1. How we actively interpret our environment.

2.  Perception: The process in which we understand sensory information.  Illusions are powerful examples of how we misinterpret sensory information and perceive information incorrectly.

3.  Selective attention is purposely focusing your conscious awareness onto a specific stimulus.  This means that if you are in a noisy place with lots of people and you purposely pay attention to the person you are speaking with, you are engaging in selective attention.

4.  The ability to focus one‘s listening attention on a single talker among a mixture of conversations and background noises, ignoring other conversations. Enables most people to converse in a noisy place.  When in a noisy crowded party, most people can still listen and understand the person they are talking with, while simultaneously ignoring background noise and other conversations. However, if someone calls out their name from across the room, people will sometimes notice (the "own name effect").

5.  At the beginning of the 20 th century. a group of researchers called Gestalt psychologists studied how people integrate and organize perceptual information into meaningful wholes, how we perceive groups of objects. We usually perceive images as groups, not isolated elements. Is this innate?  They believed the whole is greater than the sum of its parts.

6.  For example, can you recognize this, (: > o) ? The reason you may be able to recognize that these symbols look like a face, is because of Gestalt principles of perception.  Gestalt principles of organization explain how people are able to see some meaningful organization and shape when individual parts are seen together.  Although each of the parts that make up the face have meaning by themselves, when they are put together, we are able to perceive them as a whole unit.

7.  Illusions indicate that our mind does not always accurately represent the perceptual input it receives, illusions are inaccurate perception of stimulus being presented.  Gestalt suggested that the mind was "actively" involved in interpreting the perceptual input rather than passively recording the input.  There are a number of descriptive principles of perceptual organization  http://faculty.washington.edu/chudler/flash/nill.swf http://faculty.washington.edu/chudler/flash/nill.swf

8.  Gestalt found there are two main visual components necessary for a person to see an object properly; a figure (the object) and the ground (the background or surroundings in which the object occurs).  We group sensations into an object or figure that stands out on a plain background. The figure is the distinct shape with clearly defined edges.

9.  Which horizontal line is longer?

10.  The center connecting line is seen as shorter in the top figure that in the lower figure. The figure below shows the line as it appears in both figures.    The figure below shows both figures superimposed on one another in order to demonstrate in yet another way that the center line is of equal length in both figures.

11.  Ambiguous figures exemplify the fact that sometimes the same perceptual input can lead to very different representations. Gestalt took this as suggesting that the mind was actively involved in interpreting the input.

12.  This ambiguous figure demonstrates our ability to shift between figure and ground which provides the basis for the two interpretations of these figures.

13.  Completion figures are figures which the mind rather unambiguously interprets in a particular way despite the fact that the input is incomplete relative to what is typically "seen."

14. These two figures illustrate the mind's willingness to see an equilateral triangle despite the fact that no border information about the center triangle is in the picture.

15.  Humans have a tendency to organize stimuli into some coherent groups. We like to categorize things and maintain some organization with most stimuli.  For example, we meet a new person, and immediately we group them into gender, height, weight, race, etc. This categorization process is done by "grouping" information into logical categories.

16.  Proximity - group objects near each other together  Continuity - perception toward simplicity or continuity, we prefer smooth continuous patterns  Closure - figures that have gaps are seen as completed

17.  Depth perception is the ability to judge the distances of objects, which also allows us to see them in three dimensions.  Images that strike the retina are two dimensional, but because our visual systems have the capacity to interpret stimuli in terms of relative depth, we see these objects not as flat, but as having some depth.

18.  Visual Cliff: Gibson & Walk’s (1960) research to measure depth perception in infants and toddlers, to see if and when they develop depth perception.  Depth perception – the ability to see objects in three dimensions although the images that strike our retina are two dimensional; allows us to judge distance  Two types of visual cues allow us to perceive depth:

19.  Binocular Cues: Humans are able to see things that are both far and near, and can actually identify where those objects are in space (meaning, they can determine if those objects are close or far away).  This sort of depth perception requires both of our eyes, which is referred to as binocular cues (depth cues that requires both of our eyes).

20.  Based on the simple fact that a person's eyes are located in different places. One cue, retinal disparity, the difference in locations, on the retinas, of the stimulation by a single object. This means an object viewed by both eyes will stimulate one spot on the right retina and a different spot on the left retina This is because the object is at a different distance from each eye. By processing information about the degree of disparity between the images it receives, the brain produces the impression of a single object that has depth in addition to height and width.

21.  Cues of depth that can be detected by one eye instead of two.  For example: size is a monocular clue. One doesn't need two eyes to tell how large an object is, and because of its size, how close it is perceived to be.