M2L1: Attention and Perceptual Processes

NIOS Senior Secondary 12th Standard Module 2 Basic Psychological Processes Lesson 1 Chapter 6

attention

• the process of narrowing down stimuli that requires our processing

• perception isn’t possible without attention

• organises perception and other cognitive functions

alerting function (4 components of attention)

(4 components of attention)

• complete physiological and mental preparedness

• (eg. waiting for instructions)

selective function (4 components of attention)

(4 components of attention)

• selecting an object of attention as it is impossible to pay attention to multiple things at once

• automatic processing - two or more activities are performed simultaneously but one is automatic and doesn’t require much attention (eg. driving a car and talking on the phone)

limited capacity channel (4 components of attention)

(4 components of attention)

• the selected number of articles of stimuli that one pays attention to

• (eg. a friend’s voice in a crowd of voices)

vigilance (4 components of attention)

(4 components of attention)

• or sustained attention, is paying attention to one task continuously for a long time

• (eg. looking at the screen at Air Traffic Control)

selective attention (classification of attention)

(classification of attention)

• being able to focus on the task and ignoring distractions

sustained attention (classification of attention)

(classification of attention)

• giving attention to one task at a time

external / outer / physical factors (factors affecting selective attention)

(factors affecting selective attention)

• movement

• intensity

• novelty

• size

• change

• repetition

• clarity

• colours

• contrast

internal / psychological factors (factors affecting selective attention)

(factors affecting selective attention)

• need

• interest

• emotional state

transduction (understanding the role of sensation in perception)

(understanding the role of sensation in perception)

• transforming sensation into perception

perception (understanding the role of sensation in perception)

(understanding the role of sensation in perception)

• organisation, interpretation, analysis and integration of stimuli carried out by sense organs and brain

form perception (understanding the role of sensation in perception)

(understanding the role of sensation in perception)

• the process of organising

laws of perceptual organisation (understanding the role of sensation in perception)

(understanding the role of sensation in perception)

• also known as gestalt laws of organisation 

• early 1990s - German psychologists, particularly Kohler, Koffka, and Wertheimer 

• good figure or pragnanz laws → tendency to perceive in an organised form 

• figure-ground segregations

principles of perceptual organisation (understanding the role of sensation in perception)

(understanding the role of sensation in perception)

• proximity

• similarity

• continuity

• symmetry

• closure

depth perception (understanding the role of sensation in perception)

(understanding the role of sensation in perception)

• distance → measurement of length between observer and object

• depth → measurement of length between two objects perceived by an observer

monocular / psychological cues (depth perception)

(depth perception)

• relative size

• interposition / overlapping

• linear perspective

• aerial perspective

• light and shade

• relative height

• texture gradient

• motion parallax

relative size (monocular cues )

(monocular cues )

• we can easily perceive the size of a common object due to seeing it often as it is a familiar object and the bigger it is the closer it is and vice versa

interposition / overlapping (monocular cues )

(monocular cues )

• when one object blocks another object, the blocked object seems farther away

linear perspective (monocular cues )

(monocular cues )

• when parallel lines go off into the distance, they seem to converge at a point because farther things seem closer

aerial perspective (monocular cues )

(monocular cues )

• when objects in landscape are clearer they are closer to the observer but when they are hazy they are closer to the horizon (farther from observer)

light and shade (monocular cues )

(monocular cues )

• using the source of light to assess the object’s shadow’s length and distance from the object

relative height (monocular cues )

(monocular cues )

• smaller objects seem farther away while bigger objects seem closer

texture gradient (monocular cues )

(monocular cues )

• when a feature of the landscape is closer (like grass in a meadow) you can see it in detail - rough texture (individual blades of grass), when it is farther you can only see finer texture (a green haze)

motion parallax (monocular cues )

(monocular cues )

• (kinetic monocular cue) occurs when objects at different distances move at different relevant speed - the distant objects seem to move slower than closer objects 

  • rate of an object’s movement provides a cue to its distance

binocular / physiological cues (depth perception)

(depth perception)

• retinal or binocular disparity

• convergence

• accomodation

retinal or binocular disparity (binocular cues)

(binocular cues)

• objects that are nearer or farther than the fixation point which indicates the distance of the object from the fixation point

convergence (binocular cues)

(binocular cues)

• when the vision of both eyes are parallel the object is farther while the angle indicates the closeness of the object

accomodation (binocular cues)

(binocular cues)

• when the retina is focusing on an image and the convexity of ciliary muscles change, allowing us to decipher approximate distance

  • if the convexity is more, the object is closer and vice versa

perceptual constancy

• size constancy

• shape constancy

• brightness constancy

muller-lyer illusion (illusions)

(illusions)

• line a is perceived as longer than line b even though both lines are equal 

• experienced even by children and some studies suggest animals

illusion of vertical and horizontal lines (illusions)

(illusions)

• vertical lines are perceived as longer than horizontal lines even when both are equal

ponzo illusion (illusions)

(illusions)

• geometrical-optical illusion demonstrated by Italian psychologist Mario Ponzo in 1911

• when there are two identical lines across a pair of converging lines (like train tracks), the upper line looks longer as the converging lines make it look farther 

  • since it is perceived to be farther, the assumption is that it must be longer to appear the same length and the lower line

zollner illusion (illusions)

(illusions)

• created by German astrophysicist Johann Karl Friedrich Zollner (1834-18882)

• first published in journal Annalen der Physikin 1860

• an illusion where a central aspect of a simple line image (such as length, straightness, parallelism, etc) appears distorted due to the other aspects of the image (such as background-foreground lines, other intersecting shapes, etc)

poggendorff illusion (illusions)

(illusions)

• German physicist Johann Poggendorff (1796-1877) first described it in 1860

• the lines appear to be misaligned due to the intersecting line

apparent movement illusion (illusions)

(illusions)

• also known as phi phenomenon - when motionless pictures are projected one after another at a certain rate 

• eg. moving pictures in a cinema, flickering lights, etc

• Max Wertheimer said that there needed to be an appropriate level of brightness, size, spatial gap, and temporal contiguity of different lights