introduction to psychology sensation & perception

Introduction to Psychology

Sensation & Perception

Sensation v. Perception

Sensation: the stimulation of sensory receptors; neural signals from environmental stimuli (neural process) The process of conversion between physical

energy (i.e. light) into neural impulses is called transduction

Perception: the process of apprehending, recognizing, understanding, and learning of environmental stimuli (cognitive process)

Psychophysics

Psychophysics: the study of the relationship between physical stimuli and the behavior or cognitive experiences which they evoke

Absolute Threshold: the minimum amount of physical energy needed to produce a sensory experience (neural impulse)

Difference Threshold: The smallest physical difference between two stimuli that can still be recognized as a difference.

Sensory Adaptation (habituation): the diminishing responsiveness of sensory systems to prolonged stimulus input

Sensitization: prolonged sensory input increases or amplifies a response

Sensation & Perception: Vision


Retina: the inside covering of the eyeball where images from the lens project Full of neurons called photoreceptors

Rods: work best in low light; sees edges Cones: works in brightness; sees color


Face Perception

Nuanced facial perception is typically associated with a place in the brain referred to as the Fusiform Face Area (FFA)

Located on the ventral surface of the temporal lobe

Damage to the FFA results in Prosopagnosia or “face blindness”

People are typically very good at recognizing faces……almost too good

Faces in weird places (i.e. toast)


Depth Perception

The ability to view the world in three dimensions and to perceive distance

Occurs through processing the difference (Binocular Disparity) between the images seen by the right and left eyes

Depth perception and the fear of heights is acquired in infancy through experience

https://www.youtube.com/watch?v=p6cqNhHrMJA


Color blindness: there are 3 types of cones; when a person lacks one or more types of cones they see the world differently Some animals have more kinds

of cones and can see different wavelengths of color

Qualia: is a term used in philosophy to refer to individual instances of subjective, conscious experience.

Is my red the same as your red? Do I taste the same as you do?

Sensation & Perception: VisionMantis Shrimp have 12 types of photoreceptors and can see much more of the light spectrum than humans (with our measly 3 photoreceptors).

Mantis Shrimp must think we look really boring!


Blindness https://www.youtube.com/watch?v=ZDHJRCtv0WY https://www.youtube.com/watch?v=919GzqpFDBk

Sensation & Perception: Auditory

Sound: The movement of air particles brought about by some source of vibration

This vibration is sensed by various structures within the ear Eardrum (Tympanic Membrane) Tiny bones in the middle ear

Hammer, Anvil, & Stirrup Cochlea

Basilar membrane Hair cells


Sound localization: 2 ears allow organisms to locate the origin of sound in the environment Relative timing Relative intensity

Sensation & Perception: Olfaction

Sensation & Perception: Gustation

Both olfactory and gustatory receptors are chemoreceptors. Smells are through distance chemoreceptors Tastes are through direct chemoreceptors

Taste buds on the tongue are bundles of chemoreceptors

Taste buds are also located on the roof of the mouth and interior cheeks, just in less density.

Touch, Vestibular, & Kinesthetic Senses

Touch (cutaneous [skin] senses) Include touch, pressure, temperature, and pain Sensitivity based on the density of nerve fibers and

sensory cortex allocated to that area Includes pressure and temperature

Vestibular Senses your orientation in the world with respect to

gravity Information comes from the inner ear People with vestibular issues may have vertigo

Kinesthetic Sensory feedback for motor activities

Sensation & Perception: Pain

Pain: body’s response to stimuli that cause or threaten to cause tissue damage; includes: Temperature Mechanical Chemical

Pain is (somewhat) subjective and can be moderated by a variety of factors: Conflicting or distracting stimuli Holding hands with a loved one

Intersensory Redundancy

Intersensory Redundancy occurs when multiple senses contribute to one synchronous experience

Intersensory redundancy occurs with amodal properties of stimulation (tempo, intensity, frequency)

Intersensory redundancy recruits attention and promotes learning and memory

Our reality is constructed with redundant stimulation

Infants can perceive events as synchronous even if they are offset considerably (700ms); the window of synchrony narrows in adulthood (300ms)

When sensory experiences are out-of-sync, attention learning becomes difficult and frustrating

Out of sync movie

Intersensory Redundancy

Problems can occur when there is conflicting stimulation from multiple senses

The McGurk Effect occurs when a sound does not match the facial movements of the person speaking The more “dominant” sense (in this case vision) wins

out over the other (auditory), and perception of the stimuli changes

https://www.youtube.com/watch?v=G-lN8vWm3m0

Perceptual Narrowing

Perceptual Narrowing is a sensory attunement process that helps organisms “hone in” on native stimuli, while ignoring irrelevant or improbable stimuli

Early in development, neurons are pruned from sensing environmentally rare stimuli and recruited for making nuanced distinctions for relevant stimuli

Needs to happen for the organism to function in it’s particular environment

Perceptual narrowing occurs as soon as senses “come online” and works extremely quickly; most sensitivity to non-native stimuli is lost within the first year

Can inadvertently contribute to ethnocentrism and racism

Has implications for: Language processing Facial recognition Taste

Perceptual Organization

Top-Down processing Perception is guided by higher-level

knowledge, experience, expectations, and motivations

Bottom-Up processing Perception consists of the progression of

recognizing and processing information of individual components of a stimuli and moving up to the perception of the whole

Perceptual Organization

Perception and Perspective https://www.youtube.com/watch?v=hCV2Ba5wrcs

Perceptual Constancy

Perceptual Constancy The phenomenon in which physical objects

are perceived as unvarying and consistent despite changes in their appearance or in the physical environment

Piaget (cognitive perspective) demonstrated how object permanence and perceptual constancy develops in childhood

https://www.youtube.com/watch?v=gnArvcWaH6I

Other Sensory Disorders

Anesthesia: Lack of sensation, lack of consciousness

Synesthesia: stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory process https://www.youtube.com/watch?v=BWGNWgBk76k

introduction to psychology sensation & perception

Documents

visionsensation perception

auditorysensation perception

toastsensation perception

responsesensation perception

colorsensation perception

left eyesdepth perception

physical stimuli

physical energy