Exam 2 Review Flashcards by scott johnson

VR sickness

Symptoms similar to those of motion sickness due to a VR experience

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List the symptoms of VR sickness

headaches
stomach	awareness 
nausea
vomiting
pallor
sweating
fatigue
drowsiness
disorientation

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What should be done to reduce VR sickness?

Reduce the FOV

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What should be done with the FOV?

Dynamically adjusted depending on virtual movement

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What data was collected during the FOV on VR sickness experiment?

Discomfort scores every five waypoints

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Was it found that decreasing the FOV affected the presence?

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T/F Distance and size perception are often biased in VR

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What were the three settings used in distance estimation?

Negative parallax
Zero parallax
Positive parallax

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Define: Negative parallax

Virtual object is rendered in front of physical display

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Define: Zero parallax

Virtual object is rendered at the physical display

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Define: Positive parallax

Virtual object is rendered behind the physical display

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What task was used in the distance estimation experiment?

A blind triangulation pointing task

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What was the finding of the distance estimation experiment?

Increased distance underestimation for positive parallax conditions

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What was the pointing task procedure?

Viewed a target’s position

Virtual view was blinded by pressing a button

Participants would take two steps left or right

Then point at the target as accurately as possible

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T/F Most users experience some imbalance in VR

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What did the imbalance experiment investigate?

how a static rest frame (SRF) affects balance in an HMD

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Define: static rest frame

A cross-hair always rendered in the same position on the user’s display screen

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What task were the participants asked to do in the balance impairment study?

Dodge tennis balls

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What did the balance impairment study conclude?

An SRF significantly improves balance for users with balance impairments

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What was investigated in the body ownership experiment?

Investigated the effects of visual realism of virtual hand representations

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What is low realism?

Abstract (sphere)

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What is medium realism?

Iconic (skeleton hand)

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What is high realism?

Human (actual hand model)

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What task would you use in a body ownership study?

Pick-and-place and spinning saw tasks

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What could be concluded from a study on body ownership about the sense of agency?

Found sense of agency (i.e., motor activity control) to be greater for less realistic hands

What could be concluded from a study on body ownership about the sense of ownership?

Found sense of ownership (i.e., one’s own body is the source of sensations) to be greater for the human hand

What was investigated in the virtual human study?

Investigated the effects of a shared real-virtual object (a wobbly table) on presence and social presence

Define: Social presence

Sense of being socially connected with another person

What were participants asked to do during the virtual human study?

Play a game of twenty questions with a virtual human

What were the results of the virtual human study?

Found that the wobbly table condition resulted in greater presence and social presence

What was investigated in the collaborative environments study?

Investigated the effects of including virtual objects within a mixed reality (MR) environment on deictic speech

Define: Deictic speech

Spatial indications that cannot be fully understood by speech alone

What tasks did participants in the collaborative environments study do?

Dyads of participants completed object identification and object positioning tasks

In the collaborative environments study, what were the findings?

Found that the inclusion of virtual environment objects decreased deictic speech for both tasks

What was done in the AR study?

Compared two augmented reality (AR) visualization techniques for assembly guidance

What else was investigated in the AR study?

Also investigated the effects of error detection

What were the findings of the AR study?

Found that the side-by-side mode resulted in faster completion times and fewer errors

Define: Independent variable

A variable that is manipulated and controlled by the researcher to help answer the research questions

What is an independent variable also know as?

Factor

T/F All studies have an independent variable

What kind of study does not have an independent variable

A baseline study observing a single user interface

Define: levels

The distinct states that an independent variable is controlled at

Define: multi-factor experiment

An experiment that simultaneously investigates multiple independent variables at multiple levels

Define: Condition

The intersection of independent variables at specific levels

Define: dependent variable

A measure that is expected to vary with changes to the independent variables

List examples of dependent variables

Completion time Number of errors Perceived usability Presence

Define: confounding variable

An unintended variable that correlates with both the independent variables and the dependent variables

What is a confounding variable also known as?

Confound

Give an example of a confounding variable

Airflow in an olfactory display study

What are the three primary types of user studies?

Within-subject Between-subjects Mixed-design

Define: Within-subject

Every single subject experiences every single condition

Define: Between-subjects

Each subject experiences one condition

Define: Mixed-design

Each subject experiences multiple conditions but not every single condition

What are the pros of within-subject?

Requires the fewest subjects Allows for direct subjective comparisons

What are the cons of within-subject?

Requires the longest procedures Cannot be used to evaluate the effectiveness of instruction

What are the pros of between-subjects?

Requires the shortest procedures Can be used to evaluate the effectiveness of instruction

What are the cons of between-subjects?

Requires the most subjects Does not allow for direct subjective comparisons Results prone to being biased by subjects

What are the pros of mixed-design?

Requires fewer subjects Requires shorter procedures Allows for some direct subjective comparisons

What are the cons of mixed-design?

Cannot be used to evaluate the effectiveness of instruction

T/F The order of conditions can influence results

What is an example of the order of conditions influencing results?

Learning a task improves performance regardless of interaction technique

Define: counterbalancing

Ensuring the order of conditions is balanced among subjects

List the methods of counterbalancing

Full-factorial permutations of conditions Latin squares designs

T/F Participants cannot bias cohort results

F. they can

List unbiased assignments methods

Randomization | Aptitude balancing

What is randomization?

Randomly assign subjects to available cohort slots

What's the downside of randomization?

Requires a decent number of subjects to avoid bias

What is aptitude balancing?

Assign subjects to available cohort slots to balance aptitude and/or experience across all cohorts

What does an aptitude balance require?

Requires a validated aptitude test or experience survey

If your participants are expected to have balance impairments, what can you implement to help them?

A static rest frame (SRF)

What was used in the virtual human study to try and improve presence and social presence?

A wobbly table