Visual Expert Human Factors: Attorney's Guide to Perception

An Attorney's Guide to Perception & Human Factors

"We shall understand accidents when we understand human nature"
- Kay (Accidents: Some facts and theories, 1971.)

Human Factors is defined as "the application of scientific data to make the world compatible with human abilities, fitting the product to the sensory, information processing, and motor attributes of the user." It is a mix of psychology and engineering that arose 60 years ago in the aviation industry. Up until then, accidents were almost invariably attributed to mechanical fault, to weather or to human error. Careful analyses began to show the cause of most accidents was a mismatch between human abilities and predispositions and the design of controls. The discipline of human factors developed as the science of understanding and reducing human error and accidents by means of proper design.

Human factors uses scientific knowledge of human capabilities, such perception and attention, memory and behavior, to understand how people interact with the world. This can mean interactions with buildings, computers, medical or other electronic devices, vehicles or other technology. Human factors helps design better environments and analyzes the source of error and accident in existing ones. It is widely applicable, since human error occurs at some point in most of our interactions with the world.

Almost all human interactions with the world involve visual perception. Most everyday activities, driving, reading, watching TV, operating a computer or medical device, deciding which brand of soap to buy, etc., involve the human ability to see, to recognize and to decide whether two things appear the same or different, and then to make a decision and to respond. Understanding how this happens is often the key to analyzing human choice and behavior and to understanding accident and trademark confusion.

Many studies have purported to show that human error is the most common accident cause:

In the first major study, "The Origin of Accidents" (1928), Herbert Heinrich examined 75,000 industrial accidents and attributed 88% to "unsafe human acts."
Former National Transportation Board Chair Jim Hill has testified before a congressional committee that human error causes 70% of accidents in all walks of life.
A Boeing study of major worldwide airline crashes found that 71.7% were due to human error.
Reason (Human Error, 1992), studied 180 nuclear power plants in 1983 and 1984 and concluded that human error was 52% of the root causes.
Rasmussen et. al. (New Technologies and Error, 1987) found that 88% of all occupational accidents are caused primarily by individual workers.
Wood et al. (CSERIAC, 1994) concluded that over 70% of operating room anesthetic incidents involve human error.
According to the most complete surveys, over 90% of all highway accidents are caused fully or in part by human error. And of these, 90% are caused by perceptual error and 10% by response error. In short, perception is a factor in over 80% of all highway accidents. Most of this error is due to perceptual and attentional failure or to inadequate highway visibility conditions. Moreover, visibility of warning labels, usability of computer/medical devices, legibility of instructions, placement of signs and warnings, recognition of people and objects, etc are all ultimately an issue in visual perception.

These percentages are amazingly large, but hide one important fact - that accidents attributed to human error are often really caused by a poorly designed system, product or environment. The role of the human factors expert is to determine the contributions of the individual and the circumstances.

Many people have heard the term "human factors" but are unsure what it means. Here is list of articles which provide a general overview of perception and human factors. They should be useful in gaining understanding of how human factors people think and analyze the huge number of accidents which involve human behavior. We also provide seminars on most of these topics

Personal Injury: Road Accidents Is The Moth-Effect Real? Human Error in Road Accidents Reaction Time Vision in Older Drivers Weather and Accidents: Rain & Fog Accidents At Rail-Highway Crossings Seeing Pedestrians At Night Night Vision	Personal Injury: Warnings Warnings and Warning Labels The Psychology of Warnings Drugs, Adverse Effects & Warnings Are Warnings Effective?
Personal Injury: Other Product Misuse And "Affordances" Diving Accidents in Pools Falls Down Steps Medical Error Computer & Medical Error Nursing Error	Criminal & Police Errors in Eyewitness Identifications Perceptual Error in Police Shootings Eyewitness Memory Is Unreliable
Intellectual Property "Any Fool Can See The Trademarks Are Different" Measuring Confusion For Intellectual Property Color in Trademark and Tradedress Disputes Color Functionality: A Case Example	Forensic Human Factors Seeing Color Determining Visibility "Inattentional Blindness" & Conspicuity Computer animation has perceptual limitations Photographs vs. Reality What is "inattention?" Human Error Vs. Design Error