Sensation & Perception

DEFINITIONS Sensations-information you are constantly receiving from your environment through your senses. Perceptions-The process by which the brain organizes and interprets sensory information. How we take this jumble of sensations and create meaning.

Synesthesia- syn·es·the·sia A condition in which stimulation of one sense also evokes another.

Psychophysics one of the oldest areas of psychology Psychophysicists try to find mathematical relations between the physical regularities of the world and their effects on the senses.

SIGNAL DETECTION Absolute Threshold. The smallest quantity of physical energy that can be reliably detected by an observer. Difference Threshold (also know as Just noticeable difference or jnd) The smallest difference in stimulation that can be reliably detected by an observer when two stimuli are compared.

Sensory Adaptation and Deprivation The reduction or disappearance of sensory responsiveness when stimulation is unchanging or repetitious. Prevents us from having to respond continuously to unimportant information. Deprivation The absence of normal levels of sensory stimulation.

SENSORY ADAPTATION

Sensory Overload Over-stimulation of the senses. Can use selective attention to reduce sensory overload. Selective attention: the focusing of attention on selected aspects of the environment and the blocking out of others. Inattentional blindness- failure to consciously perceive something you are looking at because you are not attending to it.

Reduction of unwanted sensations SENSORY REDUCTION Reduction of unwanted sensations

VISION

VISION What we See Hue Visual experience specified by color names and related to the wavelength of light. Brightness Visual experience related to the amount or intensity of light emitted from or reflected by an object. (Maximum height of the wave) Saturation (colorfulness) Visual experience related to the complexity of light waves. (How wide or narrow the range of wavelengths is.)

6 An eye on the world Retina Rods Cones Neural tissue lining the back of the eyeball’s interior containing the receptors for vision Rods Visual receptors that respond to dim light Cones Visual receptors involved in color vision

TRICHROMATIC THEORY OR YOUNG-HELMHOLTZ THEORY OPPONENT PROCESS THEORY- HOW WE SEE COLORS TRICHROMATIC THEORY OR YOUNG-HELMHOLTZ THEORY Proposed that the eye detects 3 primary colors: Red, Blue, and Green All other colors derived by combination. OPPONENT PROCESS THEORY- A competing theory of color vision,. proposes that there are four primary types of cones. In addition to the red-sensitive, green- sensitive and blue –sensitive cones, the opponent process theory claims that there are also cones that are sensitive to yellow light. This theory also argues that these four cone types are organized into two opponent system a red-green system and a blue-yellow system. A competing theory of color vision, which assumes that the visual system treats pairs of colors as opposing or antagonistic.

Form Perception Gestalt principles describe the brain’s organization of sensory building blocks into meaningful units and patterns.

Gestalt principles Proximity Closure Things close to one another are grouped together. You perceive the dots on the left as three groups of dots, not as twelve separated unrelated one. Similarly, you perceive the pattern on the right as vertical columns of dots, not as horizontal rows. Closure The brain tends to fill in gaps to perceive complete forms.

Gestalt principles Similarity Continuity Things that are alike are perceived together as belonging to one another. Continuity Seeing continuity in lines that could be interpreted as either continuous or abruptly shifting in direction.

Reversible: Gestalt Ground Figure

VISUAL & PERCEPTAL ILLUSIONS The Ponzo Illusion Versions of the Muller-Lyer illusion

COLOR IN CONTEXT

What we hear Loudness Pitch Timbre The dimension of auditory experience related to the intensity of a pressure wave. Pitch The dimension of auditory experience related to the frequency of a pressure wave. Timbre The dimension of auditory experience related to the complexity of a pressure wave.

Four tastes Four tastes Four basic tastes Salty, sour, bitter, sweet, Umami is considered the fifth taste from the Japanese for delicious. Different people have different tastes based on: Genetics Culture Learning Food attractiveness

Smell: The sense of scents (olfaction) detects gasses diffused in the air. Airborne chemical molecules enter the nose and circulate through the nasal cavity. Vapors can also enter through the mouth and pass into nasal cavity. Receptors on the roof of the nasal cavity detect these molecules.

SENSES OF THE SKIN Skin protects innards, (the internal organs of a human being or animals). helps identify objects, involved in intimacy. Skin senses include: Touch (pressure), Temperature (warmth or cold) and pain.

Gate-control Theory of Pain Experience of pain depends in part on whether the pain gets past a neurological “gate” in the spinal cord.

The Environment Within Kinesthesis- (Kin-a-the-sia) The sense of body position and movement of body parts. Equilibrium The sense of balance Semicircular canals Sense organs in the inner ear, which contribute to equilibrium by responding to rotation of the head.

Critical period If infants miss out on experiences during a crucial period of time, perception will be impaired. When adults who have been blind since birth have vision restored, they may not see well. Innate abilities will not survive because cells in the nervous system deteriorate change or fail to form appropriate neural pathways. Other senses such as hearing may be influenced similarly.

Inborn abilities: The visual cliff 6 Inborn abilities: The visual cliff Glass surface, with checkerboard underneath at different heights Visual illusion of a cliff Baby can’t fall Mom stands across the gap. Babies show increased attention over deep side at age 2 months, but aren’t afraid until about the age they can crawl.

Perceptual set A habitual way of perceiving, based on expectations.

Psychological and Cultural influences: We are more likely to perceive something when we need it. What we believe can affect what we perceive. Emotions, such as fear, can influence perceptions of sensory information. Expectations based on previous experiences can influence perception. All are influenced by culture.

Parapsychology- Field concerned with the study of ESP ESP-Extrasensory perception The ability to perceive something without ordinary sensory information. What your eyes actually see and your perception of it. Has not been scientifically demonstrated. Telepathy-the direct communication of messages from one mind to another without the usual sensory signals. Pre-cognition-the perception of an event that has not happened yet.