Chapter 9. Selection of Action

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Chapter 9. Selection of Action

• OVERVIEW
• skill-based behavior the most automated level
  a rapid automatic responses with a minimum
  investment of resources extensive training and
  experience
• rule-based behavior action by bringing into WM
  a hierarchy of rule less automatic and timely
• knowledge-based entirely new problems neither
  rule nor automatic mappings exist diagnoses,
  decisions, troubleshooting
• selection of skill-based actions response time
  or reaction time (RT) simple and choice RT
• VARIABLES INFLUENCING BOTH SIMPLE AND CHOICE
  REACTION TIME
• stimulus Modality
• simple RT to auditory stimulus (130 msec) is
  faster than visual stimuli (170 msec)
• Stimulus Intensity
• simple RT decreased with increases in intensity
  of the stimulus to an asymptotic value
• aggregation over time of evidence in the sensory
  channel until a criterion is exceeded
• temporal Uncertainty
• the degree of predictability of when the stimulus
  will occur
• manipulated by warning interval (WI) between a
  warning signal and imperative stimulus to which
  the person must response
• short and constant WI ? imperative stimulus is
  highly predictable (temporal uncertainty is low)
  ? short RT
• long or variable WI ? high temporal uncertainty ?
  long RT

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• Expectancy
• RT increases as the average WI of a block of
  trials becomes longer (temporal uncertainty)
• an opposite effect is observed within a block
  having randomly varied long and short WIs the
  concept of expectancy
• VARIABLES INFLUENCING ONLY CHOICE REACTION TIME
• The Information Theory Model The Hick-Hyman Law
• choice RT was longer than simple RT ? RT was a
  negatively accelerating function of the number of
  stimulus-response alternatives
• Hick (1952) and Hyman (1953) applied information
  theory to quantify the uncertainty of stimulus
  events
• choice RT increased linearly with stimulus
  information (log2N)
• RT a bHs (Hick-Hyman law)
• human has a relatively constant rate of
  processing info, defined by inverse slope (1/b)
  (bits/sec)
• The Speed-Accuracy Trade-off
• they tend to make more errors as they try to
  respond more rapidly
• bandwidth as Ht/RT (bits/sec) ?constant bandwidth
  model of human performance is not quite accurate
• Howell and Kreidler (1963, 1964) easy and
  complex choice RT tasks by different instructions
  fast, accurate, fast and accurate, maximize Ht
• instructions changed RT and error rate speed
  instruction having the largest effect
• easy choice RT max. Ht obtained by maximize Ht
  instruction
• complex choice RT highest level of performance
  efficiency with speed set instruction

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• The Speed-Accuracy Operating Characteristic
  (SAOC)
• RT is on the x-axis and accuracy (error rate) on
  the y axis
• info. transmission (performance efficiency) is
  optimal at intermediate speed-accuracy sets
• accuracy (logP(correct)/P(errors)) ? linear
  SAOC
• one important aspect of the speed-accuracy
  trade-off is its usefulness in deciding what is
  best
• The Speed-Accuracy Micro-Trade-off
• compare the accuracy of fast and slow responses
  within a block of trials, using the same system
  (or experimental condition) depend on the
  particular nature of the RT task
• when the criterion is conservative ? processing
  full info, taking longer time ? high accuracy
• when the criterion is risky ? response initiated
  rapidly, based on little evidence ? errors will
  be likely
• in the extreme ? fast guess a random response
  initiated as soon as the stimulus is detected ?
  error RTs are faster than correct RTs when RTs
  are short and stimulus quality is good
• if poor stimulus, long processing or working
  memory load opposite form of micro-trade-off ?
  error responses tend to be slower than correct
  ones
• DEPARTURE FROM INFORMATION THEORY
• Stimulus Discriminability
• RT is lengthened as a set of stimuli are made
  less discriminable from one another
• similarity or difference the ratio of shared
  features to total features within a stimulus
• discriminability difficulty reduced by deleting
  shared and redundant features where possible

