LUC MALCONTENT
Summary Sensation and Perception
Luc Malcontent
0
, LUC MALCONTENT
Contents
Introduction ............................................................................................................................................ 2
The eye ................................................................................................................................................... 6
Spatial vision........................................................................................................................................ 11
Object perception and recognition ....................................................................................................... 14
Colour perception................................................................................................................................. 18
Space and binocular vision .................................................................................................................. 23
Attention .............................................................................................................................................. 26
Motion perception ................................................................................................................................ 30
Vestibular system ................................................................................................................................. 35
Sound and the ear ................................................................................................................................. 37
Auditory processing ............................................................................................................................. 40
Auditory perception ............................................................................................................................. 43
Touch ................................................................................................................................................... 46
Olfaction .............................................................................................................................................. 51
Gustation .............................................................................................................................................. 54
1
, LUC MALCONTENT
Introduction
Sensation and perception: Interactions between physical forces in the world and sensory organs produce
neural activity that carries information about the world. We analyse these patterns in the physical forces
and neural responses to understand what is happening around us.
Senses: within the sensory organs there are specific parts or sensory receptors that interact with something
physical in the outside world.
- Within vision and audition processing is separated into different pathways (shape, motion,
frequency).
Vision: primary sense that guides almost every action. Analysis of vision is used for object recognition,
space, and motion.
Neural computations: neurons can analyse information from other neurons to help us understand the world.
- These neurons respond to light in the
centre and when configured in a line
the connected neuron responds to a
line of light.
Sensation: a translation of the external physical environment into a pattern of neural activity by a sensory
organ.
Perception: analysis of the neural activity to understand the environment and guide behaviour. It is the
subjective conscious experience of the outside world.
Sensation and perception reflect interactions between our sensory organs and physical properties of
the world.
o Dependent on physical properties of the world.
o Limited by the physical properties of our senses.
Properties: sensation and perception have evolved to help us survive and reproduce:
- Optimized for useful representations of the environment.
- Influenced by interpretation: context and experience.
- Dependent on limited resources of attention and awareness.
2
, LUC MALCONTENT
Experimental methods
Psychological approach: quantitative measurements of behaviour resulting from perception.
- Psychophysics: the scientific study of the relation between stimulus and sensation.
Just noticeable difference: (JND), testing whether subjects
perceive a difference between two stimuli.
Perceived intensity: of a stimulus doesn’t increase linearly with its physical intensity, we perceive intensity
in orders of magnitude (doubling of units).
- Weber-Fechner law: describes the logarithmic relation
between physical and perceived intensity.
Ψ = 𝑘 ∗ 𝑙𝑜𝑔(𝐼)
Perceptual threshold: as the difference in stimuli increases the chance of perceiving the difference
increases.
2-alternative forces choice: presenting two stimuli and
participants make a choice between two alternatives.
Method of constant stimuli: testing every possible
difference in stimuli over a wide range and plotting the
choice as a function of the difference.
Psychometric function: sigmoid curve (s-shaped), where
we measure the 75% threshold, because it is the steepest
point.
3
Summary Sensation and Perception
Luc Malcontent
0
, LUC MALCONTENT
Contents
Introduction ............................................................................................................................................ 2
The eye ................................................................................................................................................... 6
Spatial vision........................................................................................................................................ 11
Object perception and recognition ....................................................................................................... 14
Colour perception................................................................................................................................. 18
Space and binocular vision .................................................................................................................. 23
Attention .............................................................................................................................................. 26
Motion perception ................................................................................................................................ 30
Vestibular system ................................................................................................................................. 35
Sound and the ear ................................................................................................................................. 37
Auditory processing ............................................................................................................................. 40
Auditory perception ............................................................................................................................. 43
Touch ................................................................................................................................................... 46
Olfaction .............................................................................................................................................. 51
Gustation .............................................................................................................................................. 54
1
, LUC MALCONTENT
Introduction
Sensation and perception: Interactions between physical forces in the world and sensory organs produce
neural activity that carries information about the world. We analyse these patterns in the physical forces
and neural responses to understand what is happening around us.
Senses: within the sensory organs there are specific parts or sensory receptors that interact with something
physical in the outside world.
- Within vision and audition processing is separated into different pathways (shape, motion,
frequency).
Vision: primary sense that guides almost every action. Analysis of vision is used for object recognition,
space, and motion.
Neural computations: neurons can analyse information from other neurons to help us understand the world.
- These neurons respond to light in the
centre and when configured in a line
the connected neuron responds to a
line of light.
Sensation: a translation of the external physical environment into a pattern of neural activity by a sensory
organ.
Perception: analysis of the neural activity to understand the environment and guide behaviour. It is the
subjective conscious experience of the outside world.
Sensation and perception reflect interactions between our sensory organs and physical properties of
the world.
o Dependent on physical properties of the world.
o Limited by the physical properties of our senses.
Properties: sensation and perception have evolved to help us survive and reproduce:
- Optimized for useful representations of the environment.
- Influenced by interpretation: context and experience.
- Dependent on limited resources of attention and awareness.
2
, LUC MALCONTENT
Experimental methods
Psychological approach: quantitative measurements of behaviour resulting from perception.
- Psychophysics: the scientific study of the relation between stimulus and sensation.
Just noticeable difference: (JND), testing whether subjects
perceive a difference between two stimuli.
Perceived intensity: of a stimulus doesn’t increase linearly with its physical intensity, we perceive intensity
in orders of magnitude (doubling of units).
- Weber-Fechner law: describes the logarithmic relation
between physical and perceived intensity.
Ψ = 𝑘 ∗ 𝑙𝑜𝑔(𝐼)
Perceptual threshold: as the difference in stimuli increases the chance of perceiving the difference
increases.
2-alternative forces choice: presenting two stimuli and
participants make a choice between two alternatives.
Method of constant stimuli: testing every possible
difference in stimuli over a wide range and plotting the
choice as a function of the difference.
Psychometric function: sigmoid curve (s-shaped), where
we measure the 75% threshold, because it is the steepest
point.
3
