Perception Flashcards
What is perception and how does it function in relation to sensory information?
Perception is the cognitive process through which our brain interprets and organizes sensory information from the environment, enabling us to understand and interact with the world around us. This process involves two main stages:
1. Sensation: The conversion of physical stimuli (light, sound, touch) into neural signals through specialized sensory receptors.
2. Interpretation: The brain processes these neural signals to create a coherent mental representation of our surroundings.
What is apperceptive agnosia?
unable to name, match, or discriminate visually presented objects. They cannot combine basic visual information into a complete percept, meaning they may perceive shapes, colors, and lines but cannot integrate these features to identify the object as a whole.
What is an example of apperceptive agnosia?
A patient may be shown a picture of a cat and may describe its lines and colors but cannot identify it as a cat.
What is agnosia?
a deficit in recognition despite normal vision
What is associative agnosia?
can combine visual features into a coherent whole but cannot associate that visual pattern with its meaning. They can copy objects accurately but fail to recognize or name them.
What is an example of associative agnosia?
A patient might be able to draw a key from memory but cannot identify it as a key when shown the actual object. They may retain some knowledge about the object’s use or function, but the visual recognition of the object itself is impaired.
What are the separate steps to visual perception?
- Input/ sensation
- basic visual components assembled
- meaning is linked to visual input
What is the “experience error” in visual perception?
The “experience error” refers to the misconception that our sensory experiences provide an accurate and direct representation of the external world. It highlights that our perceptions can be influenced by various factors, leading to inaccuracies.
How do visual illusions illustrate the experience error?
Visual illusions demonstrate that what we perceive can significantly differ from the actual physical properties of stimuli. For example, our brains may misinterpret depth through shadows or contextual cues, leading to errors in perceiving size, shape, or distance.
What is the role of saccades in visual perception?
Saccades are rapid movements of the eyes that occur when we shift our gaze from one point to another. During these movements, visual receptors are less active, and the brain suppresses visual input, creating the illusion of a continuous image despite processing discrete snapshots.
What does the experience error reveal about the nature of perception?
The experience error underscores that perception is a complex interpretative process rather than a straightforward reflection of sensory input. Our brains construct perceptions from a series of fixations and saccades, rather than providing a seamless view of the world.
How does the brain create a stable perception despite the rapid movements of the eyes?
The brain integrates visual information from multiple fixations and compensates for the brief periods of suppressed input during saccades, resulting in a perception that appears stable and continuous.
Can you give an example of how context affects visual perception?
An example is how our brains interpret the lightness of an object based on surrounding cues. A surface perceived as white in bright light may appear darker in shadow, even if the actual reflectance remains constant.
What are the implications of the experience error for understanding visual processing?
The experience error suggests that our understanding of visual processing must account for the brain’s interpretative role, as it often relies on assumptions and contextual information, rather than simply reflecting sensory data.
What are the approaches to studying perception?
- computational approach
- Gestalt approach
- Perception/action approach
What does the computational approach to perception focus on?
It focuses on discovering how the brain represents and interprets the distal stimulus, emphasizing the mechanisms and processes that transform sensory input into coherent perception.
What is the primary goal of the computational approach?
The primary goal is to understand how sensory data is processed and how the brain constructs a mental model of the external world based on that data.
What is the central tenet of Gestalt psychology?
The whole is different than the sum of its parts, meaning that the brain organizes sensory inputs into meaningful units.
Name some Gestalt principles that describe how features of stimuli are grouped together.
Proximity, similarity, good continuation, and common region.
How do Gestalt principles contribute to perception?
They help create a unified perceptual experience by grouping sensory inputs based on their characteristics.
What is the main idea behind the perception/action approach?
The goal of perception is to facilitate action, suggesting that perception is closely tied to the actions one intends to perform.
Who is a key figure associated with the perception/action approach?
James J. Gibson, known for his concept of direct perception.
What role does motion play in the perception/action approach?
Motion is essential as it provides information about the environment through the ambient optic array, which changes as one interacts with it.
How does the perception/action approach differ from traditional views of perception?
It emphasizes that perception is not merely about recognizing objects but is fundamentally linked to how we act upon those objects in our environment.
What are all the computational approaches presented in class?
- top-down and bottom-up processing
- template matching
- feature matching
- Biederman’s Recognition by Components
- View-based recognition
What is the definition of Bottom-Up Processing?
Bottom-up processing refers to perception that starts with sensory input, meaning perception is driven by data received from the environment without the influence of prior knowledge or expectations. The brain builds a perception from the smallest pieces of sensory information.
Can you provide an example of Bottom-Up Processing?
A classic example is recognizing a flower. When you see a flower, your visual system processes the light reflecting off its petals, stem, and leaves. The sensory receptors in your eyes detect colors, shapes, and patterns, which are sent to the brain to form a complete perception of the flower based solely on sensory input.
What is the definition of Top-Down Processing?
Top-down processing involves perception that is influenced by prior knowledge, experiences, and expectations. Our understanding of sensory information is shaped by what we already know about the world.
Can you provide an example of Top-Down Processing?
If a sentence reads “He Slept in the Bed,” but the letter “B” in “Bed” is obscured, we might still interpret the sentence correctly. Our brain uses contextual clues and understanding of language to fill in the gaps, demonstrating how top-down processing works.
How do Bottom-Up and Top-Down Processing interact in perception?
The interplay between bottom-up and top-down processing is crucial for effective perception. Bottom-up processing allows us to gather and analyze sensory information, while top-down processing helps us make sense of that information based on our experiences and knowledge. For example, when viewing a complex scene, our brains may first analyze basic features (bottom-up) and then apply previous knowledge and context (top-down) to interpret the scene more accurately.
Why is the interaction between Bottom-Up and Top-Down Processing important?
This interaction is important because it enables us to perceive the world more accurately. Bottom-up processing ensures we gather detailed sensory information, while top-down processing allows us to interpret and understand that information in the context of our experiences, leading to a more coherent perception of our environment.
