A Study of Speech
Perception:
The Psychological Reality of the
Obligatory Contour Principle
Julie Langevin
Communication
Sciences and Disorders
Faculty Mentor: Timothy Bryant
What is the Obligatory Contour
Principle?

A linguistic constraint first developed by Leben
(1973) to account for tones in languages
– It was extended to accommodate grammatical factors
by McCarthy 1988.

Is a part of our phonological grammar

Shapes the linguistic performance of English
listeners
Speech Language Triangle
Perception
Lexicon
Production
Purpose of the Study

The study was done to replicate the
work done by Coetzee, 2001 and to
demonstrate that:
• There is a phonological grammar
(phonotactics)
• The OCP has ‘psychological reality’
(i.e. influences how words are
pronounced and is thus an inherent
part of a phonological grammar) for
English speakers.
Specific Research Questions
Does the OCP influence English speakers
acceptability of nonsense words?
Prediction:

OCP factors do influence production: thus perception
plays a role in shaping English words

English makes a distinction for coronal place /t/
Continuum Construction
Three stimulus sets of two continua
each were constructed. Each
continuum had a range of tokens
ambiguous between two ‘words’. The
stimulus sets are shown below:
Continua from
[K]~[P]
[P]~[T]
[K]~[T]
[sKaK] to [sKaP]
[sPaP] to [sPaK]
[sTuT]~[sTuP]
[sPuP]~[sPuT]
[sKeK]~[sKeT]
[sTeT]~[sTeK]
Construction of the Experiment
 Each non-word was recorded in the carrier sentence,
John said ____again to me. Using an audio program each
token word was spliced so that either 40% or 60% of the
vowel was cut out.
 Filler items were included for each of the continuums
 Each continuum was
presented independently over
the course of 2 trials
Experimentation
Setting-The setting for the experiment took place in a
small, quite lab room. Each participant listened to the
experiment through noise reduction headphones and
pressed a button on the computer key board
indicating the final consonant that they heard
Subjects- Subjects for this
experiment were 40
undergraduate native
speakers of English from
the University of New
Hampshire.
[P]~[K] Continuum
[sKaP] to [sKaK] continuum
[P]~[K]
Bias
Towards
Prediction
100
80
60
[sKaP] to
[sKaK]
p
Bias will be towards
[p] because [skak]
goes against OCP
picked p
40
picked k
20
0
P Bias
[sPaP] to
[sPaK]
k
Bias will be towards
[k] because [spap]
goes against OCP
[sPaP] to [sPaK] continuum
100
80
60
picked p
40
picked k
20
0
K Bias
[P]~[T] Continuum
[sPuT] to [sPuP] continuum
100
[P]~[T]
Bias
Prediction
Towards
80
60
picked t
40
[sPuT] to
[sPuP]
t
Bias will be towards
[t] because [spup]
goes against OCP
picked p
20
0
T Bias
[sTuT] to [sTuP] continuum
[sTuT] to
[sTuP]
p
Bias is uncertain
because both [stup]
and [stut] follow the
OCP
100
80
60
picked t
40
picked p
20
0
P Bias
[K]~[T] Continuum
[sKeT] to [sKeK] continuum
[K]~[T]
Bias
Towards
Prediction
100
80
60
[sKeT] to
[sKeK]
[sTeT] to
[sTeK]
t
k
Bias will be towards
[t] because [skek]
goes against the
OCP.
Bias is uncertain
because both [stek]
and [stet] follow
the OCP
picked t
40
picked k
20
0
T Bias
[sTeT] to [sTeK] continuum
100
80
60
picked t
40
picked k
20
0
K Bias
Discussion
Our results do support the earlier work
done by Coetzee (2001). There does
appear to be categorical speech
recognition of nonsense words.
 Thus, like Coetzee we conclude that the
OCP does play a role in speech
production.

Implications
A growing body of work (e.g. Guy & Boberg
1997; Bybee, 2000, 2004) have all shown that the
OCP can account for variable output data. This
converging evidence suggests that gradience has to
be accommodated for within formal theories of
Phonology.
Clinical Implications:
 When assessing the linguistic competence of
individuals, clinicians must consider the role
perception plays in word learning.
 Acquisition work must take perception into account
normal word learning
Acknowledgements
The Hamel Center for Undergraduate
Research whose financial support made
this research possible
Thanks to my faculty mentor, Professor
Bryant for his guidance and support.
References

Alan Prince & Paul Smolensky (1993): Optimality Theory: Constraint Interaction in
Generative Grammar. Rutgers University Center for Cognitive Science Technical
Report 2.

Bleile, Ken., (2004). Manual of Articulation and Phonological Disorders: Infancy
Through Adulthood 2d ed. Clifton Park, NY: Thompson/Delmar Learning,

Coetzee, A. W., (2003). In Prosodies. Selected papers from the Phonetics and
Phonologicy in Iberia Conference, 2003. Sonia Frota, Marina Vigario and Maria Jolio
Freitas, eds. New York: Mouton de Gruyter.

Leben, W., (1978). The representation of tone. In Tone: A Linguistic Survey. Victoria
Fromkin (ed.), 177-219. New York Academic Press.

McCarthy, John J. (1986). OCP Effects: Gemination and antigemination. Linguistic
Inquiry 17:207-263

Presentation (2008). Neurobehavioral Systems.
<http://www.neurobs.com/nbs_online>
Questions?