Vision

Most frequently studied senseMost information comes through

eyes

Objectives

• Analyze the different psychological aspects of vision (HUE/BRIGHTNESS/ SATURATION)

• Synthesize the anatomy of the eye ( CREATE A picture) including the image-focusing portion (cornea, lens, pupil)

• How does the eye connect to the brain?

Vision: How the Nervous System Processes light

• Anatomy of Visual Sensation: Eye is like a camera

• Extracts info. From light waves• Same as X-rays and radio waves

You create Color

• Color is a Sensation that the Brain creates on a wavelength

• As a result color is created in your mind (psychological experience).

• Create visible light- Pure Energy

Psychology of vision= ob #1

• Wavelength-the distance traveled on a wave cycle. Like ripples on a pond

• Electromagnetic Spectrum- the light we can see.

• We see through a Visual Spectrum. Like a window

Light Spectrum

What we see

HueVisual experience specified by color names and related to the wavelength of light

BrightnessVisual experience related to the amount of light emitted from or reflected by an object

SaturationVisual experience related to the complexity of light waves

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3 psychological aspects of vision OB#1

• Hue- the dimension of visual experience specified by color names related to the wavelength of light

• Brightness-Intensity or amplitude of light. • How much light reaches the Retina.• Brain senses neural activity.

• Saturation- (colorfulness) vividness or purity of color

• Dimensions of visual experience related to the complexity of light waves

What we see

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An eye on the worldCorneaProtects eye and bends light toward lensLensFocuses on objects by changing shapeIrisControls amount of light that gets into eyePupilAperture through which light reaches the retina

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Eye on the World

Anatomy of eye (photoreceptor cells- rods/cones)

• Retina-light sensitive layer; like chip in digital camera

• Rods: 125 million, see in the dark. They detect low intensities of light at night. For Example rods help you find a seat in a dark theater.

• Cones: 7 million, color, bright light. See either blue, red or green

An eye on the worldRetinaNeural tissue lining the back of the eyeball’s interior containing the receptors for visionRodsVisual receptors that respond to dim lightConesVisual receptors involved in color vision

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Structures of the retina

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Your turnYou have a hard time locating your red car at night, in the poorly lit mall parking lot. Why?1. Your rods are less sensitive to color in dim light.2. Your cones, which detect color, do not function well in dim light.3. Your ganglion cells receive insufficient overall stimulation to function.4. Your rods, which detect color, do not function well in dim light.

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Your turnYou have a hard time locating your red car at night, in the poorly lit mall parking lot. Why?1. Your rods are less sensitive to color in dim light.2. Your cones, which detect color, do not function well in dim light.3. Your ganglion cells receive insufficient overall stimulation to function.4. Your rods, which detect color, do not function well in dim light.

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More anatomy- IN THE BACK

• Fovea: small, concentrated area=sharpest vision

• Bipolar neurons (cells): collect from many photoreceptors (rods & cones) then shuttles them to Ganglion cells

• Ganglion cells- Form axons that go to optic nerve carries info to back of eye

Objective #3

• You look with your eyes but see with your brain.

• Visual cortex lies in Brain’s occipital lobe• V.C. turns neural impulses into visual

sensations: color, form, boundary, movement and depth.

• Ultimately cortex combines with memories, emotions, motives and sensations

The visual system is not a camera

Much visual processing is done in the brainSome cortical cells respond to lines in specific orientations (e.g., horizontal).

Other cortical cells respond to other shapes (e.g., bulls-eyes, spirals, faces).

Feature detectorsCells in the visual cortex that are sensitive to specific features of the environment

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Summary

• PYSCHIOLOGICAL= VISION• ANATOMY,FRONT, MIDDLE BACK• WHAT PLUGS IN?