04-perception-handout(1).pdf

The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Perception Cognitive Processes – PSYCH 24300 Carolina Lopera-Oquendo...

The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Perception Cognitive Processes – PSYCH 24300 Carolina Lopera-Oquendo Department of Psychology September 18, 2024 Perception Department of Psychology 1 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Outline 1. The Nature of Perception 1.1 Why Is It So Difficult to Design a Perceiving Machine? 2. Information for Human Perception 3. Conceptions of Object Perception 3.1 Helmholtz’s Theory of Unconscious Inference (1866/1911) 3.2 The Gestalt Principles of Organization 4. Perception and Action: Behavior 5. Perception and Action: Physiology Perception Department of Psychology 2 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Last Topic: Cognitive Neuroscience - Levels-of-Analysis: Understand the multi-level approach in studying brain function and behavior. - Nerve Net vs. Neuron Doctrine: Differentiate between the early nerve net model and the modern neuron doctrine. - Neural Firing & Sensory Experience: Explain how firing rates relate to stimulus intensity and sensory perception. - Hierarchical Visual Processing: Describe how the brain processes visual information to recognize complex stimuli. Perception Department of Psychology 3 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Last Topic: Cognitive Neuroscience - Coding Mechanisms: Identify how the brain encodes sensory information. - Brain Localization: Review evidence supporting specific brain regions linked to functions. - Distributed Neural Representation: Discuss how functions are represented across different brain areas. - Structural vs. Functional Connectivity: Distinguish between brain structure and functional communication in networks. Perception Department of Psychology 4 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Learning Topics 1. Describe the challenges involved in visual perception in humans and in computer-vision systems. 2. Distinguish between bottom-up (data-based) and top-down (knowledge-based) processing. 3. Describe how Helmholtz’s process of unconscious inference, Gestalt principles of perceptual organization, use of regularities in the environment, and the process of Bayesian Inference contribute to our ability to accurately perceive objects. Perception Department of Psychology 5 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Questions that we will explore in this chapter 1. Why can two people experience different perceptions in response to the same stimulus? 2. How does perception depend on a person’s knowledge about characteristics of the environment? 3. How does the brain become tuned to respond best to things that are likely to appear in the environment? 4. What is the connection between perception and action? Perception Department of Psychology 6 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Outline 1. The Nature of Perception 1.1 Why Is It So Difficult to Design a Perceiving Machine? 2. Information for Human Perception 3. Conceptions of Object Perception 3.1 Helmholtz’s Theory of Unconscious Inference (1866/1911) 3.2 The Gestalt Principles of Organization 4. Perception and Action: Behavior 5. Perception and Action: Physiology Perception Department of Psychology 8 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Activity: Discussion What is the difference between perception and sensations? Perceptions vs Sensation [2:23m] Perception Department of Psychology 9 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Definitions - Sensation - The stimulation of sensory receptors and the transmission of sensory information to the central nervous system. - Perception - The process by which sensations are organized into an inner representation of the world - the interpretation of information from the environment so that we can identify its meaning. - Sensation usually involves sensing the existence of a stimulus, whereas perceptual systems involve the determination of what a stimulus is. Perception Department of Psychology 10 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Has this building the same size? Perception Department of Psychology 11 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action From Sensation to Perception - Where does one building end and the next one start? - Which part of the percept belongs to which object? Perception Department of Psychology 12 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action From Sensation to Perception - We do not perceive the world exactly as our eyes see it. pn - Objects can look different depending on viewpoint, revealing different details - Our brain actively tries to make sense of the many stimuli. - Perception involves more than just seeing what’s projected onto the retina - The process of perception is complex and involves interpretation by the brain - It’s necessary to go beyond light and dark patterns on the retina to determine what’s "out there" Perception Department of Psychology 13 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Neurophysiology of the Visual System Check the Additional Materials– Reading Folder in Blackboard for the recommended lecture Perception Department of Psychology 14 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action What is Perception? - Definition - Experiences resulting form stimulation of the senses (American Psychological Association, 2015) - Process or results of becoming aware of objects, relationships, and events by means of the sense - “It’s a bird. It’s a plane. It’s Superman!” Perception Department of Psychology 15 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Basic concepts about Perception - Perception can changed based on added information - Involves a process similar to reasoning or problem solving - Plays a central role in cognition in general. - Perceptions occur in conjunction with actions - It is possible that true human perceptual process are unique to humans. - Attempts to create artificial forms of perception (machines) have been met with limited success and each time have had problems that could not be solved. Perception Department of Psychology 16 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Why Is It So Difficult to Design a Perceiving Machine? The Stimulus on the Receptors Is Ambiguous - Inverse projection problem: the task of determining the object responsible for a particular image on the retina - starting with the retinal image, and - extending rays out from the eye. - A particular image on the retina can be created by many different objects in the environment, therefore the image in the retina is ambiguous. Perception Department of Psychology 17 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Why Is It So Difficult to Design a Perceiving Machine? Objects Can Be Hidden or Blurred Who are these people? Perception Department of Psychology 18 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Why Is It So Difficult to Design a Perceiving Machine? Objects Can Be Hidden or Blurred - Can you locate the hidden pencil and the author’s glasses? What other objects can you identified? Perception Department of Psychology 19 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Why Is It So Difficult to Design a Perceiving Machine? Objects Can Be Hidden or Blurred - Hidden or blurred objects occurs frequently in the environment, but people easily - Understand that the part of an object that is covered continues to exist, - Use their knowledge of the environment to determine what is likely to be present. - Computers perform poorly on this task (Sinha, 2002). Perception Department of Psychology 20 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Why Is It So Difficult to Design a Perceiving Machine? Objects Look Different from Viewpoints Can you recognize the same object at different angles? Perception Department of Psychology 21 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Why Is It So Difficult to Design a Perceiving Machine? Objects Look Different from Viewpoints - Viewpoint Invariance: Ability to recognize the same object at different viewpoints - Computer-vision systems can achieve viewpoint invariance only by a laborious process that involves complex calculations designed to determine which points on an object match in different views. Perception Department of Psychology 22 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Why Is It So Difficult to Design a Perceiving Machine? Scenes Contain High-Level Information What is the basis for deciding the planes are probably on display at an air show? Perception Department of Psychology 23 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Why Is It So Difficult to Design a Perceiving Machine? Scenes Contain High-Level Information - Transitioning from individual objects to entire scenes introduces an additional layer of complexity. - Scenes often contain multiple objects that offer clues about the environment, requiring reasoning to interpret accurately Perception Department of Psychology 24 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Why Is It So Difficult to Design a Perceiving Machine? How Do We Make Sense of What We See? - Do we just perceive whatever is being projected on our retina, or is there more to perception? - Does our knowledge, and other rules we have learned throughout our life, perhaps influence our perception of the world? - Two types of information used by the human perceptual system: - Environmental energy that stimulates sensory receptors, and - Knowledge and expectations the observer brings to the experience. Perception Department of Psychology 25 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Outline 1. The Nature of Perception 1.1 Why Is It So Difficult to Design a Perceiving Machine? 2. Information for Human Perception 3. Conceptions of Object Perception 3.1 Helmholtz’s Theory of Unconscious Inference (1866/1911) 3.2 The Gestalt Principles of Organization 4. Perception and Action: Behavior 5. Perception and Action: Physiology Perception Department of Psychology 26 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Theoretical Perspectives on How We Perceived the World Bottom-Up theories - Perception begins with the stimuli taken in through the senses 1. Visual stimuli create an image on the retina. 2. This image generates electrical signals, which are transmitted through the retina. 