HF Ch 11+12

Secondary tasks

: if someone is performing a primary task, ask them to perform a secondary task as well. Performance on the secondary task indicates how much workload is being consumed by the primary task Note - secondary tasks degrading primary task performance is a potential problem

Reasons to Automate

A task is impossible for a human to perform Humans have performance limitations, so a machine would be better at it Humans are doing a task well enough, but performance could be augmented or workload saved by assisting them with automation Economical reasons: machines don't want a paycheck! Productivity: outside of maintenece/repairs, machines can work forever; like economical reasons, machines won't demand petty human requirements like "food" or "sleep" - amateurs!

Environmental Solutions

Basically, if we can change the environment to remove a stressor, go ahead and remove it!

Arousal Theory

An individual's level of activity, usually as a result of the influence of some stressor stimulus (or stimuli) We can measure this through many of the same physiological measures we talked about with workload This close association with workload makes sense: increased arousal "trying harder" to complete a task; this is essentially the same thing as workload

Effects of Stress Components

Attentional Narrowing Selective Attention; Distraction Working Memory Loss Perseveration Under high levels of stress, people will tend to continue on with their present course of action; this is seen as an impact of stress on decision-making, driving people toward confirmation bias Strategic Control: can have positive or negative outcomes

Subjective measures

Bedford, Modified Cooper-Harper These are totally dependent on self-reports which can be difficult to compare Multidimensional workload: NASA-TLX ("task load index")

Further into the future

Brain-computer interfaces Injured/Disabled Why not the healthy too!

Dynamic function allocation

Break it down - we talked about function allocation earlier in the chapter; now what happens when a system does it dynamically, in real time? That's what dynamic function allocation is!

Design Solutions

Can we provide the user with additional information? Can we automate something? Can we provide additional support in emergency situations? Can we determine what cognitive constructs are being most taxed and redesign to relieve that?

Variables impacting trust/dependence

Complexity of the automation process: the less a person understands or relates to what the machine's process of the automated actions are, the less they will trust the machine's automation Perfect example from "Office Space"

Measurement tools

EEG: Electroencephalogram ERP: Event-related potentials Cerebral blood flow ultrasounds fMRI Heart rate Pupil diameter Visual scanning: eye tracking, fixation duration

Complacency

over-trust - users blindly accept the machine's functioning. In its worst form, the users shirk their responsibilities under the assumption that automation will take care of it.

Behavioral measures

simply observing the actions of the worker Note - can't determine internal cognitive processes

Calibration curve

slide

Levels of Automation (not all or nothing)

slide

Mental workload

sometimes the task is just really difficult, and taxes our cognitive resources heavily We have limited resources to deal with all of the differing cognitive aspects of any task we're given to complete The level of mental workload is discussed in the same way we discuss physical workload: rather than demands on the energy and force our muscles are capable of producing, it's the demands on the processing power of our different cognitive processes

Training

How can we prepare people ahead of time to cope with stress? Can we teach them to move their thinking toward some of the more beneficial strategic control outcomes? Can additional exposure to stressors ahead of time train them for stress in the field?

Fitts' List (remember this guy?) (keep in mind it's from 1951)

Humans are better at: detecting minor sensory information, discerning patterns in sensory information, improvisation & flexibility, long-term memory store is lasting and able to recall relevant information quickly, inductive reasoning, exercising judgment Machines are better at: responding quickly to control signals, applying great amounts of force smoothly and precisely, performing repetitive/routine tasks, storing information briefly and deleting it entirely, deductive reasoning, complex reasoning/multitasking

The NASA Task Load Index (NASA TLX) is an example of a ________ method of mental workload assessment.

subjective

Dependence

the behavioral, objective actions that a person takes when interacting with an automated system

Trust

the cognitive, subjective evaluation of an automated system by a person

Automation

Imagine aviation or healthcare without it!

