causation
Continentalist view:
 Back to knowledge = innate
 French: Jean-Jacques Rousseau: 1712-1778
 Wrote Emile, or On Education
 Believed in stages of human development
 Critical for French revolution and our own formation of the U.S.
 German: Immanual Kant (1724-1804): Innate categories of
thought:
 Careful analysis of our experiences reveals certain categories of thought
 Categories included: Causality, unity, totality, reality, existence, necessity,
reciprocity, (and 5 more)
 Mental faculties superimposed over our sensory experiences, providing them
with structure and meaning
Other Historical influences
 Thomas Reid: Naïve Realism (1710-1796)
 What we perceive = naïve realism
 Mind has powers of its own which strongly influence how we
perceive world
 Faculty of psychology: mixture of nativism, rationalism,
empiricism
 Franz Joseph Gall: Role of Physiology (1758-1828)
 Faculties housed in specific brain locations
 Before this assumed the heart held all important information!
 Phrenology: two lasting effects
 Led to emerging neuroscience research
 Belief that faculties become stronger with practice- the mental
muscle
Other Historical influences
 Three important scientists/philosophers make an important
impact on how we approach learning theory today:
 Charles Darwin
 Karl Marx
 Sigmund Freud
 What? Why those 3?
 Darwin: suggests we have common ways in which our bodies and our learning
operate.
 Karl Marx: suggested that people were equal
 Royalty or upper class were not “smarter”
 People were people
 Freud: suggested that our early experiences were critical for forming our later
experiences
Evolution’s influence on Psychology
 Charles Darwin (1809-1882): Biological and Behavioral Evolution
 1859 book: Origin of Species
 Argued species originated from other species and eventually become distinct
from their ancestors
 Thus: many animals have common, but very distant, ancestors
 Evidence from domesticated plants and animals
 Breeding programs; hybrid plants, purebred dogs, cats, etc.
 Great similarity in body parts across animals: paws, arms, etc.
 Embryology: most embryos look HIGHLY similar
 Fossil records:
First “Psychological” Research in Learning
 Hermann Ebbinghaus (1850-1909)
 First empirical test of associationist hypotheses
 used nonsense syllables to avoid prior associations
 served as own subject
 measured length of time took to learn, amount remembered after some passage of
time
 Results: Several major findings
 List length: the greater the list- the greater the time to learn PER item
 Effects of repetition: over-learning and mastery
 Effects of time on remembering and forgetting:
 discovered forgetting curve
 serial position curve
 Role of contiguity: more contiguity = greater learning
 Backwards associations
 Provided DATA for associationist principles
Behaviorism
It’s not your Mother’s Skinner!
American Behaviorism
 E.L. Thorndike: (1874-1949): Studied animal behavior and how animals
learned to react to consequences.
 Did not have access to Pavlov’s work
 John B. Watson (1878-1958) founded the school of psychology known as
behaviorism.
 Psychology should be a science of behavior only.
 Believed that environment molds behavior
 By 1920s, behaviorism became dominant force in American psychology
 B.F. Skinner (1904-1990): Blended Watson and Thorndike’s approaches
 Heavily influenced by Edwin Guthrie, Clark Hull, Edward Tolman
 Studied how behavior is shaped by rewards and punishments
 Principles of learning apply to animals and humans alike
 Thordike(s) and Guthrie also had profound effects on learning/education
Thorndike: began to look at
Instrumental Behavior
 Son of a Methodist Minister
 Graduate of Harvard, student of and highly influenced by
William James
 Professor at Columbia University, influential in starting
the psych program there
 Animal Intelligence (1911)
 Rated the intelligence of various animals
 One of the first contemporary psychologists to examine how
animals learned
 Focus on trial and error learning
 Did NOT have access to Pavlov’s work.
 Experimented with cats in a puzzle box
 Put cats in the box
 Cats had to figure out how to pull/push/move lever to get out;
when out got reward
 The cats got faster and faster with each trial
Thorndike: Law of Efect
 Law of Effect emerged from this
research:
 When a response is followed by a
satisfying state of affairs, that
response will increase in frequency.
