Open plan offices became standard across American workplaces, and the most consistent complaint about them concerns sound. The mechanism is specific: overheard speech, rather than volume.
Intelligible speech is the disruptive component
Background noise at a constant level is largely filtered out. Speech behaves differently, because language is processed automatically whether or not it is directed at the listener.
A conversation that can be understood competes for the same processing used to read, write or hold a thought in mind. Comprehension is not something a listener can decline.
This is why a nearby quiet conversation can be more disruptive than louder mechanical noise, and why a coffee shop's undifferentiated hum bothers people less than an adjacent phone call.
Layout determines how far speech travels
Acousticians describe the distance at which speech stops being intelligible, and open layouts with hard surfaces extend it considerably.
Glass, exposed ceilings and polished floors reflect sound rather than absorbing it. Removing partitions removes barriers that previously blocked a direct path between desks.
Densification compounds this. Cost per square foot drives desks closer together, which places more potential speakers inside the intelligible radius of every worker.
Sound masking works by reducing contrast
Some buildings introduce a low engineered background sound tuned to the frequencies of speech, which raises the floor and makes distant conversation less decipherable.
The system does not cancel anything. It reduces the contrast between speech and background so the words stop resolving into meaning.
Done poorly it simply adds noise, which is why masking is commissioned and tuned rather than installed at a fixed setting.
Visual exposure adds a separate load
Open layouts also remove visual privacy. Movement in peripheral vision draws attention involuntarily, and awareness of being observable changes behavior.
Workers report modifying what they do and how they sit when a screen is visible to passing colleagues, which is a form of sustained low-level monitoring.
That is one reason headphones became standard equipment: they signal unavailability as much as they attenuate sound.
Recovery depends on interruption, not hours
Fatigue from this environment comes from frequency of interruption rather than total time worked, since each recovery of a lost thread costs attention.
Workplaces that address it successfully usually change the layout or the norms — enclosed rooms, quiet zones, agreed meeting spaces — rather than asking individuals to concentrate harder.
Persistent exhaustion, sleep disruption or dread that continues away from the office is describing something beyond acoustics and is worth raising with a clinician.