Week 1 notes Ch 1 &2
Week 1 notes Ch 1 &2 psych 303
Cal State Fullerton
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This 7 page Class Notes was uploaded by Michelle Ibrahim on Wednesday January 27, 2016. The Class Notes belongs to psych 303 at California State University - Fullerton taught by James Neuse in Winter 2016. Since its upload, it has received 75 views. For similar materials see Sensation and Perception in Psychlogy at California State University - Fullerton.
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Date Created: 01/27/16
Sensation and Perception 01/27/2016 ▯ Theme of this book: the idea of perception depends on the properties of the sensory receptors ▯ The Perceptual Process o Begins with outside stimuli suck as outside environment (birds, smells, buildings, etc) o It ends with behavioral response of precieving, recognizing, and taking action o 7 Steps to the process include: Stimulus (environmental) Light is reflected and transformed Receptor processes Neural processing- how neurons work and operate in different parts of the brain Perception Recognition Action o The last three steps do not always happen in chronological order, steps can happen at the same time or even in reverse o For instance if examining a tree and you want to look closer at the tree (action) this might change our (perception) of what we think the tree really is Stimuli (Steps 1 and 2) o Step 1 =the environmental stimuli (the tree) o Step 2 = stimulus on receptors, when the light reflects the tree we are able to see what it is. It is not that the tree is in our actual eye but the reflection that is creating a picture for us too see/perceive o Principle of transformation, the first transformation happens with light reflects off the tree into the persons eyes o When the light reaches the eye it is transformed by the cornea (eye’s optical system) and the lens which is found behind the cornea, then form an image on the receptors of the persons retina (covers the back of eye & contains receptors for vison) o step 1 and step 2 illustrate both transformation and representation. Tree is transformed as an image on the retina, image represents a tree in the persons eyes o Next transformation is within the receptors in the back of the eye. Receptor Processes/Transduction (step 3) o Sensory receptors- visual receptors respond to light, auditory receptors respond to pressure changes in air, touch receptors through pressure in the skin, smell and taste receptors through chemical that enter through nose or mouth o When visual receptors receive light they 1. transform the environmental energy into electrical energy. 2. Shape perception by the way they respond to stimuli. o Rods and cones lines the back of the eye, they change light energy into electrical energy to influence what we perceive Neural Processing (step 4) o After transduction occurs, the tree is represented by electrical signals in visual receptors, they enter an interconnected network of neurons. o First in the retina, then out the back of the eye, and then the brain. o This networks transmits signals through the retina to the brain, then within the brain, changes/processes the signals. Behavioral Responses (Steps 5-7) o Electrical signals from step 4 are transmitted into conscious experience o Step 5= person perceiving the tree o Step 6= person recognizes is as a tree ( creating an association between the image and the object) o 1 behavioral response is action. o Perception leads to action and everytime we move the image in the back of our eye changes there for changing our perception of things Knowledge o Info that people bring to the situation o We use our knowledge to put things in categories o ▯ ▯ ▯ ▯ ▯ ▯ ▯ Key Terms: Environmental stimuli- The object that the person is actually observing, ex.( the tree) Principle of transformation- stimuli and response created by stimuli are transformed or changed, between the environmental stimulus and perception Principle of representation- everything a person perceives is not on direct contact with stimuli but on representation of stimuli that are formed on the receptors and on activity in the person’s nervous system Sensory receptors- cells specialized to respond to environmental energy, which each sensory system’s receptors specialized to respond to a specific type of energy Visual pigment- a light sensitive chemical that reacts to light Transduction- it the transformation of one type of energy to another ex. Light energy to electrical energy. Neural Processing- change sin the signals that occur as they are transmitted through the maze of neurons, happens in places such as the retina Occipital lobe- Primary receiving area for vision Pariental lobe- skin senses processes here, pain, temperature Temporal lobe- Primary receiving area for hearing processes here, auditory nerve Frontal lobe- receives signals from all senses, plays an important role in perceptions that involve coordination of info received from two or more senses Primary receiving area- electrical signals from each sense arrive in the cerebral cortex as the primary receiving area Cerebral Cortex- contains the machinery for creating perceptions as well as other functions, such as language, memory, and thinking Perception- conscious awareness of an object Recognition- placing an object in a category such as “tree” that gives it a meaning Visual form ahnosia- an inability to recognize objects, cause by a brain tumor, he could see objects in its parts but not as a whole and recognize it Action- behavioral response which involves motor activities Knowledge- any information that the perceiver brings to the situation Bottom up processing (data based processing)- processing based on the stimuli reaching the receptors, taking apart components of the image to figure out what the image is exactly. Ex) I see a car, then look at all the feature of the car and realize this is a certain type of Ferrari (gestalt) Top down processing (knowledge based processing)- refers to the processing that is based on knowledge. Ex. I have seen a car before, this looks like a car, this is a car. Even though