Which sounds like a bigger time commitment: three hours or two hours and 55 minutes? The answer seems obvious. Three hours is longer. Yet research suggests that when people hear these durations described in different ways, they may perceive the shorter one as lasting longer. A new study published in the Journal of Marketing Research found that adding a smaller unit of time, such as minutes alongside hours, can make a duration feel longer than expressing it in hours alone. The effect can influence how people judge deadlines, set goals and make everyday decisions.
The
research is titled ‘Every Minute Counts: The Added-Unit Effect in Time Perception.’ It examined how the way time is presented shapes people's perception of its length. The researchers analysed data from more than 10,000 online course listings and conducted nine experiments involving more than 6,000 participants. They found that people tended to perceive a duration as longer when it was expressed using both a larger and a smaller unit, such as “2 hours and 55 minutes”, rather than simply “3 hours”.
The researchers call this the “added-unit effect”. Their findings suggest that the way time is described can shape how people think about a task, even when the actual duration is similar or the more detailed version is shorter.
Why can a shorter duration feel longer?
The explanation lies in how people mentally process the units used to describe time. When someone hears “three hours”, they may think of the duration as three large blocks of time. But “two hours and 55 minutes” draws attention to both hours and minutes. The additional unit can make the period feel as though it contains more separate parts, creating the impression of a longer commitment. In an interview with
Phys.org, lead researcher Deepak Sirwani, an assistant professor at the University of British Columbia's Sauder School of Business, explained that people mentally represent time using the units they are given. Mentioning minutes brings smaller units into focus, which can make a duration feel longer even when it is actually shorter.
The effect is not limited to hours and minutes. The researchers found that adding smaller units can also influence how people perceive dates and other time intervals.
How the way time is described can affect goals
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The findings have practical implications for people setting personal goals, planning work or deciding whether to commit to an activity. For example, someone who plans to exercise for two hours a week may feel that the goal is manageable. Presenting the same target as “one hour and 55 minutes” may make the commitment feel larger, potentially leading the person to set a lower goal. The research found that people set less ambitious weekly exercise goals when the time commitment was expressed in hours and minutes rather than in rounded hours. The way the duration was presented affected how demanding the goal appeared.
The effect may also influence deadlines. Sirwani explained to Phys.org that a deadline described as “December 15 at 8 p.m.” can feel farther away than one described simply as “December 15”. Including the time of day may shift attention from days to hours, making the wait feel longer. In one experiment, participants were less willing to wait a few days for a larger payment when the payment date included a specific time of day. The researchers did not directly test whether this leads people to procrastinate, but they suggested that a deadline that feels more distant could potentially encourage delay.
The same effect may influence everyday decisions
The way time is presented can also affect how people judge products and their usefulness. One example discussed in the a University of British Columbia's
report involves expiry dates. A product labelled “September 30, 2026” may feel as though its expiry is further in the past than a product labelled “September 2026”, even when both refer to the same date. A detailed date, deadline or time commitment can feel different from a broader description, even if the underlying information has not changed. This does not mean that a particular way of writing time will influence everyone in the same way. The study identifies a pattern in how people judge durations, rather than a rule that applies to every person and situation.
Can people use this finding to their advantage?
Experts say if the aim is to make a task feel manageable and encourage people to get started, a rounded duration may help. If someone is comparing deadlines or making an important decision, it is useful to look beyond how the time is worded and consider the actual duration. The key is to separate the feeling created by a description from the time it represents. Two hours and 55 minutes remains five minutes shorter than three hours, regardless of which sounds more demanding. The research shows that even a small change in wording can influence how people evaluate a commitment. Time itself has not changed, but the way it is presented can change how long it feels.