تئوری کنترل توجه: اضطراب، احساسات و برنامه ریزی حرکتی

Abstract The present study investigated how trait anxiety alters the balance between attentional control systems to impact performance of a discrete preplanned goal-directed motor task. Participants executed targeted force contractions (engaging the goal-directed attentional system) at the offset of emotional and non-emotional distractors (engaging the stimulus-driven attentional system). High and low anxious participants completed the protocol at two target force levels (10% and 35% of maximum voluntary contraction). Reaction time (RT), performance accuracy, and rate of change of force were calculated. Expectations were confirmed at the 10% but not the 35% target force level: (1) high anxiety was associated with slower RTs, and (2) threat cues lead to faster RTs independently of trait anxiety. These new findings suggest that motor efficiency, but not motor effectiveness is compromised in high relative to low anxious individuals. We conclude that increased stimulus-driven attentional control interferes with movements that require greater attentional resources

. Results 5.1. Primary analyses Table 2 shows RT, RMSE, and rate of change of force data from the high and low anxiety groups for each target force level across each level of valence. Table 2. Force onset, RMSE, and rate of force means (+1SE) for high and low anxiety groups for each target force level across each level of valence. Target force Group Valence Onset RMSE Rate of force M SE M SE M SE 10% MVC Low Adventure 376.82 24.74 2.72 0.35 52.45 4.30 Erotica 384.04 30.95 2.66 0.31 59.03 5.13 Attack 341.54 30.93 2.33 0.25 48.36 4.96 Mutilation 344.68 33.12 2.76 0.33 49.8 4.00 Neutral 366.66 36.27 2.45 0.23 47.37 3.84 High Adventure 468.29 23.14 1.86 0.34 35.59 4.16 Erotica 486.29 28.95 1.79 0.30 35.13 4.96 Attack 433.1 28.94 1.43 0.24 33.03 4.80 Mutilation 443.31 30.98 1.53 0.32 30.9 3.87 Neutral 484.26 33.93 1.77 0.23 33.85 3.71 35% MVC Low Adventure 394.09 25.07 5.34 0.50 147.48 15.03 Erotica 370.69 22.65 5.21 0.56 141.01 14.48 Attack 356.75 27.51 5.20 0.51 144.03 15.11 Mutilation 400.84 27.26 6.18 0.66 141.59 15.34 Neutral 346.53 18.83 4.67 0.52 141.86 15.12 High Adventure 403.75 26.80 4.90 0.56 121.66 16.06 Erotica 426.23 24.22 5.19 0.62 117.9 15.48 Attack 379.29 29.41 4.67 0.57 115.8 16.16 Mutilation 420.07 29.14 4.78 0.74 114.93 16.4 Neutral 415.93 20.13 4.95 0.58 118.76 16.16 Table options 5.1.1. Force onset (RT) at 10% MVC A two-way mixed model ANOVA confirmed the trends shown in Table 2, revealing significant between group differences for RT, F (1, 28) = 6.89, p = .014, η2 = .20. Follow-up tests showed that the high anxiety group was slower than the low anxiety group to initiate movements (HA: M = 362.75, SE = 27.91; LA: M = 463.05, SE = 26.11). A significant main effect of valence was also evidenced, F (3.03, 84.74) = 3.59, p = .017, η2 = .02, with follow-up tests showing a general bias of faster RT's to unpleasant images. Specifically, RT's following the offset of attack images were faster than following adventure, erotica, and neutral images, as well as following mutilation images as compared to erotica images. The Group × Valence interaction was not significant, F (3.03, 84.74) = .24, p = .87, η2 = .01. 5.1.2. Force onset (RT) at 35% MVC Force onset varied significantly as a function of valence (F (4, 112) = 2.52, p = .045, η2 = .08), with follow-up tests revealing faster responses following exposure to attack as compared to mutilation images. Neither a significant main effect of Group nor a Group × Valence interaction were evidenced (Group: F (1, 28) = 1.34, p = .26, η2 = .05; HA: M = 409.05, SE = 22.25, LA: M = 373.78, SE = 20.82; Group × Valence: F (4, 112) = 1.49, p = .21, η2 = .051). 5.1.3. RMSE at 10% MVC Follow-up analyses on a significant main effect of group (F (1, 29) = 8.26, p = .008 η2 = .22) revealed that the high anxiety group executed the task with greater accuracy as compared to the low anxiety group (HA: M = 1.68, SE = .22; LA: M = 2.58, SE = .23). The main effect of Valence and the Group × Valence interaction were not significant (Valence: F (3.02, 87.52) = 1.08, p = .36, η2 = .04; Group × Valence: F (3.02, 87.52) = .43, p = .73, η2 = .02). 5.1.4. RMSE at 35% MVC With the target force set to 35% of MVC, analyses revealed that accuracy of performance was not significantly different between groups (F (1, 27) = .35, p = .56. η2 = .01), valence categories (F (4, 108) = 1.22, p = .31, η2 = .04) (HA: M = 4.89, SE = .53; LA: M = 5.32, SE = .48) or between any combination of these two factors (Group × Valence: F (4, 108) = 1.89, p = .12, η2 = .07). 5.1.5. Rate of change of force at 10% MVC The rate of change of force data for the high and low anxiety groups at each force level for each valence category is shown in Table 2. For contractions made to target force levels at 10% of MVC, rate of change of force differed significantly between groups (F (1, 29) = 9.63, p = .004, η2 = .25), with the high anxiety group displaying an attenuated rate of change of force production relative to the low anxiety group (HA: M = 33.70 SE = 3.97; LA: M = 51.40 SE = 4.10). Rate of change of force production was also significantly altered by valence (F (2.84, 82.32) = 4.47, p = .007, η2 = .13), with follow-up tests revealing a general increase in rate of change during pleasant images (erotica > attack, mutilation, neutral; adventure > neutral). The Group × Valence interaction was not significant (F (2.84, 82.32) = 2.05, p = .12, η2 = .07). 