Perception

Gestalt Psychology Gestalt means “an organized whole.” These psychologists emphasize our tendency to integrate pieces of information into meaningful wholes.

Gestalt Psychology To perceive forms, we must organize the visual field into objects (figures) that stand out from their surroundings (ground). This is figure-ground perception.

Gestalt Grouping Principles Gestalt psychologists focused on how we GROUP objects together. We innately look at things in groups and not as isolated elements. Proximity (objects that are close together are seen as being part of same group). Similarity (objects similar in appearance are perceived as being part of same group). Continuity (objects that form a continuous form are perceived as part of the same group). Closure (we fill gaps in if we can recognize it).

Gestalt Grouping Principles

Depth Perception The ability to see objects in three dimensions although the images that strike the retina are two dimensional. Allows us to judge distance.

Depth Cues Eleanor Gibson and her Visual Cliff Experiment. If you are old enough to crawl, you are old enough to see depth perception. We see depth by using two types of cues: Monocular Cues (w/ 1 eye) Binocular Cues (w/ 2 eyes)

Monocular Cues Interposition: if something is blocking our view, we perceive it as closer. Relative Size: if we know that two objects are similar in size, the one that looks smaller is farther away. Relative Clarity: we assume hazy objects are farther away.

More Monocular Cues Texture Gradient: distant objects look smoother than closer objects. Relative Height: things higher in our field of vision, they look farther away. Relative Motion: things that are closer appear to move more quickly. Linear Perspective: parallel lines seem to converge with distance.

Monocular Cues Examples of… Linear Perspective Interposition Relative size Texture gradient Relative Motion

Motion Perception Stroboscopic effect - (flip book effect). Phi phenomenon - (blinking neon lights; like the marquee in front of the school).

Binocular Cues We need both of our eyes to use these cues. Retinal Disparity – slightly different images produces by the retina of each eye. Convergence - degree to which our eyes turn inward to focus on an object.

Perceptual Constancy Perceiving objects as unchanging even as illumination and retinal images changes.

Perceptual Constancy Types of Constancy Shape Constancy Size Constancy Lightness Constancy

Perceptual Set Mental predisposition to perceive one thing and not another. What you see in the center picture is influenced by a perceptual set. (A good example of top-down processing). Based on schemas (mental frameworks).

Illusions = inaccurate perceptions Not always a “mistake” by us; sometimes we change what we perceive so that the world makes more sense. Sometimes we make guesses in the context of what we think should be the case.

Famous Illusions Muller-Lyer IllusionAmes Room

Extrasensory Perception Extrasensory perception (ESP): the ability to perceive events without using normal sensory receptors. Parapsychology: the field that studies ESP and other paranormal phenomena.

Types of ESP – Telepathy: the ability to read minds. – Clairvoyance: the ability to perceive objects or events. – Precognition: the ability to predict the future. – Psychokinesis: the ability to move objects.

There Is Little Scientific Evidence for Extrasensory Perception!!! Reasons for skepticism: – Many published ESP studies have used flawed research methodologies or failed to detect outright fraud by those they were testing.