the person has never seen this exact object (car) they can relate it to previous knowledge. Psychophysical approach (psychophysics)- measures the relationship between the stimuli and the behavioral responses. The physiological approach- involves measuring the relationship between stimuli and physiological responses (step 1 & 2) and physiological responses (step 3 &4), behavioral responses (step 5-7) Absolute threshold- the minimum stimulus intensity that can just be detected Psychophysical methods- methods used to measure the relationship between stimuli and perception Method of limits- the experimenter presents stimuli in either ascending order or descending order Method of adjustment- stimulus intensity is either increased or decreased until the stimulus can just be detected Method of constant stimuli- experimenter presents 5 to 9 different stimuli with different intensities and in random order. This is the most accurate method b/c it contains many different stimuli and in random order. Difference threshold- the absolute threshold measure the stimulus level above zero that is necessary for detecting a stimulus. Response comprehension- the increase in perceived magnitude is smaller than the increase in stimulus intensity Response expansion- as intensity is increased, perceptual magnitude increases more than intensity Visual search- in which the observers task is to find one stimulus among many as quickly as possible Reaction time- the time between presentation od the stimulus and the observers response to it Response criterion- a way to describe the difference between the two people who are answering. Julie says yes a lot if she see even a little light therefore meaning she has a low response criterion, regina responds yes only if she actually sees the light, she has a high response criterion ▯ ▯ ▯ Steps of perception Step 1- environmental stimuli Step 2 – light is reflected and transformed to create an image of the tree on the way to the visual receptors (the retina) Step 3- how the receptors transform light into electrical signals and determine our sensitivity to light and which part of the light we see. Step 4- electrical signals are proceed as they travel in neurons These are the physical steps to the process and what we see in the retina is seeing in focus, what we see because of cones and rods is seeing in dim light, what we see in the neural processing is seeing fine details ▯ Light and Focusing Light is the stimulus for vision, it is also a band of energy within the electromagnetic spectrum The cornea and the lens are located at the front of the eye The receptors and neurons in the retina are in the back of the eye 2 transformations occur in the retina o light that is reflected from the object into an image of the object o the transformation of the image of the object into electrical signals the cornea and lens focus the image into the retina ▯ Loss of Accommodation Presbyopia occurs because as we get older the lens start to harden then have a hard time adjusting ▯ Myopia/nearsightedness Inability to see distant objects clearly Moving an object closer pushes the focus point further back ▯ Hyperopia/farsightedness Can see distant objects clearly Vision does not occur in the retina but in the brain. Before the brain can create vision the light in the retina must activate visual receptors in the brain. ▯ Receptors and Perception Visual pigments trigger electrical signals that go to the brain to be able to tell what the object is. They also determine our ability to see dim light and light in other parts of the visual spectrum ▯ Transforming Light Energy Into Electrical Energy Transduction occurs in the rods and cones Visual pigments have two parts o A long protein called opsin o A smaller light sensistive component called retinal When a visual pigment molecule absorbs one phton of light the retinal changes its shape Photons can be used to describe light ▯ Adapting to the Dark High threshold corresponded to low sensitvity ▯ ▯ Key Terms: Electromagnetic spectrum- is a continuum of electromagnetic energy that is produced by electric charges and is radiated as waves. Wavelength- the energy in a electromagnetic spectrum, the distance between the peaks of the electromagnetic waves Visible light- the energy within the electromagnetic spectrum that humans can perceive, has wavelengths Photons- small packets of energy in which light can be described Eye- contain the receptors for vision Pupil- light reflected from object enters here Cornea- light is focused through here, transparent covering over the front of the eye , 80% of eye focusing power Lens- form sharp images of the objects, remaining 20% of focus. Can change its shape to adjust the focus Retina- the network of neurons that covers the back of the eye and that contains the receptors for vision, where the image is stored Rods and cones- visual receptors Visual pigments- contain light sensitive chemicals that react to light and trigger electrical signals Optic nerve- conducts signals towards the brain Ciliary muscles- are the muscles that change shape to focus in the lens Accommodation- is the change in lens shape that occurs when the ciliary muscles at the front of the eye tighten and increases curvature to create a sharp image Near point- the distance at which you lens can no longer accommodate to bring close objects into focus Presbyopia- the distance of the near point increase as the person gets older Far point- the distance at which light becomes focused on the retina Isomerization- change of shape, creates a chemical chain reaction Dark adaption- increasing sensitivity in the dark Fovea- part of the retina that only contains cones, when we look directly at an object Peripheral retina- includes all of the retina outside the fovea, contains both rods and cones Blind spot- where the optic nerve leaves the eye, absence of receptors Dark adaption curve- the function relating sensitivity to light to time in the dark, beginning when the lights are extinguished Light adapted sensitivity- the sensitivity measured in the light ▯
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