Human Lec (2) PDF

The Human Lec (2) Dania Mohamed Ahmed  Introduction The human, the user, is, after all, the one whom computer systems are designed to assist. The requirements of the user should therefore be our first priority. To design effective intera...

The Human Lec (2) Dania Mohamed Ahmed  Introduction The human, the user, is, after all, the one whom computer systems are designed to assist. The requirements of the user should therefore be our first priority. To design effective interactive computer systems, it is essential to understand human capabilities and limitations, which is why studying cognitive psychology is important. This field provides insights into how humans perceive the world, store and process information, solve problems, and physically manipulate objects. By understanding these aspects, designers can create systems that are easier and more intuitive for people to use.  Introduction Cont.. In 1983, the Model Human Processor was introduced as a simplified view of human processing in interaction with computer systems. It consists of three subsystems: the perceptual system (handling sensory input), the motor system (controlling actions), and the cognitive system (processing information to connect the two). Each subsystem has its processor and memory, with varying complexity depending on the tasks. The model also outlines principles of operation that govern the behavior of these systems under different conditions. we will first look at the human is input-output channels, the senses, and responders or effectors. This will involve some low-level processing. Secondly, we will consider human memory and how it works. We will then think about how humans perform complex problem-solving, how they learn and acquire skills, and why they make mistakes. Finally, we will discuss how these things can help us in the design of computer systems.  Input-output Channels A person interacts with the outside world by receiving (input) and sending (output) information. In computer interactions, the user receives information from the computer (output) and responds by providing input to the computer. The user's output becomes the computer's input, and vice versa. We will focus on the channels involved in these interactions to avoid confusion with the terms input and output. Input in the human occurs mainly through the senses and output through the motor control of the effectors. There are five major senses: sight, hearing, touch, taste, and smell. Of these, the first three are the most important to HCI. Taste and smell do not currently play a significant role in HCI. However, vision, hearing and touch are central.  Input-output Channels Cont.. Similarly there are many effectors, including the limbs, fingers, eyes, head, and vocal system. In the interaction with the computer, the fingers play the primary role, through typing or mouse control, with some use of voice, eye, head, and body position. When using a personal computer with a mouse and keyboard, you primarily receive information visually from the screen. You might also get auditory feedback, such as a beep indicating an error or a voice in a multimedia presentation. Touch is involved through the feel and sound of pressing keys or moving the mouse, providing essential feedback. You send information to the computer using your hands by typing or moving the mouse. Although sight and hearing do not directly send information to the computer, they can help you receive information from other sources, like a book or another person, which you then transmit to the computer.  Vision Human vision is a complex process with physical and perceptual limitations, but it is the main source of information for most people. Visual perception can be divided into two stages: the physical reception of stimuli and the processing and interpretation of those stimuli. The eye and visual system have inherent limitations, but visual processing can construct images from incomplete information. Understanding both stages is crucial for designing computer systems. We will first examine the eye as a physical receptor, then the processing involved in basic vision.  Visual perception Vision starts with light. The eye receives light and converts it into electrical energy. Light reflects off objects and forms an upside-down image on the back of the eye. The eye's receptors change this light into electrical signals that are sent to the brain (physical reception is a mechanism for receiving light and transforming it into electrical energy) Images are focused upside-down on the retina, the retina contains rods for low-light vision and cones for color vision. Visual perception involves more complex processes. The visual information must be filtered and processed to recognize coherent scenes, determine relative distances, and differentiate colors. To design effective visual interfaces, it is essential to understand how we perceive size, depth, brightness, and color, as these aspects are crucial in visual processing.  The capabilities and limitations of visual processing The capabilities and limitations of visual processing involve the transformation and interpretation of a complete image, from the light that is thrown onto the retina our expectations affect the way an image is perceived. Example: 12 13 14 ABC An ambiguous shape?  