5.1.6. Rate of change of force at 35% MVC Main effects of Group and Valence and the interaction between these factors were all non-significant (Group: F (1, 28) = 1.45, p = .24 η2 = .05; HA: M = 117.81, SE = 15.37, LA: M = 143.19, SE = 14.38; Valence: F (4, 112) = .46, p = .77, η2 = .02; Group × Valence: F (4, 112) = .10, p = .92, η2 = .004. 5.2. Secondary analyses All significant differences are reported for the secondary analyses, as well as non-significant findings that deviated from the primary analyses (covariate: 10%: 42.05N; 35%: 52.01N). Fig. 1, Fig. 2 and Fig. 3 show the adjusted means for RT (Fig. 1), RMSE (Fig. 2), and mean rate of change of force (Fig. 3). Although data from the 35% target force level are shown in Fig. 1, Fig. 2 and Fig. 3, note that data from the 35% target force level are not reported below because the critical p-values in the secondary analyses did not differ from those in the primary analysis. As such, Fig. 1, Fig. 2 and Fig. 3 are presented for each target force level to provide a visual comparison between data for each group, target force level, and valence category. Adjusted reaction time data across the valence conditions for each target force ... Fig. 1. Adjusted reaction time data across the valence conditions for each target force level. The black bars represent adjusted mean RT for the low anxiety group. White bars represent adjusted mean RT for the high anxiety group. The high anxiety group were slower than the low anxiety group at 10% of MVC (left), but there was no between group difference at 35% (right). A main effect of valence was evidenced at 10% (attack < adventure, erotica, neutral; mutilation < erotica), and at 35% (attack < mutilation). The error bars are +1SE from the adjusted mean for each group. Valence conditions: Adv, adventure; Ero, erotica; Att, attack; Mut, mutilation; Neu, Neutral. Figure options Adjusted accuracy data (represented as RMSE) across the valence conditions for ... Fig. 2. Adjusted accuracy data (represented as RMSE) across the valence conditions for each target force level. The black bars represent adjusted mean RMSE for the low anxiety group and the white bars represent adjusted mean RMSE for the high anxiety group. Accuracy scores at each target force level did not vary as a function of trait anxiety or valence, or a combination of trait anxiety and valence. The error bars are +1SE from the adjusted mean for each group. Valence conditions: Adv, adventure; Ero, erotica; Att, attack; Mut, mutilation; Neu, Neutral. Figure options Adjusted mean rate of change of force for each target force level across the ... Fig. 3. Adjusted mean rate of change of force for each target force level across the valence conditions. The black bars represent adjusted mean peak rate of change of force for the low anxiety group and the white bars represent adjusted mean peak rate of change of force for the high anxiety group. Relative to the low anxiety group, the high anxiety group displayed attenuated rate of change at the 10% target force level. No between group effects were found at the 35% target force level. The rate of change of force production at each target force level did not vary as a function of valence, or a combination of trait anxiety and valence. The error bars are +1SE from the adjusted mean for each group. Valence conditions: Adv, adventure; Ero, erotica; Att, attack; Mut, mutilation; Neu, Neutral. Figure options 5.2.1. Force onset (RT) RT analyses with the target force at 10% of MVC remained largely unchanged from our primary analyses. A significant main effect of Group (F (1, 27) = 4.57, p = .042, η2 = .15) corroborated our initial findings by showing that the high anxiety group was slower than the low anxiety group (HA: M = 453.32, SE = 24.88; LA: M = 373.97, SE = 26.66). A main effect of Valence was also evidenced (F (4, 108) = 4.35, p = .003, η2 = .14) with the follow-up analyses also unchanged from the primary analyses (attack < adventure, erotica, neutral; mutilation < erotica). 5.2.2. RMSE With regard to movement accuracy at the 10% target force level, although the trend within the data remained in the same direction as the primary analysis (HA < LA: HA: M = 1.88, SE = .20; LA: M = 2.36, SE = .20), the between group difference was not significant (F (1, 28) = 2.70, p = .11 η2 = .09). Hence, when controlling for MVC level, the effect of trait anxiety on performance accuracy was lost, removing the speed-accuracy trade-off that emerged at the 10% MVC target force level in the primary analyses. 5.2.3. Rate of change of force Mean rate of change of force production was altered by Group when the target force was set at 10% of MVC (F (1, 28) = 4.17, p = .05, η2 = .13) with the high anxiety group still displaying attenuated rate of change (M = 36.57, SE = 3.83) as compared to the low anxiety group (M = 48.34, SE = 3.97).