 When a response is followed by a
non-satisfying state of affairs, that
response will decrease in frequency
Also studied conditioned reflex
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University of Chicago PhD. With John Dewey, who’s ideas he rejected
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STRICT behaviorism: Everything is learned, no affect from
biology
 Started out as an educator; developed his theory of behaviorism
 Felt that any research should use ONLY observable events: rejecting
structualism and gestalt schools
 Rejected traditional study of “thoughts” and “feelings”
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Had access to Pavlov’s work (unlike E.L. Thorndike)
 But felt that this Classical Conditioning could be used in other ways
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Most famous work: Little Albert Study
 Demonstrated classical conditioning of the emotion of fear
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But: got in hot water:
 Behavioral “eugenics”: believed if he could control environmental variables,
could control outcome of any human
 Had an affair with his grad student
 Ethics of Little Albert study
Pavlov’s Contribution
 Ivan Pavlov was
 Son of a Russian Orthodox priest
 Russian physiologist: Studied salivation
 1901: discovered and wrote about classical conditioning
 Found that his dogs reacted to both his presence and the time
of day for feeding/experimentation
 Wanted a way to study conditioned reflexes systematically
 Researched this:
 Measured amount of salivation during baseline:
 Present food to dogs
 Measure slobber
 Then added a predictive stimulus: a Bell
 Presented the BellFood
 Measured slobber to see if dogs would begin to slobber to the bell
Classical Conditioning
 Remember the Reflex Arc
 Reflex is elicited by a stimulus
 At first, must directly stimulate this reflex
 But, a predictive stimulus can elict the reflex after many pairing
 Classical conditioning is learning to react to a predictive
stimulus
 The predictive stimulus predicts the eliciting stimulus
 The eliciting stimulus elicits the reflex
 Learn to anticipate the reflex behavior so that it occurs to the
predictive stimulus is productive and potentially lifesaving!
Classical Conditioning Procedure
CS  US  UR
Bell
Food
CR
Slobber with less
Digestive enzymes
Slobber
Why so important to American
Behaviorism?
 In the 1930s and 1940s:
 Physics is “the” science
 Move towards laws and strict scientific notation of events and
variables
 Use of equations to describe physical phenomenon
 Pavlov USED strict notation
 Used clear labels to identify variables
 Strict notation system for denoting behavioral events
 Very “scientific”
 Thorndike had not access to Pavlov’s work; Watson had some
contact, Skinner was a student of Pavlov’s writings
Burris Frederick Skinner
1904-1990
Skinner’s influence on modern Behaviorism
 Skinner studied at Harvard
 Started out as English major, but was unsuccessful
 Taught at Minnesota and Indiana University; founded a true Psych
department at Indiana just after Harvard started theirs
 Lifelong friend of Fred Simmons Keller
 Keller was developing concepts of operant conditioning at Harvard
with more of an applied/educational focus
 Also Nate Schoenfield at Columbia
 Formed the first “group” of behaviorists
Skinner’s influence on modern Behaviorism
 Behavior of Organisms (1948)
 Laid out tenants of his operant or instrumental conditioning
 Focus on contingencies and consequences
 Again, avoided non-observable events
 but did not say they didn’t exist, just that they needed to be operationalized as
observable to be studied
 For more information see his books On Verbal Behavior or
Beyond Freedom and Dignity- very relevant for today!
 Utopian society:Walden Two (1948)
Several kinds of behaviorism:
 Methodological Behaviorism:
 Behaviors as such can be described scientifically without recourse
either to internal physiological events or to hypothetical constructs
such as thoughts and beliefs
 Watson was a methodological behaviorist:
 Objective study of behavior;
 No mental life or internal states- only internal behavior
 Thought is merely covert speech.
Several kinds of behaviorism:
 Radical behaviorism: Skinner’s behaviorism
 Expands behavioral principles to processes within the organism
 In contrast to methodological behaviorism it is not mechanistic or
reductionistic;
 Hypothetical (mentalistic) internal states NOT considered causes of
behavior
 Phenomena must be observable at least to the individual experiencing
them.
 Teleological Behaviorism:
 Post-Skinnerian,
 Purposive behaviorism
 Highly related to microeconomics
 Focuses on objective observation as opposed to cognitive processes.
Several kinds of behaviorism:
 Theoretical Behaviorism:
 Post-Skinnerian,
 Accepts observable internal states as long as can measure with modern technology
 Dynamic, but eclectic in choice of theoretical structures, emphasizes parsimony.
 Biological Behaviorism:
 Post-Skinnerian,
 Centered on perceptual and motor modules of behavior
 Theory of behavior systems.
 Psychological Behaviorism
 Centers on human behavior.
