Chapter 3, Perception Flashcards
What is perception?
The process of recognizing, organizing, and interpreting information from the senses.
Is perception an exact copy of “the world”
No, it is not an exact copy of the world
Is our perception based on our past experiences and expectations?
Yes, it is based on our past experiences and expectations.
Why has it been so difficult to design a perceiving machine?
- Because of the inverse Projection Problem
- Objects can be hidden or blurred
- Objects look different from different viewpoints
What is the Inverse Projection Problem?
- It refers to the task of determining the object responsible for a particular image on the retina
- It also involves starting with the retina image and then extending outward to the source of that image.
What is Viewpoint Invariance?
The ability to recognize an object from different viewpoints.
- easy for people
- hard for computers
What are the two types of human processing?
- Bottom-up processing
- Top-down processing
What is Bottom-up Processing?
It begins with the sensory receptors and then works up to the brain to identify the object/scene being perceived
What is Top-down Processing?
Begins in the brain then works down to the receptor.
What else happens with Bottom-up processing?
- Perception comes from stimuli in the environment
- Parts are identified and put together, and then recognition occurs
What else happens with Top-down Processing?
- Occurs very quickly
- People actively construct perceptions using information based on expectations and experiences
What is Speech Segmentation?
Knowing when a word begins and ends in speech based on previous experience with the language.
What is the Bottom-up Process for Pain Perception?
The direct pathway model, which is a stimulation of nociceptors
What is the Top-down Process for Pain Perception?
It can be affected by other factors such as expectation, attention, and the Placebo effect
What are some Bottom-up approaches?
- Template Matching Theory
- Feature Approaches
- Recognition-by-Components
What is Template Matching Theory?
it is comparing a stimulus with a set of templates (or specific patterns) that are stored in memory.
- Templates are exact copies
- Identify when a match is made
Do Humans have a tolerance to partial info?
Yes, our perception is fairly good at dealing with partial info, as when objects are degraded or occluded.
Our system has to fill in the gaps when dealing with the incomplete and variable info.
What are some Feature Approaches?
- Pandemonium Model
- the idea- Pattern recognition is a gradual process of evidence accumulation based on a feature-by-feature analysis - A result of hierarchically organized chaos
What is Recognition-by-components?
- We perceive objects by perceiving elementary features
- Objects are recognized when enough info is available to identify objects three-dimensional volumes
What are Geons?
Three-dimensional volumes/ shapes
What else is important for the Recognition-by-Component Theory?
- That object recognition is a matter of separating, analyzing, and recombing features (this occurs for all objects familiar and unfamiliar to us)
- That there are 36 Geons, that are simple shapes combining to form complex shapes. These shapes then look the same no matter the orientation.
How does the Recognition-by-Component work?
At first information about the edges of an object is extracted, then the boundaries of the object are analyzed and then components are determined and matched with object representations in memory.
What are some of the Top-down approaches?
- Helmholtz’s Theory of Unconscious Inference
- Gestalt Theory
- Environmental Regularities
- Bayesian Inference
What is Helmholtz’s Theory of the Unconscious Inference?
It is the theory of how some of our perceptions are the result of unconscious assumptions we make about the environment. We use our knowledge to inform our perceptions
What is the likelihood Principle?
It is that we perceive the world in a way that is “most likely” based on our past experiences.
What was the Structuralist view of Perceptual Organization?
Perception involves adding up sensations.
What is the Gestalt view of Perceptual Organization?
The mind groups patterns according to the laws of perceptual organization.
What is the Law of Good Continuation?
Lines tend to be seen as following the smoothest path
What are the Gestalt Principles of Perceptual Organization?
- Law of good continuation
- Law of good figure
- Law of similarity
- Law of familiarity or meaningfulness
- Law of proximity
- Law of common fate
What is the Law of Good Figure?
That every stimulus pattern is seen so the resulting structure is as simple as possible.
What is the Law of Similarity
Similar things appear grouped together.
What is the Law of Familiarity or Meaningfulness?
Things are more likely to form groups if the groups appear familiar or meaningful.
What is the Law of Proximity?
Things near each other appear grouped together
What is the Law of Common Fate?
Things moving in the same direction appear to be grouped together. (Flock of Birds)
What are regularities in the environment?
Characteristics of the environment that occur frequently
What are the two types of regularities in the environment?
- Physical Regularities
- Semantic Regularities
What are the Physical Regularities?
They are regularly occurring physical properties of the environment.
What are Semantic Regularities?
The meaning of a scene
What is a light-from-above heuristic?
- Light comes from above
- Is usually the case in the environment
- We perceive shadows as specific information about depth and distance.
What is another way to look at Semantic Regularities?
It is the meaning of a given scene and is related to what is happening within that scene.
These regularities are characteristics associated with the functions carried out in different types of scenes
What is a Scene Schema?
It is the knowledge of what a given scene ordinarily contains.
What was the Palmer Experiment?
- Observers saw a context scene flashed briefly, followed by a target picture
- The results showed that targets congruent with the context were identified 80% of the time.
- The results also showed that targets that were incongruent were only identified 40% of the time.
Who created the Bayesian Inference?
Thomas Bayes (1701-1761)
What was the Bayesian Inference based on?
It was based on the Unconscious Inference theory and Physical and Semantic Regularities
What is the Bayesian Inference?
One’s estimate of the probability of a given outcome is influenced by two factors:
- The prior probability (our initial belief about the probability of an outcome)
- The likelihood of a given outcome - the extent to which the available evidence is consistent with the outcome
What is the equation Bayesian Inference created?
Prior + Evidence = Inference
What do Helmholtz, The Regularities, and Bayesian Inference have in common?
- Use info from the environment gathered through experience
- Top-down processing
How is Gestalt different than the Helmholtz, Bayesian Inference, and the Regularities.
- Principles of the organization are built-in (biological-bottom up processing)
- Experience can be over-ridden
What is Experience-dependent plasticity?
Response properties of neurons shaped by learning
Can Neurons become tuned to respond best to what we experience?
Yes, it can be for common experiences. For example, we have more neurons that respond to horizontals and verticals and this can be due to natural selection.
What can shape our biological process?
Experience
What is the Greeble experiment?
Participants were trained to name every greeble, after this the participants responded to the Greebles almost as strongly as they did to faces.
What is Perception and Action in terms of “What and Where”?
Interactions between “what” and “where” - so movement facilitates perception
What is the interaction between Perception and Action?
- Perceive
- Initiate action
- Conclude action based on perception.
What is Brain Ablation?
It is a method that allows scientists to damage specific areas of otherwise normal brains, and they controlled their damage to allow for clear conclusions to be drawn (usually on animals like monkeys and cats)
If your trying to understand a complex mechanism what can you do?
You can logically deduce conclusions from “malfunctions”
What are the “what and where” pathways in Perception and action?
It is first received in the Occipital lobe and splits in two directions:
- The Dorsal pathway that leads to the Parietal lobe (where/how)
- The ventral pathway that leads to the temporal lobe (what)
What were the two types of discrimination tasks used by Ungerleider and Mishkin?
- Object discrimination: Pick the correct shape, damage to the temporal lobe makes this difficult
- Landmark Discrimination: Pick the food well closer to the cylinder, damage to the Parietal lobe makes this difficult.
What does the Ventral pathway do?
It identifies an object
What does the Dorsal pathway do?
It identifies the location of the object
What are Mirror Neurons?
They are neurons that respond both when a monkey observes someone else grasping an object such as food on a tray and when the monkey itself grasps the food.
