3.1. General Intellectual Functioning and Self-Reported Autistic
Traits
All group comparisons were made using independent samples t-tests, unless otherwise specified. There were no differences between the groups on any measure of general
intellectual functioning (t ≤ 1.87, p ≥ 0.08) or on any of the four WASI subtests (t ≤ -1.48, p ≥ 0.16). However, there was a significant difference between the two groups on the AQ (t = 5.12, p < 0.001). The ASC group reported a significantly higher mean score on the AQ than the TD group. These results are shown in Table 2.
Table 2: The AQ and IQ scores for each group
Group Name: Autistic Spectrum Conditions Typically Developed t p(t) AQ Score (mean +/- s.d) 29.4 (9.0) 12.2 (6.0) 5.12 <0.001 FSIQ (mean +/- s.d) 109.6 (12.5) 119.4 (11.9) -1.87 0.08 VIQ (mean +/- s.d) 106.5 (12.9) 115.9 (11.7) -1.81 0.09 PIQ (mean +/- s.d) 112.3 (11.4) 119.0 (10.7) -1.43 0.17
AQ = Autism Spectrum Quotient; FSIQ = Full Scale Intelligence Quotient; PIQ = Performance Intelligence Quotient ; VIQ = Verbal Intelligence Quotient
3.2. Behavioural Results for the Figures
3.2.1. Figure Copy and Recall – Standard scoring system (Osterrieth, 1944)
There were no significant differences between the groups on the House copy score (t = -1.81, p = 0.09); the ROCF score (t = 0.52, p = 0.61); the time taken to complete the House (t = 0.00, p = 1.00); or the time taken to complete the ROCF (t = 0.98, p = 0.34). The individual ROCF completion times are shown below in Figure 1. There were also no group differences for the House memory scores (t ≤ -1.36, p ≥ 0.19) or the ROCF memory scores (t ≤ -0.82, p ≥ 0.42). These results are shown in Table 3. The ROCF was scored by two raters. A Pearson’s correlation between the two raters scores showed a high level of agreement for all three conditions (Copy: r = 0.97, p < 0.001; Immediate memory: r = 0.995, p < 0.001; Delayed memory: r = 0.99, p < 0.001).
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There was a correlation between the Block Design (BD) subtest and the ROCF copy score for the whole sample (r = 0.51, p = 0.03). However, this was no longer significant when the sample was split into the ASC and TD groups (p ≥ 0.09).
Figure 1: The ROCF completion time of each participant
Table 3: The figure copy and memory recall results for each group
Group Name: Autistic Spectrum
Conditions Typically Developed t p(t) House Copy (mean +/-
s.d) 10.5 (0.9) 11.1 (0.7) -1.81 0.09
House Immediate Recall
(mean +/- s.d) 9.7 (1.3) 9.7 (1.8) 0.00 1.00
House Delayed Recall
(mean +/- s.d) 9.4 (1.0) 10.1 (1.4) -1.36 0.19
House copy time (in
seconds) 52.9 (25.5) 46.7 (22.9) 0.60 0.56
ROCF Copy (mean +/-
s.d) 34.5 (1.4) 34.1 (2.5) 0.52 0.61
ROCF Immediate Recall
(mean +/- s.d) 18.8 (7.7) 21.0 (7.5) -0.68 0.51
ROCF Delayed Recall
(mean +/- s.d) 18.2 (7.4) 20.9 (7.9) -0.82 0.42
ROCF copy time (in
seconds) 182.3 (73.3) 156.7 (46.6) 0.98 0.34
3.2.2. Figure Copy and Recall - BQSS
There are three hypotheses relating to the ROCF BQSS results. These will be discussed in order.
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1) Participants with ASC will achieve poorer BQSS Planning and Organisation scores than TD controls.
Contrary to Hypothesis 1, there were no differences between the two groups on the Planning score (ASC mean = 3.18, s.d. = 0.75; TD mean = 2.64, s.d. = 0.67; t = 1.79, p = 0.09) or the Organisation summary score (ASC mean = 6.27, s.d. = 1.35; TD mean = 5.27, s.d. = 1.70; t = 1.54, p = 0.14).
2) Participants with ASC will achieve better Cluster and Detail Presence and Accuracy scores and lower Configural Presence and Accuracy scores on the BQSS than TD controls.
