Scourge of the 'halfalogue'

The overheard mobile phone conversation is a scourge of modern times. Why is it so irritating? According to a team of psychologists led by Lauren Emberson at Cornell University, at least one reason has to do with the relative unpredictability of what they call a 'halfalogue' - hearing just one side of a conversation. This unpredictability, they explain, makes the overheard phone call more attentionally demanding and therefore distracting (Psychological Science).

Twenty-four undergrads performed two attention tasks while simultaneously listening to: a conversation between two people; a monologue, in which one person recalled both sides of a conversation; or a halfalogue, in which they heard just one side of a conversation. A silent condition acted as a baseline.

Only the halfalogue was found to impair performance on the two tasks - one of which involved using a computer mouse to track a moving on-screen target; the other was a choice reaction time task in which participants had respond as fast as possible to four letters whilst ignoring any others.

Emberson and her colleagues say halfalogues are more unpredictable than full conversations because we're unable to use the unheard conversational partner's utterances to predict what the overheard conversant is going to say next. To test this claim, a second study was similar to the first but this time the halfalogue, dialogue and monologue speech was low-pass filtered, rendering the content incomprehensible (it sounded like speech under water) whilst retaining the acoustic 'on/off' properties. Under these conditions, the halfalogue was no longer distracting.

Emberson told us she hopes the results will encourage a reconsideration of mobile phone etiquette. 'Having conducted this study, I have certainly changed my own cell phone use to avoid talking on phones in situations where others are working and listening (e.g. in the laboratory) or in the presence of a captive audience (e.g. on public transport),' she said.

'The other implication of our study that might have an effect on cell phone use is the idea that paying attention to an overheard cell phone conversation is reflexive or beyond our control,' Emberson added. 'When talking on a cell phone, one can often have a feeling of privacy, that no one is listening in. However, our results show that likely everyone is listening in to the point where their attention is disrupted in other tasks. If people know that their phone conversations are being heard, perhaps this will also act as a deterrent to talking on a cell phone in public.'

--Christian Jarrett