PS1061: Sensation and Perception 2014-15
Term 2,    Thursday 11 am - 1 pm    (Windsor Auditorium)

Lecture 1: Introduction - Perception as Gateway to the World

Course co-ordinator: Johannes M. Zanker,, (Room W 246)

Lecture Topics

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perception and psychology

psychology =  the study of human behaviour and thinking

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')

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

Because these two processes are difficult to separate, in the prsent context they are used exchangably, as the basic entry process of collecting information about the external world.

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


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

the information processing paradigm

The central scientific approach to understand the working of the brain is focused on infromation processing: 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

... note that the understanding of brain function is related to the key technology of the period

historical development
of metaphors for brain function

Difference Engine

Science Museum, London

the usual concerns raised by many people interested inpsychology who are surprised to see this as crucial topic in the discipline

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 ? 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... 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

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


in imaging studies it can be demonstrated that different brain areas are active
when a participant is communicating with others by means of language

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

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

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, …)

  • 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 ?
  • 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?
  • ---> see Koch & Crick (2001)

  • how is memory organized ?
  • how much can we memorize?
  • are some things easer to remember?
  • why doo we forget?
  • can you train your memory?

---> see Lewin (1992)         (the 4 sketches above are based on this paper from New Scientist)

so why do we study sensation & perception ?

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 ?

you enter the café and look around  
PS 1061, 2061
you ignore almost everything and find your friend
you approach the table without knocking over chairs
planning action
you find the problem sheet in your bag
learning & memory
PS 1021, 2021 
you start a conversation
you try to memorize the contents of the lectures
you select the right equation and compute the result

the full program of sensation & perception


Introduction: Perception as a Gateway to the World



Visual Perception 1: Learning to read the neural code



Visual Perception 2: Illusions as key to reality



Visual perception 3: Travelling through space and time



Auditory perception: From noise to sound



-- reading week --



Touch, Taste and Smell: Basic but hidden senses?



Eye movements and perception



Attentional modulation of perception



Multi-Sensory Integration



Integration and Conceptual frameworks: Making sense of the world



at the beginning of every human activity, there is perception as initial data mining   

why is reliable information vital ?

sensory information processing is incessant and effortless: Data Mining
!!!    no computational work (thinking, behaviour) without input    !!!

computer :    information input through keyboard,  camera, microphone, modem, ...
brain           information input through separate senses = channels << note that Aristotle distinguished only five senses ! >>
                     vision  -  touch  -  hearing  -  taste  -  smell 
                     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



a bottleneck limits the amount of information that can be processed at the same time - intelligent coding strategies are used to minimise information loss !

a filter selects the type of information that is to be processed in a given channel - it helps to optimise processing performance

Sensory modalities  :  Channels & filters of the brain


channel 1 (lecture 7)

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



channel 2 (lecture 7)

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?

see Ramachandran (1988)




channel 3 (lecture 5)

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


channel 4 (lectures 2, 3, 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

Summary: sensation & perception and its relation to psychology

Specific readings:

main textbook : Zanker, J.M. (2010) Sensation, Perception, Action - an evolutionary perspective. Palgrave (152.1 ZAN) : chapter1

additional textbook : Goldstein, E.B. (2007) Sensation and Perception (7th ed.) Wadsworth-Thompson (152.1 GOL), (in particular first pages of chapter1)

to download a pdf copy of lecture slides, click here

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last update 18-01-2015
Johannes M. Zanker