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.
What is the Kanizsa triangle?
The triangle is not really there - it is a fiction that our perception has created, suggested by the shapes around it - but it appears to so clearly that it even seems to stand out from the paper. The perceptual system generates an image which fills in the gap to create something plausible.
How do you draw the Kanizsa triangle?
What cognitive strategy is used by the Kanizsa triangle?
Fiction.
What are the visual constancies?
- Shape constancy: A teacup
- The Ames room
What is perceptual constancy?
It is how we perceive objects as being the same, even if the visual image we are receiving is quite different.
How do you draw shape constancy: a teacup?
Why can we understand what we are looking at?
We apply constancy scaling, making allowances for those changes. That is called shape constancy.
What is the Ames room?
If we look at it from a special angle, we see one person as being much larger than the other. It works because, although the room looks square it actually isn’t. The person who looks smaller really is further away, but the lines of the room are carefully drawn so the viewer doesn’t see it that way.
How do you draw the Ames room?
What cognitive strategy is used by the Ames room?
Size constancy.
Which theory mentions the influence of nature?
Gibson’s direct theory of perception.
What is direct perception?
It is the idea that we perceive simply by using the information we receive through our senses. This gives us enough information to make sense of the world. Essentially that sensation and perception are the same processes.
What did Gibson believe in relation to perception?
Gibson’s Direct Theory of Perception is the idea that we perceive simply by using the information we receive through our senses and this is enough information for us to make sense of the world around us. He proposed people, as well as animals, do not receive simply passive images about the world around them but they are active within it and this activity changes the visual images we receive.
What is a cue mentioned in Gibsons direct theory of perception?
Motion parallax.
What is motion parallax?
The way that the visual field changes with movement, with close objects seeming to move more than objects that are further away.
What are other cues in Gibsons theory of perception?
- Gradient of texture.
- Gradient of colour.
What is gradient of texture?
There is a gradual change in appearance of objects from coarse to fine.
What is an example of gradient of texture?
If you look at lawn or a wide area of paving, the bits which are closest to you will look more detailed, showing individual blades of grass or individual bits of stone or concrete. Further away, it will seem smoother, and the furthest parts will look even smoother.
Why does gradient of texture happen?
This is because as the depth cues of relative size and height in plane combine to change the apparent texture of what we’re looking at . This produces a texture gradient.
What is gradient of colour?
Colours are brighter close up, and paler when they are further away.
What did texture gradients and gradients of colour prove to Gibson?
As examples of how the real world gives us plenty of information for perception.
What did Gibson argue about in reference to the real world?
The real world, he argued, is three dimensional, and where we stand and how we move about in it is as much a part of real-world perception as shape and colour.
Why is Gibsons direct theory of perception known as an ecological theory?
Gibson’s direct theory of perception was also known as an ecological theory of perception because he believed perception evolved in order to help animals best deal with their environment.
For what circumstances did Gibson believe that animals evolved for?
Gibson believed humans, birds and primates developed colour vision to help us pick ripe fruits and berries while depth perception is seen as essential for jumping across branches by primates to avoid potential threats on the ground. Dealing with the environment includes our own actions in addition to the information our senses receive.
What did Gibson believe about dealing with our environment and our own actions, as well as the information we receive?
For example, a tree stump offers us various possibilities for interaction: we can stand on it to see further away, sit on it to relax or use it as a table. Gibson argued our perception includes the possibilities for actions which they afford (their affordances) and affordances were a part of his theory of direct perception. He argued the environment was not totally separate from us and we perceived what was around us in terms of ourselves and what this allowed us to do.
What does Gibsons direct theory of perception tell us?
That we live in a perceptual world, which is not just three-dimensional but includes our own behaviour aswell. So, we do not need to make inferences or guesses about what we are seeing. We have enough information from our senses to be able to understand the world around us.
What are some advantages of Gibsons direct theory of perception?
The theory proposes perceptual abilities such as depth perception are due to nature and this is supported by various research from infant studies. This means we do not always have to use past experiences or make inferences in order to perceive the world around us and depth perception may actually be innate.
- Yhe theory focuses on movement, and our perception depends on the way visual cues change as we move. This is sensible as we never perceive anything from a static point of view, and even when we try to keep still, our eyes are in constant motion.
What are some disadvantages of Gibsons direct theory of perception?
- The theory suggests that sensation and perception are the same thing, but we know from illusions that they are separate processes.
- We also know that our past knowledge and information about the world affects some of our perception. We often interpret something as what we expect it to be. Rather than what is actually is.
What kind of theory is Gibsons theory?
A bottom-up theory. This is because it takes the basic information which our eyes receive and shows how that basic information can produce the higher mental process of perception.
What is the name of the constructivist theory of perception?
Gregory’s constructivist theory of perception.
