For the EET, a 2 (TBI vs. no TBI group)*(7 - emotion) ANOVA was conducted to explore potential differences in emotion perception. A further 2*(7) *(3 – eyes, nose, mouth AOI) repeated measures ANOVA was conducted to investigate potential differences in fixation duration and count between the TBI and non-TBI groups.
3.1.1. Behavioural data
As demonstrated in
Table 2, the descriptive statistics indicated that the group with TBI had lower overall accuracy scores on the EET compared to the group without TBI.
The analysis showed a significant main effect of emotion, (F (6, 204) = 6.85, p ≤ .001, ηp2 = 0.17), but the interaction between emotion and group was non-significant, (F (6, 204) = 1.08, p = .375, ηp2 = 0.03). The test of between-subjects effects was also significant, (F (1, 34) = 20.28, p ≤ .001, ηp2 = 0.37) with the group means indicating that the TBI participants had significantly fewer correct responses across the EET compared to the non-TBI group. When comparing the descriptive statistics, it appeared that the TBI group scored lower on negative emotions compared to positive, particularly interpreting sad, anxious, and revolted displays of emotion, compared to the non-TBI group, although these differences were not statistically significant.
Eye-tracking data
Fixation duration across the EET in seconds
The group with TBI had shorter fixation durations to the eyes and nose compared to participants without TBI, while both groups displayed similar fixation durations to the mouth (
Table 3).
The analysis showed a significant main effect of emotion, (F (1.83, 62.17) = 38.99, p ≤ .001, ηp2 = 0.53), and a significant interaction between emotion and AOI, (F (4.19, 142.35) = 12.29, p ≤ .001, ηp2 = 0.27). The main effect of AOI, (F (1.70, 57.87) = 0.09, p = .884, ηp2 = 0.003), and the interactions between emotion and group, (F (1.83, 62.17) = 1.67, p = .198, ηp2 = 0.05), AOI and group, (F (1.70, 57.87) = 2.17, p = .130, ηp2 = 0.06), and emotion, AOI and group, (F (4.19, 142.35) = 1.26, p = .289, ηp2 = 0.04) were all non-significant. The tests of between-subjects effects was also not significant, (F (1, 34) = 2.84, p = .101, ηp2 = 0.08).
The significant interaction between emotion and AOI was explored through three one-way ANOVAs, with emotion as the independent variable (IV) and fixation duration as the dependent variable (DV). There was a significant effect of eyes, (
F (1.40, 48.90) = 36.35,
p ≤ .001,
ηp2 = 0.51), nose, (
F (2.53, 88.41) = 5.99,
p = .002,
ηp2 = 0.15) and mouth, (
F (1.40, 48.90) = 36.35,
p ≤ .001,
ηp2 = 0.51) on fixation duration in response to different facial expressions, with follow-up paired-samples
t tests in
Appendix C. In brief, the post-hoc tests indicated that participants made longer fixations to the eyes when viewing sad faces compared to all other emotions. Participants also spent significantly longer looking at the eyes of neutral faces compared to the other emotions (bar sad). The group elicited longer fixations to the nose when viewing angry, sad, and neutral faces and more fixations to the mouth when looking at happy and sad faces.
Fixation count across the EET
The group affected by TBI had fewer fixations compared to those without TBI across all of the emotions and across most of the AOIs within the emotions (
Table 4).
The analysis showed a significant main effect of emotion, (F (3.40, 115.65) = 41.78, p ≤ .001, ηp2 = 0.55) and a significant interaction between emotion and AOI, (F (5.85, 198.88) = 10.77, p ≤ .001, ηp2 = 0.24). The main effect of AOI, (F (1.60, 54.41) = 0.44, p = .602, ηp2 = 0.01) and the interactions between emotion and group, (F (3.40, 115.65) = 1.79, p = .146, ηp2 = 0.05), AOI and group, (F (1.60, 54.41) = 2.26, p = .124, ηp2 = 0.06), and emotion, AOI and group, (F (5.85, 198.88) = 1.88, p = .088, ηp2 = 0.05) were all non-significant. The tests of between-subjects effects was also not significant, (F (1, 34) = 2.96, p = .094, ηp2 = 0.08).