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• The Repetition Effect
• repetition effect, the advantage of repetitions
  over alternations, is enhanced by increasing N
  (the number of S-R alternatives), by decreasing
  S-R compatibility, and by shortening the interval
  between each response and the subsequent stimulus
• No repetition effect
• long intervals between stimuli and may be
  replaced by an alternation effect (faster RT with
  a stimulus change) gamblers fallacy ? do not
  expect a continuous run of the same sort
• rapid repetition of the same finger slower than
  alternations
• Response Factors
• RT is lengthened as the confusability between
  responses is increased
• RT is lengthened by the complexity of the
  response
• Practice
• practice decreases the slope of the Hick-Hyman
  law function relating RT to info
• compatibility and practice appear to trade off
  reciprocally in their effect on this slope
• Executive Control
• it takes time to load or activate these rules
  when they are first used or shift from one to
  another ? the function of central executive
  control
• Stimulus-Response Compatibility
• Location Compatibility
• provided by humans intrinsic tendency to move or
  orient toward the source of stimulation

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• colocation principle controls next to the
  relevant display not always possible to achieve
• congruence congruence between spatial controls
  and displays often defined in terms of an
  ordered array rule
• increase from left to right, aft to forward,
  clockwise, bottom to top
• far-right to top when left-right array mapped to
  a vertical display
• top-down ordering is not strong ? vertical
  display (or control) arrays that are not
  congruent with control (display) arrays should be
  used with caution
• put a slight cant, or angling, of one array in a
  direction that is congruent with the other
• Movement Compatibility
• the set of expectancies that an operator has
  about how the display will respond to the control
  activity Cognitive-Response-Stimulus (C-R-S)
  compatibility
• congruence principle of location compatibility
  applied to the compatibility of movement
• when congruence violated, a common mapping of
  increase
• also governed by a principle of movement
  proximity (Warrick principle) -- not related to
  congruence
• Compatibility Ambiguities
• mental model
• movement proximity principle was far less
  pronounced for psychology students than ME
  students, ME having the strong mental model of
  the mechanical linkage
• a design for the vertical speed of an aircraft
• frame or reference -- exocentric viewpoint
  (compatible S-R movement), egocentric viewpoint
• distinction between status and command displays

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• Transformations and Population Stereotypes
• any S-R mapping that requires some transformation
  will be reduced in its compatibility
• population stereotypes define mappings that are
  more directly related to experience
• Consistency and Training
• be wary of possible violation of consistency to
  optimize the compatibility of each
• training can also be used to formulate correct
  mental model and enhance the agreement between
  the mental model and the correct dynamics
• Knowledge in the World
• should provide an invitation to the appropriate
  actions (affordance) or forcing function, as well
  as a lockout of the inappropriate actions
• STAGES IN REACTION TIME
• The Subtractive Method
• delete a mental operation entirely form the RT
  task the decrease in RT is assumed to reflect
  the time required to perform the absent operation
• Additive Factors Technique
• confirming evidence for the existence and
  identity of processing stages
• to define the existence and distinctiveness of
  different stages by manipulating variables that
  are known to lengthen reaction time
• interactive (influence a common stage of
  processing) additive (influence different
  stages)
• Experimental Techniques
• make inferences about what manipulations
  influence what stages of processing
• patterns of additivity and interactions (fig 9.12)

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• the response selection is a major bottleneck in
  speeded information processing
• stimulus probability appears to affect two stages
• improbable stimuli require longer to be
  recognized
• their associated responses take longer to be
  selected
• Applications of Additive Factors Methodology
• how information processing speed is influenced by
  aging, poisoning, mental workload
• Problems With Additive Factors
• the assumption that stages proceed strictly in
  series ? convincing evidence that information
  processing does not strictly proceed in a serial
  fashion
• underadditive relationship delay by increasing
  the difficulty at one stage of processing is
  actually smaller at the more difficult level of
  the other stage
• The Event-Related Brain Potential as an Index of
  Mental Chronometry
• event-related brain potential (ERP)
• a direct estimate of the timing of processes up
  to the intermediate stage of stimulus
  categorization a series of electric voltage
  from the surface of the scalp
• The Value of Stages
• the separation of processing stages should not
  taken too literally
• some overlap in time between processing in
  successive stages parallel processing
• the stage concept more than compensates for any
  limitations in its complete accuracy
• SERIAL RESPONSES
• The Psychological Refractory Period
• PRP a situation in which two RT tasks are
  presented close together in time

