Cognitive Aspects

• Explain the important of understanding users
• Discuss the main elements of cognitive process

• Selecting things to concentrate on at a point in time from the mass of stimuli around us
• Allows us to to focus on information that is relevant to what we are doing
• Involves audio and/or visual senses
• Focussed 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), colour, reverse video, sound and flashing lights

• Tullis (1987) found that the two screens produced quite different results
  • 1st screen - took an average of 5.5 seconds to search
  • 2nd screen - took 3.2 seconds to search
• Why, since both displays have the same density of information (31%)?
• Spacing
  • In the 1st screen the information is bunched up together, making it hard to search
  • In the 2nd screen the characters are grouped into vertical categories of information making it easier

• Lotteridge et al. (2015) conducted another study involving writing an essay under 2 conditions: relevant or irrelevant information
• heavy multitaskers were easily distracted but able to put this to good use if the distracting sources were relevant to the task in hand
• irrelevant information was found to negatively impact task performance

Increasingly common for workers to multitask

• e.g. hospital workers have to attend to multiple screens in an operating room that provide new kinds of real-time information
• requires clinician’s constant attention to check if any data is unusual or anomalous
• need to develop new attention and scanning strategies

• No, as same type of cognitive processing is happening when talking
• Same happens when talking with front seat passenger
  • but both can stop in mid-sentence if see a hazard meaning driver can switch immediately to the road
  • So less dangerous talking to a front seat passenger than a remote person
  • a remote person on the end of a phone is not privy to what the driver is seeing and will carry on the conversation when there is a hazard
  • makes it difficult for the driver to switch all their attention to the road

• Make information salient when it needs attending to
• Use techniques that make things stand out like color, ordering, spacing, underlining, sequencing and animation
• Avoid cluttering the interface with too much information
• Avoid using too much because the software allows it
• Consider designing different ways of supporting effective switching and returning to an interface

• How information is acquired from the world and transformed into experiences
• Obvious implication is to design representations that are readily perceivable, e.g.
  • Text should be legible
  • Icons should be easy to distinguish and read

• Weller (2004) found people took less time to locate items for information that was grouped
  • Using a border (2nd screen) compared with using color contrast (1st screen)
• Some argue that too much white space on web pages is detrimental to search
  • Makes it hard to find information
• Do you agree?

• Research proper color contrast techniques when designing an interface
  • Yellow on black or blue is fine
  • Yellow on green or white is a no-no
• Haptic feedback should be used judiciously

• Involves first encoding and then retrieving knowledge
• We don’t remember everything - involves filtering and processing what is attended to
• Context is important in affecting our memory (i.e. where, when)
• We recognize things much better than being able to recall things

• We remember less about objects we have photographed than when we observe them with the naked eye (Henkel, 2014)

• Encoding is first stage of memory
  • determines which information is attended to in the environment and how it is interpreted
• The more attention paid to something ...
• The more it is processed in terms of thinking about it and comparing it with other knowledge ...
• The more likely it is to be remembered
  • e.g. when learning about HCI, it is much better to reflect upon it, carry out exercises, have discussions with others about it, and write notes than just passively read a book, listen to a lecture or watch a video about it

• Context affects the extent to which information can be subsequently retrieved
• Sometimes it can be difficult for people to recall information that was encoded in a different context:
  • “You are on a train and someone comes up to you and says hello. You don’t recognize him for a few moments but then realize it is one of your neighbours. You are only used to seeing your neighbor in the hallway of your apartment block and seeing him out of context makes him difficult to recognize initially”

• Try to remember the dates of your grandparents’ birthday
• Try to remember the cover of the last two DVDs you bought or rented
• Which was easiest? Why?
• People are very good at remembering visual cues about things
  • e.g. the color of items, the location of objects and marks on an object
• They find it more difficult to learn and remember arbitrary material
  • e.g. birthdays and phone numbers

• 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

(cont)

• 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

• Is a growing problem for many users
  • they accumulate a 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 10,000s ’ s
  • How might such a process be facilitated taking into account people memory abilities?

