ACQ Vol 13 No1 2011

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ACQ Volume 13, Number 1 2011 9
Communicative efficiency was measured by the number
of correct information units per minute (CIU/min) relating to
how quickly and correctly each topic was produced. The
procedure for calculating CIU/min followed Nicholas and
Brookshire’s (1993) rules for analysis.
Breakdown in language production was investigated at
word and utterance levels. The percent of words in mazes
(revisions, repetitions, and filler words) (Miller & Chapman,
2002), number of word errors (Word errs) and number of
utterance level errors (Utt errs) were measured. The number
of dysfluencies as indicated by the percentage of words in
mazes may be an indication of the participant attempting to
correct difficulties in communication either before speaking,
or once she had started speaking (Merlo & Mansur,
2004). Word errors occurred when an incorrect word
was produced. Utterance errors included utterances that
provided incorrect information, or did not add to the overall
flow of the discourse (Ciccone, 2003). These were coded
during transcription and calculated as the total number of
each type of error contained in each sample.
The amount of content recalled by the participant was
measured by the percent of predetermined main ideas (%MI)
and optional ideas (%OI) (Li et al., 1995).
Results
Table 3 provides an example of the procedure, for a familiar
and an unfamiliar topic, played to the participant as well as
the participant’s corresponding discourse samples.
For each measure, the results were grouped according to
familiarity or unfamiliarity to allow for statistical comparison
(see table 4 for the results). Comparisons were undertaken
using a paired-samples t- test or a Mann-Whitney U test
when assumptions of normality and homogeneity of variance
were violated. The alpha level was set at 0.05.
Significant differences in the discourse measures between
familiar and unfamiliar topics were noted. The unfamiliar
topics resulted in a reduction in the speed and accuracy of
discourse production. The slower rate of production was
characterised by a decreased number of words per minute,
an increase in the total amount of pause time, and a reduced
number of correct information units per minute. The samples
also contained a larger number of utterances that provided
incorrect information or information that was conveyed
ineffectively. These utterances had an increased number of
filler words, repetitions and revisions. The unfamiliar samples
also contained fewer optional ideas.
Discussion
There were statistically significant differences between the
discourse samples produced in response to topics rated as
familiar and unfamiliar. The more familiar topics resulted in
higher quality discourse samples. The number of main ideas
recalled was similar for both familiar and unfamiliar samples.
This result is consistent with the findings of Li et al. (1995)
and when considered in light of the significant difference in
the number of optional ideas recalled suggests that the
unfamiliar topics had an impact on the participant’s ability to
recall all procedural details (Williams et al., 1994). It may also
be evidence of the individual’s lack of previous exposure to
the experiences outlined in the unfamiliar procedural topics.
No significant differences were found between familiar
and unfamiliar topics on the measures of mean length of
utterance (MLU), type token ratio, and the number of word
errors. Williams et al. (1994) found the syntactic complexity
of the utterances increased when participants produced
average of 6 utterances, with 11 words per utterance, and
included an average of 7 main ideas and 3 optional ideas.
The number of main and optional ideas were predetermined,
consistent with Williams et al.’s study (1994). Average word
frequency was calculated for all topics using the word
frequency lists from the MRC psycholinguistic database
(Wilson, 1998). A t-test showed no statistically significant
difference in word frequency between familiar and unfamiliar
topics t (18, 17.21) = .137, p = 0.715.
Procedure
The participant attended two 60-minute data collection
sessions conducted by the first author. The first session
involved collection of case history information, the
completion of BDAE, and the ranking of procedural topics.
During the second session, the 10 pre-recorded discourse
samples were presented via a laptop computer to the
participant in a random order. Presentation of stimuli and
instructions was consistent with the retell tasks in Williams et
al.’s (1994) and Li et al.’s (1995) studies. After listening to the
discourse sample once, the participant retold the procedure
in her own words. For each discourse topic, she was
prompted to provide as much detail as she could recall.
During discourse production nonspecific prompting was
used such as “can you tell me anything else?” to encourage
as much output as possible for each topic.
Samples were recorded and timed using a JNC USB-350
digital voice recorder with a lapel microphone. Discourse
samples were transcribed using Systematic Analysis of
Language Transcripts software (SALT; Miller & Chapman,
2002) and analysed by the first author.
Discourse analyses
The discourse samples were analysed using the measures
outlined below.
Mean length of utterance (MLU) measured in words
and type token ratio (TTR) were calculated. Mean length
of utterance is a measure of syntactic complexity (Miller &
Chapman, 2002). TTR is a ratio of the number of different
words produced compared to the total number of words
produced and reflects diversity in the lexical items produced
in response to the discourse topics.
Speech rate was measured by the number of words
produced per minute (WPM) which reflects the speed with
which the participant was able to formulate and produce the
language required for each sample. The amount of pause
time compared to the total discourse time was calculated as
a percentage figure (%pauses). This percentage reflected the
amount of additional time required to formulate the language
output.
Table 2. Complete list of familiar and unfamiliar
topics
Familiar topics Unfamiliar topics
Going grocery shopping Going mountain climbing
Going out to dinner Saddling a horse
Clearing the table after dinner Making a clay bowl
Getting children ready for bed Making a bean bag
Getting a haircut Painting a watercolour landscape
Changing bed sheets Participating in a marathon walk
Making a cup of tea Writing a haiku poem
Having a shower Auditioning for a play
Going to the doctors Conducting a symphony
Making a sandwich Preparing to scuba dive