PS1061: Sensation and Perception
Term I, THURSDAY 2-4 pm (Windsor Auditorium)
Lecture 1: Introduction - Perception as Gateway to the
World
Course co-ordinator: Johannes M. Zanker,
j.zanker@rhul.ac.uk, (Room W
214)
Lecture Topics
- basic aims and methods of the course: perception as important
area of study between biological & cognitive psychology
- the fundamental paradigm underlying this course: understanding
the human nervous system in terms of information processing
- perception/cognition and the brain: neuroscience offers
a basis to understanding structure and function of mental events
- why is this an interesting subject area? some exciting
questions addressed by researchers studying perception/cognition
- sensory channels serving perception are the initial bottleneck
and filter for collecting data about the world
- the lecture program & topics
perception and psychology
psychology = the study
of human behaviour and thinking
- OED: the science of the nature, functions, and phenomena
of the human mind
- we spend all our life thinking, can’t switch it
off ! this is fundamentally different from other activities
- what is the machinery of thinking ? mechanisms studied in cognitive
psychology & biological substrate studied in neuroscience
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sensation and perception is studied in the context of a variety of disciplines,
it is about the 'window' between the outside (physical) world and inside
world (mental states); information about the environment is collected
and interpreted in 'sensory channels' (usually referred to as 'senses')
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perception : conscious
sensory experience, high-level processing, usually related to activity in cortex
sensation : automatic
and unaware collection of low-level information: coding through the sensory
organs
sensation, perception, cognition
cognition : acquiring, handling,
storing and using knowledge
cognitive sciences : a multidisciplinary
group of scientific approaches (psychology, linguistics, artificial intelligence,
neuroscience, philosophy) with the common goal of understanding the human mind
- experimental cognitive psychology : studying perception,
behaviour, etc...
- cognitive science (in narrow sense) : computational modelling
- cognitive neuropsychology : analysing impairments
of brain-damaged patients
- cognitive neuroscience : using various techniques to
record/map/image brain function
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behaviour & thinking is based on a chain (or perhaps better: network)
of information processing: bottom-up processes transmit information
into higher areas of the human nervous system, lower areas are moderated
through top-down processes
sensation & perception is the starting point for all other
areas of psychology
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the information processing paradigm
central scientific approach: acquisition, processing, storage, recall
of data in the human brain
the analogy to a computer is obvious !
if you can build a machine that does exaclty the same as the brain, then
you were succesful to understand the underlying processes
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... note that the understanding of brain function is related to the key
technology of the period
the usual concerns raised by many people interested inpsychology who
are surprised to see this as crucial topic in the discipline
- cognitive psychology is difficult
we are used to operate machines and understand them, even
if they are quite complex - so why should we not look at the brain in action and
try to understand it ?
- cognitive psychology is irrelevant, not real psychology
on the contrary - it is fundamental to other disciplines
of psychology; it provides a solid scientific basis for understanding issues in
social, personality, occupational, health psychology, etc...
- cognitive psychology is boring
it tackles some of the most exciting questions of mankind,
such as: how do we think ? what constitutes the mind ?
perception, cogniton and the brain - is perception/cognition always difficult
?
a straight forward and simple approach is to divide processing in functional units (components): isolate brain regions that are
responsible for distinct operations
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understanding the brain in terms of compartments has a long tradition
(Albertus Magnus, 1260: 3 ventricles were believed to host imagination,
cognition, memory, resp.)
modern imaging
techniques allow to advance from speculation to hard scientific
evidence
the distribution of activity during various activities allows us to
asses the functional architecture
of the brain
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thinking about thinking : is perception/cognitiom a relevant part of psychology
?
neuroscience is a key approach to understand the fundamental processes to all
mental events
Franz Gall, 1812 (Phrenology)
this map of brain areas responsible for human behavioural
attributes and activities is a historical image which has been generated
by 'phrenologists' on the basis of data collected by methods which today
are recognised as seriously flawed - so it is much closer to fiction than
to science!
however, what survives is the idea of functional components
in the brain
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all of the following aspects of human life are mediated through the
brain and its sensory systems:
- how we interact with the world
- how we sort & storie acquired information
- how we communicate
- how we organise social life
- how we maintain mental health
- hpw we plan actions, make decisions
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some typical questions : is perception/cognition really boring ?
- how do we plan & coordinate complex motor patterns ?
- why does it sometimes go wrong?
- (Parkinson, stroke, exhaustion, …)
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- what is the basis of addiction
?
- what happens in the brain ?
- how do drugs affect perception?
- what makes drugs feel pleasant ?
- how do they change our consciousness ?
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- what is consciousness ?
- does it depend on the brain?
- how is it related to neural activity?
- how does it interact with perception ?
- why do we need it?
- are animals conscious?
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- how is memory organized ?
- how much can we memorize?
- are some things easer to remember?
- why doo we forget?
- can you train your memory?
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---> see Lewin (1992) (the 4 sketches above
are based on this paper from New Scientist)
so why do we study sensation & perception ?
- scientific curiosity: the
aim to understand the human mind as such (Psychophysics, Neurophysiology,
...)
