Fall 2013 PSYC 2000 Sec 001 003 Exam 2 Study Outline Chapter 3 Sensation Perception 1 What is sensation signals o Detect physical energy stimuli rom the environment and convert it into neural o Occurs when special receptors in the sense organs are activated allowing various forms of outside stimulus to become neural signals in the brain o Example feeling the heat from the sun someone tapping you on the shoulder 2 What is Perception o When we select organize and interpret our sensations the process o Occurs when we give meaning to our sensations interpreting them so we can act and respond to the environment o Has some individuality to it o Example if you poke someone and how they interpret based on feeling if you knew the person it is cool if you don t it s not 3 What are sensory receptors o Sensory Receptor Neurons that transduce specific environmental stimuli example your skin o Where are they located or where can you find them on the body Location on sense organs mouth nose eyes ear skin 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 process of converting outside stimuli into neural activity 4 Name the environmental stimuli that stimulate the receptors for each sense i e vision hearing taste smell touch That is what is the stimulus input that each sense picks up on from the environment and can convert for transmission note relates to table below o Eyes light o Ears vibrations o Taste and Smell chemicals o Touch pressure temperature pain 5 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 Stimulus input Elements or properties of stimulus Sensory organ Sensory receptors Vision Light waves light energy Hearing Sound waves Wavelength pitch Amplitude loudness Purity timbre Ears Hair Cells Wavelength color Amplitude brightness Saturation purity Eyes Photoreceptor s including rods cones Taste Smell Chemicals Chemicals molecules air molecules from food 5 Basic Tastes Thousands of different odors Touch Pain temperature pressure Mouth Nose Skin Taste buds receptors Olfactory cilia on olfactory receptor Location of receptors Retina of eyes Basilar Tongue membrane Top of nasal passage Visual cortex Insular cortex Olfactory Auditory cortex bulb Main location of processing in brain 6 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 Specialized receptors free nerve endings pain and touch pressure sensitive Under 1st layer of skin or muscles tendons joints organs Somatosensory cortex Minimum stimulation need to detect a particular stimulus 50 of At point of threshold anything below won t be detected anything Absolute threshold the time above will be detected Difference threshold Minimum difference between two stimuli required for detection 50 of the time also called just noticeable difference JND When you can detect a change in intensity Light bulb example What is Weber s Law Which threshold theory does it belong too You do not have to apply it Difference thresholds experienced as a just noticeable difference increase in proportion ot the size of the stimulus portion to change a stimulus remains the same no matter the initial intensity of the stimulus Two stimuli must differ by a constant minimum percentage rather than a constant amount to be perceived as different Weber fraction 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 signal amid background noise other stimulation Assumes that there is no single absolute threshold detection depends on our psychological state o What are subliminal stimuli Generally what influence do they have on us Subliminal Stimuli The stimuli just strong enough for our sensory receptors to pick them up but not strong enough for us to be able to detect them within subliminal threshold Example Picture of the guy where both good and bad images were flashed at us and we saw the man differently People are constantly picking up things in their external environment but they don t reach level to come into awareness However it can still influence us because it an cause an immediate involuntary response that isn t long lasting 7 What is habituation What is sensory adaptation How are they similar and how are they different o Habituation The tendency of the brain to stop attending to constant unchanging information Brain ignores Example An AC being on and not noticing it until it turns on or off stimuli that are being sensed but don t change o Sensory Adaptation The tendency of sensory receptors to become less responsive to a stimulus Receptors become less responsive to the stimulus and therefore no longer that is unchanging send signals to the brain Example Smelly garbage wearing rings watches o How does the human visual spectrum compare to the whole or total spectrum of We actually see a very small portion of the light spectrum 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 8 Vision light Wavelengths between wave peaks determined by the length of the wave distance Short wavelength high frequency bluish colors high pitched Long wavelength low frequency reddish colors low pitched sounds sounds Brightness Amplitude determined by the height of the wave how high or low the wave actually is Intensity amount of energy in a wave determined by amplitude related to perceived brightness Great amplitude bright colors loud sounds Small amplitude dull colors soft sounds Determined by whether or how much there is a mixture of Saturation purity wavelengths message signal to the brain o What are the parts of the eye including the part that leaves the eye to carry the Cornea Transparent tissue where light enters the eye and bends the light waves so the image can be focused on the retina Iris Muscle that expands and contracts to
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