Haverford College News

Time certainly is a crafty magician. Just ask psychology professor Marilyn Boltz, who can tick off a list of tricks that Father Time plays on us gullible human beings year after year:

You drive the same 30-minute route to work every day for three years. One morning, you pull into the parking lot, and you suddenly feel very uneasy. Not only can you hardly remember driving to work, you feel like it's taken you no time at all to get there.

Or, you have a big presentation at work and all morning long your three-year old cried, begging you to stay home. The same drive to work now seems to be taking forever. How come everybody else is driving so slow today? you think as you glare at the car that seems to be dawdling in front of you. But when you get to work, you're shocked to discover you're actually ten minutes early.

Boltz is looking into the reasons why humans sometimes get fooled by the clock - big time.

More often than not, being the fool at the hands of time amounts to nothing more than a missed deadline, a whiffed backhand on the tennis court, or a silly question like, what day of the week is it? But Boltz notes in cases of accidents, miscalculation of the duration of an event -- such as incorrectly estimating how long it will take to pass a car on the highway -- can mean the difference between life and death.

Boltz and a growing number of American research psychologists are studying various types of external situations that can lead to errors in a person's perception of time. The everyday impact from such research can be far reaching: from further proving the risks of operating machinery while under stress, to enabling employers and workers to schedule their work days more effectively around specific tasks.

And, in the ever complex field of litigation in America, such research can also be a valuable tool in validating or invalidating eyewitness testimony regarding the passage of time during a crime or other legal quandry.

No one is more aware of this last factor than Boltz, who in the summer of l995 was asked to testify as an expert witness by the U.S. Department of Labor on behalf of meat packers in the Midwest who were suing for back pay from their employer. Boltz helped them win the proper compensation for the amount of time it took them to don their protective gear and walk to their place on the mile-long production line. In the court case, Boltz used her published research on learning and its relationship to time perception to argue that the workers - intimately familiar with their jobs - were very accurate in their ability to recall the amount of time they were owed.

This isn't the only type of litigation that such research on time perception is useful. Boltz notes that in the O.J. Simpson trial, the accurate estimation by witnesses of the amount of time it took for certain events to unfold was a crucial factor in the testimony and became one of many battlegrounds between the defense and the prosecution.

But after her brief stint in the legal system, Boltz says she is more interested in the underlying mechanisms of time perception than the whodunit of crime.

Psychologists, she says, know that all humans possess an "internal tempo" - the natural tempo or speed at which a person operates. It is manifested in a person's preferred rate of speaking or walking, but, in the laboratory, it is typically measured by the rate at which one taps his or her finger. Although internal tempo differs from person to person, it serves as the baseline that each human uses to gauge the duration at which events proceed around them. Not surprisingly, she notes, city dwellers and East Coast residents generally have a faster internal tempo. Psychologists also know that clinical internal factors such as aging, mental illness, drugs and depression can disrupt a person's normal internal tempo and cause them to misjudge the duration of an event.

But Boltz and her colleagues are interested in finding how external, environmental factors such as stress or learning may also briefly alter a person's internal tempo and thus throw off their ability to accurately judge the passage of time.

In one experiment designed to test the influence of stress and relaxation on time perception, Boltz instructed three groups of volunteer subjects to listen to and learn recorded rhythmic patterns - such as the click of typewriter keys or the dribble of a basketball.

Boltz then exposed one of the three groups to the repeated wail of a loud car horn to induce stress. The second group listened to the soothing sounds of ocean waves lapping on the shore to induce relaxation. The stress-inducing car horns effectively sped up the internal tempo of the one group, while the ocean waves slowed down the internal tempo of the second group, Boltz explains.

Boltz then asked all three groups to reproduce the rhythmic patterns they had learned earlier. As the researchers suspected, only the control group, who had heard neither the loud car horn or the sooththing waves got it right.

"The group whose internal tempo was sped up with car horns misremembered the sounds as happening faster and sounding shorter than what they were," Boltz explains. "Conversely those whose internal tempo was slowed down by the wave sounds misremembered the sound patterns as being longer and slower."

Anyone who commutes to work in traffic might experience as well, Boltz explains.

"When you are stressed out or upset and driving in a car, this is the reason everybody else seems to be driving slower than you - in effect, your internal rate has been accelerated relative to that of the environment. On the other hand, when you are very relaxed, everybody else appears to be rushing around," she says, noting either of these two states can cause drivers to miscalculate the amount of time they have to pass a car. She also notes, stress can be a factor in discounting eyewitness accounts of bank robberies and other traumatic crimes.

"You're internal tempo is sped up from the stress so that environmental events, in contrast, seem to go slower," Boltz explains. "It can explain why certain tragedies appear as though they are happening in slow motion."

More recently Boltz worked with other volunteer subjects to better understand how "learning" or familiarity with a specific task might affect a person's accurate perception of time.

In another experiment, Boltz and two of her students instructed subjects to learn a statistical analysis computer program. The first time the subjects completed the program, they were asked to estimate how long it took them to run the program.

"All of them overestimated the time it took," says Boltz.

As the subjects became a little more familiar with the program, Boltz said they more accurately predicted how long it took them to perform the task. Ironically after the subjects had learned the program completely, the researchers found that most of the subjects underestimated how much time it took to run the program.

"We were expecting that accuracy would maintain with increased competance," Boltz explained, "But what we discovered was that the more automatized the task, the easier it was for people to forget specific details they had performed."

This more recent research, which will be co-presented by Boltz and Haverford senior Jessica Dunne at the meeting of the Eastern Psychological Association in Boston next month, has Boltz wondering if the meat packers really underestimated the back pay they may have been owed. But she notes, it certainly might explain why time seems to pass in the blink of an eye as you drive the same route to work or you play that Tetris game at your computer day after day.