C4 - Sensation and Perception

• What are the basic five senses of humans?

  Sight, hearing, taste, touch, and smell
• What is sensation?


  Sensation is the activation of the sense organs by a source of physical energy.
• How is perception defined?


  Perception is the sorting out, interpretation, analysis, and integration of stimuli carried out by the sense organs and brain.
• What is a stimulus?


  A stimulus is any passing source of physical energy that produces a response in a sense organ.
• How do we differentiate between light and sound stimuli?

  Light stimuli activate the sense of sight, while sound stimuli activate the sense of hearing.
• What is psychophysics?


  Psychophysics is the study of the relationship between the physical aspects of stimuli and our psychological experience of them.
• What is the absolute threshold?


  The absolute threshold is the smallest intensity of a stimulus that must be present for it to be detected.
• How does stimulus intensity affect detection?

  As the strength of a stimulus increases, the likelihood that it will be detected increases gradually.
• What is noise in the context of perception?

  Noise is background stimulation that interferes with the perception of other stimuli.
• What is the difference threshold?


  The difference threshold is the smallest level of added or reduced stimulation required to sense that a change in stimulation has occurred.
• What does Weber's law state?


  Weber's law states that a just noticeable difference is a constant proportion of the intensity of an initial stimulus.
• Why might a person in a quiet room be more startled by a ringing cell phone than someone in a noisy room?

  Because the ringing cell phone represents a larger change in stimulation in a quiet environment.
• What is adaptation in sensory perception?

  Adaptation is an adjustment in sensory capacity after prolonged exposure to unchanging stimuli.
• What is light in terms of electromagnetic radiation?

  Light is a form of electromagnetic radiation waves that are measured in wavelengths.
• What is the visual spectrum?

  The visual spectrum is the range of wavelengths that the human eye can detect.
• What organ is capable of responding to the visible spectrum?

  The eye is the only organ capable of responding to the visible spectrum.
• What is the function of the cornea?

  The cornea is a transparent, protective window that bends light as it passes through.
• How does the pupil affect focus?

  A small pupil increases the range of distances at which objects are in focus, while a wide open pupil decreases this range.
• What is the role of the lens in the eye?


  The lens bends the rays of light so that they are properly focused on the rear of the eye.
• What is accommodation in vision?

  Accommodation is the process where the lens becomes flatter when viewing distant objects and rounder when looking at closer objects.
• What is the retina's function?

  The retina converts the electromagnetic energy of light to electrical impulses for transmission to the brain.
• How does the brain interpret images from the retina?


  The brain automatically interprets the image in terms of its original position.
• What are rods in the retina?

  Rods are thin, cylindrical receptor cells that are highly sensitive to light.
• What are cones in the retina?

  Cones are typically cone-shaped, light-sensitive receptor cells responsible for sharp focus and color perception.
• Where are cones concentrated in the retina?

  Cones are concentrated on the fovea, the part of the retina responsible for sharp focus.
• What is the fovea's role in vision?

  The fovea is a particularly sensitive region of the retina where images are centered for sharper vision.
• How do rods and cones differ in their functions?

  Cones are responsible for color perception in bright light, while rods are related to vision in dim light and peripheral vision.
• What is dark adaptation?

  Dark adaptation is the phenomenon of adjusting to dim light after being in brighter light.
• What is light adaptation?

  Light adaptation is the process of adjusting to bright light after exposure to dim light.
• What is rhodopsin?

  Rhodopsin is a complex reddish-purple protein whose composition changes chemically when energized by light.
• What role do bipolar cells play in vision?

  Bipolar cells receive information directly from the rods and cones and communicate that information to the ganglion cells.
• What do ganglion cells do?

  Ganglion cells collect and summarize visual information, sending it to the brain through the optic nerve.
• What is the optic chiasm?

  The optic chiasm is a point where each optic nerve splits between the two eyes.
• How do images from the retina correspond to the field of vision?

  Images from the right half of each retina originated in the field of vision to the person’s left, and vice versa.
• What happens in the visual cortex of the brain?

  The ultimate processing of visual images takes place in the visual cortex, where complex processing occurs.
• What are feature detectors?

  Feature detectors are specialized neurons activated by visual stimuli with particular features.
• How do different brain systems process visual information?

  Different brain systems process shapes, colors, movement, location, and depth, showing distinctions in perception.
• How does the brain utilize neural firing information?

  The brain uses information regarding the frequency, rhythm, and timing of the firing of particular sets of neural cells.
• What percentage of men and women are color blind?

  Approximately 7% of men and 0.4% of women are color blind.
• What is the most common form of color blindness?

  The most common form of color blindness is where all red and green objects are seen as yellow.