The significant interaction between emotion and AOI was explored through three one-way ANOVAs, with emotion as the IV and fixation count as the DV. There was a significant effect of eyes, (
F (1.40, 48.90) = 36.35,
p ≤ .001,
ηp2 = 0.44), nose, (
F (4.17, 146.02) = 5.87,
p ≤ .001,
ηp2 = 0.14) and mouth, (
F (3.94, 138.06) = 30.97,
p ≤ .001,
ηp2 = 0.47) on fixation count in response to different facial expressions, with follow-up paired-samples
t tests presented in
Appendix D. In summary, the group made more fixations to the eyes and nose when viewing neutral and sad faces. The mouth was looked at more when participants viewed happy and sad faces.
Correlations
One-tailed Spearman’s Rho correlations were run to explore possible relationships between the behavioural data (accuracy for emotion recognition) and eye-tracking data (fixation duration and fixation count). When the groups were combined and the α-level had been adjusted to account for multiple comparisons (α= .01) there were no significant correlations (all, r's ≤ 0.29, all p’s ≥ .043). When the groups were separated there were also no significant correlations for the group with TBI (all r’s ≤ -0.23, p ≥ .352) or non-TBI group (all r’s ≤ 0.58, p ≥ .013).
Social Inference-Minimal
A 2 (TBI vs. no TBI group)*(3 – simple sarcasm, paradoxical sarcasm, sincere) ANOVA was conducted to investigate group differences during the understanding of conversational meanings. A further 2*(4 – intentions, meaning, beliefs, feelings) ANOVA was conducted to investigate the difference between the groups in understanding different facets of social interactions. With eye-tracking data, a 2*(3) *(3) mixed-design ANOVA was conducted to investigate potential differences in fixation duration and count between the TBI and control groups.
Behavioural data
Accuracy for conversation style
As demonstrated in
Table 5, the descriptive statistics indicated that the TBI group had lower overall accuracy scores across the conversational styles (simple sarcasm, paradoxical sarcasm and sincere) compared to the control group.
There was no significant effect of conversation style, (F (1.59, 52.47) = 1.37, p = .260, ηp2 = 0.04) and no interaction between conversation style and group, (F (1.59, 52.47) = 1.63, p= .203, ηp2 = 0.05). The tests of between-subjects effects was significant, (F (1, 33) = 21.03, p ≤ .001, ηp2 = 0.39) and referring to the estimated marginal means, the group with TBI scored significantly lower across the three conversation styles of the SI-M (M= 15.54, SD= 3.65) compared to the control group (M= 18.55, SD= 1.94).
Accuracy
for comprehension probes
The descriptive statistics for the four different comprehension probes (beliefs, meanings, intentions, feelings) suggested that the group affected by TBI were less accurate at understanding what the actor was trying to do, what they were trying to say, what they were thinking, and what they were feeling (
Table 6). See
Appendix B for a comprehensive description of the TASIT behavioural metrics.
There was a significant effect of comprehension probe, (F (2.38, 78.36) = 3.19, p = .038, ηp2 = 0.09) but there was no interaction between comprehension probe and group, (F (2.38, 78.36) = 1.37, p= .261, ηp2 = 0.04). To further explore the significant effect of comprehension probe, independent t tests were conducted. When post-hoc correction was applied, the intentions, meaning, beliefs, and feelings probes were significant (p ≤ .001). The tests of between-subjects effects was significant, (F (1, 33) = 17.67, p ≤ .001, ηp2 = 0.35) and referring to the estimated marginal means, the group with TBI scored significantly lower across the four comprehension probes of the SI-M (M= 11.67, SD= 2.29) compared to the control group (M= 13.84, SD= 1.00).
Eye-tracking data
Fixation duration across the SI-M in seconds
The mean scores indicated that participants spent more time fixated on the mouth than the nose and eyes during simple sarcasm and sincere videos (
Table 7). The sincere videos appeared to elicit the longest fixations, followed by the sarcastic and then paradoxical videos.
The analysis showed a significant main effect of conversational style, (F (1.34, 44.16) = 23.59, p ≤ .001, ηp2 = 0.42) and AOI, (F (2, 66) = 6.29, p = .003, ηp2 = 0.16). The interactions between conversation style and group, (F (1.34, 44.16) = 0.25, p = .78, ηp2 = 0.01), AOI and group, (F (1.78, 58.82) = 0.39, p =0.657, ηp2 = 0.01), conversation style and AOI, (F (2.39, 78.98) = 2.62, p = .070, ηp2 = 0.07), and conversation style, AOI and group, (F (2.39, 78.98) = 0.15, p =.894, ηp2 = 0.01) were all non-significant. The tests of between-subjects effects was also not significant, (F (1, 33) = 0.52, p = .476, ηp2 = 0.02).
