Psych gcse

• Sensation is the detection of stimulation, such as eyes detecting light waves and ears detecting sound waves
• Perception is the method in which sensations experienced (nerve impulses) are interpreted and organized by the brain to have meaning
• Visual constancies include size constancy, which is the ability to perceive an object as the same size regardless of moving towards or away from it
• Visual illusions occur when our visual perception is tricked into seeing something inaccurately due to the brain interpreting sensory information
• Four categories of visual illusions:

  • The Ponzo illusion: misinterpreted depth cue
  • The Muller-Lyer illusion: misinterpreted depth cues
  • The Ames room: size constancy illusion
  • The Kanizsa triangle: fictitious illusion
  • The Necker cube: ambiguous illusion
  • The Rubin’s vase: ambiguous illusion
• Two major theorists in perception:

  • Gregory's theory of Indirect perception (constructivist): perception is built up from prior knowledge and experience
  • Gibson's theory of Direct perception: perception is based on what is seen without brain interpretation
• Indirect perception involves top-down processing with input from the brain, influenced by nurture

  • Direct perception involves bottom-up processing with no input from the brain, influenced by nature
• Support for nature (genetic influence) comes from research into babies showing perceptual abilities at birth

  • Support for nurture (environmental influence) comes from research across different cultures showing differences in perception
• Gregory's constructivist theory proposes that perception depends on experience and past experience helps make sense of the world around us
• Strengths of Gregory's theory:

  • Explains visual illusions as filling in gaps and making perceptual errors
  • Supported by research showing cultural differences in perception
• Weaknesses of Gregory's theory:

  • Contradicted by research such as the visual cliff experiment with babies
  • Cannot explain how perception works in the real world
• Gibson's direct theory struggles to explain illusions and perceptual errors

  • Developed using real-world research with WWII pilots, explaining everyday perception of movement and depth
  • Research with infants supports Gibson's theory, showing innate ability to perceive depth
• Optic Array is the light entering the eye's visual field, supporting Gibson's visual cliff experiment
• Gregory can explain visual illusions, while Gibson argues illusions are man-made

  • Gregory has trouble explaining innate perception examples
• Gregory believes perception and sensation are different, with sensation being what comes through the senses into the brain and perception being how we interpret the information, shown as top-down processing
• Gibson's direct theory of perception states that the information going into our eyes is enough for us to understand, perception and sensation are the same, and we do not need higher centres to interpret what we see
• Perceptual set is influenced by factors such as expectation, cultural background, emotion, and motivation
• Perceptual set explains how individuals are biased in their perception, influenced by what they pay attention to and ignore
• Expectations play a significant role in perception, influencing how we perceive people and situations
• Bruner and Mintern's study showed that the context in which stimuli are viewed creates an expectation that shapes actual perception
• In the study by Bruner and Mintern, participants who saw letters first perceived an ambiguous symbol as 'B', while those who saw numbers first perceived it as '13'
• Gilchrist & Nesberg's study aimed to find out the effect of food deprivation on the perception of food-related pictures
• Participants who had gone without food for long periods were more likely to rate pictures of food as brighter, showing that hunger can affect perception
• Depth cues provide clues about the distance of objects from us, with monocular cues using one eye and binocular cues using both eyes
• Monocular depth cues include relative size, relative height, linear perspective, and overlap or occlusion
• Binocular depth cues, such as convergence and retinal disparity, make depth perception more accurate by comparing differences in images received by each eye
• Culture influences how objects are interpreted in drawings, with different cultures having varying expectations and beliefs
• Ethnocentrism involves judging another culture based on one's own cultural values and standards
• Emotion plays a role in perceptual set, as shown in McGininnies' study where offensive words took longer to be recognized than neutral words
• Taboo words produced a stronger response on the GSR and were recognized slower, indicating that emotion affects perception and can lead to perceptual defense
• The neural tube develops into the forebrain,midbrain and hindbrain