Attenuation Theory

What it is

Treisman proposed attenuation as a modification of Donald Broadbent's filter theory. Broadbent's filter blocks the unattended message before its meaning is analysed. Treisman's attenuates it: the signal is weakened rather than removed, and highly meaningful or pertinent information in the unattended ear can still pass through for further processing.

Her experiments used dichotic listening. In the 1960 study, two passages were switched between the ears partway through. According to the abstract, listeners occasionally repeated a word or two from the wrong ear at the switch but never followed it for longer, and did so more often when the passage was predictable. Treisman suggested that the filter raises thresholds for the rejected source instead of working as an all-or-none barrier, which a filter that blocks meaning outright could not allow. Textbooks date the model to 1960 and to 1964; the experiments are 1960, and the fuller statement of the theory is usually dated 1964.

In effect

The theory gives the own-name finding a place. Neville Moray's 1959 shadowing study found that a listener's own name could break through from an ignored message, and in later studies about a third of listeners noticed it: 34.6 per cent in 1995 and 29 per cent in 2021. A name has a permanently low threshold on this account, so a weakened signal is still enough to reach awareness.

The theory also leaves room for differences between listeners. In a 2001 study of 40 undergraduates, 65 per cent of the 20 low working memory span listeners noticed their name against 20 per cent of the 20 high-span listeners. In a 2014 study, 58 per cent of 50 young adults noticed their name against 3 per cent of 29 older adults. Neither result follows from attenuation alone. The 2014 authors proposed an inhibition factor and an attentional capacity factor to account for them, which sits alongside the attenuation account and does not replace it.

What it does not say

It does not say that everyone hears their name. A low threshold makes the name more likely to get through, and the figures above show a minority doing so.

It does not say how much of the ignored message is processed in general. Moray found that almost nothing was retained apart from the name.

It is a model of what happens to the ignored message, and it is silent on why the listeners who notice a name differ from those who do not. That question belongs to work on working memory capacity and inhibition.

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