Psychology Chapter 3: Sensory Adaptation

Sensory Experiences and Adaptation

• Sensory experiences are limited compared to potential sensory inputs of certain animals.
• Sensory Adaptation occurs when sensory receptors become less responsive to unchanging stimuli.
• Example: Olfactory receptors diminish response to constant odors, leading to the inability to detect the smell after prolonged exposure.
• Sensory receptors are more responsive to changes in stimuli rather than constant input.

Feature Detection

• The brain utilizes feature detectors to process sensory input by identifying key attributes like lines, shapes, and colors.
• Feature detectors are specialized cells in the cerebral cortex, which facilitate the processing of perceptual features over detailed sensory patterns.
• Visual pop-out demonstrates the sensitivity of the visual system to specific features, influenced by both innate traits and early life experiences.

Vision and Sensory Transduction

• The visible spectrum represents only a small fraction of the electromagnetic spectrum perceivable by the eye.
• Vision involves photoreceptors in the retina, which transduce light into electrical signals for the brain to interpret.
• There are two types of photoreceptors: cones and rods.

Photoreceptors

• Cones: Approximately 5 million per eye; function best in bright light and are responsible for color perception and detail.
  • Located mainly in the fovea, they yield high visual acuity (20/20 vision).
  • Color blindness occurs due to cone malfunction or absence, affecting color perception without visual acuity loss.
• Rods: About 120 million per eye, sensitive to dim light and responsible for peripheral vision.
  • Provide black and white vision, particularly responsive to movement.
  • Involved in dark adaptation, allowing increased sensitivity to light in low-light conditions.

Hearing and Sound

• Prolonged exposure to 85 decibels or more can lead to permanent hearing loss; 120 decibels can cause immediate damage.
• Cochlear implants are used to assist those with hearing loss by directly stimulating the auditory nerve bypassing damaged hair cells.

Theories of Hearing Pitch

• Frequency Theory: Proposes pitch is determined by the rate at which hair cells fire. Effective for sounds up to 4,000 hertz.
• Place Theory: Higher frequencies stimulate specific cochlear locations, useful for understanding sounds above 4,000 hertz. Specific cochlear areas correlate with pitch perception, leading to conditions like "hunter’s notch."

Chemical Senses: Olfaction and Gustation

• Olfaction: The sense of smell, where receptors respond to airborne chemical molecules.
• The process of transduction in olfaction converts chemical stimuli into electrical signals through nerve fibers in the nasal lining.
• Lock-and-key Theory: Suggests odors correspond to the shapes of airborne molecules fitting specific receptors.

Olfactory Sensitivity and Anosmia

• Anosmia refers to a loss of smell sensitivity, which can be caused by infections, trauma, or chemical exposure.
• Humans can detect at least 10,000 different odors through specific receptor combinations triggered by various chemicals.

Explore the fascinating concept of sensory adaptation in this quiz. Discover how our senses respond to unchanging stimuli and the remarkable ways in which different animals perceive the world. Learn about the mechanisms behind our diminishing response to constant odors and other sensory experiences.