How Does Science Work?

Risk as Perception

Risk as Science

The Risk Assessment Paradigm

How Foods from Biotech Crops are Evaluated for Human Safety

How Biotech Crops are Evaluated for Environmental Safety in the United States


Risk as Perception

Dr. Robert K. D. Peterson
Agricultural & Biological Risk Assessment
Montana State University

Perceptions of Risk
Before defining and discussing biotech crops and the risk analysis process, we need to define “risk.” There are two major categories of risk: risk as perception and risk as science. In this article, we will concentrate on risk as perception.

Although the risks associated with driving an automobile are more serious, the public typically perceives products made from agricultural biotechnology as being riskier. Why is this so? Research conducted during the past 20 years consistently has established that public assessments of risk from modern technologies and activities are different than expert assessments. Whereas experts primarily evaluate risk in terms of narrowly defined deleterious events, the public considers broader factors such as control, catastrophic potential, dread (possible delayed and/or disturbing effects), level of knowledge, equity, clarity of benefits, trust, effects on future generations, and effects on children. In general, public perceptions of risk are the product of intuitive biases and economic interests that often reflect cultural values.

Rank the Risks - Class Exercise

Have each of your students rank the risks from the following activities (from most risky to least risky):

  • alcohol, commercial aviation, construction, contraceptives, fire fighting, food preservatives, handguns, motor vehicles, motorcycles, nuclear power, pesticides, police work, private aviation, smoking, spray cans, surgery.
The students may ask what you mean by risk. At this point, it is important not to give them any guidance. Simply reiterate that they should rank the risks based on what they believe.

After they rank the risks, ask them which activity they ranked first, second, and so on. Then, ask them why they ranked the activities as they did. Note the reasons the students used to assess risk from these activities. Below are rankings from experts and college students based on data by Slovic (1987). Compare and contrast these rankings with those of your students. Ask the students why the rankings are different.


1. motor vehicles
2. smoking
3. alcohol
4. handguns
5. surgery
6. motorcycles
7. X-rays
8. pesticides
9. electric power
10. swimming
11. contraceptives
12. private aviation
13. construction
14. preservatives
15. bicycles
16. commercial aviation

College Students

1. nuclear power
2. handguns
3. smoking
4. pesticides
5. motor vehicles
6. motorcycles
7. alcohol
8. police work
9. contraceptives
10. fire fighting
11. surgery
12. preservatives
13. spray cans
14. construction
15. private aviation
16. commercial aviation

Now, ask the students the following question: Is swimming riskier than nuclear power? Obviously, there is no correct answer. If you only consider fatalities per year, then swimming is much riskier than nuclear power. However, if you consider other factors, then nuclear power is riskier. What are those other factors? The students probably identified some of the factors in the rank the risks exercise. Finally, ask the students to assess the risk from biotech crops. Note the factors they use to assess the risk.

Based on research, specific factors that influence public risk perception include:

  • Control - the ability of the individual or society to control the risk
  • Catastrophic potential - the possibility of fatalities or ill effects grouped in time and space as in an epidemic
  • Dread - the fear of the possibility of serious delayed effects, such as cancer
  • Familiarity - the degree of familiarity lay people have with the risk
  • Equity - refers to the equal distribution of risks and benefits throughout society
  • Level of knowledge - the general understanding lay people have with the process or activity posing the risk
  • Voluntariness of exposure
  • Effects on children and future generations - concerns about possible delayed effects on humans and the environment posed by the risk
  • Clarity of benefits - represents the awareness and understanding of the benefits provided by the activity posing the risk
  • Media attention
  • Trust in organizations or institutions

The public uses these characteristics to judge the acceptability of a risk rather than using risk estimates based on experiments. For example, the public views biotech crops that produce food as riskier to their health than the natural carcinogens in common foods and beverages because they believe they have no control over their exposure to the “biotech foods” they are consuming. Additionally, people may tolerate the risks from chemicals inherent in food, but they are unwilling to tolerate additional risks from biotech ingredients, no matter how small. People accept the risks from driving an automobile much more readily than the risks from biotech foods because they have control over the automobile.