Hearing Provides information about the environment: distances, directions, objects etc. Just as vision begins with light, hearing begins with vibrations in the air or sound waves. The ear receives these vibrations and transmits them to the auditory nerves through various stages. The ear consists of three sections: the outer ear, middle ear, and inner ear. 1. outer ear: protects inner and amplifies sound 2. middle ear: transmits sound waves as vibrations to inner ear 3. inner ear: chemical transmitters are released and cause impulses in auditory nerve  Sound The human ear can hear frequencies from about 20 Hz to 15 kHz. The auditory system performs some filtering of the sounds received, allowing us to ignore background noise and concentrate on important information. Sound can convey a remarkable amount of information. It is rarely used to its potential in interface design, usually being confined to warning sounds and notifications. The exception is multimedia, which may include music, voice commentary and sound effects.  characteristics of sound 1. Frequency:  Definition: The number of sound wave cycles that occur in one second, measured in Hertz (Hz).  Perception: Frequency determines the pitch of the sound. Higher frequencies correspond to higher pitches, while lower frequencies correspond to lower pitches 2. Amplitude:  Definition: The height of the sound wave, which reflects the amount of energy in the wave.  Perception: Amplitude determines the loudness or volume of the sound. Greater amplitudes produce louder sounds, while smaller amplitudes produce softer sounds. 3. Wavelength:  Definition: The distance between consecutive crests (or troughs) of a sound wave.  Relationship to Frequency: Wavelength is inversely related to frequency. Higher frequency sounds have shorter wavelengths, while lower frequency sounds have longer wavelengths.  Touch Touch provides us with vital information about our environment. Touch is an important means of feedback, and this is no less so in using computer systems. Feeling buttons depressed is an important part of the task of pressing the button. Also, we should be aware that, although for the average person, haptic perception is a secondary source of information, for those whose other senses are impaired, it may be vitally important The apparatus of touch differs from that of sight and hearing in that it is not localized. We receive stimuli through the skin. The skin contains three types of sensory receptor: 1. thermoreceptors: respond to heat and cold, 2. nociceptors respond to intense pressure, heat and pain 3. mechanoreceptors respond to pressure.  Touch Cont.. A second aspect of haptic perception is kinesthesis, which is the awareness of the body's and limbs' positions due to receptors in the joints. There are three types of receptors: 1. rapidly adapting (respond to limb movement) 2. slowly adapting (respond to movement and static positions) 3. positional receptors (respond only to static positions).  Movement Time taken to respond to stimulus: reaction time + movement time Movement time is dependent largely on the physical characteristics of the subjects: their age and fitness. Factors such as skill or practice can reduce reaction time. Speed and accuracy of movement are important considerations in the design of interactive systems, primarily in terms of the time taken to move to a particular target on a screen. The target may be a button, a menu item or an icon.  Human memory Human memory plays a crucial role in how users interact with computer systems. It influences how information is processed, retained, and recalled during interaction. Understanding memory's structure and limitations is essential for designing user- friendly interfaces. Types of Memory: 1. Sensory Memory 2. Short-Term (Working) Memory 3. Long-term memory  Sensory Memory Function: the sensory memories act as buffers for stimuli received through the senses. A sensory memory exists for each sensory channel: iconic memory for visual stimuli, echoic memory for aural stimuli, and haptic memory for touch. These memories are constantly overwritten by new information coming in on these channels. information is transferred from sensory memory to short-term memory through attention, which filters stimuli to focus only on what is of interest at a given time. Attention involves concentrating on one out of several competing stimuli or thoughts. This selective focus is necessary because our sensory and mental processes have limited capacity. Duration: Lasts for a fraction of a second (0.5 seconds). Role in HCI: Important for perceiving continuous visual and auditory streams, such as animations and speech.  Short-Term (Working) Memory Function: Holds a small amount of information for a short period, allowing for immediate processing and manipulation (memory acts as a ‘scratch-pad’ for temporary recall of information). Capacity: Limited to about 7±2 items. Duration: Lasts for about 20-30 seconds. Characteristics:  Chunking: Grouping information into larger units or chunks to increase capacity.  Rehearsal: Repeating information to extend its duration in short-term memory. Role in HCI: Interface design should minimize cognitive load and avoid overwhelming users with too much information simultaneously. Familiar icons, clear instructions, and logical grouping can aid memory.  Long-term memory Function: Stores information over extended periods, potentially indefinitely. Long- term memory differs significantly from short-term memory. First, it has a huge, potentially unlimited capacity. Second, its access time is relatively slow, about a tenth of a second. Third, forgetting occurs more slowly in long-term memory, if at all. These differences support the idea of a multi-part memory structure There are two types of long-term memory: Episodic memory represents our memory of events and experiences in a serial form. Semantic memory, conversely, is a structured record of facts, concepts, and skills we have acquired. The information in semantic memory is derived from that in our episodic memory, such that we can learn new facts or concepts from our experiences.  