Week 10-1: Selection of Action

1. 1 Week 10-1: Selection of Action This module will provide you with a general overview of the needs assessment process. Later modules will provide more detail on the steps involved. This module will provide you with a general overview of the needs assessment process. Later modules will provide more detail on the steps involved.

2. 2 Week 10 Topics Lecture 10-1 Types of Actions Simple Reaction Time Choice Reaction Time Hick-Hyman Law Lecture 10-2 Speed-Accuracy trade-offs Variables affecting Choice RT

3. Choice RT: Influence of Other Variables Stimulus discriminability: More difficult discriminations lead to longer RT Repetition effect: RTs decrease as S-R set is repeated Effect is increased if Number of S-R alternatives is increased S-R compatibility is decreased Stimulus pace is increased Response factors RT lengthened if confusability between responses is increased RT lengthened by complexity of the response 3

4. Practice Practice decreases the slope of the Hick-Hyman function (increases bandwidth?) Executive Control Switching S-R rules (e.g., discriminating high-low digits to discriminating odd-even) leads to a temporary increase in RT Thought to be the cost of switching rules (proactive interference) by the executive controller 4 The Influence of Other Variables

5. S-R Compatibility and Choice Reaction Time Stimulus-response Compatibility (Mappings) Location Compatibility Takes advantage of human tendency to orient toward the source of stimulation Produces more automatic response colocation principle: Controls should be located next to displays EXAMPLE: touch screens, Point-and-click with mouse Many systems fail to provide good colocation: Nuclear power plant example Sometimes colocation not physically possible: EXAMPLE: high performance aircraft, pilot under g-load cannot reach touch-screen 5

6. S-R Compatibility and Choice Reaction Time 6

7. When Co-location is Impractical Next best constraints are: Congruence principle: spatial array of controls should be congruent with the spatial array of displays Rules: simple rules governing the mapping between stimulus and response afford faster responses Increases move from left to right, aft to foreward, clockwise, bottom-to-top Left-right controls for vertical displays? Far right control mapped to top display 7

8. Movement Compatibility Cognitive-Response-Stimulus (C-R-S) compatibility Similar to congruence principle Sliding linear controls should be used for linear displays and move in compatible direction Rotary controls should be used for dial displays and move in compatible direction When these controls and displays are mixed, increases should be left-right, bottom-top or clockwise 8

9. Movement Compatibility (cont.) Movement proximity (Warrick) principle Closest part of the moving element of a control should move in the same direction as the closest part of the moving element of a display Can conflict with clockwise-up rule Loveless (1963) movement proximity dominates rules in cases of conflict 9

10. Multiple Serial Responses Psychological Refractory Period (PRP) Telford, 1931 Occurs when two RT tasks are presented close together in time (short ISI or interstimulus interval) Response to second stimulus is delayed 10

11. Multiple Serial Responses Implications of PRP Decision-complexity advantage Hick-Hyman law predicts that absolute amount of information governs response time: one 6-bit decision takes as much time as 6 1-bit decisions Human Performance one 6-bit decision faster than 6 1-bit decisions frequency and complexity of decisions DO NOT trade-off motor output often outpaces decision-making capacity “ums” and “ahs” in speech Applications: depth vs. breadth in computer menus, single-key vs. chorded-keys for data entry 11

12. To Prepare for Next Class… If you have not already done so Read W10 Week 11 Topic Manual Control 12