Senses and Perception Chapter 4 Questions

Senses and Perception All incoming sensation is interpreted by the brain Without much conscious effort, we are constantly taking in information about the world and sending it to our brains to make sense of it.

Well our senses do provide us with reasonably reliable information, the representations they give us of the world are not as literally accurate a we tend to believe….

“Top” “Bottom” “Side” We assign a top, bottom and side to most objects we know—and keep them that way, regardless of their position. -There is meaning given by the brain to a symbol -The object will remain the same in your mind

How many squares do you see?

16, 21, 30?? All of us see the same grid, but each of us interprets it differently? -What does this tell us about how we perceive the world? We all see it differently

The Big Five/ Senses Each of our senses delivers a unique contribution in helping us understand our external world !

Vision Most people would say they would rather lose their hearing than sight. From an evolutionary standpoint, vision has been our most important sense.

Vision Here is how it works (basic): To start with, photoreceptors in our eyes gather light, convert its physical energy into neural messages, and send it to the brain for decoding and analyzing. Transduction happens in the retina, which is composed of light sensitive layers of cells at the back of the eye called rods and cones.

Blind Spot All of us have a blind spot, a small part of the retina that is not coated with photoreceptors, which creates a small gap in our visual field. We are not aware of our blind spot because our eyes compensate for each other, and our brains “fill in” the spot with the information that matches the background. Check out page 94 of your text! Figure 4.4

Hearing If a tree falls in the forest and no one is there…does it make a sound?

Hearing and Sound Sounds are created when actions, like banging, cause objects, like drums, to vibrate. These vibrating objects push air molecules back and forth, and as a result change the air pressure. Sound waves travel into the ear, transfer from tissues to bones, and are transformed into fluid waves in the inner ear. These vibrations stimulate tiny hair cells that generate nerve impulses to the brain

Smell Smell is our most primitive sense Our sense of smell, may also be our sense linked most closely with memory Odors are chemical molecules. When they hit the tiny hairs in our nose, the receptors translate them into nerve impulses, which are then relayed to the brain.

Taste A taste bud can tell whether foods are sweet, bitter, sour or salty, and that is about it. (Food critics rely on their sense of smell to distinguish subtle food flavors, more than on their ability to taste them) Your taste receptors, located on the upper side of your tongue, transduce chemical molecules dissolved in saliva to the taste center of your brain. Your taste buds are replaced every few days.

Touch Your skin contains nerve endings that, when stimulated by physical contact with outside objects, produce sensations of pressure, warmth and cold. These sensations are the skin senses, and you could not survive without them. Your sensitivity to touch is where you need it most, on your face, tongue and hands.

Putting it Together After your senses take all that stimulation, your brain still has to figure it all out. If you have never been proud of your organizational skills, your self esteem is about to get a boost! -Your brain has an amazing ability to sort objects by size, distance, proportion, colour, and many other categories!

Sensation At what point does physical reality become human reality? -How bright does a light have to be before we see it glowing? -What is the softest sound we can still hear? You and your friend are stargazing and you point out a faint star. Your friend says he cannot see it, despite you describing and detailing the exact location! He just cannot see it!? Why is this so?

Absolute Threshold It may be because your friend’s absolute threshold for light is lower than yours. Absolute Threshold: The smallest, weakest amount of stimulus a person can detect.

Definitions Adaptation: the gradual loss of attention to unwanted sensory information (Ex: You forget that the school change room smells after you have been in there for 15 minutes)

Consider this… - How is sensation and perception, biological and cognitive?

Perception interpretation expectation Perception is always a matter of interpretation and expectation. Since the word is something we’ve seen before, our mind can easily recognize it without actually having to think about it.

Perception Constancies Size Size Colour Colour Brightness Brightness Shape Shape Space Space

Perceptual Constancies Size Constancy The ability to retain the size of an object regardless of where it is located Colour Constancy The ability to perceive an object as the same colour regardless of the environment

Perceptual Constancies Shape Constancy The ability to perceive and object as having the same shape, regardless of the angle at which it is seen Space Constancy The ability to keep objects in the environment steady by perceiving either ourselves or outside objects as moving

Perceptual Constancies Brightness Constancy The ability to keep an objects brightness constant as the object is moved to various environments. constancy The word constancy means holding steady. And this is what we must do to the world in order to maintain order and control, to make sense out of our environment.

Depth Perception Depth Perception Depth Perception: The ability to see the relation of objects in space Retinal Disparity Retinal Disparity: The differences between the two images provided by you two eyes. Just close one eye and switch back and forth to see the differences in the images your eyes perceive.

Perceptual Organization The human brain is quite efficient. It looks for organizational strategies that require the least amount of effort. Your brain automatically assumes that objects having something in common go together. Therefore we interpret things the way we think they should be, not the way they actually are.

Gestalt Common Region Common Region Similarity Similarity Proximity Proximity Closure Closure

Gestalt Gestalt Gestalt: An organized whole, shape or form

Common Region Principle of Common Region Objects that are within the same region are perceptually grouped together. (The signs on the show how the message is perceived differently when the words are grouped in different regions)

Principle of Similarity Grouping like things together

Principle of Proximity Grouping things together that are near one another

Principle of Closure Filling in the missing details of what is viewed.

Illusions Illusions Illusions: Inaccurate perceptions

Muller-Lyer Illusion Illusions Most people think that illusions are “mistakes” that we make. That is not really the case. Instead over the years we learn to change what we perceive so that the world makes more sense. Some have thought that the illusion occurs because the arrows draw the eyes in… This is not the case We tend to mentally stretch the one line

Reversible figures Reversible figures: Illusion in which the same object is seen as two alternating figures.

Which way is this person spinning? e-truth-about-the-spinning-dancer/?_r=0 If the image is too slow go to:

This is simply an optical illusion called a reversible, or ambiguous, image. The silhouette image of the spinning dancer doesn’t have any depth cues. As a result, your eyes will sometimes see the dancer standing on her left leg and spinning to the right. And sometimes they will perceive her as standing on her right leg and spinning to the left. Most people, if they stare at the image long enough, will eventually see her turn both ways.

END Check Maplewood for missing assignments msmadsensclass.weebly.com Check msmadsensclass.weebly.com to access missing assignments Hand in Assignments… Yes you do… You have had plenty of time

END

Constancies chology/07/e07expand.html chology/07/e07expand.html Start at 17min