• Bergman and Whittaker 3 interdependent processes model (2016) to help people manage their stuff: (i) how to decide what stuff to keep (ii) how to organize it when storing (iii) which strategies to use to retrieve it later
• Most common approach is to use folders and naming
• Strong preference for scanning across and within folders when looking for something
• Search engines only helpful if know the name of the file
• Smart search engines help with listing relevant files for partial name or when type in first letter

• Online/mobile and phone banking now require users to provide multiple pieces of information to access their account
  • e.g. ZIP code, birthplace, a memorable date, first school attended
  • Known as multifactor authentication (MFA)
• Why?
  • Increased security concerns
• Password managers such as LastPass have been developed - only need one master password
  • Reduce stress and memory load on users
• Passwords could become extinct with the widespread use of biometrics and computer vision algorithms

• Don’t overload users’ memories with complicated procedures for carrying out tasks
• Design interfaces that promote recognition rather than recall
• Provide users with various ways of encoding information to help them remember
  • e.g. categories, color, flagging, time stamping

• The ease with which people can read, listen, or speak differs
  • Many prefer listening to reading
  • Reading can be quicker than speaking or listening
  • Listening requires less cognitive effort than reading or speaking
  • Dyslexics have difficulties understanding and recognizing written words

• Speech-recognition systems allow users to interact with them by using spoken commands
  • e.g. Google Voice Search app
• Speech-output systems use artificially generated speech
  • e.g. written-text-to-speech systems for the blind
• Natural-language systems enable users to type in questions and give text-based responses
  • e.g. Ask search engine

• Speech-based menus and instructions should be short
• Accentuate the intonation of artificially generated speech voices
  • they are harder to understand than human voices
• Provide opportunities for making text large on a screen

models

• You arrive home on a cold winter’s night to a cold house. How do you get the house to warm up as quickly as possible? Set the thermostat to be at its highest or to the desired temperature?
• You arrive home starving hungry. You look in the fridge and find all that is left is an uncooked pizza. You have an electric oven. Do you warm it up to 375 degrees first and then put it in (as specified by the instructions) or turn the oven up higher to try to warm it up quicker?

thermostat-controlled

• Many people have erroneous mental models (Kempton, 1996)
• Why?
  • General valve theory, where ‘more is more’ principle is generalised to different settings (e.g. gas pedal, gas cooker, tap, radio volume)
  • Thermostats based on model of on-off switch model

thermostat-controlled (cont)

• Same is often true for understanding how interactive devices and computers work:
  • poor, often incomplete, easily confusable, based on inappropriate analogies and superstition (Norman, 1983)
  • e.g. elevators and pedestrian crossings - lot of people hit the button at least twice
  • Why? Think it will make the lights change faster or ensure the elevator arrives!

• Your mental model
  • How accurate?
  • How similar?
  • How shallow?
• Payne (1991) did a similar study and found that people frequently resort to analogies to explain how they work
• People’s accounts greatly varied and were often ad hoc

• Based on modeling mental activities that happen exclusively inside the head
• Do not adequately account for how people interact with computers and other devices in real world

• The distributed problem-solving that takes place
• The role of verbal and non-verbal behavior
• The various coordinating mechanisms that are used (e.g. rules, procedures)
• The communication that takes place as the collaborative activity progresses
• How knowledge is shared and accessed

load

• Diaries, reminders, calendars, notes, shopping lists, to-do lists
  • written to remind us of what to do
• Post-its, piles, marked emails
  • where placed indicates priority of what to do
• External representations:
  • Remind us that we need to do something (e.g. to buy something for mother’s day)
  • Remind us of what to do (e.g. buy a card)
  • Remind us when to do something (e.g. send a card by a certain date)

Write down how you think a contactless card or smartphone app like Apple Pay works

• What information is sent between the card/smartphone and the card reader when it is placed in front of it?
• What is the maximum amount you can pay for something using a contactless card, Apple Pay or Google Pay?
• Why is there an upper limit?
• How many times can you use a contactless card or Apple/Google Pay in a day?
• What happens if you have two contactless cards in the same wallet/purse?
• What happens when your contactless card is stolen and you report it to the bank? What does the bank do?