- applications: the objective to
implement knowledge in thinking machines (Artificial Intelligence)
- search for a basis to understand
pathology and manage impairments (Cognitive Neuroscience)
prominent example: memory loss in Alzheimer
Type Dementia
An example : a trivial, everyday problem
you meet your friend in the café to work on your statistics exercise
- what are the necessary processing steps in your brain ?
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you enter the café and look around |
perception |
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you ignore almost everything and find your friend |
attention |
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you approach the table without knocking over chairs |
planning action |
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you find the problem sheet in your bag |
learning & memory |
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you start a conversation |
language |
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you try to memorize the contents of the lectures |
knowledge |
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you select the right equation and compute the result |
reasoning |
the full program of sensation & perception
1. 11/01/08 Introduction:
Perception as Gateway to the World
JMZ
2. 18/01/08 Visual
Perception 1: Learning to Read the Neural Code
JMZ
3. 25/01/08 Visual
Perception 2: Illusions as Key to Reality
JMZ
4. 01/02/08 Visual
Perception 3: Traveling through space and time
JMZ
5. 08/02/08 Auditory
Perception: From Noise to Sound
JMZ
6. 15/02/08 Touch,
Taste and Smell: Basic but Hidden Senses? JMZ
8. 29/02/08 Eye Movements and Perception
SD
9. 07/03/08 Multisensory integration SD
7. 22/02/08 Attentional Modulation of Perception: Processing
Bottlenecks
SD
10. 14/03/08 Conceptual Frameworks: Making
Sense of the World
JMZ
at the beginning of every human activity, there is perception as initial
data mining
why is reliable information vital ?
- we need to operate and navigate in a dangerous world
- we need ‘intelligence’ to understand the world (‘make
sense’)
sensory information processing is incessant and effortless: Data Mining
!!! no computational work without input
!!!
computer :
information input through keyboard, camera, microphone, modem, ...
brain :
information input through six senses = channels << note that Aristotle
distinguished only five senses ! >>
vision - touch - hearing - taste -
smell - temperature
however:
there are additional senses in humans, such as temperature, pain, balance;
and further senses in other animals, such as infrared vision, ultrasound, magneto/electro-ception
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a bottleneck limits the amount
of information that can be processed at the same time - intelligent
coding strategies are used to minimise information loss !
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a filter selects the type of information
that is to be processed in a given channel - it helps to optimise processing
performance
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Sensory modalities : Channels & filters of the brain
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channel 1
olfactory perception
is a very basic sensory system which is often forgotten, but it helps
us a lot to find our way through a complex and dangerous world,
and is crucial for our well-being and emotional balance
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channel 2
somatosensory perception
is essential for maintaining the integrity of the body, for controlling
movements, etc.
phantom sensations demonstrate the hidden but continuous operation
of the somatosensory system - do you feel the glasses on your nose?
Ramachandran (1988)
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channel 3
auditory perception
mediates orientation, relaxation, stress, communication
the ear is the intelligent microphone of the brain organ - it captures
a wide range of acoustic information
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channel 4
visual perception
is often regarded as the most important of the senses, because it
is an immediate and very rich source of information -- large channel
capacity !!!
- 100 million recepters per retina
- 1 million nerve fibres per eye
- 30 brain areas, 20% of brain
- 10 billion cortical neurons
for more numbers click here
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Summary: sensation & perception and its relation to psychology
- studying sensation & perception, together with cognitive
psychology is part of a multidisciplinary attempt to study the human mind
: how do we think ?
- the central scientific paradigm is the information
processing approach : the brain is interpreted as a computer dealing
with huge & complex data sets
- by localising and modelling brain function
we can address a number of very interesting questions of great cultural and
practical importance
- perceptual processes are required as
input for the neuronal machinery – which is absolutely
crucial for a wide range of vital functions
- perception is both a bottleneck reducing
the amount information and a filter selecting relevant information
- we speak of channels, tuning, capacity
Specific readings:
- Blakemore, C (1977) Mechanics of the mind.
Cambridge University Press (612.82 BLA)
- Eysenck, MW (2001) Principles of Cognitive Psychology.
(2nd ed.) Hove: Psych. Press (153.4 EYS), chapters 1 & 2
- Lewin, R (1992) The secret life of the brain.
New Scientist, 5/12/1992 - click here
(download from virtual resources)
- Ramachandran VS Blakeslee S (1988) Phantoms in the Brain.
Marrow New York
general textbook : Goldstein, E.B. (2007) Sensation
and Perception (7th ed.) Wadsworth-Thompson (152.1 GOL), (in particular
first pages of chapter1)
a textbook reflecting the course contents will
be published in March 2010: Zanker (2010) Sensation, Perception, Action - an
evolutionary perspective. Palgrave, (chapter1)
see also Koch & Crick 'The zombie within' Nature 411, p 893 (June
2001) - click here
(download from Journal)
to download e-handout click here
to download pdf-file of the draft textbook chapter click here
(feedback very welcome!)
back to course
outline
last update
8-10-2009
Johannes
M. Zanker
