Sensation and Perception Flashcards
What is perception?
Making sense of the constant stimuli and information were bombarded with
How does one measure the sensory experience?
- Bottom up processing: analysis of sensory info Begins with sensory reception and proceeds to the brain fort integration
- Top down processing: Analysis of sensory info guided by our higher level metal processes in which we give meaning to what we perceive.
What are thresholds?
There exists physical energy in our sorroundings that were not able to detect with our senses
- Absolute thresholds: Minimus stimulation necessary to detect sensory info 50% of the time
- Signal detection theory: Assumed there is no absolute threshold, examined the factors that affect one’s ability to detect weak stimuli
- personality
-experience
- expectations
- motivation
- fatigue - Difference thresholds: The minimum difference between two stimuli necessary to detect sensory information 50% of the time
What is sensory adaptation?
Diminished sensitivity to a stimulus as a consequence of constant stimulation. Allows us to attend to informative changes in environment
What are the sensations covered in class?
Vision and hearing
What is vision?
Eyes receive sensory input in the form of light energy
- Wave length: distance between one peak and the next, determines the hue or color
- Intensity: amount of energy contained in light waves, determines the brightness
- Purity: number of wavelengths that make up the light, determines the saturation
What is the process of traduction for visual processing ?
Conversion of light wavelengths into neural signals
- Light enters through the cornea and passes through the pupil
- The lens focuses incoming light rays into an image in the retina
- In the retina there’s two types of receptor cells
- rods: detect black, white and gray, necessary for peripheral and twilight vision
- cones: detect fine detail and produce color vision. Functions in well lit conditions
How is visual info processed?
- Feature detection: feature detection cells that respond to specific features (facial recognition, gaze recognition, body movements and postures, etc)
- Parallel processing: brings the different types of visual info together as an integrated whole (color, depth, motion, form)
- Color vision: colors that we perceives reside in the brain
- young Helmholtz trichromatic theory: the retina contains three color receptors (red green and blue)
- herrings opponent process theory: three types of color receptors, each responsible for a pair of opposing colors (red and green, blue and yellow, black and white)
Current thinking suggests that color vision occurs because of a combination of both
What is hearing?
Changes in air pressure determined by
- Amplitude: strength of a sound wave, influences loudness
- Wavelength: distance between one peak to the next, influences pitch
- Purity: influences tonal quality
What is the process of traduction for auditivo processing?
- The outer ear channels the sound waves through he auditory canal to the ear drum
- The middle ear transmits the ear drums vibrations to the chochlea located in the inner ear
- The hair cells in the coclear membrane bend when the membrane vibrates, triggering neural impulses
- Auditory nerve sense info to auditory cortex in temporal lobe
How is auditory info processed?
Loudness: interpreted from the number of activated hair cells of the coclear membrane. An increase in amplitude is an increase in activation
Pitch:
1. Place theory: different pitches are produced because different sound waves activate hair cells in different places. However neural signals from low pitch sounds are no very organized
2. Frequency theory: different pitches are perceived because different sounds produce different nerve impulses at different rates. However, neurons cannot fire impulses faster than 1000 waves per second, so it doesn’t explain how we can perceive frequencies above that
It is believed we perceive high pitches through place theory and low pitches through frequency theory
How do we perceive the location of sounds?
Stereophonic hearing
- Sounds that come from one direction are received more intensely and sooner by one ear than another
What are the processes to convert sensation into perception?
- Gessalt approach: we tend to perceive sensory stimuli that are close together as a single experience. The whole is greater than the sum of its parts
- Form perception: there are certain rules we follow when grouping stimuli
- Proximity
- Similarity
- Continuity
- Connectedness
- Closure
What has been discovered in regards to depth perception?
That it is an innate ability but it can be perfected through experience
