PSYC20007 Lecture Notes - Lecture 3: The Automatic, Hear Music, Habituation
14 Jun 2018
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Lecture 3 - Tuesday 8 August 2017
PSYC20007 - COGNITIVE PSYCHOLOGY
LECTURE 3
CONCEPTS & CATEGORIES
TODAY
•What is categorization and how do we use concepts to guide our actions?
•Categorization is the engine of cognition
•Fundamental ideas for understanding categorization
•The multifaceted nature of stimuli
•Benefits of categorization
•How do we represent categories?
CATEGORISATION
•Categorisation is the ability to form equivalence classes of discriminable entities.
•“The pulsating heartbeat of thought”
•At every moment, we are faced with an indefinite number of overlapping and intermingling
situations.
•Understanding the world involves the automatic and effortless evocation of categories.
•Imagine you’re in a new city, surrounded by strangers. There are ads everywhere, some you can
read; others that you cannot. Some things you recognize; others are unfamiliar. Some catch your
attention and interest; others you don’t even register as having seen. As you walk down the street,
you’re absorbed in your own introspective thoughts. You hear people talking, some in your own
language, some in a language which is foreign to you. You wonder if you’re hungry, if you are
getting a cold, if that person just smiled at you. You’re troubled by the news headline you just
read but chuckle at a clever piece of street art. You hear music. There’s a cat digging in a rubbish
bin. You wonder where to catch the subway... [Inspired by Hofstadter & Sanders, 2013; Surfaces
and Essences]
•Rather than experiencing one situation, you’re faces with a multitude of ill-defined situations,
none of which is sharply defined either in space or in time. The brain constantly makes sense of
this sea of information and chaos. “What does it mean to make sense of? The automatic triggering
of familiar categories is what helps us make sense of the incoming information. Without any
effort, we find ourselves thinking “funny looking guy”, “pretty girl”, “stupid commercial”, “dumb
politicians”, “what’s she reading?”, “who’s whistling?”, “will that child never stop crying?”,
“where did that cat come from?”
CATEGORISATION IS NECESSARY FOR SURVIVAL
•Categorization is necessary for survival. It provides a basis of deciding what constitutes
appropriate action. This type of fast categorisation appears to be present in every species.
•The bacterium E. coli tumbles randomly in a molecular sea. When it encounters a stream of
molecules that it categorizes as a nutrient, it suppresses tumbling and swims upstream to the
nutrient source. A recently inseminated female mouse sniffs urine near her nest. If she categorizes
it as from an unfamiliar male mouse, implantation and pregnancy are prevented (Bruce, 1959;
Parkes & Bruce, 1962). All organisms divide objects and events in the environment into separate
classes or categories. If they did not, they would die and their species would become extinct.
Therefore, categorization is among the most important decision tasks performed by organisms
(Ashby & Lee, 1993).
BENEFITS OF FORMING CATEGORIES
•Benefits of forming categories:
•1. Provides a means for identification
•2. Reduces the complexity of the environment
•3. Allows organization of knowledge
Lecture 3 - Tuesday 8 August 2017
PSYC20007 - COGNITIVE PSYCHOLOGY
•Used to only have 8 colours and
now have heaps of stupid ones.
•There are more than 7 million
discriminable colors; if we tried to
respond to all of these colors as
unique, we could spend our
lifetime trying to learn the names
of all of the colors. When we
classify different objects as
belonging to the same category we
treat them as equivalent. We can
respond based on category
membership rather than as unique
items.
•The World Color Survey is a
massive research project which
attempts to understand
how colors are
categorized in different
languages. The
researchers studied 110
different languages, none
of which had a written
component, which
ensured that only spoken
word categories would be
used to describe the
colors. In the World
Color Survey, a total of
six to ten color names were identified
as accounting for most of the colors
black, white, red, green, yellow and
blue (plus orange, pink, purple &
brown)
•4. Allows for generalization
•We do not have to be taught about
novel objects if we can classify them;
we can use our knowledge of items
in the category to respond to the
novel object
CATEGORISATION
INDUCTION:
GENERALISATION AT
MULTIPLE LEVELS
•Induction: Generalizing from the particular to the general
•Given a set of examples, what is the general conclusion that one could draw
•Following examples illustrate 5 key empirical effects that help us understand generalization
•Categorization & Generalization
•Typicality of Instances
•Typicality of Generalization
•Category Size
•Category Variability
Lecture 3 - Tuesday 8 August 2017
PSYC20007 - COGNITIVE PSYCHOLOGY
HOW DO CATEGORY INDUCTION
TASKS WORK?
•The more typical the example the more willing
we are to generalise to the rest of the category.
Eg using robins as a bird example works better
than using penguins.
•This slide illustrates the typical method in
which inductive reasoning is studied.
•The premise statements above the line are
taken to be true, and the task is to judge the
degree to which the conclusion statement,
below the line, follows from the premises.
Essentially this is a judgment of argument
strength.
•Any number of premises can be used, and
various properties could be swapped in for
Tricket’s disease. The next few slides
will explore a number of properties of
inductive reasoning
EFFECT OF TYPICAL PREMISE
EXAMPLES
•The more typical the examples are of
the category in the conclusion, the
more the conclusion is supported by
the premises. Robins are more typical
than penguins so the conclusion at the
top is supported more than the
conclusion at the bottom.
EFFECT OF TYPICAL CONCLUSION
EXAMPLES
•Conclusions are supported more by
premises that are similar
•Bluejays and robins are more similar to
sparrows than bluejays and robins are to
geese...
EFFECT OF CONCLUSION
CATEGORY SIZE
•More specific conclusions are
supported more than less specific
conclusions. All birds is more
specific than all animals...
