Attention
4/09/07
Selective attention
“Cocktail party phenomenon”: the problem of attending to one conversation among several
conversations
What are the characteristics of a channel will permit us to attend to its message? Speaker’s voice,
direction, intensity…
If we are successful at attending to one channel, are we completely unaware of anything being said on
the other channel?
What high-priority events will cause us to switch our attention from the attended to the unattended
channel?
The dichotic listening task: one message is played to one ear, while a second message is played to another ear.
Shadowing task: to repeat what you have heard
Cherry (1953) dichotically present message, attending to one message and shadowing it.
 Subjects could shadow perfectly with a delay of one or two words, but retained almost nothing of the
meaning of the message. They were also unaware of the unattended message except for very obvious
physical characteristics.
Early selection The filtering can be done on more than merely physical grounds. The unattended
channel doesn’t get monitored for meaning.
Broadbent (1958) The split-span experiment. Right ear: 8,2,4; Left ear: 7,1,3. To report all the
digits.
 Subjects recalled the digits by ear (They attend primarily to one ear.) and reported no more than 4 or
5 digits (Switching between channels takes time or effort. The digits of unattended ear decayed rapidly.).
Late selection The unattended channel is analyzed for meaning.
Oxford, Gray and Wedderburn (1960) 3 digits + a simple three-word phrase (dear-aunt-Jane) or
three syllables of a word (ex-tir-pate). Right ear: dear-2-Jane, Left ear: 7-aunt-3.
 Subjects reported the word or phrase together and the digits together. (grouping by categories)
Treisman (1964) difficulty of shadowing [physical (male vs. female), phonetic (known language,
unknown language), semantic differences].
 A known language spoken in the unattended ear caused more errors in shadowing the attended ear.
MacKay (1973) attended ear: shadowed sentences containing polysemous words; unattended ear: a
word that biased the subjects toward one of the meanings.
 Subjects were more likely to select a paraphrase of the sentence that emphasized the biased
meanings.
Selective attention in vision
Sperling (1960) whole vs. partial report. Cue: spatial location , color ,category (letters vs. digits) 
 For brief visual presentations, subjects cannot use categorical information as a channel of attention.
Neisser and Becklen (1975) two games. 1. Subjects attended to one game and ignored the other. 
attended: 100%, unattended: subjects failed to noticed changes. 2. Attended to both games  error rate
40%
Subjects were able to selectively attend to one game but not able to efficiently divide their attention.