COMP1649 - HUMAN COMPUTER INTERACTION AND DESIGN
Lecture 03: HUMAN COGNITION
HCI's main objective has been to understand and represent how humans interact with computers, example how knowledge is transmitted between the two.
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Activity 1: It is important we understand how we (re)cognize things. What do you see?
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Outcomes:
- discuss the role of cognitive frameworks in interaction design;
- explain what Mental Models are;
- outline the differences between mental models and distributed cognition.
- apply a mental model to a suitable interaction design problem.
Cognition and Reasoning
- Cognition refers to the processes by which we gain knowledge. Processes include: understanding, remembering, reasoning, attending, being aware, acquiring skills and creating new ideas.
- Cognitive psychology provides the theoretical grounding: it attempts to explain how human beings achieve the goals they set.
- The dominant framework that has characterize HCI has been cognitive, Cognitive frameworks include those of:
- Internal Cognition - Mental models
- External Cognition and
- Distributed Cognition - an alternative frameworks, currently being developed.
Cognitive processes
- Attention
- Perception and recognition
- Memory
- Learning
- Reading, speaking and listening
- Problem-solving, planning, reasoning and decision-making
It is important to note that many of cognitive processes are interdependent: several may be involved for a given activity. It is rare for one to occur in isolation. For example, when you try to learn material for an exam, you need to attend to the material, perceive and recognize it, read it, think about it and try to remember it. Below we describe the various kinds in more detail, followed by a summary box highlighting core design implications for each. Most relevant for interaction design are attention and memory which we describe in greatest detail.
Attention
- Selecting things to concentrate on at a point in time from the mass of stimuli around us
- Allows us to focus on information that is relevant to what we are doing
- Involves audio and/or visual senses
- Focused and divided attention enables us to be selective in terms of the mass of competing stimuli but limits our ability to keep track of all events
- Information at the interface should be structured to capture users’ attention, e.g. use perceptual boundaries (windows), color, sound and flashing lights
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Activity 2: What do you remember? You need to write the answer down.
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Extending the human processing model
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Activity 3: So how does your cognition/thought process work? You need to be able to write your answer down
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Recent trends
Focus is on explaining how knowledge is represented and how
- Mental models (mind representations of the individuals, others, objects, and the environment, which enable individuals to be able to anticipate how things work) develop and are used in HCM. So what was their mental model?
- to apply this knowledge to HCI design via
- interface metaphors (example desktop, bin) to match the knowledge requirements of users.
- conceptual models (these are the various ways in which systems are understood by different people) to help designers develop appropriate interfaces.
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Activity 4: You have 10 seconds to remember the following words. You will then be asked to write them down?
How many of you wrote slumber, night or sleep?
==> Research says that over 70% of people do.
Activity 5: you will see three words, write down the first word that comes into your mind when you read each of these words.
- COLOR
- FURNITURE
- FLOWER
- COLOR: Red or Blue
- FURNITURE: Chair or Couch
- FLOWER: Rose or Daisy?
==> Research shows that over 60% of people do
Many of you will and this is to do with our mental model. Our Neurological pathways or neural nets become to associating the same things together. The more these pathways are used the more entrenched in our thought processes we become.
Recognition versus recall
- Command-based interfaces require users to recall from memory a name from a possible set of 100s
- GUIs provide visually-based options that users need only browse through until they recognize one.
- Web browsers, MP3 player etc, provide list of visited URLs, song titles etc, that support recognition memory.
Miller’s 7+-2 What some designers get up to…
- Present only 7 options on a menu
- Display only 7 icons on a tool bar
- Have no more than 7 bullets in a list
- Place only 7 items on a pull down menu
- Place only 7 tabs on the top of a website page
Why?
- Inappropriate application of the theory
- People can scan lists of bullets, tabs, menu items for the one they want
- They don’t have to recall them from memory having only briefly heard or seen them
- Sometimes a small number of items is good
- But depends on task and available screen estate
Personal information management
- Personal information management is a growing problem for many users
- vast numbers of documents, images, music files, video clips, emails, attachments, bookmarks, etc.,
- where and how to save them all, then remembering what they were called and where to find them again
- naming most common means of encoding them
- but can be difficult to remember, especially when have 1000s and 1000s
- How might such a process be facilitated taking into account people’s memory abilities?
- Memory involves 2 processes: recall-directed and recognition-based scanning
- File management systems should be designed to optimize both kinds of memory processes: e.g. Search box and history list
- Help users encode files in richer ways: Provide them with ways of saving files using colour, flagging, image, flexible text, time stamping, etc
Evaluation based on Cognitive Modeling
- Keystroke-Level Model: low-level description of what users must do to perform a task.
- GOMS: structured, multi-level description of what users must do to perform a task
- Fitts’ Law: Used to predict time needed to select a target
Keystroke-level Model
Carried out by an expert(s):
Walk through the interface and count the number of operations it would take an expert user to complete a task.
Identify if this could be optimised and if yes, then optimise the task.
Identify any potential sources of error and minimise the impact of these.
KLM is used for very small tasks.
Replace all instances of a 4-letter word. (example from Hoc hstein)
GOMS
A family of techniques , known as GOMS (Goals, Operations, Methods and Selection rules) have been abstracted from this model, that translate the qualitative descriptions into quantitative measures. Higher level than KLM
- Goals represent the goals that a user is trying to accomplish, usually specified in a hierarchical manner.
- Operators are the set of operations the user will undertake to achieve their goal.
- Methods are a group of operators that achieve a single goal (Use case eg login to system).
- Selection Rules are used to decide which method to use to achieve a given goal (eg select a toolbar button or use a drop down menu).
Applications of GOMS analysis
It is goal directed and can
- Compare user interface designs
- Support Profiling
- Build a help system as it makes user tasks and goals explicit and therefore can suggest questions users will ask.
Fitts’ Law
- Models movement time for selection tasks
- The movement time for a well-rehearsed selection task:
- increases as the distance to the target increases
- decreases as the size of the target
External Cognition
Rogers (2004) defined this as being the "interaction between internal and external representations when performing cognitive tasks (e.g., learning)". The main ones include:
- Externalizing to reduce memory load (diaries, phone book)
- Computational off loading (pen/paper, calculator)
- Annotating (e.g. crossing off items from a to-do list or underlining) and cognitive tracing (externally manipulating items into different orders or structures eg scrabble)
Distributed cognition
- This involves describing cognition as it is distributed across individuals and the setting in which it takes place. A main goal of the distributed cognition approach is to analyse how the different components of the functional system are coordinated. A functional system refer to users, computer system and other technology (sometimes referred to as cognitive artefacts by psychologists) and their relations to each other in the environmental setting in which they are situated.
- Main concerns are to map out how the various representational states of the functional system are coordinated across time, location and objects.
- Analyze and explain the breakdowns in coordination that emerge in work settings.
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Next section 4. Emotional Interaction
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