Perception Flashcards
What is sensation?
The information that we receive through our senses.
What in our body detects information from the outside world?
Special organs that detect information form the outside world and convert that information into tiny electrical signals.
What is perception?
How we interpret or make sense of the sensory information that we receive.
Why is perception so important?
We would receive a lot more information than we could cope with, if we really paid attention to everything.
What are visual cues?
A type of sensory cue that is processed by the eye.
How do we judge distance?
- We do this using depth cues, they allow us to work out how far or near something is; an important survival tool.
- Using monocular depth cues.
- Using binocular depth cues.
What is a depth cue?
A feature of an image which indicated distance.
What are monocular depth cues?
A way of detecting depth or distance, which will work with just one eye.
What are binocular depth cues?
A way of detecting depth or distance, which requires two eyes in order to work.
What are some monocular depth cues?
- Height in plane.
- Relative size.
- Occlusion.
- Linear perspective.
What is height in plane?
How high the object appears in the image.
How would we use height in plane to judge distance?
Things that are further away often appear to be positioned higher up.
How would you draw height in plane?
What is relative size?
How large an object appears in an image.
How would we use relative size to judge distance?
It decreases as you move away from it and if two objects are similar in size, we perceive the one that casts a smaller retinal image to be farther away
How would you draw relative size?
What is occlusion?
When one object seems to cover part of another object.
How would we use occlusion to judge distance?
Objects that partially block other parts of the scene are perceived to be closer to an observer than the blocked objects.
How would you draw occlusion?
What is linear perspective?
When straight lines are angled so that they would come together at a point on the horizon.
How would we use linear perspective to judge distance?
For instance, when a long stretch of highway is seen by the human eye, the lanes seem to join together on the horizon.
How would you draw linear perspective?
What are some binocular depth cues?
- Convergence.
- Retinal disparity.
What is convergence?
A form of depth perception which uses how eye muscles focus on images.
What is an example of convergence?
We focus our eyes differently to see things that are closer, to how we focus to see things that are further away - the brain detects this difference and uses it as a cue to distance.
How do you draw convergence?
What is retinal disparity?
A form of depth perception which compares the images from two eyes, side by side.
What is an example of retinal disparity?
If somethin gis close to us, there is quite a difference in what the two eyes see. But further away, there will be less of a difference between the images.
How do you draw retinal disparity?
What is a visual illusion?
A visual perception which is wrong or misinterprets what is actually there in reality.
Why would visual illusions happen?
- Misinterpreted depth cues.
- Ambiguity.
- Fiction.
- Size constancy.
What are misinterpreted depth cues?
Wrongly applying the ‘rules’ of depth perception.
What is ambiguity?
When an image could equally well be one thing or another.
What is fiction?
Creating something that isn’t really there, to complete an image.
What is size constancy?
Keeping our original perception of the size of an object, even when the information received by the eyes changes.
What are the visual illusions?
- The Ponzo illusion.
- The Müller-Lyer illusion.
- Rubins vase illusion.
- The Necker cube.
- The Kanizsa triangle.
- Shape constancy: A teacup.
- The Ames room.
What is the Ponzo illusion?
The two outer lines of the drawing create an illusion of perspective, as if they were railway lines stretching out before us. We see the top inner line as being further away than the bottom line so we perceive it as longer. However, if we measure it - we find out that they are exactly the same.
How do you draw the Ponzo illusion?
What cognitive strategy is used by the Ponzo illusion?
Uses the depth cue of linear perspective.
What is the Müller-Lyer illusion?
The outward-pointing arrowheads seem to be ‘pushing’ the line towards us, whereas the inward-pointing arrowheads on the right line suggest that it is further away. We perceive the left line being closer, we see it as shorter than the other one.
How do you draw the Müller-Lyer illusion?
What cognitive strategy is used by the Müller-Lyer illusion?
Misinterpreted depth cues
What is the Rubins vase illusion?
The shape in the Rubin’s vase illusion might be a vase, or it might be two faces seen from the side. We can see either one of these - when looking at the face the vase disappears and vice-versa. In this case, the brain copes with the ambiguity by focusing on one explanation or the other.
How do you draw the Rubins vase illusion?
What cognitive strategy is used by the Rubins vase illusion?
Ambiguity.
What is the Necker cube?
It seems to flip backwards and forwards. The drawing is perfectly balanced - it can be seen either way - so your brain cannot decide which is the ‘right’ way around. So, it flips the perceived image from one to the other.
How do you draw the Necker cube?
What cognitive strategy is used by the Necker cube?
Ambiguity.