To explore the significant main effect of conversation style, two-tailed paired samples t tests were conducted and the post-hoc correction was applied. Participants generated significantly longer fixation durations during the sarcastic videos compared to paradoxical videos, (t (34) = 5.67, p ≤.001, d = 0.96, CI= 0.61-1.30), sincere videos compared to sarcastic videos, (t (34) = -3.00, p =.005, d = 0.51, CI= -1.82- -0.35), and sincere videos compared to paradoxical videos, (t (34) = -6.50, p ≤.001, d = 1.09, CI= -2.68- -1.41).
Additional two-tailed paired-samples t tests were conducted to investigate the significant main effect of AOI. When the post-hoc correction was applied, participants exhibited significantly longer fixations to the mouth (M =2.30, SD= 1.69) compared to the eyes (M =1.13, SD= 1.07), (t (34) = -3.24, p = .003, d = 0.55, CI= -1.90- -0.44).
Fixation count across the SI-M
From the mean scores presented in
Table 8, there appeared to be a similar pattern for both the TBI and control participants, with both groups having higher fixation counts for the sarcastic and sincere compared to paradoxical videos.
The analysis showed a significant main effect of conversational style, (F (1.39, 45.91) = 22.40, p ≤ .001, ηp2 = 0.40). The other main effect of AOI, (F (1.69, 55.77) = 2.96, p = .068, ηp2 = 0.08), and the interactions between conversation style and group, (F (1.39, 45.91) = 0.37, p = .617, ηp2 = 0.01), AOI and group, (F (1.69, 55.77) = 0.38, p = .648, ηp2 = 0.01), conversation style and AOI, (F (2.26, 74.71) = 2.40, p = .091, ηp2 = 0.07), and conversation style, AOI and group, (F (2.26, 74.71) = 0.44, p =.671, ηp2 = 0.01) were all non-significant. The tests of between-subjects effects was also not significant, (F (1, 33) = 0.002, p = .965, ηp2 ≤ 0.001).
To explore the significant main effect of conversation style, two-tailed paired-samples t tests were conducted with post-hoc corrections applied. Participants generated significantly more fixations during the sarcastic videos compared to paradoxical videos, (t (34) = 7.24, p ≤.001, d = 1.22, CI= 1.83-3.26), and to sincere (M = 5.73, SD = 3.41) videos compared to paradoxical videos, (t (34) = -6.30, p ≤.001, d = 1.06, CI= --4.97- -2.54).
Correlations
One-tailed Spearman’s Rho correlations were used to investigate potential relationships between the behavioural data (accuracy for conversation style and comprehension probe) and eye-tracking data (fixation duration and fixation count). When the groups were combined and once the α-level had been adjusted to account for multiple comparisons (α= .01), there were no significant correlations (all, r's ≤ 0.001, all p’s ≥ .110). When the groups were separated, there were still no correlations for the group with TBI (all r’s ≤ 0.51, p ≥ .032) but there were significant correlations for the control group between fixation duration to the eyes and the intentions comprehension probes (r= 0.74, p= .001), fixation count to the eyes and the intentions comprehension probes (r= 0.73, p= .001) and between fixation duration to the eyes and simple sarcasm comprehension probes (r= 0.69, p= .002).
SI-E
A 2 (TBI vs. no TBI group)*(2 – sarcastic and lie) ANOVA was conducted to investigate group differences during the understanding of conversational meanings. A further 2*(4 – intentions, meanings, beliefs and feelings) ANOVA was conducted. Again, this analysis investigated the difference between the groups in understanding different facets of social interactions. A 2*(2) *(3 – eyes, nose and mouth AOI) repeated measures ANOVA was conducted to investigate potential differences in fixation duration and count between the TBI and control groups.
Behavioural data
Accuracy for conversational style
As demonstrated in
Table 9, the mean scores indicated that the group affected by TBI had lower overall accuracy scores across the two conversational styles (sarcastic and lie) compared to the control group.
The effect of conversation style was non-significant, (F (1.00, 33.00) = 0.64, p = .428, ηp2 = 0.02) but there was a significant interaction between conversation style and group, (F (1.00, 33.00) = 9.86, p= .004, ηp2 = 0.23). Simple effects analysis revealed that the group with TBI scored significantly lower on the sarcastic vignettes (M = 22.56, SD = 4.77) compared to controls (M = 29.41, SD = 3.37) (p ≤ .001). The tests of between-subjects effects was also significant, (F (1, 33) = 16.31, p ≤ .001, ηp2 = 0.33). Referring to the estimated marginal means, the group affected by TBI had significantly lower accuracy scores across the two conversation styles of the SI-E (M= 23.94, SD= 4.78) compared to the control group (M= 28.58, SD= 3.24).
