What is sensation?

The process by which our sensory receptors and nervous system receive stimulus from the environment.

 There are actually 12.

 Basically idea is to draw diagonals rectangles, now as sides of the squares are parallel (either horizontal or vertical) so diagonals should also be parallel, as the outer most rectangle is nothing but square we should take this as a reference.

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We all experience (sensation) the same thing but we all perceive (perception) something different.

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Let me try something on you

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I'm thinking of two simple geometric shapes, one inside the other. Try to draw what I'm thinking of. Draw it on your mind map in the space I left you. Do not show me.

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Bottom-up processing:

we start with the sensory receptors sand work up to higher levels of processing.

Bottom-up processing:

we start with the sensory receptors sand work up to higher levels of processing.

The human fovea can only focus on a very small area at one time We fixate on one location for a moment and then move on to the next fixation. We take in little at each fixation and it’s through a pattern of saccades that we take in our visual environment.

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Top-Down Processing

The top-down process is driven by prior knowledge and expectations as well as our specific goals of the moment. 

Suppose though, I asked you to find all the occurrences of the letter “P” in the image? Now as you scan the image the letter “P” should start to stand out a bit more and it’s possible that even the highly visible red letters start to fade into the background. At the very least you likely aren’t noticing the words they spell out.

You see more of what you’re looking for and less of what you aren’t.

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Three blind mice, three blind mice, See how they run, see how they run, They all ran after the farmer's wife, Who cut off their tails with a carving knife, Did you ever see such a thing in your life, As three blind mice?

 Comics and cartoons provide many examples of top-down processing. Simple cues are used to suggest complex feelings and emotions. Cartoonists have a set of conventions for conveying information about mental and physical states. Tiny popping bubbles, for example, show drunkenness. Movement is shown by lines and little puffs of dust trailing after shoes. Spoken language is shown inside a bubble made out of a continuous line. A silent thought is shown inside a broken line. A sudden idea may be shown as a lightbulb lighting up over a character's head. Beads of sweat flying off a character show anxiety or physical exertion. After one gains some experience reading comics, these cues are processed automatically; one is hardly aware of them.

In many situations, however, your knowledge or expectations will influence perception. This is called schema-driven or top-down processing. A schema is a pattern formed earlier in your experience.

 In the figure Bottom-up processing enables our sensory systems to detect the lines, angles and colors that form the horses, rider and surroundings.

 Using Top-down Processing we consider the paintings title, notice the apprehensive expressions and then direct our attention to aspects of the painting that will give those observations meaning.;

Senses are nature’s gift that suit an organism’s needs. A frog feeds on flying insects; a male silkworm moth is sensitive to female sex-attractant odor; and we as human beings are sensitive to sound frequencies that represent the range of human voice.

A study of the relationship between physical characteristics of stimuli and our psychological experience with them.

Physical World Light Sound Pressure Sugar Psychological World Brightness Volume Weight Sweet

A relative increase in mental intensity, [Fechner] realized, might be measured in terms of the relative increase in physical energy required to bring it about (Wozniak, 1999). Gustav Fechner (1801-1887)

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Absolute Threshold

 minimum stimulation needed to detect a particular stimulus 50% of the time 

Difference Threshold

 minimum difference between two stimuli required for detection 50% of the time 

Or also called the JND just noticeable difference (JND)

Vision

SENSE

Hearing Smell Taste Touch Absolute Thresholds for Humans

STIMULUS

Electromagnetic Energy Sound Waves Chemical substances in the air Chemical substances in saliva Pressure on the skin

RECEPTORS

Rods & Cones in the retina Hair cells of the inner ear The ticking of a watch from about 20 feet away in a quiet room Receptor cells in the nose Taste buds on the tongue

THRESHOLD

A candle flame viewed from a distance of about 30 miles on a dark night About one drop of perfume diffused throughout a small house About 1 teaspoon of sugar dissolved in 2 gallons of water Nerve endings in the skin The wing of a fly falling on a cheek from a distance of about 0.4 inches

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The idea that, to perceive a difference between two stimuli, they must differ by a constant percentage; not a constant amount.

Subliminal Threshold: When stimuli are below one’s absolute threshold for conscious awareness.

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Backmasking is the process of recording hidden messages in music which can only be revealed when a song is played backward. This technique was first used by the British Broadcasting Corporation in the 1920s , in an attempt to change people's negative attitude toward radio broadcasting

 http://jeffmilner.com/backmasking/index.html

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The focusing of conscious awareness on a particular stimulus.

Explained: Aristotle’s Illusion explained: When something from the outside world causes nerves to fire, it’s called "sensation.” Light causes sensation in your eyes, sound in your ears, and pressure or temperature changes cause sensation in your fingertips. The message travels from the nerve endings to your brain at 80 miles per hour. When the brain gets the message, it interprets it. That is called "perception,” and it is caused by a variety of factors including sensation; but it also involves your past experience. Since you have always perceived messages from your fingertips with your fingers uncrossed, sensations from crossed fingers are misinterpreted as two noses.

Cocktail Party Effect: ability to listen to one voice among many…to pay attention despite distractions.

http://tywkiwdbi.blogspot.com/2013/01/what-do-you-notice-about-these-photos.html

 Inattentional Blindness: Failing to see visible objects when our attention is directed elsewhere.

 https://www.youtube.com/watch?v=tXFsH__PIRA  Change Blindness: Failing to notice changes in the environment  http://taylorappsychology.weebly.com/unit-4 sensation-and-perception.html

Change blindness is a form of inattentional blindness in which two-thirds of individuals giving directions failed to notice a change in the individual asking for directions. © 1998 Psychonomic Society Inc. Image provided courtesy of Daniel J. Simmons.

Dateline: Did you see that? July 16, 2010 http://www.msnbc.msn.com/id/38154937/ns/dateline_nbc-the_hansen_files_with_chris_hansen/ 28

Predicts how and when we detect the presence of a faint stimulus (signal) amid background noise (other stimulation). SDT assumes that there is no single absolute threshold and detection depends on: Person’s experience Expectations Motivation Level of fatigue

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Transduction

 is the process of one form of energy into another that your brain can use is called Transduction.

Remember Ethan in Sky High. He changes his body to slime. Solid form to liquid form. Change from one form of energy to another. Click the picture to watch power placement. http://www.youtube.com/watch?v=el0BSM0WRlU

Diminished sensitivity as a consequence of constant stimulation.

Put a band aid on your arm and after awhile you don’t sense it.

 Kittens raised without exposure to horizontal lines later had difficulty perceiving horizontal bars.