Long-term memory Cont.. Many other memory structures to allow access to information, representation of relationships between pieces of information, and inference (explain how we represent and store different types of knowledge.): 1. Semantic network 2. Frame 3. Script 4. Production rule  Semantic network Represents relationships between bits of information supports inference. Items are associated with each other in classes, and may inherit attributes from parent classes. They do not allow us to model the representation of more complex objects or events, which are perhaps composed of many items or activities. Semantic network  Frames Structured representations such as frames and scripts organize information into data structures. Slots in these structures allow attribute values to be added. Frame slots may contain default, fixed, or variable information. A frame is instantiated when the slots are filled with appropriate values. Frames and scripts can be linked together in networks to represent hierarchically structured knowledge. Frames extend semantic nets to include structured, hierarchical information. They represent knowledge items in a way which makes explicit the relative importance of each piece of information. Slots in frame memory structures can be of three types: 1. Fixed Slots: These have set attribute values. 2. Default Slots: These have usual attribute values that can be overridden in specific instances. 3. Variable Slots: These can be filled with specific values in a given instance Additionally, slots can contain procedural knowledge, meaning actions or operations can be associated with a slot and performed whenever the slot's value changes. Frames  Script Scripts attempt to model the representation of stereotypical knowledge about situations A script represents this default or stereotypical information, allowing us to interpret partial descriptions or cues fully. A script comprises a number of elements, which, like slots, can be filled with appropriate information:  Entry conditions: Conditions that must be satisfied for the script to be activated  Result Conditions: that will be true after the script is terminated.  Props: Objects involved in the events described in the script.  Roles: Actions performed by particular participants.  Scenes: The sequences of events that occur.  Tracks: A variation on the general pattern representing an alternative scenario Script  Production Rule A final type of knowledge representation which we hold in memory is the representation of procedural knowledge, our knowledge of how to do something. A common model for this is the production system. Condition–action rules are stored in long-term memory. Information coming into short-term memory can match a condition in one of these rules and result in the action being executed. For example, a pair of production rules might be IF dog is wagging tail THEN pat dog IF dog is growling THEN run away  Long-term memory processes Thereare three main activities related to long-term memory: storage or remembering of information, forgetting and information retrieval. Information from short-term memory is stored in long-term memory through rehearsal, which involves repeated exposure or rehearsal of the information. However, repetition alone is insufficient for effective learning. Information needs to be meaningful and related to existing memory structures for better retention. When information is meaningful and familiar, it integrates more easily into long- term memory due to the semantic structuring of memory.  Long-term memory processes Cont.. Storage or Remembering of Information: information moves from STM to LTM Forgetting Information: Forgetting in long-term memory can be explained by two main theories: decay and interference. 1. Decay Theory: Supported by Ebbinghaus's experiments, this theory suggests that memory fades logarithmically, meaning it is lost rapidly at first and then more slowly over time. Jost's law states that if two memory traces are equally strong, the older one will be more durable. 2. Interference Theory: Retroactive Interference: New information causes the loss of old information, such as forgetting an old phone number after learning a new one. Proactive Inhibition: Old memories interfere with new information, like accidentally driving to your old house instead of your new one.  Long-term memory processes Cont.. Proving true forgetting is difficult because what appears as forgetting might be a retrieval problem rather than complete loss. Evidence suggests that information in long-term memory is generally not entirely lost. Proactive Inhibition: Shows that older information can still be recovered despite interference from new information. "Tip of the Tongue" Phenomenon: Indicates that information is present but not easily accessible. Recognition and Recall: Information can often be recognized or recalled with prompts, even if it cannot be spontaneously retrieved. Emotional Factors: Forgetting can also be influenced by emotional states.  Long-term memory processes Cont.. Retrieval Information This leads us to the third process of memory: information retrieval. Here we need to distinguish between two types of information retrieval, recall and recognition. In recall the information is reproduced from memory. In recognition, the presentation of the information provides the knowledge that the information has been seen before. Recognition is the less complex cognitive activity since the information is provided as a cue. Recall can be assisted by the provision of retrieval cues, which enable the subject quickly to access the information in memory. One such cue is the use of categories. The use of vivid imagery is a common cue to help people remember information.  