Why does the same noise stop bothering you?
The disruption from background speech is often called the irrelevant sound effect: speech you are not trying to listen to still interferes with tasks like remembering words or prose. The leading explanation is that the sound captures attention and competes with the verbal material you are holding in mind [4]. If that is right, then repeated exposure should help only when the brain can learn that this particular sound is not worth attending to.
That is what the habituation studies point to. In two experiments using memory for prose, participants showed significant habituation to office noise and speech after about 20 minutes of exposure [2]. A separate line of work on serial recall found that repeated exposure reduced interference when the distractor matched the material heard during preexposure, and argued that earlier failures to find habituation came from ignoring how specific the learned sound features are [4]. In plain terms, the brain seems to tune out the exact sound it has heard before, not noise in general.
How long does it take, and does everyone adapt?
The laboratory figure of about 20 minutes is the clearest timing signal in this evidence [2]. A study of 36 young adults set out to test whether habituation to office noise, including speech, occurs and how long it takes to develop [1]. That framing treats habituation as something that builds over a period of exposure rather than instantly.
Adaptation is not guaranteed, though. A workplace-focused study of office noise and concentration reported no evidence of habituation to office sounds, and noted that background speech was rated highly unacceptable [3]. The contrast with the laboratory habituation findings is consistent with the idea that real offices differ from a controlled 20-minute exposure, but these studies do not settle why the outcomes diverge. What they do support is a cautious answer: habituation is real in controlled settings, but it should not be assumed for every person or every office.
What happens when the speech itself changes?
This is the part the evidence addresses only indirectly. None of these studies directly tested whether performance drops again after habituation when speech conditions change [1][2][3]. The closest support comes from the finding that habituation is tied to the specific distractor features that were heard during preexposure [4]. If tuning out depends on the particular sound, then a new talker, a new conversation, or a noticeably different speech pattern would not match what was tuned out, and the interference could return.
A discussion of open-plan offices makes a related point: habituation to irrelevant speech is expected to help performance, but that benefit depends on habituation actually occurring, and processing verbal material while speech is present places demands on working memory [5]. Read together, these results suggest that any relief from repeated exposure is likely to be sound-specific rather than a general immunity to office noise. That is a possibility raised by the pattern of findings, not a demonstrated effect of changing speech conditions.
What should you take from this if you work in an open office?
Expect adaptation to be gradual and partial. The strongest laboratory evidence puts habituation at around 20 minutes of exposure to the same office noise or speech [2], while a workplace study found no habituation at all [3]. The difference in setting matters: a short controlled task is not the same as a full working day in a live office.
Do not count on adaptation carrying over to new speech. Because habituation appears to be tied to the specific sound features heard before [4], a change in what people are saying or who is speaking is the situation most likely to undo the benefit. The direct test of that scenario is still missing from this evidence, so the practical move is to treat habituation as fragile and to reduce speech exposure when a task depends heavily on holding verbal information in mind [5].
Sources used in this answer
Effects of prior exposure to office noise and music on aspects of working memory
A study of 36 young adults examined whether habituation to office noise, including speech, occurs and how long it takes to develop.
Put-Up Or Shut-Up? Habituation to Speech and Office Noise
Two experiments using memory for prose found significant habituation to office noise and speech after about 20 minutes of exposure.
Office noise and employee concentration: Identifying causes of disruption and potential improvements
A workplace study of office noise and concentration reported no evidence of habituation to office sounds, with background speech rated highly unacceptable.
Habituation of the irrelevant sound effect: evidence for an attentional theory of short-term memory disruption.
Repeated exposure reduced interference in serial recall when the distractor matched the preexposure material, suggesting habituation depends on specific distractor features.
Open-plan offices: Task performance and mental workload
An open-plan office analysis proposes that habituation to irrelevant speech would enhance performance if it occurs, while processing verbal information alongside speech loads working memory.