Module 19 Study Guide Questions

Explain what is meant by a "critical period".

A critical period is a specific period in development during which an organism is most vulnerable to the deprivation or absence of certain environmental stimuli or experiences. Critical periods have identifiable starting and ending times, thereby tending to begin and end suddenly, rather than gradually (if it all).

Explain the insights the visual cliff study gives us regarding the nature vs. nurture debate.

Their ability to perceive depth stopped them from crawling any further over the edge despite their moms coaxing. It seems that biology predisposes us to be wary of heights and experience amplifies that fear. Depth perception is our ability to see objects in three dimensions, even though our retinas receive two-dimensional images. Without depth perception, we would be unable to judge distance, height, or depth. The visual cliff research with 6 to 14 month olds demonstrated that depth perception is in part innate. Many species perceive the world in three dimensions at, or very soon after, birth.

Explain the basic assumptions we make in our perception of motion and why our perceptions can be deceiving.

As objects move across or toward our retinas, our basic assumption is that shrinking objects are retreating, and enlarging objects are approaching. But our perception of motion is not always trustworthy. We may miscalculate the speed of movement of large objects or objects picked up by our peripheral vision. A quick succession of images on the retina can create an illusion of movement, as in stroboscopic movement or the phi phenomenon.

Explain how binocular and monocular cues are used to perceive depth.

Binocular Cues: Depth cues, such as retinal display and convergence, that depend on the use of 2 eyes. Retinal Display: By comparing images from the 2 eyeballs, the brain computes distance-the greater disparity between two images. Convergence: The extent to which eyes converge inward when looking at an object. Monocular Cues: Depth Cues, such as interposition and linear perspective, available to either eye alone.

Give examples of how each of the following types of perceptual Constancies aids our perception of sensory information: color, shape, brightness, and size constancy

Color: Enables us to perceive the color of an object as unchaining even when the illumination changes. Brain perceives the quality relative to the surrounding objects. Shape: Our ability to perceive familiar objects as unchanging in shape. Despite the changing images they cast on our retinas. Brightness: Perceive an object as having a constant brightness even with its illumination varied Size: Perceive objects as having a constant size, even while our distances from them varies

Identify the Gestalt principles of form perception - figure-ground, grouping by proximity, continuity, and closure.

Figure-Ground: The organization of the visual field into objects (the figures) that stand out from their surroundings (ground). Grouping: The perceptual tendency to organize stimulus into coherent groups. Proximity: Group nearby figures together. Continuity: We perceive smooth, continuous patterns than discontinuous ones. Closure: We fill in gaps to create a complete, whole object.

Explain Gestalt psychology's contribution to our understanding of perception.

Gestalt: An organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes. Taking different cues, tendencies, and Constancies to create our whole perception. Different perceptions work together to create a whole perception that are meaningful symmetrical, and as simple as possible..

Explain how the concept of perceptual adaptation informs our understanding of how humans perceive the sensations in our environment.

Humans don't perceive things exactly as our sense present them to us. People given glasses that shift the world slightly to the left or right, or even upside-down, experience perceptual adaptation. They are initially disoriented, but they manage to adapt to their new context.

Explain how research on restored vision and sensory restrictions helps us understand the importance of experience on perception

People born blind who gained sight as an adult could not visually distinguish between a cube and a sphere even though they could by touch because they had not learned to perceive the visual form. People that are born blind but then after surgery to see again lack the experience to visually recognize shapes and can't complete faces. Sensory restriction is a critical period for some aspects for sensory perceptual development. Perceptual adaptation, person given glasses, that shift vision more to left or right.

Explain how perceptual Constance help us to organize our sensations into meaningful perceptions.

Perceptual constancy is necessary in vision to recognize an object, regardless of its changing angle, distance, or illumination. Because of this ability, we perceive objects as having unchanging characteristics despite the changing images they cast on our retinas.