 Many applied techniques such as time-out, token-reinforcement
 Behavioral explanations of child development, education, abnormal, and clinical
areas
Commonalities among “Behaviorisms”
 Emphasis on behavior
 Classical conditioning: S-R psychology
 Relatively passive
 Organism does not have to make a response in order for the
consequences to occur
 Responses are ELICITED
 Operant conditioning: R-S psychology
 Emphasis on organism operating on environment
 Behavior is the result of a contingency on that response: If/Then
 Operant conditioning: responses are EMITTED
Radical Behaviorism
 Science of behavior = natural science
 Assumptions include:
 Animal behavior be studied profitably and compared with
human behavior
 Strong emphasis on the environment as cause of behavior
 Strong tendency to operationalize behavior
 Emphasis on operant conditioning,
 Use of jargon: Make definitions specific and clear
 Tendency to apply concepts of reinforcement/punishment
to philosophy and daily life
 Emphasis on private experience.
Radical Behaviorism
 Embraces genetic and biological aspects of the organism
 Assumes that behavior evolves as part of the nature of the
organism,
 Study of behavior is a distinct field of study, but
 Is compatible with biological and evolutionary approaches to
psychology
 Is a proper part of biology
 Radical behaviorism does not involve the claim that
organisms are tabula rasa, without genetic or physiological
endowment.
Radical Behaviorism
 Skinner's work focused on operant conditioning:
 Again, R-S, not S-R
 Emphasized schedule of reinforcement as IV; rate of responding as DV
 Emphasis on outcomes and response rates that include areas of study such as
decision making, choice, self-control
 Myth that organisms are passive receivers of conditioning: rather:
 Operant behavior is titled operant because it operates on the environment
 Operant behavior is emitted, not elicited:
 Animals act on the environment and the environment acts back on them, or
 The consequence of a behavior can itself be a stimulus;
Radical Behaviorism
 But isn’t radical behaviorism = logical positivism.
 Skinnerians maintain that Skinner was not a logical positivist and
recognized the importance of thought as behavior.
 Skinner himself noted this in his book About Behaviorism.
 Philosophically, radical behaviorism is most similar philosophically to
American pragmatism.
 Study behavior because it is observable, predictable, orderly and
functional.
Skinner’s Behaviorism: 1966 article
 What is the important event or datum to study in the science of
behavior?
o The probability of a given behavior to occur at a given time
 When, where, under what circumstances
 Experimental analysis deals with probability of
responding in terms of frequency or rate of responding.
o Specify topography of response in such a way that separate instances
of an operant can be counted.
o The specification is usually made with the help of an apparatusthe"operandum"-some device that allows the response to be counted
Skinner’s Behaviorism: 1966 article
 Responses defined so that they show a uniformity as the
organism moves about in a framework defined by its
own anatomy and the immediate environment.
o Record changes in rate of response and reinforcer
o Examine under different environmental situations
o Examine under different rules for delivery of reinforcer
o Skinner used “cumulative recorder” , we use computers
o Also examine interresponse times, interreinforcer times, slopes, etc.
o For example: different patterns of responses under 4 basic
reinforcement schedules
The Ind.Variable according to Skinner:
 Task of EAB: discover all the variables of which probability of a
response is a function
 These might include:
 The stimulus: both as an antecedent and as a consequence
 Discriminative stimuli: the stimulus control assigned to a particular stimulus
 Asks how the organism perceives the stimulus, not how the experimenter designed the stimulus to
be seen
 Examine via generalization and discrimination gradients
 The function of the behavior:
 How does the response operate on the environment
 What does it “gain” the subject; what is the reinforcer earned by that response?
 Does not alter “inner states” but environmental manipulations:
 Not hunger but food intake
 Not fear, but aversive stimuli
 Maturation is a variable
The IV according to Skinner:
 Role of the contingency is important (critical) feature of
independent variables in EAB, for example in
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Shaping
Extinction
Delay of reinforcement
Contingencies involving several stimuli and several consequences
 Examine organism’s actual behavior under different experimental
contingencies
 Examine where, when, how behavior changes under different
stimulus conditions
 Can begin to build rules or laws of behavior
The IV according to Skinner:
 Relationships among the variables are very important
 Use real time rather than trial by trial
 “Free operant”:
 Within given time period, allow subject to make responses
 Subject determines when, how often, which responses to make to
a given set of stimuli and consequences
 Subject controls the rate of behavior
 Allows a behaviorist to determine how IVs interact
to alter the DV of behavioral responding
The IV according to Skinner:
 Skinner argues his “theory” is atheoretical
 Does not rely on preconceived hypotheses
 Rather- examines behavior and from the patterns
observed
 One determines systematic rules and descriptions of
behavior under various contingency conditions
 In Applied settings, best example of this is functional
analysis.
