File Name: difference between sensation and perception .zip
The topics of sensation and perception are among the oldest and most important in all of psychology. People are equipped with senses such as sight, hearing and taste that help us to take in the world around us. Amazingly, our senses have the ability to convert real-world information into electrical information that can be processed by the brain.
What does it mean to sense something? Sensory receptors are specialized neurons that respond to specific types of stimuli.
Sensation and perception are two separate processes that are very closely related. Sensation is input about the physical world obtained by our sensory receptors, and perception is the process by which the brain selects, organizes, and interprets these sensations.
In other words, senses are the physiological basis of perception. What does it mean to sense something? Sensory receptors are specialized neurons that respond to specific types of stimuli. When sensory information is detected by a sensory receptor, sensation has occurred. For example, light that enters the eye causes chemical changes in cells that line the back of the eye. These cells relay messages, in the form of action potentials as you learned when studying biopsychology , to the central nervous system.
The conversion from sensory stimulus energy to action potential is known as transduction. You have probably known since elementary school that we have five senses: vision, hearing audition , smell olfaction , taste gustation , and touch somatosensation.
It turns out that this notion of five senses is oversimplified. We also have sensory systems that provide information about balance the vestibular sense , body position and movement proprioception and kinesthesia , pain nociception , and temperature thermoception. Figure 1. The absolute threshold for detecting light is greater than you probably imagined—the human eye can see a candle on a clear night up to 30 miles away! The sensitivity of a given sensory system to the relevant stimuli can be expressed as an absolute threshold.
Another way to think about this is by asking how dim can a light be or how soft can a sound be and still be detected half of the time. The sensitivity of our sensory receptors can be quite amazing. Under quiet conditions, the hair cells the receptor cells of the inner ear can detect the tick of a clock 20 feet away Galanter, It is also possible for us to get messages that are presented below the threshold for conscious awareness—these are called subliminal messages.
A stimulus reaches a physiological threshold when it is strong enough to excite sensory receptors and send nerve impulses to the brain: this is an absolute threshold. A message below that threshold is said to be subliminal: we receive it, but we are not consciously aware of it.
Therefore, the message is sensed, but for whatever reason, it has not been selected for processing in working or short-term memory.
Over the years there has been a great deal of speculation about the use of subliminal messages in advertising, rock music, and self-help audio programs.
Research evidence shows that in laboratory settings, people can process and respond to information outside of awareness. Figure 2. Priming can be used to improve intellectual test performance. Research subjects primed with the stereotype of a professor — a sort of intellectual role model — outperformed those primed with an anti-intellectual stereotype.
These days, most scientific research on unconscious processes is aimed at showing that people do not need consciousness for certain psychological processes or behaviors. One such example is attitude formation.
The most basic process of attitude formation is through mere exposure Zajonc, Merely perceiving a stimulus repeatedly, such as a brand on a billboard one passes every day or a song that is played on the radio frequently, renders it more positive. Interestingly, mere exposure does not require conscious awareness of the object of an attitude. In fact, mere-exposure effects occur even when novel stimuli are presented subliminally for extremely brief durations e. Intriguingly, in such subliminal mere-exposure experiments, participants indicate a preference for, or a positive attitude towards, stimuli they do not consciously remember being exposed to.
Priming generally relies on supraliminal stimuli, which means that the messaging may occur out of awareness, but it is still perceived, unlike subliminal messaging. Supraliminal messages are be perceived by the conscious mind. For example, in one study, shoppers listened to either French or German music the supraliminal messaging while buying wine, and sales originating from either country were higher when music from that same country was played overhead.
These lists contained words commonly associated with the elderly e. The remaining participants received a language task in which the critical words were replaced by words not related to the elderly. After participants had finished they were told the experiment was over, but they were secretly monitored to see how long they took to walk to the nearest elevator.
The primed participants took significantly longer. That is, after being exposed to words typically associated with being old, they behaved in line with the stereotype of old people: being slow. Such priming effects have been shown in other domains as well.
For example, Dijksterhuis and van Knippenberg demonstrated that priming can improve intellectual performance. They asked their participants to answer 42 general knowledge questions taken from the game Trivial Pursuit. Both of these studies have had difficult times replicating, so it is worth noting that the conclusions reached may not be as powerful as originally reported.
Absolute thresholds are generally measured under incredibly controlled conditions in situations that are optimal for sensitivity. Sometimes, we are more interested in how much difference in stimuli is required to detect a difference between them. This is known as the just noticeable difference jnd or difference threshold. Unlike the absolute threshold, the difference threshold changes depending on the stimulus intensity. As an example, imagine yourself in a very dark movie theater.
If an audience member were to receive a text message on her cell phone which caused her screen to light up, chances are that many people would notice the change in illumination in the theater. However, if the same thing happened in a brightly lit arena during a basketball game, very few people would notice.
