Human Factors PhD

Applying psychophysics, neuroimaging, and simulated-use validation across robotics, medical, aerospace, and autonomous systems

Case Studies

Brandon Allan Fluegel, Ph.D. — Senior Human Factors Design Engineer

Brandon Allan Fluegel, Ph.D. (also known as Dr. Brandon Fluegel) is a Senior Human Factors Design Engineer and internationally recognized expert in human-robot interaction (HRI), medical and surgical robotics, human-autonomy systems, psychophysics, neuroimaging (fNIRS), and simulated-use validation. He earned his Ph.D. in Human Factors Psychology from Old Dominion University, received the 2023 Amazon Inventor Award, and is the co-inventor of US Patent 12,532,040 B1. He pairs rapid field research (contextual inquiry, service blueprinting, rapid iterative testing) with quantitative human-performance methods (psychophysics, cognitive load modeling, simulated-use validation) across NASA, Mercedes-Benz, and Amazon.

Key Contributions, Patents, Frameworks & Quantified Impact

Amazon

Devices Design Group

Human Factors Researcher

Fig 1. Measuring Cognitive Load via fNIRS

Mapping Cognitive Load to Echo Device Design

Customers Reached
75M+

Latency and Human Factors work shaped Echo Show and Echo Hub experiences affecting 75M+ active customers.

I co-established Amazon's first neuroimaging framework — combining fNIRS brain scanning with eye-tracking to quantify cognitive load across streaming UIs, replacing assumption-driven design with direct neural and gaze evidence.

Neuroimaging Methodology

Applied a controlled within-subjects fNIRS protocol measuring prefrontal cortex activation, synchronized with eye-tracking to separate gaze behavior from cognitive effort. Findings translated directly into product requirements, shaping the interaction design of Echo Show and Echo Hub — reaching 75M+ active customers.

Context-Aware Interaction Patent

Beyond neuroimaging, I co-invented a context-aware interaction system — where the same physical input routes to contextually appropriate actions based on active UI state — granted as US Patent 12,532,040 B1 in January 2026. This work earned the 2023 Amazon Inventor Award.

Calibrating Alexa Response Latency to Human Perceptual Limits

Projected Operational Value
$50M

I established Alexa's latency satisfaction thresholds, then Alexa Economics projected $50M in incremental operational value over 15 months if those latency targets were met across high-priority voice intents.

Alexa's response latency targets were defined by engineering constraints, not human perception. I led a multi-year Human Factors research program to establish empirically grounded thresholds — identifying precisely where response delay crosses from imperceptible to trust-eroding, and anchoring those findings in the economic models that drive product investment.

Isolating the Latency Satisfaction Threshold

Used a Wizard of Oz latency injection system to manipulate visual and auditory response latency on users' devices across thousands of trials — controlling latency as an isolated variable while keeping all other system factors constant. Analysis of the resulting data identified a High Satisfaction Threshold (HST) at 1,000ms: the point where user tolerance breaks down, "too slow" ratings climb sharply, and satisfaction drops in a consistent, reliable pattern.

NVA Model Integration & Economic Validation

The HST was formally adopted by Alexa Economics and embedded into the Negative Value Action (NVA) model — redefining any response exceeding 1,000ms as a quantifiable system defect with downstream engagement consequences. Alexa Economics projected that closing the latency gap across high-priority voice intents would generate $50M in incremental operational value over 15 months — a third-party validation that became the foundation of Alexa's Latency North Star.

NVA Model

Alexa Latency vs. User Satisfaction
Impact
$50M
1,000ms Threshold
HST
Safe Zone
Revenue opportunity
Dissatisfaction Zone
Churn risk increases
0ms1000ms2000ms3000ms

Fig 2. High Satisfaction Threshold (HST): Ratings of "not slow" fall sharply beyond 1,000ms

Source: Alexa Response Latency Research — Devices Design Group, April 2021

From applications → Global standards

Evolving established models into modern Human-AI trust frameworks

From AI systems → Mission-critical systems

Where cognitive error costs lives, not conversions

From space systems → Autonomous vehicles

Translating trust frameworks to human-machine interfaces