Inductive and not Deductive
 Inductive reasoning= reasoning in which the premises seek to
supply strong evidence for (not absolute proof of) the truth of the
conclusion.
 Conclusion of a deductive argument is supposed to be certain
 Truth of the conclusion of an inductive argument is supposed to be
probable, based upon the evidence given.
 Inductive reasoning = reasoning that derives general
principles from (many) specific observations
 Deductive reasoning = reasoning that hypothesizes general
principles and then looks for specific observations to support
the hypotheses.
What does distinguish Skinner’s approach
from more typical approaches?
 Behavior is not a sign of inner mental or
physical activities
 Not a means to the end, but the end
 Allows a careful specification of the behavior and
the processes by which the behavior occurs
 Really a “functionalist” approach: What is the
FUNCTION of the behavior? What does that
behavior get for the organism?
What does distinguish Skinner’s approach from
more typical approaches?
 Changes in behavior are studied in and of themselves, and
not assumed that they belie some underlying cause
 Study behavior because behavior is interesting and a legitimate variable
that is orderly and occurs for a reason
 Every behavior has a reason
 Examine how a set of responses come under the control of a
corresponding set of stimuli
 Use probability of response and changes in probability of responses
 Skinner argues rate of responding is most basic dimension
 Not assume behavior is a sign or symptom of inner traits,
abilities, processes, etc.- look at many behaviors
 Not rely on verbal behavior alone
What does distinguish Skinner’s approach
from more typical approaches?
 Behavior is examined because behavior is
important
 Behavior is not “adjusting to a situation” or “solving
a problem”
 Examine the topography of the behavior
 Look at the ABCs:The Antecedents, the
Behavior, the Consequences
Rise of Behaviorism as a field of study
 As popularity of research grew, several specialized journals popped up:
 Journal of The Experimental Analysis of Behavior (JEAB): 1958
 Journal of Applied Behavior Analysis (JABA): 1968
 Verbal Behavior
 The Behavior Analyst
 Division 25 in APA is called Experimental Analysis of Behavior
 International Association of Behavior Analysis: late 1970’s
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Several international conferences each year
General conference
Autism
Verbal Behavior
Several specialized experimental conferences
National conferences in variety of countries
Now have one of fastest growing licensed professionals in psychology: BCBA and
BCBAc
Assumptions of Modern Behaviorism
 Focus on classical and operant behavior; highly
influenced by neuroscience
 Include internal events as part of an organism’s
environment
 Both external AND internal environments influence behavior
 But: avoid use intervening variables like cognitivists
 Instead of saying “memory” study relationship between items recalled
and length of time between presentation of stimulus and behavior.
Assumptions of Modern Behaviorism
 Feelings and behavior:
 Don’t consider feelings as “cause” of behavior, but rather as a behavior in and of
themselves.
 Feelings are REAL behaviors that can be studied
 Again, look for environmental events that may be causal (internal and external)
 But: also remember that self reported “feelings” can be unreliable:
 What you think you feel and why you feel it may causal!’
 Thinking = behavior
 Thinking and talking are BEHAVIORS
 Language = verbal behavior
 Thinking = private behavior
 Assume same rules that govern other behaviors will govern thoughts and feelings
 Obviously, verbal behavior is MUCH more complex in humans but can be studied in
similar ways as any behavior
 Verbal behavior is a HUGE research area in behaviorism.
Behaviorism Today
 Not Skinner’s behaviorism!
 Focus on both theoretical and applied areas
 EAB: focus on developing theories of behavior
 How do animals learn about contingencies
 How do animals categorize/organize stimuli
 How do animals make decisions
 ABA: focus on application
 Biggest impact on autism, developmental disabilities
 Also in education, business, industry
 Emerging as major force in animal behavior, particularly with
domestic and companion animals
Learning = Adaptation
Learning = Evolutionary behavior?
 Instinctive knowledge: knowledge obtained through the
mechanism of heredity
 Evidence in many species
 Flexible, but not learned
 Two common misconceptions about instinctive knowledge
 Instincts are not influenced by experience
 Humans do not possess instinctive knowledge
Doctrine of Evolution by Natural Selection
 Mechanism of inheritance: Observed characteristics of
individuals are inherited; that is, offspring tend to resemble their
parents more than they resemble other individuals
 Source of variation: Within a species, individuals differ from
another in both their physical structures and behavioral dispositions.
