Chapter 5: Individual Differences in Ability and Affective Variables
6.2 Results
6.2.2 Task performance on different task types in oral and
* = p < 0.05 ** = p < 0.01
A comparison of the data presented in Tables 29-32 reveals that accuracy measures show a tendency to change together in this group of participants. Furthermore, the two task-specific measures of syntactic complexity, namely the ratio of relative clauses and the ratio of subordinate clauses also show a strong correlation in three of the four tasks (Tasks 2, 3 and 4).
clauses (.01) (.12) (.11) (.10) Ratio of relative
clauses
.09 (.074)
.13 (.086)
.10 (.08)
.11 (.07) Accuracy
Ratio of error-free clauses
.81 (.08)
.82 (.09)
.75 (.11)
.76 (.12) Ratio of error-free
relative clauses
.79 (.27)
.67 (.32)
.67 (.33)
.69 (.40) Ratio of error-free
past tense verbs
.94 (.16)
.96 (18)
.81 (.29)
.88 (.28)
In order to compare the output produced by the participants on the different narrative task types across modalities, paired samples t-tests were performed, the results of which are shown in Tables 34-37 below.
Table 34 gives the results obtained when comparing the participants’ output on the two types of tasks performed in speaking (Tasks 1 and 2). As shown, participants’ performance only differed significantly with regard to the measure of lexical variety (t(43)=3.60, p<0.001). They used significantly more varied vocabulary in the cartoon description task than in the picture narration task.
Table 34. Paired samples t-test comparing performance on the oral cartoon description and picture narration tasks
t df p
Fluency
Speech rate .402 43 .690
Lexical variety
D value 3.604 43 .001**
Syntactic complexity
Clause length -.846 43 .402
Ratio of subordinate clauses .617 43 .540
Ratio of relative clauses .513 43 .610
Ratio of error-free clauses -.777 43 .442 Ratio of error-free relative
clauses -.233 43 .817
Ratio of error-free past
tense verbs -1.320 43 .195
** = p < 0.01
Table 35 provides the data comparing performance on the two task types in the written mode (Tasks 3 and 4). As shown, the participants produced significantly shorter clauses (t(43)=2.64, p=0.012) and used more relative clauses (t(43)=2.44, p=0.019) in the cartoon description than in the picture narration task. They also tended to produce more error-free relative clauses when describing the cartoon than in narrating the picture story, but this observed difference did not reach significance (t(43)=1.84, p=0.075).
Table 35. Paired samples t-test comparing performance on the written cartoon description and picture narration tasks
t df p
Lexical variety
D value 1.356 43 .183
Syntactic complexity
Clause length -2.635 43 .012*
Ratio of subordinate clauses -.465 43 .644 Ratio of relative clauses -2.437 43 .019*
Accuracy
Ratio of error-free clauses -.650 43 .519 Ratio of error-free relative
clauses
1.834 43 .075+
Ratio of error-free past tense verbs
-1.059 43 .296
+ = p < 0.08 * = p < 0.05
Table 36 demonstrates how participants’ performance compares on the cartoon description task across modalities. The comparison of the task in the two modes reveals that the participants used more varied vocabulary in writing (t(43)=6.79, p<0.001). They also produced significantly longer clauses (t(43)=3.31, p=0.002) and a significantly higher proportion of error-free clauses (t(43)=2.86, p=0.007) in the written cartoon description than in the parallel oral task.
t df p Lexical variety
D value -6.788 43 .001**
Syntactic complexity
Clause length 3.309 43 .002**
Ratio of subordinate clauses -.302 43 .764
Ratio of relative clauses .894 43 .377
Accuracy
Ratio of error-free clauses -2.858 43 .007**
Ratio of error-free relative clauses
1.202 43 .239
Ratio of error-free past tense verbs
-.363 43 .719
** = p < 0.01
Table 37 shows the effect of modality on participants’ rendition of the picture narration task.
Similarly to the cartoon description task, the participants used significantly more varied vocabulary in writing than in speaking (t(43)=9.39, p<0.001). They also tended to produce longer clauses of which a higher proportion was accurate in writing; however these differences did not reach the level of statistical significance.
