Perception is shaped by more than the optical signal: culture, motivation, emotion and expectation all bias what we see. AQA names two key supporting studies.
Culture
Cross-cultural research shows that people raised in environments with different visual features perceive the world differently:
- Müller–Lyer susceptibility. People from "carpentered" Western environments (rectangular buildings, linear perspective everywhere) are more susceptible to the Müller–Lyer illusion than people from circular/cylindrical environments (some Zulu communities, some forest-dwelling groups).
- Hudson (1960) showed pictures with depth cues (distant elephant, near hunter) to South African participants from different backgrounds; Western-educated children spotted the "trick" 3-D interpretation, while less Western-exposed groups read the picture flat.
The inference: visual experience tunes the perceptual system. Culture is not "wrong" — it is the schema-supplier.
Motivation
When you want something, you literally see it differently:
- Gilchrist & Nesberg (1952) asked one group of participants to fast for 20 hours and another group to eat normally, then showed everyone slides of food at varying brightness. The fasting group judged the food slides as brighter and more colourful — motivation (hunger) intensified the visual experience of food.
Similar effects apply to thirst, money and reward.
Emotion
Fear, disgust and excitement bias attention and perception:
- People perceive feared objects (spiders, heights) as closer or larger than they really are (Stefanucci & Storbeck, 2009).
- Strong negative emotion narrows attention onto the threat (the weapon focus effect in eyewitness testimony).
- Positive emotion broadens attention and lowers the threshold for noticing positive cues.
Expectation (perceptual set)
Bruner & Minturn (1955) showed that an ambiguous figure was read as "B" when surrounded by letters but as "13" when surrounded by numbers. The context created an expectation — a perceptual set — that determined what was seen.
Other examples:
- An expert birdwatcher spots and identifies a bird in a glance the rest of us miss.
- "Mondegreens" — misheard song lyrics — show how prior expectation can override the actual sound.
Putting it together
These factors are all top-down influences. They support Gregory's constructivist theory: the brain doesn't just process input — it interprets it through a filter of culture, drive, mood and expectation. For an exam answer, pick at least one factor and one named study (Gilchrist & Nesberg or Bruner & Minturn) and link clearly to perception, not generic "behaviour."
AI-generated · claude-opus-4-7 · v3-deep-psychology