Cognitive processes Jakub Jura Jakub.jura@fs.cvut.cz Engineering Psychology Cognitive processes perception – sensation – attention – thinking – imagination – memory – creativity – problem solving http://en.wikipedia.org/wiki/Perception http://www.cns.nyu.edu/~msl/courses/0044/handouts/Weber.pdf http://en.wikipedia.org/wiki/Weber%E2%80%93Fechner_law http://www.wikiskripta.eu/index.php/Weber-Fechner%C5%AFv_z%C3%A1kon http://en.wikipedia.org/wiki/Psychophysics#Experimentation http://en.wikipedia.org/wiki/Gestalt_psychology#Uses_in_human.E2.80.93computer_interaction http://www.sapdesignguild.org/resources/optical_illusions/gestalt_laws.html http://en.wikipedia.org/wiki/Memory http://www.akademik.unsri.ac.id/download/journal/files/scipub/jcs_si_106-111.pdf 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: 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 Percept Sence Organ Visual Perception Image Eye Auditive Perception Sound Ear Gustatory Perception Taste Taste Buds Olfactory Perception Smell Nose Haptic Perception Touch on skin Nociceptors Proprioception Body position Proprioceptor Human Feromon Affection / antipathy Vomero-Nasal Organ Magnetoception Impression of north Unknown

Lateral Inhibition Efect Sensation Delusions Lateral Inhibition Efect Mach’s Strips http://www.youtube.com/watch?v=sItlLNhhiLg

Negative afterimage

Perception 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 Similarity Closure 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. http://www.sapdesignguild.org/resources/optical_illusions/gestalt_laws.html#sim

Gestalt Laws Good Continuation Pregnantz 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 http://www.akademik.unsri.ac.id/download/journal/files/scipub/jcs_si_106-111.pdf Schema of environment Exploration Locomotion and action Cognitive map Directs

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 Sound Light Procedure: Set intensity to basic level (L) Increase intensity up to one degree (L+1) Remember this degree and set intensity up to L+2, L+3, … L+n Impresion Sensum

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