Eyewitness to the Aliens: Forensic Psychology on Mars

The strange case of the Canals of Mars, and the perils of eyewitness processes.

Posted Jun 05, 2020

 Public Domain Pictures
Source: Public Domain Pictures

The different subfields of psychology can occasionally be a bit insular. Important information sometimes goes unshared among cognitive specialists, clinicians, colleagues in social and educational psychology, and so on. 

Those of us in the forensic realm are often guilty of this type of professional isolation. Forensic work, involving collaborations with other fields as disparate as gunshot wounds and forensic accounting, may seem so weird to more mainstream colleagues that we don’t even get invited to the right parties.

Yet this professional isolation poses a potential problem. Forensic and non-forensic psychology have much to say to each other. 

Currently, among other crises, the world is deeply concerned with scientific questions of climate change and the terrible pandemic of COVID-19. The observations and interpretations of scientists, in many disciplines, have seldom been as important to society at large as they are today. 

Science is of course intended to be objective; but the individual scientist, at any given moment, can reasonably be construed as an eyewitness to his or her own evidence. As we’ve seen in previous posts of The Forensic View, eyewitness accounts run into certain problems, especially under stress and difficult social conditions. 

But can our understanding of eyewitness processes help us in our understanding of scientific observation and interpretation?

Enter Percival Lowell. 

Around the turn of the last century, using excellent telescopes at his own observatory, astronomer Lowell turned his attention to the planet Mars. Where he found canals.

Lowell saw canals all over the place on Mars. Mars being a desert world, Lowell’s assumption, which he defended in many publications, was that these canals had been built by Martians to transport the water needed to save their arid planet. Space aliens, presumably with space-alien bulldozers and what we can only hope were little green space-alien civil engineering degrees, were digging the living hell out of Mars in beautifully geometric hydraulic systems.

Some astronomers agreed. Others couldn’t see the canals at all. They attacked Lowell and all he stood for.

Lowell’s assistant A.E. Douglass saw Martian canals, at first; but then he also saw them on the moons of Jupiter. Douglass got worried. He taped what looks like a paper plate to a building in Flagstaff, pointed a telescope at it, and saw canals on the plate too. Douglass observed other canals on all sorts of “artificial planets,” featureless white surfaces posted here and there, and he figured out that the canals were psychological artifacts, rather than physical objects. 

When Lowell got wind of all this, his solution was simple.  He effectively fired Douglass.

The canals defied the laws of spherical geometry. Lowell didn’t care. The canals sometimes appeared doubled, in a phenomenon called “gemination.” Fine with Lowell. He was a man under metaphorical fire from his colleagues. His response was to defend his alien canals at all costs.

There is an interesting phenomenon called cognitive dissonance, in which we tend to overvalue things in which we’ve heavily invested. Lowell had spent a fortune in telescopes finding his canals, and an emotional fortune in defending the things from his colleagues, and he sure as hell wasn’t going to stop now. We can only guess at his state of arousal, but between cognitive dissonance and blind rage, those canals weren’t going anywhere. Especially in view of the Gestalt laws, which readily enable us to reconfigure natural features into expected contours; contours that look like canals (Sharps, 2018; Sheehan, 1988). 

Eyewitnesses will sometimes mistake a blond assailant for a brunette, or a power tool for a gun (e.g., Sharps, 2017). The study of eyewitness processes has repeatedly shown us that eyewitnesses are subject to many reconfigurative influences that can occasionally render witnesses worse than useless in court.

But can these influences operate in the sciences? 

Lowell expected Martian canals, as eyewitnesses to crimes expect their perceptions to be grounded in veridical reality. But can expectations actually cause a person to see structures, on an alien planet, which don’t exist at all? We decided to find out.

My students and I (Sharps et al., 2019) presented a slightly blurry photograph of the Moon at “Supermoon” distance to sixty-three adults with good eyesight. None of them recognized the photo as the Moon; we checked. For all they knew, it could have been an illuminated golf ball. 

But when we told them that the ball was a “planetary or lunar object” photographed in space, or that scientific “authorities” had seen “features or structures” on this celestial orb, something fascinating happened. Over 30 percent of our respondents reported colors and structures on our featureless white disk, including “purple rays of light.” They also reported “mountain ranges” and “buildings,” together with a wonderful report of “a canal.” All on a round white blob.

Expectations led our respondents to see colors, buildings, and entire landscapes where none existed at all. Oh, and a canal. The importance of expectations to observation and interpretation should not be underestimated.

Percival Lowell made many important observations and astronomical predictions that turned out to be absolutely correct. In the present writer’s opinion, he was a great astronomer. Lowell simply refused to entertain the possibility that his own psychology could influence his science. 

But just as leading questions can influence an eyewitness in a criminal case to report incorrect observations, our research shows that we can induce expectations that lead people to see—not to think about, but to see—buildings, mountains, and canals on a featureless white disk. 

There is continuity in the nervous system. If we find a process operating in one area of psychology, we generally find something similar operating in analogous areas as well. This research shows that at least some of the dynamics of eyewitness processes, generally of interest only to forensic psychologists, also operate in the realm of scientific observation and interpretation, of interest to everybody. Future research, and public policy, should take these facts into account. 


Sharps, M.J. (2018).  Percival Lowell and the Canals of Mars.  Skeptical Inquirer, 42, 41-46.

Sharps, M.J. (2017).  Processing Under Pressure: Stress, Memory, and Decision-Making in Law Enforcement (2nd ed.). Flushing, NY: Looseleaf Law Publications.

Sharps, M.J., Hurd, S., Hoshiko, B., Wilson, E., Flemming, M., Nagra, S., & Garcia, M.  Percival Lowell and the Canals of Mars Part II: How to See Things That Aren't There.  Skeptical Inquirer, 43, 48-51.

Sheehan, W.  (1988).  Planets and Perception: Telescopic Views and Interpretations, 1909-1909.  Tucson, AZ: University of Arizona Press.