Perception

Selective Attention focus of conscious awareness on a particular stimulus

https://www.youtube.com/watch?v=lHd_L7dg3U4 http://www.learner.org/series/discoveringpsychology/07/e07expand.html http://www.dailymotion.com/video/xq1rfl_national-geographic-test-your-brain-

episode-2-perception_shortfilms

Testing Selective Attention

Selective Attention

Selective Attention means that at any moment, awareness focuses on only a limited aspect of all that we are capable of experiencing. For example, even if a stimulus figure can evoke more than one perception, we consciously experience only one at a time.

Another example of selective attention: the cocktail party effect

also limits our perception, as many stimuli will pass by unnoticed.

Inattentional Blindness

What is Inattentional Blindness?Selective attention also limits our

perception, as many stimuli will pass by unnoticed. This lack of awareness is evident in studies of inattentional blindness.

Forms of this include: change blindness

http://www.gocognitive.net/sites/default/files/change_blindness.v.0.93_0.swf

change deafness choice blindness

What is Choice Blindness

Petter Johansson and Lars Hall, the researchers who originally coined the term, people " ...often fail to notice glaring mismatches between their intentions and outcomes, while nevertheless being prepared to offer introspectively derived reasons for why they chose the way they did." http://channel.nationalgeographic.com/channel/brain-games/videos/choice-blindness/

Obj. Describe the interplay between

attention and perception. Answer the following question (in your

own words) on the back of the paper that was placed on your desk: How does attention impact our perception? Use the following terms in your answer:

Choice-blindnessInattentional blindnessCocktail party effectSelective attentionTop-Down

Perceptual Illusions

Muller-Lyer Illusion-

Perceptual Illusions

Perceptual Illusions

Perceptual Illusions

Watch This: How Brains Learn to See

http://www.ted.com/talks/pawan_sinha_on_how_brains_learn_to_see

Object RecognitionBlindness -

http://www.ted.com/talks/pawan_sinha_on_how_brains_learn_to_see

Data-Driven Processing (look at the handout 6-4)

b. Abe Lincoln (matched with objects in our long term memory and b.) the 1st picture on the page (a cow) data-driven and conceptually driven processing

Visual agnosia – syndrome in which all parts of the visual field are seen, but are without meaning – Read The Man Who Mistook His Wife for a Hat, by Oliver Sacks

Visual object agnosia – no damage to the eye but unable to recognize familiar objects.

4. Simultagnosia – cannot pay attention to more than one stimulus at a time. Not being able to see objects simultaneously.

5. Spatial agnosia – trouble negotiating their way through the world (wrong turns, lost in own home)

Perceptual Organization- Gestalt

Visual Capture tendency for vision to dominate

the other sensesGrouping

the perceptual tendency to organize stimuli into coherent groups

Perceptual Organization- Gestalt

Gestalt- an organized whole tendency to integrate pieces of information into

meaningful wholesGrouping Principles

proximity- group nearby figures together similarity- group figures that are similar continuity- perceive continuous patterns closure- fill in gaps connectedness- spots, lines and areas are seen

as unit when connected

Perceptual Organization- Illusory Contours

Perceptual Organization

Figure and Ground organization of the visual field into objects (figures) that stand out from their surroundings (ground)

Perceptual Organization- Grouping Principles

Perceptual Organization- Grouping Principles

Gestalt grouping principles are at work here.

Perceptual Organization-Depth Perception

Depth Perception ability to see objects in three dimensions allows us to judge distance

Binocular cues retinal disparity

images from the two eyes differ closer the object, the larger the disparity

convergenceneuromuscular cuetwo eyes move inward for near objects

Perceptual Organization-Depth Perception

Visual Cliff

Perceptual Organization-Depth Perception

Monocular Cues relative size

smaller image is more distant interposition

closer object blocks distant object relative clarity

hazy object seen as more distant texture coarse --> close

fine --> distant

Perceptual Organization-Depth Perception

Relative Size

Perceptual Organization-Depth Perception

Perceptual Organization-Depth Perception

Monocular Cues (cont.) relative height

higher objects seen as more distant relative motion

closer objects seem to move faster linear perspective

parallel lines converge with distance relative brightness

closer objects appear brighter

Perceptual Organization-Depth Perception

Perspective Techniques