3. These signals reach the brain’s visual receiving area. - Data-driven approach: Perception is stimulus-driven. - The four main bottom-up theories of form and pattern perception are direct perception, template theories, feature theories, and recognition-by-components theory. Perception Department of Psychology 27 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Theoretical Perspectives on How We Perceived the World Top-down theories - Perception is driven by high-level cognitive processes, existing knowledge, and the prior expectations. - Processing begins in the brain, at the "top" of the perceptual system. - Knowledge helps rapidly identify objects and scenes, allowing interpretation beyond basic recognition. - Examples of top-down processing: - Perceiving objects - Hearing words in a sentence. - Constructive perception, the perceiver builds (constructs) a cognitive understanding (perception) of a stimulus. - Theories of Human Perception Perception Department of Psychology 28 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Top-down processing: Perceiving objects Perception Department of Psychology 29 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Top-down processing: Hearing Words in a Sentence - How top-down processing influences speech perception? - Listeners familiar with different languages, such as English and Spanish, can receive the same sound stimuli but perceive them differently. - Prior experience with a language significantly influences their perception Perception Department of Psychology 30 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Top-down processing: Hearing Words in a Sentence - Speech segmentation: the ability to distinguish when one word ends and the next begins in conversation. - Bottom-Up: Sound signals enters the ears and trigger signals responses in the brain’s speech areas. - Top-Down: Knowledge of a language helps the brain segment and identify individual words. - While knowing word meanings helps with segmentation, listeners also rely on additional cues. - As we learn a language, we acquire more than just word meanings; we also learn patterns, rhythms, and other linguistic clues that aid in identifying word boundaries. Perception Department of Psychology 31 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Top-down processing: Hearing Words in a Sentence - Transitional probabilities: likelihood that one sound will follow another within a word. - For example, consider the words pretty baby. In English it is likely that pre and ty will be in the same word (pre-tty) but less likely that ty and ba will be in the same word (pretty baby). - Statistical learning: Every language has transitional probabilities for different sounds. - The process of learning about transitional probabilities and about other characteristics of language. - Saffran, et. al 1996 Statitical Learning In Infants Perception Department of Psychology 32 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Recap - The examples of how context affects our perception (Blob) and how knowledge of the statistics of speech affects our ability to create words from a continuous speech stream illustrate that top-down processing based on knowledge we bring to a situation plays an important role in perception. - We have seen that perception depends on two types of information - Bottom-up (information stimulating the receptors) - Top-down (information based on knowledge) - How perceptual information system uses this information? - Approaches to perceiving objects. Perception Department of Psychology 33 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Activity. Group Discussion 1. In about a minute, think of one example of bottom-up processing and one example of top-down processing. For example: - Bottom-Up Processing: - Detecting a Color Change: When you notice a red object in a sea of blue ones, your perception starts with detecting the color red and then recognizing the object based on this basic feature. - Top-Down Processing: - Understanding a Blurry Object: When you see a blurry object, your brain uses context and experience to infer what it might be (like a car or a person) based on previous encounters with similar objects. 2. Pair up with a classmate and talk through your examples. Are they similar? Are they different? Do you feel like you understand the difference between top-down and bottom-up processing? Perception Department of Psychology 34 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Outline 1. The Nature of Perception 1.1 Why Is It So Difficult to Design a Perceiving Machine? 2. Information for Human Perception 3. Conceptions of Object Perception 3.1 Helmholtz’s Theory of Unconscious Inference (1866/1911) 3.2 The Gestalt Principles of Organization 4. Perception and Action: Behavior 5. Perception and Action: Physiology Perception Department of Psychology 35 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Helmholtz’s Theory of Unconscious Inference (1866/1911) Helmholtz’s Theory of Unconscious Inference - Proposed an early idea about how people use information - Helmholtz’s contribution is based on the idea that the image on the retina is ambiguous. - A particular pattern of stimulation on the retina can be caused by a large number of objects in the environment - What does the pattern of stimulation in figure a represent? Perception Department of Psychology 36 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Helmholtz’s Theory of Unconscious Inference (1866/1911) Helmholtz’s Theory of Unconscious Inference How does the perceptual system “decide” that this pattern on the retina was created by overlapping rectangles? - Perception as Problem-Solving: - Perception involves determining which object caused a particular pattern of stimulation. - This process resembles problem-solving, where the perceptual system