PSYC20007 Lecture Notes - Lecture 6: Cocktail Party, Sound Energy, Musical Tone
14 Jun 2018
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Lecture 6 - Tuesday 29 August 2017
PSYC20007 - COGNITIVE PSYCHOLOGY
LECTURE 6
ATTENTION (1) HISTORICAL ORIGINS
ATTENTION (1)
•(1) What we are interested in in cognitive psychology as attention is the brain's ability to self-
regulate input from the environment.
•Used in two senses in psychology:
•1. Sustained Attention (Alertness): sense of attention linked to concentration etc.
•Related to psychological arousal (continuum from drowsy, inattentive to alert, attentive)
•Problem of vigilance: performance declines over a long watch (radar operators, quality
control inspectors, etc.)
•(2)
•2. Selective Attention
•Limited in the number of stimuli we can process. At any one time there are multiple
sources of info for our receptors but we can only focus on a limited number.
•Attend to one stimulus at the expense of others.
•People as limited capacity systems: don't treat all stimuli equally; priorities some.
COCKTAIL PARTY PHENOMENON
•(3) Cherry (1953)
•How do we follow a conversation in a crowded environment.
•Can “pick out” one conversation from background despite the acoustically challenging
environment.
•“Picking out:” processes take sound energy at ear, translate to understanding
•Translation is selective (stimuli not all treated equally)
•How to study this process?
•Cherry: what happens to unattended messages?
DICHOTIC LISTENING AND
SHADOWING
•(4) “Dichotic”: “di” (two) + “oto” (ears)
•“Channel:” sensory pathway acting as a
source of information. The ears are
referred to as ‘channels’. The attended
channel receives 1 message and the other
receives the other message.
CHERRY’S FINDINGS
•(5) Shadow Message 1, then ask about contents of Message 2
•Unattended Channel:
•No memory for unattended message
•Switch from English to German: not noticed
•Switch from male to female: noticed
•Reversed speech: “something queer”
•Switch from voice to 400 cps pure tone: noticed
THE UNATTENDED MESSAGE
•(6) Conclusions:
•Only superficial (physical) features perceived
•(things distinguishing voice, non-voice, or male, female)
•Semantic content not analysed (language, meaning)
Lecture 6 - Tuesday 29 August 2017
PSYC20007 - COGNITIVE PSYCHOLOGY
•Cognitive processes could be divided into 2 types: preattentive processes (don’t need attention) vs.
focal attention (deliberate, volition) (Neisser, 1967)
•Sensory (physical) features processed preattentively
•Meaning requires focal attention
•Plausible: aware of unattended stimuli only superficially
SELECTION OF THE ATTENDED MESSAGE
•(7) Binaural presentation (Cherry): both ears receive both messages, same
voice, differ only in content
•Very difficult!
•Showed that source localisation in space is an important cue (phase
differences in arrival times at ear)
•Instead of dichotic listening, he presented message 1 and 2 in the same
voice both to the each ear! So there was no sound localisation. Picture on
the right. People took 10-20 presentations to find coherence.
•Shows if you take away localisation ability it make it more difficult.
CRITICISM OF CHERRY
•(8) Interested in what's perceived, Cherry looked at what's remembered
•Cherry’s method confounds perception and memory. We think we are measuring 1 thing but
something else is being varied too.
•May be perceived then forgotten? Perhaps attention is required to form stable, reportable
memories?
BROADBENT: FILTER THEORY (1958)
•Modern cognitive theory of
attention.
•(9) Attention acts as a filter to
select stimuli for further
processing.
•The protective
role was a
selective filter.
This filter is
what he
equated with
attention.
•The short term store here is supposed to
be a brief representation of things
attended to here.
•(10) Meaning extracted in limited capacity channel
•Filter precedes channel, protects it from overload
•All stimuli stored briefly in short term store (STS)
•Raw acoustic trace, decays quickly if not selected
EVIDENCE FOR FILTER THEORY
•Interaction of STS and filter
•Dichotic digit stream:
•Temporal order: 3-4 correct
•Ear-by-ear recall: 6 correct
•The 7+-2 intends to describe roughly adults’ normal ranges