Accuracy for comprehension probes
The descriptive statistics for the four different comprehension probes (intentions, meanings, beliefs, and feelings) suggested that the group living with TBI were less accurate at understanding what the actor was trying to do, what they were trying to say, what they were thinking, and what they were feeling (
Table 10).
There was a significant effect of comprehension probe, (F (2.46, 81.19) = 3.25, p = .034, ηp2 = 0.09) and a significant interaction between comprehension probe and group, (F (2.46, 81.19) = 4.69, p= .008, ηp2 = 0.12). Simple effects analysis revealed that the group with TBI scored significantly lower on the ‘intention’ probes (M = 11.28, SD = 2.49) compared to controls (M = 14.82, SD = 1.63) (p ≤ .001) and the same for the ‘meaning’ probes (TBI M = 11.17, SD = 2.60; control group M = 14.47, SD = 1.70) (p ≤ .001). The tests of between-subjects effects was also significant, (F (1, 33) = 21.41, p ≤ .001, ηp2 = 0.39). Referring to the estimated marginal means, the group affected by TBI scored significantly lower across the four comprehension probes of the SI-E (M= 11.97, SD= 2.34) compared to the control group (M= 14.47, SD= 1.63).
Eye-tracking data
Fixationduration across the SI-E in seconds
Table 11 shows that individuals with TBI had shorter fixation durations to the eyes, nose and mouth compared to controls (Table 43).
The analysis showed a significant main effect of conversational style, (F (1, 33) = 44.18, p ≤ .001, ηp2 = 0.57) with participants exhibiting longer fixations for sarcastic videos compared to lie videos. The main effect of AOI, (F (1.22, 40.16) = 0.92, p = .405, ηp2 = 0.03) and the interactions between conversation style and group, (F (1.00, 33.00) = 0.002, p = .969, ηp2 ≤0.01), AOI and group, (F (1.22, 40.16) = 0.01, p = .991, ηp2 ≤ 0.01), conversation style and AOI, (F (1.61, 53.26) = 2.54, p = .099, ηp2 = 0.07), and conversation style, AOI and group, (F (1.61, 53.26) = 1.42, p =.249, ηp2 = 0.04) were all non-significant. The tests of between-subjects effects was also not significant, (F (1, 33) = 1.13, p = .296, ηp2 = 0.03).
Fixation count across the SI-E
From the descriptive statistics presented in
Table 12, the TBI cohort appeared to produce fewer fixation counts to all AOI across the sarcastic and lie conditions compared to control participants. Both the TBI and control participants generated fewer fixation counts during the videos depicting lies compared to videos where the actors were being sarcastic.
The analysis showed a significant main effect of conversational style, (F (1, 33) = 75.77, p ≤ .001, ηp2 = 0.70) with participants displaying more fixations during the sarcastic vignettes compared to vignettes depicting lies. The main effect of AOI, (F (1.36, 44.95) = 0.28, p = .673, ηp2 = 0.01) and the interactions between conversation style and group, (F (1, 33) = 0.08, p = .780, ηp2= 0.002), AOI and group, (F (1.36, 44.95) = 0.20, p = .732, ηp2 = 0.01), conversation style and AOI, (F (1.58, 52.23) = 1.29, p = .279, ηp2 = 0.04), and conversation style, AOI and group, (F (1.58, 52.23) = 1.49, p =.236, ηp2 = 0.04) were all non-significant. The tests of between-subjects effects was also not significant, (F (1, 33) = 0.76, p = .390, ηp2 = 0.02).
Correlations
One-tailed Spearman’s Rho correlations explored the relationships between the behavioural data (accuracy for conversation style and comprehension probe) and eye-tracking data (fixation duration and fixation count). When the groups were combined and once the α-level had been adjusted to account for multiple comparisons (α= .01), there were no significant correlations (r ≤ 0.39, p ≥ .022). When the groups were separated, there were still no significant correlations for the group with TBI (all, r's ≤ 0.56, all p’s ≥ .016) or controls (all, r's ≤ 0.56, all p’s ≥ .019). Although the analysis did not reach the .01 set for post-hoc significance, the results are nearing significance and are significant at the typically accepted α level of .05.