What is the constructivist theory?
The idea that our perception is built up from our prior knowledge and experience.
What does Gregory’s theory propose?
Gregory proposed that perception worked by making reasonable guesses about what we are seeing based on what it is most likely to be. These were referred to as perceptual hypotheses. Gregory believed perception involved cognitive processes and that we do not simply perceive information that we receive. Instead, we also rely on stored knowledge and experiences which affects our perception.
What is a perceptual hypotheses?
The most probable explanation for the visual information we receive.
What is an advantage of Gregory’s constructivist theory of perception?
- It has a study which solidifies his findings. Research by Gilchrist and Nesberg (1952) found that hunger affected how people perceived images of food. This study is important as it showed how motivation can affect our perception with participants who were most hungry in this study perceiving images to be brighter.
- The muller-lyer illusion still works when the arrowheads are replaced with circles. It, therefore, seems that both nature and nurture have an effect on the way sensations received by us influence perception.
What are some disadvantages of Gregory’s constructivist theory of perception?
- A criticism, however, is that not everyone agrees with the explanations given for illusions such as the Muller-Lyer illusion. Critics argue the illusion works because the arrowheads on the lines make them look like the near edge of a building or the far corner of a room which makes us think the line is nearer to us than the other.
What kind of theory is Gregory’s theory?
A top-down theory which means that it takes higher mental processes and shows how they shape the way we interpret the information the eyes receive.
What is nurture?
The idea that our characteristics and behaviour are influenced by our environment.
What do we do if at any time we are receiving more information than we can take in?
At any one time, we are receiving more information than we can take in so we need to be able to select what we are going to focus our attention on and what we are going to ignore. We do this by developing a state of readiness which psychologists call the perceptual set which helps us anticipate what is coming so we can act effectively.
What is the perceptual set?
It is a state of readiness to perceive certain kinds of stimuli rather than others.
What are the factors that effect perception?
- Perceptual set.
- Culture
- Motivation
- Emotion
- Expectation.
What processes can be affected by our perceptual set?
- Memory.
- Decision making.
- Learning.
- Perception.
What is an example of how memory can be affected by our perceptual set?
For example, with memory, we remember different things dependent on our mood. If we are in a bad mood this makes it more likely that we will remember the negative things while being in a good mood makes it more likely that we remember the pleasant things.
What is an example of how decision-making can be affected by our perceptual set?
We make different decisions depending on what we are expecting, or even on what we have just seen.
What is an example of how learning can be affected by our perceptual set?
We are more prepared to learn some things than others – babies learn nursery rhymes more easily than normal sentences or letters. The alphabet song is more easily learnt if in the form of a nursery rhyme rather than if the letters are taught individually. This is because babies and toddlers are set to learn through repetition.
What is an example of how perception can be affected by our perceptual set?
We are more likely to perceive things if our perception is set to notice that kind of thing.
What is expectation?
The beliefs we have about what we are going to experience.
How does expectation affect perception?
Perception is also affected as when we expect something, we are more likely to notice it.
What study shows how expectations can influence how we interpret what we see?
Bruner and Minturn’s study.
How does Bruner and Minturn’s study show how expectations can influence how we interpret what we see?
One research study found that when participants were shown the pictures of birds heads and then shown an ambiguous picture (see below,) the participants were more likely to report seeing birds. If they were shown pictures of rabbits heads prior then this is less likely which demonstrates how expectation can influence perception.
What is culture?
A group of people who share similar customs, beliefs, and behaviour.
How does culture influence perception?
Children in western societies are raised accustomed to line drawings and cartoons which although not realistic they become used to seeing. When asked to draw an animal, they then draw one similarly from the side as seen in cartoons however children from traditional tribal societies behave differently. They instead draw it as if it were flat and spread across and they do this because they perceive the whole animal. Children from western societies, however, are shaped by their exposure to line drawings so draw them from the side showing only half the animal.
What is emotion?
The moods or feelings that a person experiences.
How can emotions influence how we perceive things?
Emotions can influence how we perceive things as they contribute to our perceptual set and make us more likely to perceive things in a particular way that is in line with how we feel.
What is an example for how emotions influence how we perceive things?
For example, someone who is already quite upset is more likely to notice other upsetting events or actions rather than positive ones. Ambiguous pictures which can be seen as either positive or negative may also be more likely to be interpreted in a negative way due to a person’s negative mood.
What is an example of a study for how emotions influence how we perceive things?
Children that are excited about Christmas approaching have also been shown to draw bigger pictures of Santa which include lots of presents compared to after once Christmas has passed due to less excitement.
What is motivation?
The drives and needs that cause a person to act in a particular way.
What is an example of how motivation affects our perception?