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• ISI (interstimulus interval) the separation in
  time between the two stimuli SOA
• the second stimulus response is delayed by the
  processing of the first under short ISI
• human being as a single-channel processor of
  information
• the processing of S1 temporarily captures the
  single-channel bottleneck ? S2 must wait until S1
  is finished ? anything that prolongs the
  processing of S1 will increase the PRP delay of
  RT2 (simple reaction vs. choice reaction)
• perceptual analysis of S2 can proceed even as the
  processor is fully occupied
• the delay in RT2 will increase linearly with a
  decrease in ISI and with an increase in the
  complexity of RT1 (fig. 9.15)
• general single-channel model
• with short ISI (lt 100 ms), both responses are
  emitted together (grouping) and both are delayed
• sometimes RT2 suffers a PRP delay even when the
  ISI is greater than RT1 ? feedback
• The Decision Complexity Advantage
• the most restricting limit in human performance
  relates to the absolute of decisions/sec rather
  than the of bits/sec (cf. bandwidth) the
  frequency of decisions and their complexity do
  not trade off reciprocally ? decision complexity
  advantage
• some fundamental limit to the central-processing
  or decision-making rate, independent of decision
  complexity, that limits the speed of other stages
  of processing 2.5 decisions/sec for decisions
  of the simplest possible kind
• Pacing
• the circumstances under which the operator
  proceeds from one stimulus to the next

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• dichotomous dimension
• force-paced schedule constant interval, ISI,
  independent of the operators response
• self-paced schedule response-stimulus interval
  (RSI), depend on the latency of the operators
  response
• continuous dimension defines the value of the
  timing parameters (RSI, ISI)
• Response Factors
• Response Complexity
• increased complexity requires more monitoring of
  the response -- sometimes delay
• Response Feedback
• two effects on performance, depending on the
  sensory modality
• delays, distortions, or elimination of the
  intrinsic feedback (the perceived sound of ones
  voice or the visualization of ones moving hand)
  substantial deficits in performance
• less serious distortion of extrinsic feedback
  (the click of a depressed key or the appearance
  of a visual letter on a screen delay or
  distortion of feedback can be harmful
• Response Repetition
• response is slowed by its repetition
• single trial RT paradigm (repetition is good)
• eliminates the repeated engagement of the
  response selection stage time saved
• reaction time relatively long (200 300 msec)
  compared to typing
• typing -- response is slowed by its repetition
• high speed in typing ? separate responses
  selected without engaging a higher-level decision
  process ? no longer any benefit to repetitions by
  bypassing ? advantageous to employ separate
  muscle groups for successive responses (advantage
  for alternation)

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• Preview and Transcription
• the class of transcription tasks (e.g., typing,
  reading aloud, and musical sight reading) allow
  the operator to make use of preview, lag, and
  parallel processing
• more than one stimulus displayed at a time
  (preview is available) ? lag the response behind
  perception ? perception and response are
  occurring in parallel ? preview (seeing into the
  future) or lag (responding behind the present)
• possible in self-paced (typing) or force paced
  (oral translation) tasks
• maintain a running buffer memory of encoded
  stimuli that have not yet been executed as
  responses
• benefits of lag
• allowance for variability
• allowance for chunking
• Allowance for Variability
• a steady stream of output at a constant rate can
  proceed even if input encoding is temporarily
  slowed
• Allowance for Chunking
• evidence in typing that inputs are encoded in
  chunks ? letters in each chunk processed more or
  less in parallel ? the output must be serial
• encoding, buffer storage, response proceed in
  parallel with little mutual interference, and are
  even time shared with a fourth mental activity,
  the monitoring of errors in response

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• Use of Preview
• preview helps performance
• benefits of preview
• making available more advance information
• giving the operator an opportunity to perceive
  chunks ? not related to the semantic level of
  processing but chunk-sized units to be processed
  in parallel
• the benefits of chunking are primarily perceptual
  and may be seen in storage but not in response