 Method of selection: Those individuals with characteristics that
favor survival in competition with others and in the face of
environmental stressors or changes will be more likely to transmit
their characteristics to offspring and thus tend to be preserved.
Natural Selection:
Darwin’s 5 major premises:
 The members of particular species have characteristics that vary
 Some of these variable characteristics are passed on from parents to
siblings
 Some of these variable characteristics aid survival
 Species produce more offspring than survive to become adults
 Those characteristics that aid survival will become more common
across generations, those that impede survival will die out.
 Remember the time line for these changes: MANY generations
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For humans, this means thousands of years
Learning = Adaptation to environment
 Learning is an adaptive specialization
 Adaptation = changes that occur over successive generations as a
species adjusts to its niche
 Adaptation = process of adjustment to circumstances in which an
individual lives.
 Thus: Are evolved as solutions to some of problems of survival
Humans use adaptation and learning
as evolutionary mechanism
 We learn to adapt to our ever changing niche
 Greater flexibility to deal with new situations
 Those that can adapt…live and pass on their genes!
 Cultural evolution: Process by which (we humans) adapt
to our environment by transmitting acquired knowledge
from generation to generation through our teaching and
imitation.
 Chimpanzees, Bonobos and the domestic canine also show
evidence of this cultural evolution.
Domestication of Dogs
 Involves both natural and artificial selection
 Natural Selection:
 Natural selection developed individuals who more likely tolerant of humans
 Remain closer in, live with humans
 Several sub categories
 Tame domesticated
 Genetically domesticated but wild (feral)
 Wild type but tame
 Interestingly, 75% of world’s dogs are feral
 Domestication: 100,000 year history of domestication
 As humans entered more agricultural lifestyle, wolves scavenged food from humans
 This led to changes in wolf morphology and behavior
 Reduced fear and aggression in presence of humans = exploitation of more food sources
 Later, humans began to selectively breed dogs
Ontogeny of social behavior in Canids
 Domestication results in both physical and behavioral changes
 Physical changes include:
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Larger size variation: dwarf and giant
Piebald coat color
Reproductive cycle changes
Changes in hair, shortened tails, floppy ears
 Social changes:
 Lack of development of fear to humans
 Exhibiting play behavior in adulthood
 Prolonged juvenile period
Ontogeny of Social Behavior in Canids
 Most important: Paedomorphosis
 Retention of juvenile traits into adulthood
 Physical characteristics
 Behavior characteristics
 Important:
 Changes in head: muzzle, ears, coat, eyes, tail
 More juvenile signaling and extended play behavior in place of
adult aggression/antagonistic signaling
 Extended play
 Reduced need for adult-type signaling
Physical and Behavioral differences
 Sharpness of features
 Roundness of features
 Pointy ears, eyes, snout
 Rounded eyes, floppy ears,
 Intense eyes
“smiling”
 Softened eyes
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http://www.youtube.com/watch?v=1QqsSw5BDA8&feature=
related
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http://www.youtube.com/watch?v=B4Z9dUkbq1g&feature=r
elated
Compare Wolf to Dog Play
Paedomorphosis
 Wolf pups have much shorter development duration
 Good motor by 3 weeks of age
 Domestic dogs: Good motor control comes around 10-12 weeks
 Wolf pups show complex social behavior much sooner than
domestic dogs
 Dogs begin socialization once begin to walk (about 3 weeks)
 Continue to form primary relationships until at least 12 weeks to 16 weeks (best
time for adopting a puppy is 8-12 weeks)
 Socialization to both dogs and humans is critical for dog
development
 Shelter dogs
 Dogs weaned/adopted too soon
 Working dogs: avoid human contact, want them to bond to cattle or sheep
Farm Fox experiment
 Dimitri Belyaev: 1959 to today (Tut, 1999)
 Manipulated breeding of foxes on fox farm
 Selected breeders based on behavioral characteristics: mostly
sensitivity to humans
 Only about 3% of males, 10% of females selected in first generation
 Not reared with humans, just a 1 time test
 Rapid effects on behavior and morphology
 By 6th generation: begin to see domestication elite: no fear of humans
 By 8th generation: morphological changes begin
 By 42 generations: about 70% meet criteria for domestication elite
Farm Fox experiment
 Interesting physical changes: Note, NOT selected for these traits
 Physical Trait changes:
 Floppy ears; Rolled tails; Splotchy coats
 Shorter tails and legs
 Correlated with “tameness”
 Behavioral Changes
 Extended developmental period for bonding/attachment
 Exhibit juvenile play traits in adulthood
 Slower to develop adult behavior repertoires
 Hormonal changes correspond with this: delay in onset of innate fear response
 Lengthened developmental periods
 Typical fox: 45 days or about 5/5 weeks.