uses knowledge of the environment to infer the nature of the object. - Likelihood Principle: - Perceptions are formed based on what is statistically most probable. - This principle allows for rapid and seemingly instantaneous perceptions. Perception Department of Psychology 37 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Helmholtz’s Theory of Unconscious Inference (1866/1911) Helmholtz’s Theory of Unconscious Inferences - Unconscious Inference: - Perception involves rapid, unconscious processes. - Perceptions are the result of unconscious assumptions, or inferences, that we make about the environment. - Rapid and Unconscious Processing: - Perceptual judgments are made quickly and without conscious awareness. - Perceptual processing can feel effortless despite its complexity. - This allows for efficient problem-solving in perception, as suggested by Helmholtz. Perception Department of Psychology 38 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Origin of The Gestalt Principles of Organization - The Gestalt approach to perception originated, in part, as a reaction to Wilhelm Wundt’s Structuralism. - Overall experience could be understood by combining basic elements of experience called sensations. - Our perception of the face in the figure is created by adding up many sensations, represented as dots in this figure. - The Gestalt psychologists rejected the idea that perceptions were formed by “adding up” sensations (Max Wertheimer) Perception Department of Psychology 39 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Origin of The Gestalt Principles: Max Wertheimer (1880–1943) - Perceptions could not be explained by adding up small sensations - How the structuralist idea that experience is created from sensations could explain the illusion of movement? - Stroboscope Perception Department of Psychology 40 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Apparent movement - Apparent movement: principles behind the illusion of movement, because although movement is perceived, nothing is actually - Physically therefore, there are two lights flashing on and off separated by a period of darkness. - But we don’t see the darkness because our perceptual system adds something during the period of darkness - The perception of a light moving through the Optical Illusion of Motion space between the flashing lights. Perception Department of Psychology 41 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Apparent movement - Conclusions from the phenomenon of apparent movement. - apparent movement cannot be explained by sensations, because there is nothing in the dark space between the flashing lights. - The whole is different than the sum of its parts (basic principles of Gestalt psychology). - Gestalt psychologists to propose a number of principles of perceptual organization to explain the way elements are grouped together to create larger objects. Perception Department of Psychology 42 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Gestalt Principles of Visual Perception: Figure-ground When perceiving a visual field, some objects (figures) seem prominent, and other aspects of the field recede into the background (ground). Perception Department of Psychology 43 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Gestalt Principles of Visual Perception: Proximity When we perceive an assortment of objects, we tend to see objects that are close to each other as forming a group. Perception Department of Psychology 44 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Gestalt Principles of Visual Perception: Similarity We tend to group objects on the basis of their similarity. Perception Department of Psychology 45 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Gestalt Principles of Visual Perception: Continuity We tend to perceive smoothly flowing or continuous forms rather than disrupted or discontinuous ones. Perception Department of Psychology 46 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Gestalt Principles of Visual Perception: Closure We tend to perceptually close up, or complete, objects that are not, in fact, complete. Perception Department of Psychology 47 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Gestalt Principles of Visual Perception: Symmetry We tend to perceive objects as forming mirror images about their center. Symmetry requires that features appear to have balanced proportions around a central axis or a central point. Perception Department of Psychology 48 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Gestalt Principles of Visual Perception: Law of Pragnanz Every stimulus pattern is seen in such a way that the resulting structure is as simple as possible. Perception Department of Psychology 49 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Regularities of the Environment - Modern perceptual psychologists take experience into account by noting that certain characteristics of the environment occur frequently. - Regularities in the environment. - Physical regularities: regularly occurring physical properties of the environment. - Oblique effect: people can perceive horizontals and verticals more easily than other orientations. Physical Regularities: Oblique Effect - Light-above assumption: The perceptual system assumes that light typically comes from above. Physical Regularities: Light-above assumption Perception Department of Psychology 50 