Chapter 3: Sensation and Perception Flashcards
What is sensation?
sensation is detecting physical energy from the environment and converting it into neural signals
o Occurs when specialized receptors in the body are activated allowing various forms of outside stimuli to become neural signals in the brain
o Process by which information from outside world enters brain § Information enters through sensory receptors ( tongue, ear, etc.)
Convert different stimuli into neural activity Consciously or unconsciously
What is Transduction?
Transduction is converting outside stimuli into neural activity.
What is perception?
When we select, organize, and interpret our sensations, the process is called perception. Perception occurs when we give meaning to our sensations, interpreting them.
What are the five senses of transduction?
Transduction
- Taste (gustation): food molecules chemical signals coming in
- Vision: light (photons)
- Hearing ( audition): sound waves
- Touch (somatosentaion): pressure and temperature
- Smell (olfaction): molecules in the air
Who was Ernest Weber?
Ernest Weber (1795-1878)
o Just noticeable differences- smallest difference between two stimuli that is detectable 50% of the time; whatever the difference might be, it is always a constant
o Ex: lifting a 55lb weight and a 50lb weight and half the time you say there is a difference
What is absolute threshold?
Absolute Threshold: Minimum stimulation needed to detect a particular stimulus 50% of the time.
What is the difference threshold?
Difference Threshold: Minimum difference between two stimuli required for detection 50% of the time, also called just noticeable difference (JND).
What is Weber law?
Weber’s law in humans, difference thresholds (experienced as a jnd) increase in proportion to the size of the stimulus
Two stimuli must differ by a constant minimum percentage to be perceived as different
k=ΔI/I
What are Sublimal Threshold?
Subliminal stimuli are those just strong enough for our sensory receptors to pick them up, but not strong enough for us to be able to detect them
What is habituation?
Habituation is tendency of the brain to stop tending to constant, unchanging information; air conditioning; at the neural level
What is the priming effect?
Priming effect reveals that we can process some information from stimuli too weak to recognize, No powerful enduring effects but really subtle
What are microsacchades?
Microsacchades constant movement of the eyes; tiny little vibrations that people do not notice consciously; prevents sensory adaption to visual stimuli
What is sensory adaptation?
Sensory adaption is the tendency for the sensory receptors to be less responsive to stimulus unchanged; don’t send the signals to the brain
What is transduction?
Transduction is the transformation of stimulus energy into neural impulses.
What is photo transduction?
Photo transduction Conversion of light energy into neural impulses that brain can understand.
Color is determined by wavelength. What is a wavelength?
Wavelength is determined by the length of the wave, distance between wave peeks
The brightness of a color is determined by amplitude and intensity of a wavelenght. What is amplitude and intensity?
- Amplitude is determined by the height of the wave, how high or low the wave actually is
- Intensity is the amount of energy in a wave; determined by amplitude; related to perceived brightness
What determines saturation?
Determined by whether or how much there is a mixture of wavelengths.
What are the parts of the eye?
The parts of the eye are the cornea, iris, lens, and the retina.
What is the cornea?
Cornea Transparent tissue where light enters the eye.
What is the iris?
The Iris is the muscle that expands and contracts to change the size of the pupil for light.
What are the lens?
The lens focuses the light rays on the retina ( through visual accommodation a process by which the eye’s lens changes the shape to help focus near or far objects on the retia)
What is the retina?
Retina Light sensitive inner surface of the eye containing photoreceptor rods and cones plus layers of other neurons (bipolar and ganglion cells that process visual information)
What are rods and cons?
Cones
- 6 million
- Center
- Low sensitivity to dim light
- Located in fovea
- Color and detail sensitive
Rods
- 120 million
- Responsible for peripheral vision
- Allow eyes to adapt to low levels of light; high sensitivity to dim lighting
- Not color or detail sensitive