 Marked by onset of fear and avoidance and reduction in exploratory behavior
 Generations 28-30: Increased to about 12 weeks and often longer
 Similar to domestic dogs
Domestication hypothesis
(see Hare, Alexandra , Kaminski, Brauer, Call & Tomasello, 2010):
 Domestication = sufficient cause of canid’s sensitivity to
human social behavior
 Human and dog convergent evolution of advanced social cognition
in response to similar social selection pressures
 Brian Hare: Number of comparisons of wolves versus dogs and
domesticated foxes:
 Hare argues against ontogeny as important factor
 Ontogeny = the entire sequence of events involved in the
development of an individual organism
 Domestication hypothesis argues genetic changes sufficient
Problems with
Domestication Hypothesis
 Not account for differences in developmental windows
 With shorter window, shorter set of experiences and opportunity to
learn
 Can’t test dogs/wolves of same chronological age, but must
compare at same developmental age
 Dogs exposed to experimental manipulation while still in
sensitive period of socialization require less experience to
produce greater effect
Note important differences:
Dogs
Wolves
Better at following several
human gestures
Only good at point/gaze
Feral dogs and dogs reared in
shelters show same unsocialized
behavior as wolves
Socialized wolves improve in
wolf-human social interactions
over unsocialized wolves
As get older dogs prefer to be
with humans
As get older wolves prefer to be
with another wolf
Are these differences due to domesticity or experience?
Proximity to humans = important factor
 Domestication correlates with proximity to humans
 Domestication theory does not account for Exposure Effects
 But: Hard to research:
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Hard to get proper comparison group
Wild wolves with no contact with humans (dangerous)
If use tame wolves, have the human issue
Wild dogs also hard to work with!
 Studies which have attempted to account for human proximity have
found that contact with humans is an important factor
 Shelter dogs show more “wild-like” behavior; increased fear and aggression
 Dogs socialized after sensitive period show similar patterns
Conditioning/Learning Experiences:
 With human contact comes opportunity to become conditioned to
human behavior
 Serendipity in learning human social cues: Get reinforced more often!
 Domestic dogs learn human cues faster than wolves
 Domestic dogs are reinforced for appropriate response to humans
almost constantly
 Learn how to “manipulate” owners
 “guilty look” = I look “guilty” then I get back with the pack
 Not necessarily have human emotion with it, but show appropriate response
due to conditioning
Arguments against
Domestication hypothesis
 Domestic dogs have smaller brains than wolves
 Socialized wolves can learn human signals as well as dogs
 Improbable that dogs have innate ability to exploit behavior of humans
 Not conspecifics
 Different morphology and behavior
 E.g., the “hat” problem: not seem to understand morphology of humans
vs. their clothing
 Ontogeny plays crucial role in development of effective conspecific
social interactions in canids (and many other species)
Two stage hypothesis
 Sensitivity of canid to human social cues depends on 2 types of
ontogenic experiences
 Interactions with humans during sensitivity developmental period
leading to acceptance of humans as social companions
 Learning that is not restricted to one particular phase of development
 Learn to use location and movement of human body parts to locate sought-after
objects
 Domestication does not qualitatively change behavior, but has
changed quantity and duration of certain behaviors
 These behaviors must then be reinforced to be maintained.
Predictions of Two-Stage theory
 Both wild and domestic canids have:
 Phylogenetic prerequisites to respond to human social signals
 Have mutually beneficial interactions with humans
 Preparedness (Seligman, 1967; also Bolles 1967; Timberlake, 2001)
 Biological boundaries
 Prepared to attend to certain cues because these increase probability of survival
 But: this preparedness to respond requires experience to elicit and
shape beneficial behaviors
 Dog will become socialized to whatever it is around:
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Other dogs
Sheep or cattle
Humans
Learns behavior that works the best
Why is this important?
 Drives research questions:
 Is it nature or nurture that is more important
 How does nature interact with nurture
 Suggests need to examine developmental stages more closely
 Authors caution: standardization of methods
 Several research questions begin to emerge:
 Breed differences?
 Experience Differences? Shelter vs. fostering dogs for adoption
 Deaf, blind or deaf/blind versus typical dogs: What is effect on socialization?
 What cognitive abilities do dogs have?