Certain patterns in our daily lives often go unnoticed until curiosity strikes. For instance, why are most TV episodes 45 minutes long?
Why are most songs about 4 minutes? The answers to these questions are deeply rooted in history, technology, and even economics, revealing a classic case of path dependency.
The 45-Minute TV Episode
Television episodes in China are consistently 45 minutes long, a standard designed to prevent networks from inserting ads in the middle of shows. But why precisely 45 minutes? The answer lies in the history of television production.
During the pre-digital era, film reels were used to shoot and broadcast movies and TV shows. These reels could hold a maximum of 15 minutes of footage, making durations divisible by 15 the norm. Short films lasted 15 or 30 minutes, TV episodes spanned 45 minutes, and movies typically ran for 90 or 120 minutes.
This segmentation also matched audience attention spans. Free TV at home allowed shorter engagement times, while paid cinema visits justified longer durations. However, excessively long films caused disruptions, such as bathroom breaks, impacting the viewing experience.
If directors insisted on unconventional lengths—say 46 or 121 minutes—it led to logistical and financial issues. Each additional reel was costly, bulky, and complicated to manage. Cinemas often shared reels to reduce costs, with theaters coordinating their schedules to pass reels between locations. A 121-minute film, for instance, disrupted this system, prompting studios to cut excess footage.
With the advent of digital technology, the U.S. adopted more flexible TV formats: 40-minute dramas and 20-minute sitcoms. The rationale was to accommodate advertising. A 40-minute episode plus 20 minutes of ads filled a one-hour time slot, while a 20-minute sitcom with 10 minutes of ads fit into a half-hour block. This simplified ratings tracking, crucial for selling ad space. Much like sports broadcasts, scheduling decisions prioritized viewer engagement over artistic considerations.
Why Songs Are Around 4 Minutes
The length of songs is also rooted in technological limitations. Early vinyl records could only store about 5 minutes of audio per side. As a result, songs were capped at around 4 minutes, a standard that persisted as the music industry evolved.
During the vinyl era, singles dominated the market. Artists recorded one main track for the A-side and often added a bonus song on the B-side. This established the habit of writing and performing 4-minute songs. Even as technology advanced and records could store up to 30 minutes of audio, the industry stuck to this convention.
Some bands, such as Queen or Pink Floyd, experimented with longer tracks, pushing creative boundaries. However, the majority of artists adhered to the 4-minute format due to its practicality. Longer tracks posed challenges for radio DJs, karaoke enthusiasts, and ringtone makers.
The Role of Path Dependency
This adherence to established norms reflects the concept of path dependency, an economic theory describing how initial choices influence long-term behaviors. Once an industry sets a standard, changing it becomes difficult due to the ripple effects across production, distribution, and consumption.
The music and film industries exemplify this phenomenon. For instance, film studios resist producing excessively long movies because the entire ecosystem—from storytelling to scheduling—aligns with 90- to 120-minute durations. Longer movies disrupt theater schedules, reducing the number of daily screenings.
Similarly, a 10-minute song might struggle to gain traction. Radio stations would avoid airing it, karaoke users might find it exhausting, and its marketability for commercials or other media would diminish. Even revolutionary films like Once Upon a Time in America (originally 6 hours) or Kingdom of Heaven (3+ hours) were trimmed for release, often at the expense of their artistic integrity.
How Standards Emerge
The creation of "standards" extends beyond TV and music. For example, railway track gauges reportedly trace back to the width of a Roman chariot, dictated by the breadth of two horses. Similarly, ancient Chinese units of measurement were based on body parts, such as the width of a finger or the length of an arm, leading to inconsistencies across dynasties.
In contrast, modern measurements like the meter are rooted in scientific precision. Initially defined as one ten-millionth of the distance from the equator to the North Pole, the meter was later refined using universal constants, such as the speed of light.
Whether it’s the 45-minute TV episode or the 4-minute song, these seemingly arbitrary standards are the product of historical, technological, and economic factors. Over time, they became entrenched due to the convenience and efficiency they offered. While technological advancements have opened new possibilities, the influence of tradition and established systems ensures these standards remain deeply ingrained in our cultural fabric.