The cell phone brightness does not change, but its ability to be detected as a change in illumination varies dramatically between the two contexts. It is the idea that bigger stimuli require larger differences to be noticed. For example, it will be much harder for your friend to reliably tell the difference between 10 and 11 lbs. Think about a time when you failed to notice something around you because your attention was focused elsewhere.
While our sensory receptors are constantly collecting information from the environment, it is ultimately how we interpret that information that affects how we interact with the world.
Perception refers to the way sensory information is organized, interpreted, and consciously experienced. Perception involves both bottom-up and top-down processing. Bottom-up processing refers to the fact that perceptions are built from sensory input.
On the other hand, how we interpret those sensations is influenced by our available knowledge, our experiences, and our thoughts. This is called top-down processing. Look at the shape in Figure 3 below. Seen alone, your brain engages in bottom-up processing. There are two thick vertical lines and three thin horizontal lines. There is no context to give it a specific meaning, so there is no top-down processing involved. Figure 3. What is this image? Without any context, you must use bottom-up processing.
Now, look at the same shape in two different contexts. Surrounded by sequential letters, your brain expects the shape to be a letter and to complete the sequence. Figure 4. With top-down processing, you use context to give meaning to this image. Figure 5. When given a context, your perception is driven by your cognitive expectations.
Now you are processing the shape in a top-down fashion. One way to think of this concept is that sensation is a physical process, whereas perception is psychological.
Although our perceptions are built from sensations, not all sensations result in perception. This is known as sensory adaptation. Imagine entering a classroom with an old analog clock. Upon first entering the room, you can hear the ticking of the clock; as you begin to engage in conversation with classmates or listen to your professor greet the class, you are no longer aware of the ticking.
The clock is still ticking, and that information is still affecting sensory receptors of the auditory system. The fact that you no longer perceive the sound demonstrates sensory adaptation and shows that while closely associated, sensation and perception are different. There is another factor that affects sensation and perception: attention.
Attention plays a significant role in determining what is sensed versus what is perceived. Imagine you are at a party full of music, chatter, and laughter. You get involved in an interesting conversation with a friend, and you tune out all the background noise. If someone interrupted you to ask what song had just finished playing, you would probably be unable to answer that question. See for yourself how inattentional blindness works by watching this selective attention test from Simons and Chabris :.
One of the most interesting demonstrations of how important attention is in determining our perception of the environment occurred in a famous study conducted by Daniel Simons and Christopher Chabris In this study, participants watched a video of people dressed in black and white passing basketballs. Participants were asked to count the number of times the team in white passed the ball.
During the video, a person dressed in a black gorilla costume walks among the two teams. You would think that someone would notice the gorilla, right? Because participants were so focused on the number of times the white team was passing the ball, they completely tuned out other visual information. Failure to notice something that is completely visible because of a lack of attention is called inattentional blindness.
In a similar experiment, researchers tested inattentional blindness by asking participants to observe images moving across a computer screen. They were instructed to focus on either white or black objects, disregarding the other color.
Perception from the Latin perceptio , meaning gathering or receiving is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous system , which in turn result from physical or chemical stimulation of the sensory system. Perception is not only the passive receipt of these signals , but it's also shaped by the recipient's learning , memory , expectation , and attention. Perception depends on complex functions of the nervous system, but subjectively seems mostly effortless because this processing happens outside conscious awareness. Since the rise of experimental psychology in the 19th century, psychology's understanding of perception has progressed by combining a variety of techniques.
Sensation and perception are interrelated processes that are developed throughout the lifespan. Although they have a close relationship, sensation and perception have discrete qualities that differentiate one from the other. Sensation is defined as the process in which a sensory receptor is stimulated, producing nerve impulses that travel to the brain, which in turn interprets such impulses as a visual image, a sound, taste, odor, touch, or pain. The physical stimulus present in the environment emits energy that is absorbed by a sensory organ known as transduction , causing sensation. Perception refers to the occurrence when the brain performs organization of information it obtains from the neural impulses, and then begins the process of translation and interpretation. It is a vital process that helps us rationalize or make sense of the information related to the physical stimulus.
This chapter is about detection what is in our environment (sensation) and determining what it is? (perception) Part of determining what it is.
Sensing and perception are fundamental psychological processes of how we acquire information. Hence, even though they are two very different processes, they occur in relation to one another. Sensation refers to the process of sensing our environment through touch, taste, sight, sound, and smell.
Sensation and perception are two separate processes that are very closely related.
The Eye and the Mind pp Cite as. If one rejects the reality of consciousness as Moore understands it, there remains the need to replace his account of perception with a better one. And since this form suggests that seeing is a relation, is there some alternative analysis which preserves its relational structure? Here is a suggestion of D.
We have five different sensory organs: eyes, nose, ears, tongue, and skin. These five sensory organs are responsible for receiving different stimulations around us through seeing, smelling, hearing, tasting, and, finally, feeling through the skin. The signals which are received through our sensory organs from the environment around us are called sensations. Simply put, sensations are what our sense organs receive and transmit to the brain.
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