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Outside the Forensic Box: Eyewitness Psychology and Science

Forensic psychology can help us understand the bases of scientific accuracy.

Key points

  • Science is a relatively objective activity, but human psychology still plays a role in scientific observation and interpretation.
  • Concepts from the realm of forensic psychology can help us to understand scientific accuracy and error.
  • One important factor that can influence scientific conclusions lies in our prior expectations, and the beliefs that generate those expectations.
Matthew J. Sharps
Source: Matthew J. Sharps

"The Forensic View," my blog on Psychology Today, obviously deals mainly with forensic issues. These include the complex processes of eyewitness cognition. However, regular readers of these posts will have noticed that we often apply these ideas elsewhere as well; not only to eyewitness processes in crimes, but also to eyewitness processes in the realms of such things as Bigfoot, ghosts, and UFOs. The reason is straightforward: These “observations” involve eyewitness psychology at the extremes and are therefore very worthy of notice. We can learn a lot from the extremes.

But can we apply these same principles to scientific observations and interpretations?

In the modern world, citizens and scientists alike are dealing with complex and rather terrifying scientific phenomena. COVID-19 and its new variants are in the news daily; and the complex issues of climate change are a continuous concern. These are scientific issues; and we rely on the relevant science to be accurate and completely unbiased.

But is this psychologically possible?

In our forensic work, my research students and I, and colleagues worldwide, have characterized principles that force eyewitness accounts to differ at astonishing levels from the physical realities on which they were based. An eyewitness account is a weird fusion of what was actually there, on the scene, with the psychological proclivities of the witness, the observer.

Scientists, though trained, have the same kinds of nervous systems as everybody else. So could the principles of eyewitness memory apply in the sciences as they do in the eyewitness realm of the criminal justice system? The answer is an unfortunate yes.

Scientific observation is not entirely objective

Since the early days of modern science, scientists have generally taken a positivistic view of observation and interpretation. The basic concept is that these activities are objective under the aegis of the scientific method, and hence generally inviolate and impervious to the psychological characteristics of the observers, the scientists themselves. Yet this is not true. Scientific observation is not entirely objective, but is actually filtered through the processes of perception and interpretation, in a manner psychologically similar to the development of an eyewitness account of a crime.

There are many examples of this. An eighteenth-century British Astronomer Royal dismissed an assistant whose observations differed slightly from his own; yet the astronomer Bessel demonstrated that such differentials are inevitable, the product of psychological processes which render precise agreement in such simultaneous observations literally impossible.

Perhaps the best-known case of such bias in science lies in the work of astronomer Percival Lowell, whose research we considered in a previous Forensic View (June 5, 2020). Lowell believed he’d seen huge numbers of artificial canals on Mars, when no such canals exist at all. Many contemporary astronomers agreed with him; yet no such canals ever existed, and in our laboratory, my students and I have begun to characterize the psychological factors involved in these observational and interpretive errors (Sharps et al., 2019). With relatively simple principles from the forensic realm (see Sharps, 2022), we can induce perfectly normal people to believe they see structures and geographical features on planets and moons, where no such structures or features exist at all.

These findings may be important for issues of observational and interpretive accuracy in the crucial area of climate change research. Given the focus on climate change in the modern world, the psychological factors involved may prove critical, both scientifically and with reference to governmental actions of grave economic and political consequences. It is of vital importance that the observations and interpretations of climate change be as accurate as possible at this stage in the history of science

Climate change is obviously real, and of the greatest importance. Widespread scientific consensus has emerged on the potentially existential results of climate change, as the many natural climate changes of this planet, in the distant past, have repeatedly demonstrated in extraordinary and frightening detail.

Yet there are continual challenges to the concept of climate change from a number of sources. The potential political misuse of scientific data renders it absolutely essential that observations and interpretations of climate change be as completely accurate as possible, but the fact is that a variety of recent climate predictions have failed to materialize. How can this be the case?

My students and I applied the principles of forensic eyewitness science to this problem, and we came up with some interesting results.

We showed people pairs of pictures of geographic features, in which each pair showed a loss of ice or an increase of water flooding previously dry lands. All of these cases may have lost ice or increased water due to local processes, such as change of seasons, greater temperature, or change of local land use. There was no reason to suggest that any of these changes reflected global climate change.

But then we showed these images to people, and asked them, using standard statistical methods, how much they believed that climate change posed a “danger” to the Earth.

Those who believed most strongly in the danger of climate change were most likely to attribute the differences in ice or water to that global factor, even though there was no evidence of this, and no information provided to them that this might be the case.

They believed it anyway.

In the absence of any actual evidence, in an individual case, people were most likely to attribute a local change in climate conditions to the danger of global climate change if they already believed in that danger. If they didn’t, not so much.

This was a scientific issue, putatively objective; but the strength of people’s belief in climate change altered their interpretation of the scientific data entirely.

These findings provide strong evidence of the usefulness of forensic concepts in other areas of psychology.

Yet another important factor here lies in the language in which scientific facts are presented. This can also be an important factor in the interpretation of scientific observation, as it is in the realm of criminal investigation; and we will take this up in our next Forensic View.


Sharps, M.J. (2022). Processing under pressure: Stress, memory, and decision-making in law enforcement. (3rd ed.). Flushing, NY: Looseleaf Law.

Sharps, M.J., Hurd, S., Hoshiko, B., Wilson, E., Flemming, M.A., Nagra, S., & Garcia, M. (2019). Percival Lowell and the canals of Mars II: How to see things that aren't there. Skeptical Inquirer, 43, 48-51.