Absolute Threshold: The minimum stimulation needed to detect a particular stimulus 50% of the time.

The human eye can see a carrot on fire from thirty miles away

Difference Threshold: The minimum difference between two stimuli required for detection 50% of the time. In simpler terms, when an individual is able tell the difference between two separate things.

The human eye can identify the difference between a carved pumpkin lit with a candle and one without a candle to illuminate it.

FUN FACT #1

• Vision is seen with the brain, not the eyes. Eyes function like a camera, capturing the light and sending data back to the brain.

FUN FACT #2

The human eye can see 500 shades of gray.

Fun Fact #3



The cornea is the only tissue in the human body which doesn't contain blood vessels.

Fun Fact #4

Our eyes are made up of over 2 million working parts.

Fun Fact #5

Eyes are able to process 36,000 pieces of information in a single hour.

Transduction:

The transformation of sight, sound, and smell into electrical signals through the brain

Stimulus Input:

Humans detect visible light. When looking at the process of vision, the stimulus input is considered visible light.

Hue is the dimension of color determined by the wavelength of light.

In other words, the short or long distance of each wave of light is what creates what color we can see.

Short Wavelengths: Blue

Long Wavelengths: Red

Cornea:

Transparent (see-through) tissue where light enters the eye

Iris:

Muscle that gets bigger and smaller to change the size of the opening (pupil) for light

Lens:

Directs the light rays to travel towards the retina

Retina:

Located at the back of the eye and has light-sensitive cells called rods and cones. When you look at something, light hits the retina. The rods and cones send electrical signals to the brain to figure out what you are seeing.

Optic Nerve:

Carries electrical signals from the eye to the brain.