Loading presentation...

Present Remotely

Send the link below via email or IM

Copy

Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

DeleteCancel

Make your likes visible on Facebook?

Connect your Facebook account to Prezi and let your likes appear on your timeline.
You can change this under Settings & Account at any time.

No, thanks

Perception

No description
by

Chelsea Murphy

on 3 December 2013

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of Perception

Perception
Introduction

Visual Perception is how we acquire knowledge about objects and events in our environment, taking information from the light they reflect and our prior knowledge.

We see our 3-D environment via a 2-D microscopic array of nerves at the back of our eyes. It comes through upside down and left-right reversed.
This is converted to a 2-D pattern of neural firings, which the brain uses to generate sight.


Indirect & Direct Approach
Helmholtz coined the indirect approach. This is the integration of properties of an objects image with other bits of information that are relevant to determining the objects properties in the environment. This means that the properties of the image (for example, size) are perceived not only from the retinal image, but also from contextual information, such as the distance from the viewer.

This contrasts with the direct approach proposed by Gibson. Gibson pointed out that there are properties of objects which are constant when viewed in different environments, which are usually correlated to the higher-order invariants of optical structure in an image. A simpler explanation of this is that the perception begins with the stimulus, and based on the retinal image, not the context or associations of the image.
Modes of Perception
Object constancy - Intrinsic properties of an object
Distal properties - Object-based properties
Proximal properties - Image-based properties
How is the size of an object perceived from its retina image?
Perception
Introduction
Indirect & Direct Approach (Hemholtz)
Perceptual Constancy
Modes of Perception: Proximal & Distal
Size-Distance Paradox
Size illusions:
1. Moon illusion and possible explanations
2. Ames room
3. Emmert's Law
3.1 Emmert's Law as an explanation for the moon illusion

TUTORIAL - WEEK 10 ¬
Moon Illusion
The Moon illusion is an optical illusion in which the Moon appears larger near the horizon than it does while higher up in the sky. This optical illusion also occurs with the Sun and star constellations. It has been known since ancient times and recorded by various cultures. The explanation of this illusion is still debated
Explanations
Moon Illusion
1. Apparent distance theory
According to this possible explanation for the moon illusion, depth perception plays an important role in how we see the moon at the horizon versus high in the sky.

This theory is centered on the idea that when you view the moon at the horizon, you are seeing it in the presence of depth cues such as trees, mountains, and other scenery.

When the moon has moved higher into the sky, those depth cues disappear. Because of this, the apparent distance theory suggests, we tend to see the moon as further away on the horizon than we see it when it elevated in the sky.
Explanations
Moon Illusion
2. Angular size-contrast theory
According to this possible explanation for the moon illusion, focus on the visual angle of the moon in comparison with the surrounding objects.

When the moon is in its horizon and surrounded by smaller objects, it appears to be larger.

When it is it in the sky, there are no nearby objects that allow the brain to make a comparison and the large sky makes it looks smaller.
Ames Room
The effect works by utilizing a distorted room to create the illusion of a dramatic disparity in size. While the room appears square-shaped from the viewer’s perspective, it is actually has a trapezoidal shape. The person on the right hand side of the room is actually standing in a corner that is much further away than the person on the left (or vice-versa)
Emmert's law
Emmert noted that an afterimage (an afterimage or ghost image or image burn-in is an optical illusion that refers to an image continuing to appear in one's vision after the exposure to the original image has ceased.

A common form of afterimages is the bright glow that seems to float before one's eyes after looking into a light source for a few seconds.) appeared to increase in size when projected to a greater distance.
.
A modern version of the law states that objects that generate retinal images of the same size will look different in physical size (linear size) if they appear to be located at different distances.

Specifically, the perceived linear size of an object increases as its perceived distance from the observer increases.

This makes intuitive sense: an object of constant size will project progressively smaller retinal images as its distance from the observer increases.
Emmert's law
According to this possible explanation for the moon illusion, depth perception plays an important role in how we see the moon at the horizon versus high in the sky.

This theory is centered on the idea that when you view the moon at the horizon, you are seeing it in the presence of depth cues such as trees, mountains, and other scenery.

When the moon has moved higher into the sky, those depth cues disappear. Because of this, the apparent distance theory suggests, we tend to see the moon as further away on the horizon than we see it when it elevated in the sky.
As an explanation for moon illusion
Veridical Perception
These processes usually result in constancy, but can sometimes produce illusions. It requires heuristic processes based on assumptions. When these assumptions aren’t true, it can create an illusion.
Perceptual Constancy
Perceptual Constancy is when people perceive the constant, unchanging properties of objects, regardless of the angle, light and environment in which they are being viewed. This can lead people to view objects as they should be, rather than the properties of their retinal image. An example of this is snow appearing white at night, as well as in direct sunlight.
Light Constancy
Distal mode - made mostly from object based
stimuli
Proximal mode - experience drawn mostly from properties of the retinal image.
Modes of Perception
In perception one mode will typically dominate another
When an experiences results from a compromise of both modes this is called under-constancy.
size constancy
The ability to observe an objects size correctly at different distances
Full transcript