The eye; the most complicated sense organ
General – Introduction to the subject
A. Adaptation of sense organs to our biological evolution
Sense organs, as the other organs, are the result of our continuous biological evolution and are built is such way so they can meet our needs.
B. The electromagnetic spectrum and what we are able to see
The electromagnetic spectrum contains a large width of energy areas but we are able to see only a small part of this spectrum, the visible light spectrum.
Figure 1
As you can see the visible area is between the Ultra-violet and Infra-red areas.
With a simple experiment we can show than light from sun can be separated into this light spectrum. Using a prism and a piece of paper with a hole on it (the hole helps us abridge the light into a single beam) and point the beam onto the prism. On the other side we place another piece of paper and we can see the light spectrum.
C. What we see differs from what animals see
It’s a fact that what see differs from what animals see. Humans see the world in a totally different way that bees see for example.
In these pictures you can observer that humans can see the entire visible light spectrum and would be able to see the rich greens of the grass on the left, prairie dogs (=τρωκτικά) and squirrels are red/green color blind, and only perceive the blues, yellows, and grey of the landscape.
Figure 2
Sharks do not possess the same variety of photoreceptors as humans. They have few retinal cones, and as a result, most have no color vision. Also, they have much larger rod receptors (which pick up light), with fewer numbers of them, so their vision is much less acute (=οξέια όραση) than ours.
Figure 3
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...he distinction of colours. Most common is the weakness to distinct red-green colour.
Special tests allow the diagnosis of achromatopsy. Without taking these special tests you won’t be able to know whether you have achromatopsy or not.
Figure 10
Figure 11
The eye illusions
Our visual perception cannot always be trusted. The components of an object can distort the perception of the complete object. Our mind is the final arbiter of truth. Most optical illusions are the result of
1) Incongruent design elements at opposite ends of parallel lines,
2) Influence of background patterns on the overall design,
3) Adjustment of our perception at the boundaries of areas of high contrast,
4) Afterimages resulting from eye movements or from kinetic displays
5) Inability to interpret the spatial structure of an object from the context provided by the picture.
A spectrum is a group of light wavelengths that are ordered in relation to their wavelength length. The electromagnetic spectrum consists radio waves, microwaves, infrared, visible, ultraviolet, X-rays and gamma rays. (1)Specifically, this lab looks at the visible light part of the spectrum because one of the colors in the visible light spectrum is shine through the sample. The visible light spectrum consists of colors of red, orange, yellow, green, blue, indigo, and violet. The color chosen to be shine through the sample is affected by the color of sample when mixed with the indicator Ammonium Vanadomolybdate (AMV). The color on the color wheel that is opposite of the solution’s color is the color that is shined through the
...nd violet wavelengths are the shortest, and violet is the least visible to the human eye. These wavelengths are scattered throughout the day and caused by a redirection of the light-waves direction due to gas molecules in the atmosphere (Mc Knight, p. 84). When the sun is setting towards the end of the day there are few blue wavelengths left and we see orange and red which are dominant and the longest wavelengths of visible light to the human eye. At the bottom of the photo (closest to the setting sun) red and orange are the dominant visible colors with the occasional blue and almost violet. If our eyes could not see orange and red our sunsets would be a dark blue or black.
Vision plays a huge role in the lives of non-human primates. Non-human primates have exceptional binocular vision, due to forward-facing eyes with overlapping visual fields (Prescott). This binocular stereoscopic color vision allows primates to see the world in terms of height, width, and depth, also known as three-dimensional vision (Haviland et al. 2010). Highly developed vision allows the later arboreal primates to judge depth, distance, and location when moving at speed from branch to branch (Haviland et al. 2010). This bino...
Different Visual Illustrations in Perception How can visual illusions illustrate top down processes in perception?
Richard Gregory came up with the top-down process theory in 1970. His theory states that perception is a hypothesis and you make your best guess on what you’re seeing/ perceiving. He also makes the point that when we perceive things we use prior know facts, information, experiences, or memories to infer them. (Gregory, 1966) The top-down process is like reading. If you are trying to understand the whole page, you would need to read the beginning, middle, and end, instead of trying to understand based on two or three sentences. Gregory also argues that we lose around 90% of visual information before it reaches the brain to be processed. (Gregory, 1966). This would explain visual illusions. In 1935, John Ridley
On average they weigh 4,000-7,000 pounds and grow approximately 16-20 feet long ( Great white sharks 1). < commentary needed>Great Whites are the apex predator of the ocean containing 300 serrated teeth and highly-developed senses to hunt prey. Sharks have a great senses of smell, the Great White can smell a drop of blood thousand of miles away. They’re hearing is very powerful , being able to hear the vibrations of prey distances of about 800 ft away and find the exact location through ‘ear stone’( Great white 3). A shark 's sense of hearing truly shows their uniqueness as an apex predator. In addition to great hearing they’re known to have great sight by being able to see up to 50ft away and transition into seeing in light and dark. Additionally sharks have a lateral line on their back that reaches from the front to the back tail, allowing
A spectrum is an image or distribution of colour of any electromagnetic radiation arranged in a progressive series according to wavelength.
Human beings depend on their senses to tell them what is there and what is not. Some believe only what their eyes show
The spectrum that is taken by the hubble space telescope is the visible light spectrum, ultraviolet. Light ...
Sensation refers to the process of sensing what is around us in our environment by using our five senses, which are touching, smell, taste, sound and sight. Sensation occurs when one or more of the various sense organs received a stimulus. By receiving the stimulus, it will cause a mental or physical response. It starts in the sensory receptor, which are specialized cells that convert the stimulus to an electric impulse which makes it ready for the brain to use this information and this is the passive process. After this process, the perception comes into play of the active process. Perception is the process that selects the information, organize it and interpret that information.
Light is what lets you experience colour. The pigment of the retina in your eyes is sensitive to different lengths of light waves which allows you to see different colours. The wavelengths of light that humans can see are called the visible colour spectrum.
we can’t see in the UV spectrum, and there are other animals such as butterflies which have 4 or 5 different photoreceptor types and can see more colors than us
The sensory system’s organs are the sense organs of the body. The purpose of the sensory system is to allow us to experience outside stimuli and identify alterations in the environment by sensory receptors and eyes, nose, ears, tongue, and skin, which are the sensory organs. The sensory system is actually one of the main elements of the body used to process sensory information.
There are many different Visual Perception principles in perception. The main principles are Gestalt. Gestalt is a German word meaning 'form' or 'shape'. Gestalt psychologists formulated a series of principles that describe how t...
The Eye is the organ of sight. Eyes enable people to perform daily tasks and to learn about the world that surrounds them. Sight, or vision, is a rapidly occurring process that involves continuous interaction between the eye, the nervous system, and the brain. When someone looks at an object, what he/she is really seeing is the light that the object reflects, or gives off.