Sensation, Perception and Gestalt

Sensation and Perception

Patti Amos, MAEd

OpenStax Psychology Resource

Sensation vs. Perception

• Sensation occurs when sensory receptors detect sensory stimuli.

• Perception involves the organization, interpretation, and conscious experience of those sensations.

• All sensory systems have both absolute and difference thresholds, which refer to the minimum amount of stimulus energy or the minimum amount of difference in stimulus energy required to be detected about 50% of the time, respectively.

Sensation vs. Perception

• Sensory adaptation, selective attention, and signal detection theory can help explain what is perceived and what is not.

• Our perceptions are affected by a number of factors, including beliefs, values, prejudices, culture, and life experiences.

• https://youtu.be/TLHlfPTRekA

Multiple Choice

_____________________ occurs when sensory receptors detect sensory stimuli.

• perception

• consciousness

• sensation

• intelligence

Waves and Wavelengths

• Both light and sound can be described in terms of wave forms with physical characteristics like amplitude, wavelength, and timbre.

• Wavelength and frequency are inversely related so that longer waves have lower frequencies, and shorter waves have higher frequencies.

Waves and Wavelengths

• In the visual system, a light wave’s wavelength is generally associated with color, and its amplitude is associated with brightness.

• In the auditory system, a sound’s frequency is associated with pitch, and its amplitude is associated with loudness.

Multiple Select

Can be described in terms of wave forms with physical characteristics like amplitude, wavelength, and timbre.

• light

• scent

• sight

• sound

Vision

• Light waves cross the cornea and enter the eye at the pupil. 

• The eye’s lens focuses this light so that the image is focused on a region of the retina known as the fovea.

• The fovea contains cones that possess high levels of visual acuity and operate best in bright light conditions.

• Rods are located throughout the retina and operate best under dim light conditions.

Vision

• Visual information leaves the eye via the optic nerve. Information from each visual field is sent to the opposite side of the brain at the optic chiasm.

• Visual information then moves through a number of brain sites before reaching the occipital lobe, where it is processed.

• https://youtu.be/z-Dg-06nrnc

Two theories explain color perception

• The trichromatic theory asserts that three distinct cone groups are tuned to slightly different wavelengths of light, and it is the combination of activity across these cone types that results in our perception of all the colors we see.

• The opponent-process theory of color vision asserts that color is processed in opponent pairs and accounts for the interesting phenomenon of a negative afterimage.

• We perceive depth through a combination of monocular and binocular depth cues.

Multiple Select

Which 2 theories explain color perception?

• sensory theory

• sensoperception theory

• trichromatic theory

• opponent-process theory

Hearing

• Sound waves are funneled into the auditory canal and cause vibrations of the eardrum; these vibrations move the ossicles.

• As the ossicles move, the stapes presses against the oval window of the cochlea, which causes fluid inside the cochlea to move.

• As a result, hair cells embedded in the basilar membrane become enlarged, which sends neural impulses to the brain via the auditory nerve.

Hearing

• Pitch perception and sound localization are important aspects of hearing. 

• Our ability to perceive pitch relies on both the firing rate of the hair cells in the basilar membrane as well as their location within the membrane.

• In terms of sound localization, both monaural and binaural cues are used to locate where sounds originate in our environment.

Hearing

• Individuals can be born deaf, or they can develop deafness as a result of age, genetic predisposition, and/or environmental causes.

• Hearing loss that results from a failure of the vibration of the eardrum or the resultant movement of the ossicles is called conductive hearing loss. 

• Hearing loss that involves a failure of the transmission of auditory nerve impulses to the brain is called sensorineural hearing loss.

• https://youtu.be/7X_WvGAhMlQ

Multiple Select

Which are important aspects of hearing?

• sound localization

• pitch perception

• pitch localization

• sound perception

The Other Senses

• Taste (gustation) and smell (olfaction) are chemical senses that employ receptors on the tongue and in the nose that bind directly with taste and odor molecules in order to transmit information to the brain for processing.

• Our ability to perceive touch, temperature, and pain is mediated by a number of receptors and free nerve endings that are distributed throughout the skin and various tissues of the body.

The Other Senses

• The vestibular sense helps us maintain a sense of balance through the response of hair cells in the utricle, saccule, and semi-circular canals that respond to changes in head position and gravity.

• Our proprioceptive and kinesthetic systems provide information about body position and body movement through receptors that detect stretch and tension in the muscles, joints, tendons, and skin of the body.

Gestalt Principles of Perception

• Gestalt theorists have been incredibly influential in the areas of sensation and perception.

• Gestalt principles such as figure-ground relationship, grouping by proximity or similarity, the law of good continuation, and closure are all used to help explain how we organize sensory information.

• Our perceptions are not infallible, and they can be influenced by bias, prejudice, and other factors.

Multiple Choice

What principles are used for perception?

• Psychoanalytic

• Gestalt

• Behavioral

• Cognitive

• Gestalt Psychology is a school of thought that looks at the human mind and behavior as a whole not in parts.

• The essential point of Gestalt Psychology is that in perception the whole is different from the sum of its parts.

Multiple Choice

Gestalt psychology is based on the principle that:

• we tend to view the parts before we see the whole

• the whole is greater than the sum of its parts

• we see with two eyes

• perception is the same for everyone

The human brain will attempt to simplify and organize complex images or designs that consist of many elements, by subconsciously arranging the parts into an organized system that creates a whole, rather than just a series of disparate elements.

Our brains are built to see structure and patterns in order for us to better understand the environment that we’re living in.

Gestalt Principles

There are 6 principles associated with Gestalt Theory: Similarity, Proximity, Continuation, Closure, Figure/Ground, Symmetry & Order

​It’s human nature to group like things together. In gestalt, similar elements are visually grouped, regardless of their proximity to each other. They can be grouped by color, shape, or size. Similarity can be used to tie together elements that might not be right next to each other in a design.

Similarity

Continuity​

The human eye will follow the smoothest path when viewing lines, regardless of how the lines were actually drawn.

Closure ​

Your brain will fill in the missing parts of a design or image to create a whole.

Proximity ​

How close elements are to one another. 

Proximity is most often used in order to get users to group certain things together without the use of things like hard borders.

Figure/Ground

Your brain will distinguish between the objects it considers to be in the foreground of an image (the figure, or focal point) and the background (the area on which the figures rest).

 

Symmetry and Order

Your brain will perceive ambiguous shapes in as simple a manner as possible.

Multiple Choice

Rubin's vase is a special example of which Gestalt principle?

• Closure

• Proximity

• Similarity

• Figure-Ground

Multiple Choice

Which Gestalt principle explains why you see these lines as a circle and a square?

• Proximity

• Closure

• Figure-Ground

• Similarity

Multiple Choice

Which Gestalt principle is used to create this logo?

• Figure-Ground

• Closure

• Similarity

• Proximity

Multiple Choice

Which Gestalt principle explains how we are able to perceive two different interpretations of this image?

• Figure-Ground

• Closure

• Similarity

• Proximity

Multiple Choice

Which Gestalt principle explains why we perceive these dots as horizontal rows.

• Figure-Ground

• Similarity

• Closure

• Proximity

Multiple Choice

Which Gestalt principle explains why we perceive two groups of dots in this image?

• Figure-ground

• Similarity

• Closure

• Proximity