Stress

the nature of a task itself can be stressful (environmental conditions, temporal pressure, consequences), and we can bring our own personal stresses from our everyday lives into whatever we're doing

Is higher workload "bad?"

this can be subjective to some degree, much like our discussion of what makes for "good" decision making. Like that, there are some general guidelines to determine whether a given level of workload may be "good" or "bad."

The exponential rate of changes over the years in the speed and capacity of computers is known as:

Moore's Law

One of the most critical factors influencing trust in automation is:

automation reliability

Not without its flaws

automation-induced complacency

Current research

big focus on genetic differences in cognition Expect this data to become big in the near future as genetic analysis becomes more commonplace!

Remediating the negative effects of stress on performance should focus on:

both design and training

How do we adapt to increased workload?

People allow their task performance to degrade People find a way to perform tasks more efficiently, using fewer resources People eliminate tasks perceived to be unnecessary Optimal vs. non-optimal

Individual differences

People have varying levels of skill at different tasks - it is almost inevitable that you'll be a low performer on some things, and a high performer on others

Strategic Control

People take on a set of strategies to consciously attempt to cope with added levels of stress Recruitment of more resources: "try harder" Remove the stressor Change the goals of the task: adaptation Do nothing

Three main manifestations of stressors in people

Phenomenological experience: emotions, episodic memory Physiological arousal Change in performance characteristics/information processing

Automated systems that give frequent warnings that turn out to be false reduce operator trust and dependence, so that when a true alarm does occur, operators may ignore it. This phenomenon is known as:

cry wolf effect

Human-centered automation

designing automation for JOINT human-machine work, not a machine taking over a human's work

In order to avoid the problem of disruption of primary task performance when using the secondary task method of workload measurement, investigators have used:

embedded secondary tasks

Moore's Law

exponential rather than linear growth of computational power

Automation is often implemented in the work place because of:

human performance limitations economic factors safety factors

Yerkes Dodson Law

The level of performance on a task improves as arousal increases, but only to a limited threshold. Beyond that threshold, performance drops sharply.

Absolute workload

The overall "total" workload - composed of the combined smaller parts of mental workload, as well as other forms of workload (e.g. physical) - as you might expect, difficult to quantify

Neuroergonomics

The study of the human brain in relation to performance at work and in everyday settings

Transactional/Cognitive Appraisal Theories

These approaches focus instead on the reaction elicited by the stressor More of an "individual differences"-flavored approach Essentially, what we can study as an outcome of stress is an interaction between the environmental (stimulus) impact and the individual's cognitive appraisal of the situation

Which areas of data/research are most prone to this? (Individual differences)

Time-sharing/multi-tasking Working memory

"Cry wolf" effect

under-trust - users ignore automated warnings/indicators because they occur too frequently or at too low a threshold. In its worst form, the users will allow potentially dangerous/deadly events to occur because they fail to follow up on an automated warning.

Major concerns

What to adapt: pretty much the same considerations as regular automation When to adapt: environmental triggers vs. performance BEWARE: system lag can throw this off! Who decides to adapt: does the change occur because the human requests it? Or does the machine step in when it detects a need for it? Both?

Embedded secondary tasks

keep these related to the primary task so as to prevent them from being intrusive

A computerized diagnosis system that offers a complete set of decision/action alternatives to the human decision maker is an example of automation at a relatively ________ level.

low

Relative workload

must consider that our "mental resources" are not one monolithic structure: it's composed of smaller parts, and different parts can be taxed at different rates Think: Automaticity!

Stages of Automation

While our levels of automation are about the amount of control yielded to the machine by the human, stages of automation are the types of control yielded to the machine by the human Closely mimics the human information processing model Stages: Information Acquisition Information Analysis Decision Making and Action Selection Action Implementation

Automation reliability

Who counts cash when you take it out of an ATM? 100% reliability is rare unless it's extremely simple automation

The inverted-U relationship between performance and arousal is known as:

Yerkes Dodson Law

Stressor

any stimulus which causes stress Environment: noise, vibration, heat, dim lighting, high acceleration, etc. Psychological: anxiety, fatigue, frustration, anger