6. Cognition

1. 6. Cognition • people perceive, think, and remember • three stages of human information processing system – perception, central processing or transforming, responding INFORMATIN PROCESSING MODELS top-down processing learning retrieval

2. SELECTIVE ATTENTION • not guarantee perception, but necessary to achieve it • four factors for the selection of channels to attend • salience: bottom-up process, attentional capture (blindness) • expectancy, value: top down processes • effort PERCEPTION Three Perceptual Processes • bottom-up feature analysis • unitization: sets of features familiar (represented in LTM), more rapid and automaticthan perceptual processing • poor bottom-up processing: degradation of visual stimulus (short glance, tiny text, poor illumination) and auditory event (masking noise, low intensity, unfamiliar accents)

3. top-down processing: correct guess from expectations, based upon past experience in LTM; associations between the perceived stimulus and event (frequency and context) Human Factors Guidelines in Perception • maximize bottom-up processing • maximize automaticity and unitization • maximize top-down processing • avoid confusion; use a smaller vocabulary; create context; exploit redundancy WORKING MEMORY A Model of Working Memory • Baddeley (1986, 1990) – central executive component • visuospatial sketch pad – analog spatial form while it is being used • phonological loop – verbal info in an acoustic form

4. Limits of Working Memory Capacity • Around 72 chunks of information (Miller, 1956) • What makes a single chunk  Familiarity based on past experience (LTM), similar to unitization in perception • Chunking reduces the number of items in WM, increasing the capacity of working memory • Chunking makes use of meaningful associations in LTM  retention of the information • Material more easily rehearsed, more likely to be transferred to LTM • Perceptual chunks by spatial separation Time • Maintenance rehearsal • Half life in WM (Card, Moran, Newell, 1986) – 7 sec for a memory store of three chunks and 70 secs for one chunk

5. Confusability and Similarity Attention and Similarity • WM is resource-limited Human Factors Implications of Working Memory Limits • Minimize WM load • Provide visual echoes • Provide placeholders for sequential tasks • Exploit chunking • Physical chunk size – 3 to 4 numbers or letters per chunk • Meaningful sequences • Superiority of letters over numbers • Keeping numbers separate from letters • Minimize confusability • Avoid unnecessary zeros in codes to be remembered • Consider WM limits in istructions

6. LONG-TERM MEMORY • Learning, training, retrieval, forgetting • Semantic memory (memory for facts or procedures) or event memory Basic Mechanism Strength • Frequency and recency of its use Associations WM and LTM • Rote memory (rehearsal through simple repetition) Forgetting • Weak strength due to low frequency and recency • Weak or few associations with other information • Interfering associations • Recall, recognition

7. Organization of Info in LTM • Info in LTM in associative networks (semantic network) • The structure of the database compatible or congruent with the user’s semantic network Schemas and Scripts • Schema – the knowledge structure about a particular topic • Scripts – schemas that a typical sequence of activities Mental Models • schemas about dynamic systems • Generates a set of expectancies • Population stereotype Cognitive Maps • Mental representations of spatial information • Mentally straightening • Preferred or canonical orientation (mental rotation)

8. LTM Implications for Design • Encourage regular use of info to increase frequency and recency • Encourage active verbalization or reproduction of info that is to be recalled • Standardize • Use memory aids • Knowledge in the world vs. knowledge in the head • Careful design info to be remembered • Design to support development of correct mental models • Visibility (affordance) Episodic Memory for Events • The personal knowledge or memory of a specific event or episode is acquired from a single experience – very much based on visual imagery  not always faithful “video replays”, having a number of biases • Episodic memory process is far from perfect

9. Police lineup recognition – 20% incorrect at all 3 stages of encoding, storage, retrieval • Cognitive interview (CI) – not recognition but recall procedure

10. Prospective Memory for Future Events • Failures of prospective memory are forgetting to do something in the future– sometimes called absentmindedness • Reminders, checklists SITUATION AWARENESS • characterize user’s awareness of the meaning of dynamic changes in their environment • Endsley (1995) -- the perception of the elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future • SA is distinct from performance Measuring SA • SA global assessment technique (SAGAT) • subjective awareness -- metacognition

11. Importance of SA to Human Factors • designing easy-to-interpret displays of dynamic systems • an important tool for accident analysis • important for training PROBLEM SOLVING AND TROUBLESHOOTING • troubleshooting a step within a problem-solving sequence • troubleshooting requires a series of tests to diagnose the problem while problem solving involves actions to implement the solution Challenges • heavy cognitive activity, and human performance often limited • in troubleshooting, two or three active hypotheses in WM • troubleshooting closely depend upon appropriate cues and test outcomes  susceptible to attention and perceptual biases

12. an important top-down processing bias in troubleshooting – cognitive tunneling or confirmation bias • high system complexity • intermittent failures of a given system component PLANNING AND SCHEDULING • planningmay be invoked in the absence of problem solving • in dynamic systems, predicted state and command (ideal) state • sluggish (higher inertia) systems – longer range planning • the importanceto planning – level 3 SA, mental model (simulation) • predictive displays

13. METACOGNITION AND EFFORT • meta-knowledge or metacognition – people’s knowledge about their own knowledge • anticipated effort – seeking additional information related to selective attention is also related to another metacognition ATTENTION AND TIME-SHARING • divide attention – do two or more things at one time • resource demand, structure, similarity, resource allocation Mental Effort and Resource Demand • the relationship between single-task difficulty and dial-task divided attention decrements -- resource theory • automaticity

14. Structural Similarity • structural similarity – the similarity between key processing structures of both tasks in a concurrently performed pair • multiple resource theory (Navon & Gopher, 1979; Wickens, 1984, 2002) -- different structures in human information processing behave as if they were supported by multiple resources

15. Confusion • similarity between items in WM; similarity-based confusion in visual sensation; • concurrent performance of two tasks that both have similar material Task Management and Interruptions • if interference, then will they both suffer? Or will one or the other be “protected”? • dual task performance (primary task vs. secondary task )  task management  resource allocation • successful time-sharing strategies – optimal switching of attention between tasks  parallel processing vs. cognitive tunneling

16. Addressing Time-Sharing Overload • Task redesign • interface redesign • training • automation