Study Notes on Sensation and Perception

3.1 Distinguish sensation from perception.
3.2 Identify sensory threshold theories in applied examples.
3.3 Differentiate subliminal perception from subliminal persuasion.
3.4 Describe how light travels through various parts of the eye.
3.5 Recall the stages involved in visual processing.
3.6 Distinguish the major theories of color vision.
3.7 Label the anatomy of the ear.
3.8 Describe the different theories of hearing and types of hearing impairment.
3.9 Explain how the senses of smell and taste work together.
3.10 Identify important components of the body senses including touch, pain, and the kinesthetic and vestibular senses.
3.11 Distinguish top-down from bottom-up processing.
3.12 Recognize how perceptual constancies and perceptual sets help to organize sensations and guide perception.
3.13 Explain the different Gestalt principles of perception.
3.14 Differentiate monocular cues and binocular cues with respect to depth perception.
3.15 Recognize the different types of perceptual illusions and the factors involved in producing them.

Defining Sensation:
- Sensation: The process when energy is detected by one (or more) of the senses.
- Perception: The brain's process of selecting, organizing, and interpreting sensory information.
- Stimulus detection: Occurs when a receptor cell in a sense organ is stimulated by energy.
- Transduction: The conversion of physical energy into an electrical signal by receptor cells.

Absolute Threshold:
- Definition: The minimum amount of energy needed for a person to detect a stimulus 50% of the time.
Just Noticeable Difference (JND):
- Definition: The minimum difference between two stimuli necessary for detection at a rate of 50%.
Variability in Sensory Capabilities:
- Acknowledgment that variability exists between individuals and within individuals under different circumstances, elaborated through Signal Detection Theory.

Subliminal Perception:
- Definition: Occurs when sensory input falls below the threshold of conscious awareness.
Subliminal Persuasion:
- Definition: Involves using subliminal techniques to influence behavior.
- Note that effects of subliminal priming on behavior are typically short-lived.
Sensory Adaptation:
- Definition: The decrease in sensitivity to a constant stimulus as a result of continued exposure.

Vision Mechanisms:
- Vision depends on the availability of light; light is a form of energy within the electromagnetic spectrum.
- Wavelengths of light are described in terms of hue, brightness, and saturation.

Key Structures:
- Retina: Converts incoming light into neural signals; contains photoreceptors (rods and cones).
- Iris: The colored part of the eye that controls pupil size based on light conditions.
- Pupil: Adjusts diameter to regulate light entry.
- Cornea: Transparent outer layer focusing light onto the retina.
- Lens: Focuses light by changing shape.
- Fovea: Area of highest visual acuity in the retina, rich in cones.
- Blind Spot (Optic Disc): Area where the optic nerve exits, lacking photoreceptors.
- Optic Nerve: Transmits visual information to the brain.

Visual Processing Stages:
- Light travels through various structures to reach the retina. Rods function in low-light, while cones are responsible for color and detail vision.
- The optic nerve relays neural messages to the brain, typically processed through contralateral control.

Major Theories:
- Trichromatic Theory: Proposes three types of cones sensitive to different wavelengths of light (short, medium, long).
- Opponent-Process Theory: Suggests visual receptors work in opposing pairs (red-green, blue-yellow, black-white).
Colors perceived in objects originate from reflected light.
Subtractive Color Mixing: Involves the absorption of light (Pigments: Yellow, Cyan, Magenta).
Additive Color Mixing: Combines light of different colors (RGB - Red, Green, Blue).

Sound Wave Characteristics:
- Sound waves have wavelength, amplitude, and purity; determined by frequency measured in Hertz (Hz).
- Human hearing range: 20 Hz to 20,000 Hz.
- Ear anatomy includes outer, middle, and inner sections, each with distinct components like the pinna, eardrum, and cochlea.

Place Theory: Different pitches stimulate specific areas of the cochlea.
Frequency Theory: Pitch perceived by the frequency of neuron firing.
Volley Principle: Neurons fire in succession to create a complex auditory signal.
Hearing Loss Types:
- Sensorineural: Damage to inner ear or pathways to the brain.
- Conductive: Sound conduction issues in outer or middle ear.
- Mixed: Combination of sensorineural and conductive losses.

Olfaction:
- Involves the detection of airborne chemical signals reaching receptors in the nasal cavities.
- Humans possess 5 million olfactory receptors; dogs have at least 300 million.
- Olfactory Regeneration: Olfactory cells can regenerate throughout life.
Taste Mechanism:
- Taste buds located in papillae; basic tastes include sweet, salty, sour, bitter, and umami.
- Concept of Supertasters: Individuals with more taste buds who may avoid certain high-fat and high-sugar foods.

Touch: Part of somatosensory system, involving sensory-discriminative, affective-motivational, and cognitive-evaluative dimensions.
Gate Control Theory of Pain: Proposes two types of nerve fibers relay pain and other tactile signals, managing pain perception.
Kinesthetic Sense: Monitors muscle and joint movement.
Vestibular Sense: Informs brain about body orientation and balance in space.

Processing Types:
- Bottom-Up Processing: Begins with raw stimuli and builds perception from that level.
- Top-Down Processing: Relies on prior knowledge and expectations to shape perception.

Perceptual Constancy: Recognizes the same object despite changes in sensory input (e.g., size constancy, color constancy).
Perceptual Sets: Preconceived frameworks that influence how we perceive stimuli based on expectations.

Grouping Principles:
- Proximity: Items near each other are perceived as a group.
- Similarity: Similar items are grouped together.
- Closure: Perception of complete shapes despite incomplete images.
- Continuity: Perception of continuous patterns rather than disconnected segments.

Cues:
- Monocular Cues: Depth perception using one eye (e.g., size, texture gradient).
- Binocular Cues: Depth perception using both eyes, primarily through retinal disparity, which accounts for slightly different images seen by each eye.

Types of Visual Illusions:
- Literal (Physical) Illusions: Created images differing from objects or situations.
- Physiological Illusions: Result from overstimulation of visual pathways.
- Cognitive Illusions: Shape perception based on higher-level assumptions and knowledge about the world.

Overview of the mechanics of sensation, the visual and auditory systems, chemical senses, and perception theories.