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Regularities of the Environment - Semantic regularities are the characteristics associated with the functions carried out in different types of scenes. - This meaning is often related to what happens within an scene - Scene schema: - Information based on our knowledge of different kinds of scenes - Expectations created by scene schemas contribute to our ability to perceive objects and scenes. Perception Department of Psychology 51 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Bayesian Inference: Starting Point 1. Helmholtz’s idea that we resolve the ambiguity of the retinal image by inferring what is most likely, given the situation 2. Regularities in the environment provide information we can use to resolve ambiguities—are the starting point for our last approach to object perception Perception Department of Psychology 52 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Bayesian Inference - Thomas Bayes (1701–1761) proposed that our estimate of the probability of an outcome is determined by two factors: 1. The prior probability: which is our initial belief about the probability of an out- come, and 2. Likelihood of the outcome: the extent to which the available evidence is consistent with the outcome. - Implies mathematical procedure: prior is multiplied by the likelihood to determine the probability of the outcome. 1. start with a prior, and 2. use additional evidence to update the prior and reach a conclusion Bayesian Inference: Example Perception Department of Psychology 53 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Comparing the Four Approaches Which one is different from the other three? Table 1: Comparison Approaches about Perception of Objects Approach Bottom-up Top-down Helmholtz’S Unconscious Inference X The Gestalt laws of organization X Regularities in the environment X Bayesian Inference X Perception Department of Psychology 54 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Activity: Group Discussion 1. Pick one of the following perspectives: - Helmholtz’s process of unconscious inference - Gestalt principles of perceptual organization - Use of irregularities in the environment - Process of Bayesian inference 2. Using your perspective, discuss how it would explain how we see a photograph of a sunset. Take around 2 minutes to discuss this with your partners. 3. Report the group’s conclusions to the class. Perception Department of Psychology 55 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action The Gestalt Principles of Organization Neurons and Knowledge About the Environment - Experience can shape the way neurons respond - Some neurons respond best to things that occur regularly in the environment - Horizontal and vertical lines (oblique effect and experiments) - Perceptual functioning has been shaped by process of evolution - Experience-dependent plasticity (fMRI) - Learning can shape the response properties of neurons Perception Department of Psychology 56 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Outline 1. The Nature of Perception 1.1 Why Is It So Difficult to Design a Perceiving Machine? 2. Information for Human Perception 3. Conceptions of Object Perception 3.1 Helmholtz’s Theory of Unconscious Inference (1866/1911) 3.2 The Gestalt Principles of Organization 4. Perception and Action: Behavior 5. Perception and Action: Physiology Perception Department of Psychology 57 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action What is the purpose of perception? - Possible answer: - Create our awareness of what is happening in the environment, as when we see objects in scenes or we perceive words in a conversation. - Why it is important that we are able to experience objects in scenes and words in conversations? - An important purpose of perception is to enable us to interact with the environment. - Interact implies taking action Perception Department of Psychology 58 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Movements facilitate perception - Role of Movement in Perception: - Movement adds complexity but enhances our ability to perceive objects accurately. - By moving, we gain access to multiple viewpoints of an object. - Revealing Hidden Aspects: - Movement helps reveal features that aren’t visible from a single, static perspective. - This provides a more comprehensive understanding of the object’s shape, depth, and spatial relations. Perception Department of Psychology 59 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Movements facilitate perception - Dynamic Perception: - Continuous changes in viewpoint offer a richer and more detailed perceptual experience. - Movement helps resolve ambiguities that might arise from viewing an object from just one angle. Perception Department of Psychology 60 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Perception-Action Interaction - Perception and action are closely linked processes. - Movement not only aids perception but also requires continuous coordination between perceiving stimuli and responding to them. - Coordination of Perception and Movement: - As we perceive objects, we adjust our actions based on this information. - For example, when reaching for an object, we perceive its distance, size, and shape to guide our hand movements accurately. Perception Department of Psychology 61 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Perception-Action Interaction - Dynamic Feedback Loop: - Perception influences action, and action, in turn, provides new sensory information that updates perception. - This dynamic interaction is essential for effective navigation and interaction with the environment. Perception Department of Psychology 62 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Outline 1. The Nature of Perception 1.1 Why Is It So Difficult to Design a Perceiving Machine? 