Concise Summary of Sensation and Perception

Basic Concepts

  • Sensation: Raw data of experience; basic process of obtaining information about external reality.
  • Perception: Organization of sensory information into meaningful experiences.
  • Cognition: Mental processes related to knowing and understanding.

Sensation and Thresholds

  • Absolute Threshold: Minimum stimulus intensity required to detect a sensation (e.g., dimmest light a lifeguard can perceive).
  • Difference Threshold: Minimum distinction between two stimuli detectable by a person.
  • Humans perceive sounds from 20 Hz to 20,000 Hz; can hear dog whistles (40,000-50,000 Hz) but not detect them.
  • Sensory Adaptation: Reduced sensitivity to unchanging stimuli over time.

Senses Overview

  • Vision: Primary sense; depends on light (photons). Three sensations: hue, brightness, saturation.
  • Hearing: Relies on sound waves, characterized by pitch, loudness, and timbre. Measured in Hertz (Hz) and decibels (dB).
  • Chemical Senses (Taste and Smell):
    • Taste: Four basic sensations - sweet, salty, bitter, sour (10,000 taste buds).
    • Smell: Detected by olfactory epithelium; interacts with taste and other senses.
  • Somatic Senses: Include touch (light and deep), temperature (hot and cold), and pain (cutaneous).

Kinesthetic and Balance Senses

  • Kinesthesis: Awareness of body position; important in activities like dance and music.
  • Sense of Balance: Related to the body's position relative to the Earth's gravitational field, located in the inner ear.

Perception and Gestalt Theory

  • Perception: Organizing sensory information to create a psychological understanding of the environment.
  • Gestalt Laws:
    • Focus on patterns and whole forms. The principle of figure-ground helps to differentiate between foreground and background.

Illusions and Depth Perception

  • Illusions: False perceptions caused by distorted cues. Different from delusions (false beliefs) and hallucinations (fabricated perceptions).
  • Depth Perception: Ability to perceive distance; involves binocular cues (retinal disparity).

Attention

  • Definition: Awareness of a selected environmental aspect; selective and fluctuating mental process.
  • Types: Controlled, voluntary, involuntary, and habitual attention.
  • Factors Influencing Attention: Personal interests, goals, environmental changes, and stimulus properties.
  • Distractions: Can affect focus through continuous or discontinuous interference.
  • Disorders: Hyperprosexia, inattention, and distractibility.

Extrasensory Perception (ESP)

  • ESP: Awareness of external events without conventional senses, including precognition, telepathy, and clairvoyance. Case for skeptic views in scientific validation of these phenomena.