We may have physical motives such as being hungry or thirsty which may then encourage us to eat or drink or social motives may drive us to stay in contact with friends. Motivation can also influence perception and a key research study into this is Gilchrist and Nesberg’s need and perceptual change study.
What is the Aim of Gilchrist and Nersberg’s study?
To investigate how motivation affecst perception.
What is the study design of Gilchrist and Nersberg’s study?
Laboratory experiment.
What is the method of Gilchrist and Nersberg’s study?
26 university students who volunteered to go 20 hours without any food and consume only water were recruited as participants.The students were randomly allocated to be in either one of two groups: one group which went without food (the experimental group) and the other, which was a control group, which had normal meals during the 20 hours. The participants were told they would see a set of pictures on the screen for 15 seconds before the screen turned off. After 15 seconds the screen would come on again with the pictures however they would not look the same. The student’s task was to adjust each picture so that it looked the same as before in the first instance they were shown it. The pictures were a set of 4 colour images that were taken from magazines that showed typical meals such as T-bone steaks, fried chicken, hamburgers and spaghetti. The second time the students were shown the pictures, the brightness of the pictures was changed and the students were asked to re-adjust the brightness by turning on a knob. They were tested at the beginning of the study just after their lunchtime meal and again after the 6-hour interval as well as the 20-hour interval.
What were the results of Gilchrist and Nersberg’s study?
The control group had showed little difference in their memory of the brightness of the pictures as time went on. But as the experimental group became hungrier, they judged the pictures to be brighter. Chart A shows the differences between the teo groups on the different occasions.
What was the conclusion of Gilchrist and Nersberg’s study?
Hunger can affect the way that we perceive images of food, which suggests that motivation affects perception.
What are some advantages of Gilchrist and Nersberg’s study?
- The study showed that motivation can affect our perception.
- The study has ecological validity because the participants were really hungry.
- The study was carefully controlled, with matched timing and exactly the same conditions for both groups, apart from hunger. This means that it would be easy for other researchers to replicate the study.
What are some disadvantages of Gilchrist and Nersberg’s study?
- There were not very many participants and they were all students of a similar age, so it is difficult to apply these results to other types of people.
- The participants were volunteers so their behaviour might not have been representative, as they were keen to take part in the study. They might also have guessed what the study was about, which could have also affected their behaviour.
What was the aim of Bruner and Minturn’s perceptual set study?
To investigate how expectations can direct perception.
What was the study design of Bruner and Minturn’s perceptual set study?
Laboratory experiment.
What was the method of Bruner and Minturn’s perceptual set study?
24 participants took part in an experiment on recognising letters and numbers. Letters and numbers were flashed on the screen very quickly initially faster than the eye could see at 30 milliseconds and then this increased by 20 milliseconds each time. The participants were then asked to draw the letter or number as soon as they could recognise it. The test stimulus used was a broken letter “B” which was designed to be ambiguous and be seen as either the letter B or the number 13.Half the participants were shown a series of 4 stimulus letters (L, M, Y and A) as training on what to do. They were then shown the test stimulus followed by a series of test numbers (16, 17, 10 and 12) and then the test stimulus again. They were then shown a series of mixed letters and numbers, again followed by the test stimulus which meant each participant saw the test stimulus 3 times: once when they were expecting a letter, again when they were expecting a number and again when they were expecting either to come up. The other half of the participants were exposed to the same procedure except they were counterbalanced. The participants were shown the stimulus numbers first, followed by the test stimulus, then the letters followed by the test stimulus and then a mixture of letters and numbers followed by the stimulus.
What were the results of Bruner and Minturn’s perceptual set study?
Bruner and Minturn’s results found that most participants drew an open figure B similar to the number 13 (as above in the image) when expecting a number to come up and a closed figure (B) when they were expecting a letter. When they were expecting either letter or number, they produced mixed results with some drawing an open figure and others drawing the closed letter.
What was the conclusion of Bruner and Minturn’s perceptual set study?
The researchers concluded that the participants’ expectations had directly affected how they interpreted the stimulus figure.
What was the advantages of Bruner and Minturn’s perceptual set study?
- The study was carefully controlled and counterbalanced, so it could be replicated, increasing is the reliability of these findings.
- The study showed importance of human experience and context in perception, challenging the idea that perceptual rules, always work, the same way. (As stated by Gibson).
- The study confirmed how recognition can be influenced by expectation. It provides support for Gregory’s explanation of how we interpret information.
What was the disadvantages of Bruner and Minturn’s perceptual set study?
- There were not very many participants.
- The participants were all volunteers so their behaviour might not have been representative, as they were keen and enthusiastic participants. They might also have guessed the purpose of the study, which could have affected the results that were produced.
- The task was not very similar to perception in real life, where we are rarely faced with invented ambiguous figures, so it lacked ecological validity.
