Sensation and Perception Flashcards

Sensation and Perception Concepts

• Distal vs. Proximal Stimuli: Proximal stimuli are the direct interactions with sensory receptors (e.g., heat from a campfire), while distal stimuli are the actual sources (e.g., the campfire itself).

• Ganglia: Clusters of neuron cell bodies located outside the central nervous system (CNS) that transmit sensory information to the CNS.

Receptive Fields and Stimuli

• Types of Receptors:
  • Photoreceptors: Respond to visible light waves.
  • Hair Cells: Detect fluid movement in the inner ear, related to hearing and balance.
  • Nociceptors: Triggered by harmful or painful stimuli.
  • Thermoreceptors: Sensitive to temperature changes.
  • Osmoreceptors: Monitor blood osmolarity.
  • Olfactory Receptors: Respond to volatile compounds (smell).
  • Taste Receptors: Triggered by dissolved substances (taste).

Sensory Thresholds

• Absolute Threshold: The minimum intensity required for a stimulus to elicit an action potential.
• Threshold of Conscious Perception: The lowest intensity for a stimulus to be perceived consciously by attention-related brain areas.
• Difference Threshold: The smallest change in stimulus that can be detected; increases with intensity of the original stimulus.
• Weber's Law: States a constant ratio exists between the change needed for a just noticeable difference (jnd) and the original stimulus magnitude.

Perceptual Theories

• Signal Detection Theory: Perception influenced by non-sensory factors, including personal experiences and expectations.
• Duplicity Theory of Vision: The retina has two types of photoreceptors: rods for light/dark and cones for color.

Vision and the Eye

• Visual Acuity: Highest at the fovea (cone-rich area); a blind spot exists where the optic nerve exits (no photoreceptors).
• Superior Colliculus: Brain region responsible for eye alignment in response to sudden loud noises.
• Parvocellular Cells: Detect shapes and contribute to visual detail.
• Magnocellular Cells: Specialize in motion detection.

Auditory and Sensory Systems

• Utricle and Saccule: Structures in the ear sensitive to linear motion; semicircular canals detect rotational motion.
• Thalamic Nuclei:
  • Lateral Geniculate Nucleus (LGN): Processes visual input.
  • Medial Geniculate Nucleus (MGN): Processes auditory input.

Sound Perception

• Place Theory: Pitch perception is determined by hair cell location on the basilar membrane; higher frequencies vibrate cells near the oval window.

Somatosensory Modalities

• Four Main Modalities: Pressure, vibration, pain, and temperature.

Pain Perception

• Gate Theory of Pain: Suggests pain perception can be modulated by a mechanism that adjusts pain signal flow.

Processing Methods

• Bottom-Up Processing: Data-driven approach relying on sensory input to build a perception from individual components.
• Top-Down Processing: Recognizes whole objects based on memories and expectations, subsequently identifying components.

Gestalt Principles

• Gestalt Principles: Include elements such as proximity, similarity, and good continuation to infer missing parts in images.
• Law of Prägnanz: Perceptual organization favors simplicity, regularity, and symmetry in visual interpretation.

Test your knowledge of sensation and perception concepts with these flashcards. Learn about the differences between distal and proximal stimuli, as well as the role of ganglia in the nervous system. Ideal for psychology students seeking to enhance their understanding of sensory processes.