Psychology Chapter Sensation and Perception

Sensation and Perception

• Knowledge originates from perceptions.
• Sensation involves detecting, converting, and transmitting raw sensory information to the brain from sense receptors.
• Sense organs include eyes, ears, nose, tongue, skin, and internal organs.
• Perception is the brain's assembly and combination of sensory input into meaningful patterns.
• Perceptions are personal interpretations of reality.

Psychophysics

• Studies the relationship between physical stimuli and the sensations they evoke.
• Examples: brightness (light), volume (sound), weight (pressure), sweetness (taste).
• Transduction converts physical energy (light waves, sound waves, pressure) into neural signals.

Sensation Thresholds

• Absolute Threshold: The minimum stimulation needed to detect a stimulus 50% of the time.
• Difference Threshold (JND): The minimum difference between two stimuli that a person can detect 50% of the time.
• Weber's Law: The JND is a constant proportion of the original stimulus intensity, not a constant amount.

Signal Detection Theory

• Predicts how and when we detect a stimulus (signal) amidst background noise.
• No single absolute threshold exists; detection varies among and within individuals.

Somesthetic Senses

• Vestibular Sense: Balance and body position in space (semicircular canals in the ear filled with fluid).
• Kinesthetic Sense: Body position and movement of individual body parts.
• Touch (Somatosensory): Pressure, warmth, cold, and pain.

Vestibular System and Motion Sickness

• Motion sickness arises from conflicting sensory information; vestibular system sensations don't match eye and body sensations.

Audition (Hearing)

• Transduction of air pressure waves (sound waves) into neural impulses.

• Sound Waves: Oscillations of pressure that stimulate the hearing organs.

• Amplitude: Perceived as loudness (height of the waves).

• Frequency: Perceived as pitch (number of waves in a given time).

• Sound Localization: Sounds are heard first and loudest by the nearest ear.

Factors Influencing Perception

• Attention (selective vs. divided).
• Organization (figure-ground).
• Expectations (Perceptual Set).
• Motivation.

Perceptual Attention

• Selective Attention: Focusing on one stimulus.

• Divided Attention: Splitting focus between tasks.

• Cocktail Party Effect: Focusing on a conversation amongst other conversations.

• Inattentional Blindness: Inability to perceive sensory stimuli due to limited attentional capacity.

Perceptual Constancies

• Experience of constant perception despite changing retinal images.
• Examples: Color, size, and shape constancy.

Depth Perception

• Judging distance and seeing in three dimensions.
• Monocular Depth Cues: Clues based on cues from one eye.
• Examples: Linear perspective, relative size, relative height, interposition, texture gradient, light and shadow, accommodation.
• Binocular Depth Cues: Clues based on differing views from two eyes.
• Examples: Convergence, retinal disparity.

Perceptual Expectations (Perceptual Set)

• Predisposition to perceive things a certain way based on past experiences, thoughts, and expectations.

Top-Down vs. Bottom-Up Processing

• Top-down processing: Influenced by expectations and prior knowledge.
• Bottom-up processing: Influenced by stimulus features.

Parallel Processing

• Simultaneous processing of different stimuli.

Perceptual Adaptation

• Adjustment to altered viewing fields.

Explore the fascinating world of sensation and perception in this quiz. Discover how our sense organs detect stimuli, how our brain interprets sensory information, and the principles of psychophysics. Test your knowledge on thresholds and the laws governing our sensory experiences.