Contrary to Hypothesis 2, there were no differences between the two groups on the Cluster or Detail Presence or Accuracy scores (t ≤ -1.88, p ≥ 0.08). There were also no differences on the Configural elements Presence or Accuracy scores (t ≤ 1.00, p ≥ 0.34) or the Presence and Accuracy summary scores for the Copy (t = 0.79, p = 0.44), Immediate memory (t = -0.35, p = 0.73), or Delayed memory (t = -1.27, p = 0.22) conditions. These results are shown in Table 4
Table 4: The Configural, Cluster and Detail Presence and Accuracy Scores
Group Name: Autistic Spectrum
Conditions Developed Typically t p(t) Copy Configural presence score (mean +/-
s.d.) 4.0 (0.0) 3.8 (0.6) 1.00 0.34
Copy Configural accuracy score (mean +/-
s.d.) 3.7 (0.5) 3.6 (0.7) 0.37 0.72
Copy Clusters presence score (mean +/- s.d.) 3.8 (0.4) 3.9 (0.3) -
0.60 0.56 Copy Clusters accuracy score (mean +/- s.d.) 4.0 (0.0) 3.9 (0.3) 1.00 0.34 Copy Details Presence score (mean +/- s.d.) 3.7 (0.5) 3.6 (0.5) 0.44 0.67 IM Configural presence score (mean +/- s.d.) 3.2 (1.2) 3.0 (1.1) 0.38 0.71 IM Configural accuracy score (mean +/- s.d.) 3.8 (0.4) 3.7 (0.6) 0.40 0.70
IM Clusters presence score (mean +/- s.d.) 2.2 (0.9) 2.9 (1.0) -
1.78 0.09 IM Clusters accuracy score (mean +/- s.d.) 2.9 (0.9) 2.8 (0.6) 0.27 0.79
IM Details Presence score (mean +/- s.d.) 1.1 (0.7) 1.2 (0.8) -
0.29 0.77 DM Configural presence score (mean +/- s.d.) 3.3 (1.1) 3.2 (0.9) 0.21 0.83
DM Configural accuracy score (mean +/- s.d.) 3.6 (0.5) 3.7 (0.6) -
0.37 0.72 DM Clusters presence score (mean +/- s.d.) 2.2 (0.8) 2.9 (1.0) -
1.88 0.08 DM Clusters accuracy score (mean +/- s.d.) 2.4 (1.0) 3.0 (0.9) -
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DM Details Presence score (mean +/- s.d.) 0.8 (0.6) 1.2 (0.8) -
1.25 0.23 DM = Delayed Memory; IM = Immediate Memory
3) There will be a correlation between the Block Design subtest and the Detail Presence scores.
In support of Hypothesis 3, there was a correlation between the BD subtest and both the ROCF Copy Detail Presence score (r = 0.47, p = 0.04), and the ROCF Delayed memory Detail Presence score (r = 0.48, p = 0.04). The correlation did not reach significance for the ROCF Immediate memory Detail Presence score (p = 0.13). When the sample was split into the ASC and TD groups only the correlation between the BD subtest and the ROCF Copy Detail Presence score remained significant and only for the TD group (r = 0.66, p = 0.03).
3.3. Eye Tracking Results for the Figures
3.3.1. General Eye Tracking Measures
Despite large mean differences, there were no differences between the two groups for the number of gazes for the House (t = 1.10, p = 0.29) or the ROCF (t = 1.01, p = 0.33). This was due to large within group differences shown by the standard deviations of each mean. There were also no differences between the two groups for the mean length of each gaze for either the House (t = 0.69, p = 0.50) or the ROCF (t = 0.60, p = 0.55). Finally, there were no differences between the two groups for the mean number of cycles between the original figure and the participant drawn reproduction during the Copy condition for either the House (t = 0.96, p = 0.35) or the ROCF (t = 0.01, p = 0.99). These results are shown in Table 4.
Table 5: The mean number of gazes and gaze length for each group
Group Name: Autistic Spectrum Conditions Typically Developed t p(t) House number of gazes (mean +/- s.d) 85.7 (46.9) 65.4 (37.9) 1.10 0.29 ROCF number of gazes (mean +/- s.d) 271.6 (92.6) 236.1 (64.5) 1.01 0.33 House gaze length in
seconds (mean +/- s.d)
0.70 (0.32) 0.78 (0.20) 0.69 0.50 ROCF gaze length in
seconds (mean +/- s.d)
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(mean +/- s.d) 25.29 (10.89) 21.19 (8.63) 0.96 0.35 ROCF Cycles/Min
(mean +/- s.d) 24.69 (3.66) 24.68 (4.83) 0.01 0.99 ROCF = Rey-Osterrieth Complex Figure
3.3.2. Specific Eye Tracking Measures for the ROCF
There are two hypotheses relating to the eye tracking results. These will be discussed in order.
4) Participants with ASC will spend less mean total copy completion time looking at the Configural main elements of the ROCF than TD controls and more mean total copy completion time looking at the Cluster and Detail elements.
Contrary to Hypothesis 4, there were no differences between the two groups on the mean percentage of time spent looking at the Configural main elements or the Cluster and Detail elements of the ROCF during copy completion (ASC mean = 11.2, s.d. = 4.0; TD mean = 11.3, s.d. = 2.6; t = -0.05, p = 0.96).
5) Participants with ASC will be slower to fixate on ‘Cluster 5’ (see Appendix A), which is the round element in the upper right side of the ROCF.
Despite large mean differences, there were no differences on a Mann-Whitney U test between the two groups for the number of gazes made before the participant fixated on Cluster 5 (ASC mean = 26.5, s.d. = 42.5; TD mean = 4.8, s.d. = 7.5; U(10) = 42.0; p = 0.36). This was due to large differences within the ASC group, but not the TD group, shown by the standard
deviations of each mean. Because of this intra-group variability a post-hoc analysis was conducted to examine any relationship between the AQ scores and the number of gazes taken to fixate on Cluster 5. This correlation was significant (rs(20) = 0.43, p = 0.04), showing that the higher a participants AQ score, the more gazes it took them before they fixated on Cluster 5.