Perception

• Auditory Perception: Hearing
• Olfactory Perception: Smell
• Tactile Perception: Touch
• Visual Perception: Sight
• Gustatory Perception: Taste
• Perception: How we interpret or make sense of the sensory information we recieve.
• Sensation: The information we receive through our senses.
• Monocular Depth Cues: Can be used with one eye. Allow us to tell how far away things are but not perfectly.
• Binocular Depth Cues: Involve 2 eyes and compare the slight differences in each image the eye receives. This is more accurate.
• Height in Plane: Things further away appear to be higher up.
• Relative Size: Things closer seem larger.
• Occlusion: An object covering another object, appears to be closer.
• Linear Perspective: Straight lines seem to be pointing towards a single point in the horizon. The point is known as the vanishing point; line disappears when lines reach it.
• Convergence: One way of detecting the difference in our eye muscles. We focus our eyes differently to see things that are closer, to how we focus our eyes to see things that are further away.
• Retinal Disparity: Comparing the two images received by the two eyes.
• Direct Perception: We perceive by using the information we receive through our senses. This gives us enough information to make sense of the world.
• Gibson's direct theory of perception - influence of nature.

  • Gibson's said: the key to perception is to remember what it's used for.
  • People/animals do not receive passive images of the world; we are active in it.
  • This activity changes the visual images we receive.
  • This is known as motion parallax.
• Gibson's Theory 1966

  • Gibson argues that perception is direct, and there is enough information in our environment to make sense of the world in a direct way.
  • His theory is sometimes known as the 'Ecological Theory, because of the claim that it perception can be explained solely in terms of the environment.
• Gradient of Texture: Happens as depth cues of relative size and height in plane, combined to change the apparent texture of what we are looking at. It produces a texture-gradient: things further away look smoother.
• Gradient of colour: Colours are brighter closer up.
• Gibson's Theory Evaluation

  • Strength: Real World Applications: Theory explains how we fill in visual details in real life according to what we expect. Therefore, theory has high ecological validity.
  • Weakness: Past experiences and the role of nature: Our past knowledge and information about the world affects some of our perception. Gibson's theory ignores the role of nurture in perception, unlike Gregory's theory.
• Affordances: Our perception of objects includes the possibilities for actions which they have.
• Visual Illusions happen when our visual perception is 'tricked' into seeing something inaccurately.

  • Some of them happen because they brain is using inappropriate strategies for interpreting the sensory information it receives.
• Misinterpreted Depth Cues: When the depth cues are misinterpreted, the depth of the object is not what is perceived.
• Ambiguity: When an image could equally be one thing or another.
• Fiction: Creating something that isn't really there, to complete an image.
• Size Constancy: Keeping our original perception to the size of an object, even when the information received by the eye changes.
• The Ponzo Illusion. We see the top inner line as further away therefore longer. Two outer lines create an illusion of perspective.

  Cognitive Strategy: Misinterpreted Depth Cues.

  Depth Cue: Linear Perspective.

  
• The Ames Room. Uses size constancy to produce the visual illusion. If we look from a certain viewpoint, we see one person larger than the other. Room looks square, but isn't. Person who looks smaller is further away but lines of the room drawn carefully so viewer doesn't see it.

  
• The Kanisza Triangle. The triangle isn't really there, it's a fiction of our perspective has created. Our perception fills in gaps to create something that's plausible.

  
• Rubin's Vase. Might be a vase or two faces seen from the side but we can only see one image at a time, not both as our brain can only focus on one explanation.

  
• The Muller-Lyer Illusion. Uses depth cue of relative size. Inward pointing arrows suggest further away. Misinterpreted Depth Cues

  
• The Necker Cube. So ambiguous that the brain cannot decide what it sees. The drawing is perfect, it can be seen either way. Ambiguity.

  
• Gregory's Constructivist Theory of Perception. Influence of Nurture.

  • Argues our past knowledge and experience is the most important in making sense of what is around us.
  • Says our perception works by making reasonable guesses about what we see, on the basis of what is most likely to be.
  • Known as perceptual hypotheses and are the 'most probable' explanations for the visual information we are receiving.
• Inference: Reaching a logical conclusion about something based on what you already know/existing knowledge.
• How does the brain make inferences?

  • Brain has help making inferences in the form of visual cues.
  • Visual cues ensure that our perception of reality is usually accurate but not always.
• Negative After-Image: You see the shape you were looking at but in a different colour.
• Gregory's Constructivist Theory Evaluation

  Strength: Supporting evidence: Research has found that people interpret visual cues differently e.g. Hudson's study, who found that schooled participants were better at perceiving depth cues in comparison to unschooled participants. This supports Gregory's idea of the influence of nurture on perception. High Internal Validity.
• Gregory's Constructivist Theory Evaluation

  Weakness: No real world application: Gregory's use of visual illusions to support his theory. They are artificial 2D images that are deliberately designed to fool us much - about how perception works in the real world. Low External Validity.
• Factors Affecting Perception

  • Culture
  • Emotion
  • Motivation
  • Expectation