Engineering Psychology
Cognitive processes
perception – sensation – attention – thinking – imagination – memory – creativity
– problem solving
Jakub Jura
Jakub.jura@fs.cvut.cz
http://users.fs.cvut.cz/~jura/ing-psych/
What is Cognitive?
• From latin cognoscere = getting to know
• Distinguish emotional and rational
• Descarte’s „Cogito ergo sum“.
Mental processes mediate between stimulus and response.
Cognitive processes
• Base Cognitive processes:
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Perception
Sensation
Attention
Thinking
Imagination
Memory
Learning
• Advanced Cognitive processes
– Creativity
– Problem solving
Sensation
• Sensation is about sense organ and basic
processes on this level.
• Perception is about creating whole percept.
Sensation
Perception
Visual Perception
Auditive Perception
Gustatory Perception
Olfactory Perception
Haptic Perception
Proprioception
Human Feromon
Magnetoception
Percept
Image
Sound
Taste
Smell
Touch on skin
Body position
Affection /
antipathy
Impression of
north
Sence Organ
Eye
Ear
Taste Buds
Nose
Nociceptors
Proprioceptor
Vomero-Nasal
Organ
Unknown
Sensation Delusions
Lateral Inhibition Efect
• Mach’s Strips
Negative afterimage
Perception
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Perception is perception of diference.
Sensuals limits
Gestalt law
Multistable figures
Invariance in perception
Weber–Fechner law
Perception Delusionss
Which of these circles is bigger?
Perception Delusionss
• Effect of Contrast
Lighter
Darker
Perception Delusionss
Is
anything
here?
Gestalt Laws
• Proximity
– We tend to group nearby objects.
• Similarity
– We tend to group objects with
similar properties
• Closure
– We are so accustomed to seeing
closure that we sometimes close
things that aren't.
Gestalt Laws
• Good Continuation
– We tend to assign objects to an entity that is defined by
smooth lines or curves
• Pregnantz
– We tend to good shape
Experiment 2
Multistable perception
• Mind separate figure and
backgroun.
• Unstably between two or more
alternative interpretations.
• Since you see both, you can’t
see both.
• Changing may be under control
only partially.
Invariance in perception
• Objects are recognized independent of rotation,
translation, scale, elastic deformations, different
lighting, and different component features.
Neisser's cycle of perception
Cognitive Ecology
Actual world
Object
available
information
Samples
Modify
Exploration
Schema
of environment
Cognitive map
Directs
Locomotion
and action
Psychophysics
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Ernest Heinrich Weber (1795–1878)
Gustav Theodor Fechner (1801–1887)
Stimulus  Percept
Stimulus  Sensation  Percept
Weber law
• Ernest Heinrich Weber (1795–1878)
• Experiment with weight difference
– Just noticeable difference (jnd) between two weights was
approximately proportional to the mass of the weights
• I = kw* I
– I … Base intensity (Total weight)
– I … Discrimination threshold (Weight difference)
– kw Constatnt (Weber Fraction)
• We can‘t perceive the intensity of stimulus directly,
but in relation to the reference value.
Fechner law
• Gustav Theodor Fechner (1801–1887)
• Dependence of sense impression on the
intensity of stimulus is logarithm.
• P = k * ln (S)
– P … percept
– k … constant
– S … stimulus
Experiment 1
• Dependence of sense impression on the
intensity of stimulus
1. Sound
Impresion
2. Light
Sensum
Procedure:
a) Set intensity to basic level (L)
b) Increase intensity up to one
degree (L+1)
c) Remember this degree and
set intensity up to L+2, L+3,
… L+n
Fechner law
Weber–Fechner Law
• P = k * (S/S)
• dP = k * dS/S,
• P = k * ln (S/S0)
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P … percept
k … constant
S … stimulus
S0 … lower possible stimulus
Weber-Fechner law
• Weber-Fechner principle in the acoustics:
• LI=10 log (I/I0)
• Lp=20 log (pe/pe0)
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L … Level of intensity
I … Intensity
P … Aacoustic pressure
I0, pe0 ... Minimal perceived value