Perceptions of Risk from Biotechnology (adapted, in part, from Peterson, R.K.D. 2000. Public perceptions of agricultural biotechnology and pesticides: recent understandings and implications for risk communication. American Entomologist 46:8-16.).
Public perceptions of biotechnology are extremely complex and cannot be generalized easily. There are differences in perception by age, gender, income, education, cultures, and among types of biotechnology products. Additionally, separate studies and surveys cannot be compared empirically because different questions were asked. As a broad generalization, lay knowledge of biotechnology continues to be poor throughout Europe, the United States, New Zealand, and Latin America (Hagedorn and Allender-Hagedorn 1997, Hallman 1996, Lujan and Moreno 1994, Richardson-Harman et al. 1998, Sant’Ana and Valle 1995, Torgersen and Seifert 1997, Zechendorf 1994). Although the public in most countries perceives substantial potential risk from biotechnology products, most people have a relatively high acceptance of biotechnology, including Europeans (Hallman 1996, Zechendorf 1994). Indeed, the public seems much more concerned with the risks associated with specific products produced from biotechnology than with the process of genetic engineering itself (Hallman 1996). This lay position seems to diverge from the current position of several environmental groups (Tal 1997).

Public concerns about biotechnology products typically are not centered around technical issues, but rather focus on issues of ethics, morality, safety, and value (Hagedorn and Allender-Hagedorn 1997, Hoban et al. 1992). Scientific and regulatory communities tend to focus on research and technical issues such as the escape of transgenes by cross-pollination with wild species, escaped and mutated viruses and bacteria, inadvertent production of toxins, and selection for resistance (Boulter 1997).

In most countries where studies have been conducted, sociological and economic variables generally explain attitudes about biotechnology. Support for biotechnology generally is lower for women and less educated and older age groups, whereas support is higher among males, higher income and well educated, urban, and younger age groups (Torgersen and Seifert 1997). The use of biotechnology for new drugs typically receives more support than agricultural biotechnology. The benefits associated with medical biotechnology products are most likely more apparent and immediate than other uses, and therefore, acceptance is greater.

The United States
In general, acceptance of biotechnology is relatively high, but the majority of survey respondents in several polls fear potential health hazards (Zechendorf 1994). Although there were differences in questions and measurement among surveys, “acceptance” generally means that those surveyed support or tolerate risk from biotechnology (Gaskell et al. 1999, Zechendorf 1994). In other words, they do not oppose biotechnology. Acceptance of genetically-modified organisms varies between transgenic plants and animals. In a 1992 survey of 552 North Carolina residents, 70% accepted plant biotechnology whereas only 42% accepted animal biotechnology (Hoban et al. 1992).

A relatively thorough survey of 604 New Jersey residents in 1993 revealed several aspects of risk perception from biotechnology products. Nearly 20% of respondents had negative initial thoughts about genetic engineering (Hallman 1996). Most residents (61%) approved of using genetic engineering techniques to produce hybrid plants, but only 28% approved of genetic engineering to produce hybrid animals. Interestingly, about 50% of the residents who believed genetic engineering is morally wrong also indicated they approved of its use to create new drugs and more nutritious grain to feed people in poor countries (Hallman 1996).

The New Jersey survey also provided a glimpse into perceptions of agricultural biotechnology. Approximately 55% of those surveyed indicated they would buy genetically-engineered apples, and 60% would buy fresh vegetables as long as they were labeled as being produced by genetic engineering. Approximately 85% believed that “growing genetically engineered plants that contain higher levels of naturally occurring chemicals that protect against pests and disease is better than using pesticides” (Hallman 1996). However, 40% were concerned that genetically engineered organisms could pose a “likely threat” to the environment if they could reproduce.

Despite the complex nature of public perceptions in the New Jersey study, more than 66% indicated that “the potential danger from genetic engineering is so great that strict regulations are necessary.” Additionally, 60% favored the labeling of agricultural biotechnology products for reasons of choice and consumer empowerment (Hallman 1996).

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