Table 37. Paired samples t-test comparing performance on the picture narration task across modalities
t df p
Lexical variety
D value -9.393 43 .001**
Syntactic complexity
Clause length 1.760 43 .086+
Ratio of subordinate clauses -.933 43 .356 Ratio of relative clauses -1.169 43 .249 Accuracy
Ratio of error-free clauses -1.918 43 .062++
Ratio of error-free relative clauses
.425 43 .673
Ratio of error-free past tense verbs
1.349 43 .185
++ = p < 0.07 + = p < 0.09 * = p < 0.05 ** = p < 0.01
Having compared participants’ output on the two task types in both speaking and writing, it is interesting to note that effect of task type showed in both written and oral task performance albeit on different measures. Lexical variety appeared to differentiate performance on the oral tasks while syntactic complexity and accuracy on the written tasks. Language data from this group of participants showed that modality affected their performance to a greater extent on the cartoon description task than on the picture
narration task. Nevertheless the impact of modality can be observed with regard to measures of lexical variety, accuracy and complexity as well.
Tables 38-39 display the correlation matrix of the pairs of output measures on these task types across different modes of performance. Measures of linguistic performance on the two oral tasks display several correlations, namely between speech rate, clause length and the ratio of error-free clauses. In writing the output variables for the same task types appear to be independent from one another except for the lexical variety measure and the ratio of error-free past tense verbs, a task-specific accuracy measure.
Examining the output measures of the same task types across modalities indicates that only the measure of lexical variety on the picture narration tasks shows a statistically significant relationship.
Table 38. Correlations of the same linguistic measures on the two task types in oral mode (Task 1 = cartoon description, Task 2 = picture narration)
Variables N Pearson correlation Sig.
Fluency
Speech rate on Task 1 and Task 2 43 .74 .001**
Lexical variety
D value 43 .24 .13
Syntactic complexity
Clause length 43 .32 .036*
Ratio of subordinate clauses 43 .10 .50
Ratio of relative clauses 43 .04 .78
Accuracy
Ratio of error-free clauses 43 .33 .03*
Ratio of error-free relative clauses 43 -.18 .32
Ratio of error-free past tense verbs 43 .15 .37
* = p < 0.05 ** = p < 0.01
Table 39. Correlations of the same linguistic measures on the two task types in written mode (Task 3 = cartoon description, Task 4 = picture narration)
Variables N Pearson correlation Sig.
Lexical variety
D value on Task 3 and Task 4 43 .39 .013*
Syntactic complexity
Clause length 43 .17 .29
Ratio of subordinate clauses 43 .30 .06
Ratio of relative clauses 43 .01 .96
Accuracy
Ratio of error-free clauses 43 .27 .08
Ratio of error-free past tense verbs 43 .55 .001**
* = p < 0.05 ** = p < 0.01
Table 40. Correlations of the same linguistic measures on Task 1 and Task 3 (cartoon description task across modalities)
Variables N Pearson correlation Sig.
Lexical variety
D value on Task 1 and Task 3 43 .18 .27
Syntactic complexity
Clause length 43 -.10 .51
Ratio of subordinate clauses 43 -.05 .75
Ratio of relative clauses 43 -.14 .39
Accuracy
Ratio of error-free clauses 43 .18 .26
Ratio of error-free relative clauses 43 -.29 .10 Ratio of error-free past tense verbs 43 .08 .66
Table 41. Correlations of the same linguistic measures on Task 2 and Task 4 (picture narration task across modalities)
Variables N Pearson correlation Sig.
Lexical variety
D value on Task 2 and Task 4 43 .30 .05*
Syntactic complexity
Clause length 43 -.01 .94
Ratio of subordinate clauses 43 .25 .12
Ratio of relative clauses 43 09 .56
Accuracy
Ratio of error-free clauses 43 .06 70
Ratio of error-free relative clauses 43 -.02 .90 Ratio of error-free past tense verbs 43 .18 .26
* = p < 0.05