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Unlock This CourseRichard Gregory was a British psychologist who revolutionised how we understand perception. His Constructivist Theory suggests that perception isn't just about passively receiving information through our senses - instead, we actively construct what we see based on our knowledge, experience and expectations.
Think of your brain as a detective trying to solve a mystery. When light hits your eyes, you don't get a complete picture - you get clues. Your brain then uses these clues, along with what it already knows, to build a complete picture of what you're seeing.
Key Definitions:
Bottom-Up: Starting with sensory information and building up to understanding (like putting together a jigsaw puzzle piece by piece).
Top-Down: Using existing knowledge and expectations to interpret sensory information (like looking at the puzzle box picture first to guide your assembly).
Expectation effects happen when our brain fills in gaps or interprets ambiguous information based on what we expect to see. This process is usually helpful - it allows us to quickly make sense of our world. However, it can also lead to perceptual errors.
Your brain is constantly making predictions about what you're going to see next. These predictions are based on:
The same object can look different depending on what surrounds it. A grey square looks darker when surrounded by white than when surrounded by black.
Experts in a field can spot details that novices miss. A doctor might immediately notice symptoms that seem invisible to others.
People from different cultures may interpret the same visual information differently based on their cultural experiences.
Bugelski and Alampay (1961) showed participants either pictures of animals or faces, then showed them an ambiguous drawing that could be seen as either a rat or a man's face. Those who saw animals first were more likely to see a rat, while those who saw faces first saw a man. This demonstrates how recent experience creates expectations that influence perception.
Understanding expectation effects helps explain many everyday experiences and has practical applications in various fields.
You encounter expectation effects constantly in daily life:
You can often understand text messages with typos because your brain expects certain words based on context. "I'll mee you at the caff" is easily understood as "I'll meet you at the café".
When looking for a friend's house, you might mistake similar-looking houses for theirs because you expect to find it in that area.
Expectation effects have important implications in professional settings:
Drew et al. (2013) inserted a gorilla image into lung scans shown to radiologists. Despite being 48 times larger than the average cancer nodule, 83% of radiologists failed to notice it. They were so focused on looking for lung problems that they missed an obvious, unexpected object. This shows how professional expectations can create blind spots.
Several factors determine how strongly expectations influence our perception:
When we really want or need to see something, we're more likely to perceive it. A hungry person might be more likely to notice food-related objects.
The more unclear the sensory information, the more our expectations fill in the gaps. Clear, unambiguous stimuli are less affected by expectations.
When we need to make quick decisions, we rely more heavily on expectations and shortcuts, making us more susceptible to expectation effects.
Not everyone experiences expectation effects equally. Factors that influence individual susceptibility include:
While Gregory's Constructivist Theory explains many perceptual phenomena, it has some limitations:
Critics argue that Gregory may overemphasise the role of expectations and knowledge, underplaying the importance of direct sensory information.
It's challenging to design experiments that clearly separate expectation effects from other perceptual processes.
In 2015, a photograph of a dress went viral because people saw it as either blue and black or white and gold. This wasn't just about expectation effects - it was about how our brains make assumptions about lighting conditions. Some people's brains assumed the dress was in shadow (seeing white and gold), while others assumed it was in bright light (seeing blue and black). This shows how automatic perceptual processes work alongside expectation effects.
Understanding expectation effects has practical benefits in many areas of life:
Knowing about expectation effects can help us become more accurate observers:
Teachers can use understanding of expectation effects to:
Gregory's Constructivist Theory and the concept of expectation effects reveal that perception is far more complex and active than we might initially think. Our brains don't just passively receive information - they actively construct our reality based on sensory input combined with our knowledge, experience and expectations.
This understanding has profound implications for how we interpret the world around us. While expectation effects can sometimes lead to errors, they're generally adaptive, allowing us to quickly make sense of complex and ambiguous information. By being aware of these processes, we can become more critical observers and make better decisions in our daily lives.