Sensation and Perception Chapter 4 Sensation and Perception

Sensation and Perception: Section 1 Sensation and Perception: The Basics

Sensation The stimulation of sensory receptors and the transmission of sensory information to the central nervous system Brain and spinal cord Sensory receptors are located in the eyes, ears and elsewhere in the body. The stimulation of the senses is automatic

Perception Process through which we interpret sensory simulation. Reflects learning, expectations and attitudes.

Stimulation of the senses and the ways in which people interpret that stimulation is effected by concepts Absolute threshold Difference threshold Signal detection theory Sensory adaptation

Absolute Threshold The weakest amount of a stimulus that can be sense. Some people are more sensitive than other Hearing test The first sound you can hear

Difference Threshold Low enough so we can see, hear, smell, taste, and feel But not too low to overload us with information The minimum amount of difference that can be detected between 2 stimuli Paint chips Dark-dark Dark-a little lighter

Signal Detection Theory A method of distinguishing sensory stimuli that takes into account not only their strengths but also: Setting Your physical state Your mood Your attitudes Also considers psychological factors such as: Motivations Expectations Learning We focus on what we deem important.

We focus on what we consider important

Sensory Adaptation The process by which we become more sensitive to real stimuli and less sensitive to unchanged stimuli Low light in a theater Noise of the city

Section 2 Vision

“Seeing is believing” Why do we put so much more trust in evidence that we have seen than evidence we have heard?

The eye Very similar to a camera The amount of light entering the eye determines the size of the pupil. Very similar to a camera The amount of light entering the eye determines the size of the pupil.

Lens Retina Adjusts to the distance of objects by changing its thickness When you squint, you’re adjusting the thickness. The sensitive surface in the eye that acts like film in a camera Photoreceptors Neurons that are sensitive to light Carry visual input to the brain

2 type kinds of photoreceptors Cones Allow you to see in color Blind Spot The Point where the optic nerve leaves they eye. We would never be able to “see” without it. Rods Sensitive to brightness of light Allow you to see in black and white

Adaptation Dark light Walk into a dark room too dark to find a seat Starts to adjust to lower light Will continue for 45 minutes Walking into a bright room A first blink/ hurts Within a minute you can see Adaptation to light happens a lot faster

Visual acuity Determined by the ability to see visual details in normal light Nearsighted Can not see details farther away Farsighted Can not see details close up

Color Vision Afterimages Complementary color of the original color. Staring at one will create an afterimage of another

Color Vision Color blindness Partially or totally unable to distinguish color due to the absence of or malfunction in the cones Color Vision

Optical Illusions Mona Lisa

Section 3 Hearing

Hearing Sound is caused by the changes in air pressure that result from vibration. Each vibration is called a cycle or a sound wave. Every wave has it’s own pitch and loudness.

Pitch Pitch of a sound How low and high the sound is depends on its frequency or the # of cycle per second More cycles the higher the sound Women- short Higher voices Men- long Lower voices

Loudness is determined by the amplitude of sound waves Is measured by decibels

Deafness Conductive Sensorineural Occurs because of damage to the middle ear (hearing aids) Sensorineural Damage to the inner ear Concerts---jobs

Can you hear this

Help of the Deaf Sign Language Implants Sign language Closed captioned shows Use of light as alter devices Sign Language

Would You Rather? Lose your eyesight or hearing? WHY?

Section 4 Other senses

Do you have food cravings?

Do you have food cravings? Research suggest women are more likely to crave sweet foods with lots of fat such as chocolate. Men are prone to crave foods high in protein and fat, such as burgers and lasagna. Do you think food cravings are influenced by societal standards?

Chemical senses Taste Smell Dogs taste sweetness cats can not. Dogs have 7 times stronger sense of smell than humans Without it could not taste as much. Olfactory Nerve Adapts quickly Locker room Perfume Smoke Harmful fumes Taste Dogs taste sweetness cats can not. 4 basic qualities Sweetness Saltiness Sourness bitterness

The Taste Buds Bitter Sour Sweet Salty

The Skin Senses Pressure Temperature Sensory receptors fire when the skin is touched Fingertips, lips, nose and cheeks are more sensitive Shoulders, thighs and calves less sensitive. Is relative Neurons just beneath the skin Adapt to difference in temperature Pool water Going out into heat from an air conditioned building

Pain Gate theory Phantom limb pain A certain amount of information can be processed at a time. Rubbing/ scratching interrupts the pain message Phantom limb pain Pain in missing limbs Stored memories of missing limb

Pain

Video Helen Keller

Section 5 Perception- The way we organize or make sense of our sensory impressions

Closure Tendency to perceive a complete or whole figure even when there are gaps in what your sense tell you.

Figure ground perception Is the perception of figures against a background. Look out a window People, dogs, cars, trees, houses on a background

Proximity

A presentation showing slide examples of the Gestalt Theory's principle of Proximity in different mediums of advertising, art and photography. Gestalt Theory Principle: Proximity

Similarity- people think of similar objects belonging together.

The rule of Continuity The perceptual tendency to group stimuli into continuous patterns. People prefer to see smooth continuous patterns not disrupted ones.

Common Fate Things moving in the same direction are perceived as belonging together. Example: Group of runners people running together in the same direction would appear to have the same purpose.

Visual Illusions Illusions