Thinking: reasoning and problem-solving Thinking can require varying amounts of knowledge. Some activities, like performing a subtraction calculation, require a small, constrained amount of knowledge. Others, like understanding newspaper headlines, demand vast knowledge from multiple domains, including politics, social structures, public figures, and world events. There are two categories of thinking: reasoning and problem-solving. Reasoning is the process by which we use the knowledge we have to draw conclusions or infer something new about the domain of interest. There are many different types of reasoning: deductive, inductive, and abductive.  Deductive reasoning Deductive reasoning derives the logically necessary conclusion from the given premises. For example, If it is Friday then she will go to work It is Friday Therefore she will go to work It is important to note that this is the logical conclusion from the premises; it does not necessarily have to correspond to our notion of truth. So, for example, If it is raining then the ground is dry It is raining Therefore the ground is dry. Logical conclusion not necessarily true  Inductive reasoning Induction is generalizing from cases we have seen to infer information about cases we have not seen. For example, if every elephant we have ever seen has a trunk, we infer that all elephants have trunks. Of course, this inference is unreliable and cannot be proved to be true. Despite its unreliability, induction is a useful process, which we use constantly in learning about our environment. Humans are not good at using negative evidence: e.g. Wason's cards.  Wason's cards 7 E 4 K If a card has a vowel on one side it has an even number on the other Is this true? How many cards do you need to turn over to find out? …. and which cards?  Abductive reasoning The third type of reasoning is abduction. Abduction reasons from a fact to the action or state that caused it. This is the method we use to derive explanations for the events we observe. For example, Sam drives fast when drunk. If I see Sam driving fast, assume drunk. This too is unreliable (can lead to false explanations) since there may be another reason why she is driving fast: she may have been called to an emergency, for example.  Problem solving Reasoning: Involves drawing new inferences from known facts to arrive at new information. Problem Solving: The process of using existing knowledge to address unfamiliar tasks, characterized by its adaptability and creativity in applying known solutions to new situations. Theoretical Perspectives: 1. Gestalt View: Focus: Emphasizes the reuse of knowledge and insight in problem solving. Legacy: Although largely replaced by other theories, it still influences contemporary understanding of problem solving. 2. Problem Space Theory (Newell and Simon, 1970s): Concept: Views problem solving as navigating a problem space with the mind functioning as a limited information processor. 3. Analogical Reasoning: Method: Solving problems by identifying similarities with previously solved problems and applying known solutions to new but similar issues.  Problem solving Types of error: 1. Slips right intention, but failed to do it right causes: poor physical skill, inattention etc. change to aspect of skilled behavior can cause slip 2. Mistakes wrong intention cause: incorrect understanding humans create mental models to explain behavior. if wrong (different from the actual system) errors can occur  Emotion Our emotional responses impact our performance: positive emotions foster creativity and problem- solving, while negative emotions lead to narrow thinking. Problems that are easy to solve when relaxed become difficult when we are frustrated or afraid. Various theories of how emotion works 1. James-Lange: emotion is our interpretation of a physiological response to a stimuli 2. Cannon: emotion is a psychological response to a stimuli 3. Schacter-Singer: emotion is the result of our evaluation of our physiological responses, in the light of the whole situation we are in The biological response to physical stimuli is called affect Affect influences how we respond to situations positive creative problem solving negative narrow thinking “Negative affect can make it harder to do even easy tasks; positive affect can make it easier to do difficult tasks” (Donald Norman)  Individual differences Shared Processes: While humans share common cognitive and perceptual processes, individual differences must be considered in design. Types of Differences: Long-Term: Includes factors like sex, physical capabilities, and intellectual abilities. Short-Term: Encompasses transient conditions such as stress or fatigue affecting user performance. Temporal Changes: Involves changes over time, such as those related to aging. Designs should accommodate these differences to ensure accessibility and usability for a diverse range of users.  Psychology and the design of interactive systems To apply knowledge of how humans receive, process, and store information, solve problems, and acquire skills to the design of interactive systems, straightforward conclusions can sometimes be drawn. For example, since recognition is easier than recall, users should be able to select commands from a menu rather than inputting them directly. However, most applications are not so simple, and improper application of psychological principles can lead to invalid generalizations. Proper application requires understanding the context of these principles within the broader field of psychology, as well as details of the relevant experiments, including measures used and subjects involved (However, correct application generally requires understanding of context in psychology, and an understanding of particular experimental conditions) A lot of knowledge has been distilled in guidelines (chap 7) cognitive models (chap 12)  experimental and analytic evaluation techniques (chap 9)