Cognitive processes

Cognitive processesperception – sensation – attention – thinking – imagination – memory – creativity

– problem solving

Jakub Jura

[email protected]

http://users.fs.cvut.cz/~jura/ing-psych/

Engineering Psychology

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:– 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.

SensationPerception Percept Sence Organ

Visual Perception Image EyeAuditive Perception Sound EarGustatory Perception Taste Taste BudsOlfactory Perception Smell NoseHaptic Perception Touch on skin NociceptorsProprioception Body position ProprioceptorHuman Feromon Affection /

antipathyVomero-Nasal Organ

Magnetoception Impression of north

Unknown

Haptic sensibility

• Tactile compasses • The brain –

projection zone.• Skin surface and

brain surface.

Sensation Delusions

• Mach’s StripsLateral Inhibition Efect

Blind spot

• Close the right eye. Leave your head in the central position.

• Look to the cross, by the left eye.• Approach your head to the paper.• The circle disappears in a given distance.

Negative afterimage

Perception

• Perception is perception of diference.• Sensuals limits• Gestalt law• Multistable figures• Invariance in perception• Weber–Fechner law

Perception DelusionssWhich 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 perceptionCognitive Ecology

Objectavailable

information

Schemaof environment

Exploration

Directs

SamplesModify

Actual world

Cognitive mapLocomotion and action

Psychophysics

• 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

Sensum

Impr

esio

n

1. Sound

2. Light

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)

– 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)– L … Level of intensity– I … Intensity– P … Aacoustic pressure– I0, pe0 ... Minimal perceived value