2. Information for Human Perception 3. Conceptions of Object Perception 3.1 Helmholtz’s Theory of Unconscious Inference (1866/1911) 3.2 The Gestalt Principles of Organization 4. Perception and Action: Behavior 5. Perception and Action: Physiology Perception Department of Psychology 63 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Perception and Action: What and Where Streams - What pathway: - Determining the identify of an object - Ventral pathway (lower path of the brain) - Where pathway: - Determining the location of an object - dorsal pathway Perception Department of Psychology 64 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Perception and Action: What and Where Streams - What pathway: - Determining the identify of an object - Ventral pathway (lower path of the brain) - Where pathway: - Determining the location of an object - dorsal pathway Perception Department of Psychology 65 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Perception and Action: What and Where Streams 1. Milner and Goodale (1995) 2. Perception pathway: - From visual cortex to temporal lobe - Corresponds to the what pathway 3. Action pathway: - From visual cortex to parietal lobe - Corresponds to the where pathway - Also called the how pathway Perception Department of Psychology 66 / 73 The Nature of Perception Information for Human Perception Conceptions of Object Perception Perception and Action Mirror Neurons - There neurons respond while a subject watches an action being performed in the same way as if the subject was performing the - action. - fMRI research has found evidence of a mirror neuron system in human’s brain. - In humans, they seem to be involved in determining the goal and intentions behind an action. - Iacoboni (2005) found higher rate of mirroring if the subject’s intention to perform the action was greater. Perception Department of Psychology 67 / 73 Four Main Bottom-Up Theories of Form and Pattern Perception: 1. Direct Perception: We perceive the world directly from sensory input without needing prior knowledge or cognitive processing. The environment provides all the necessary information. 2. Template Theories: The brain stores templates or mental blueprints for objects. When we perceive something, it’s compared to these stored templates to find a match. 3. Feature Theories: Perception involves breaking down objects into their basic features (e.g., lines, edges). The brain then combines these features to recognize and identify the object. 4. Recognition-by-Components Theory: Objects are perceived by identifying basic 3D shapes, called "geons." The brain combines these geons to recognize complex objects, regardless of their orientation. Perception Department of Psychology 68 / 73 Example Responses for Bottom-Up 1. Recognizing a Face: When you see a face, you start by detecting basic features like edges, shapes, and colors. Your brain then combines these features to recognize the person. This process begins with raw sensory input and builds up to a complete perception. 2. Detecting a Color Change: When you notice a red object in a sea of blue ones, your perception starts with detecting the color red and then recognizing the object based on this basic feature. 3. Hearing a New Sound: If you hear an unfamiliar sound, your brain initially analyzes the basic properties of the sound (frequency, pitch) before identifying it as, for example, a bird chirping or a doorbell. 4. Recognizing Shapes in a Picture: When viewing a complex image, you first identify individual shapes and lines (like circles and rectangles) before recognizing the overall picture, such as a car or a tree. Perception Department of Psychology 69 / 73 Example Responses Top-Down Processing 1. Reading Jumbled Text: If you see a sentence with some letters jumbled (e.g., "I can raed tihs"), your prior knowledge of language and context helps you quickly understand the intended meaning. Your brain uses expectations and experience to make sense of the incomplete or distorted input. 2. Interpreting Ambiguous Speech: If you hear someone say "I scream" in a noisy environment, you might interpret it as "ice cream" based on context and your knowledge of likely topics of conversation. 3. Understanding a Blurry Object: When you see a blurry object, your brain uses context and experience to infer what it might be (like a car or a person) based on previous encounters with similar objects. 4. Reading a Spelled-Out Word: When reading, you often predict upcoming words based on context. For instance, in the sentence "The cat sat on the _," you quickly fill in "mat" based on common language patterns and context. Perception Department of Psychology 70 / 73 Physical Regularities: Oblique Effect Regularities of the Environment Perception Department of Psychology 71 / 73 Physical Regularities: Light-above assumption Regularities of the Environment Perception Department of Psychology 72 / 73 Bayesian Inference: Example Bayesian Inference Perception Department of Psychology 73 / 73