Fall 2013 PSYC 2000 Sec 001 003 Exam 2 Study Outline Chapter 3 Sensation Perception 1 What is sensation What is Perception Can you distinguish between the two o Sensation is detecting physical energy stimuli from the environment and converting it into neural signals It occurs when special receptors in the sense organs are activated allowing various forms of outside stimuli to become neural signals in the brain o Perception is when we select organize and interpret our sensations Perception occurs when we give meaning to our sensations interpreting them so we can act and respond based upon them 2 What are sensory receptors o Where are they located or where can you find them on the body Sensory receptors are the neurons that translate specific environmental stimuli Sensory Receptors are located on our skin tongue nose eyes and ears o How do they take in information from outside stimuli and convert it into something that can be transmitted in the body and brain hint transduction Transduction is the process of converting outside stimuli into neural activity Sensory receptors are the neurons that actually do the translating 3 Be able to fill in the blanks of the table below This table represents understanding of how each sensory organ brings in sensations through its receptors to be converted for transmission to and interpretation by the brain I have provided one example to get you started Vision Stimulus input Light waves light energy Hearing Sound waves Taste chemical Smell chemical Touch Touch pressure temperature pain Elements or properties of stimulus Wavelength color Wavelength frequency of pitch Sweet Sour Salty Bitter Brothy Amplitude brightness Saturation purity Eyes Photoreceptors including rods cones Retina of eyes Amplitude volume how loud or soft the sound is Purity timbre the richness in tone of the sound Ears Hair cells Ear canal Visual cortex Temporal lobe Sensory organ Sensory receptors Location of receptors Main location of processing in brain Tongue Gustatory receptors Nose Olfactory cilia Mouth tongue cheeks roof of mouth Insular cortex Skin skin skin 4 What we detect or become consciously aware of has to do with sensory thresholds o Be able to define differentiate and recognize examples of the Just Noticeable Difference or Difference Threshold and the Absolute Threshold Just Noticeable Difference Threshold minimum difference between two stimuli required for detection 50 of the time minimum stimulation needed to detect a difference or change between two stimuli Absolute Threshold minimum stimulation needed to detect a particular stimulus 50 of the time minimum stimulation needed in order to perceive the presence of a stimulus What is Weber s Law Which threshold theory does it belong too You do not have to apply it 1 Belongs to Just Noticeable Difference Threshold difference thresholds increase in proportion to the size of the stimulus two stimuli must differ by a constant minimum percentage to be perceived as different k I I o What is an alternate theory to the above two thresholds difference and absolute that has been used to explain the detection of stimulus hint Sensation Perception Part 1 lecture Signal Detection Theory predicts how and when we detect the presence of a faint stimulus amid other background noise assumes that there is no single absolute threshold and detection depends on our psychological state o What are subliminal stimuli Generally what influence do they have on us Stimuli that are just strong enough for our sensory receptors to pick them up but not strong enough for us to be able to detect them they can influence our mind and how we behave 5 What is habituation What is sensory adaptation How are they similar and how are they different o Habituation is the tendency of the brain to stop attending to constant unchanging information Ex air condition Ex response to drugs o Sensory adaptation is the tendency of sensory receptors to become less responsive to a stimulus that is unchanging Ex dirty smells disappear Ex adjusting to hot or cold water in a brief time o Similarity o Difference In habituation the sensory receptors are still responding to stimulation but the lower centers of the brain are not sending the signals from those receptors to the cortex The process of sensory adaptation differs because the receptor cells themselves become less responsive to an unchanging stimulus Habituation is somewhat conscious whereas sensory adaptation is not conscious Sensory adaptation occurs in the brain whereas habituation occurs in the body 6 Vision o How does the human visual spectrum compare to the whole or total spectrum of light The wavelengths that people can see are only a small part of the whole electromagnetic o Be able to describe each of the three characteristics or properties of light and what they allow us to perceive e g different wavelengths of light relate to different colors we see Color Hue wavelength determined by the length of the wave or the distance between spectrum wave peaks 1 Short wavelengths 400nm blues purples 2 Long wavelengths 700nm reds oranges Brightness amplitude determined by the height of the wave or how high or low the wave is 1 High amplitude bright 2 Low amplitude dull Saturation Purity determined by how much there is a mixture or wavelengths o What are the parts of the eye including the part that leaves the eye to carry the message signal to the brain light Cornea light enters the eye first point of focusing light Iris colored part muscle that expands and contracts to change the size of opening for Lens focuses the light rays on the retina through visual accommodation process by which the eye s lens changes shape to help focus near or far objects on the retina final part of focusing light Retina contains sensory receptors that process visual information and send it to the brain projects image upside down and reversed 1 Light sensitive inner surface of the eye 2 Visual info gets processed here 3 Contains rods peripheral and night vision and cones color and detail 4 Bipolar cells receive messages from photoreceptors and transmit them to ganglion cells which form the optic nerve integrates and compresses info o Describe the step by step process through which light waves are picked up by the sensory receptors of the eye focused converted into neural activity and transmitted to the brain Light travels in a straight line through the cornea and lens resulting in the image projected on the retina being upside down are
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