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|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|29900||2014||8 صفحه PDF||سفارش دهید||محاسبه نشده|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Psychology of Sport and Exercise, Volume 15, Issue 1, January 2014, Pages 89–96
Objective To investigate the aftereffects of anticipating future self-control and motivation on self-control strength depletion patterns. Design Single blind, randomized 2 (autonomy-supportive motivation/controlling motivation) × 2 (anticipation/no anticipation) factorial. Method Participants (N = 72) performed four sequential self-control strength challenges: an initial endurance handgrip squeeze followed by the Stroop task and two additional endurance handgrip squeezes. A sequential randomization procedure was used to allocate participants to one of four conditions: anticipation/autonomy-supportive motivation (n = 19), anticipation/controlling motivation (n = 17), no anticipation/autonomy-supportive motivation (n = 18), and no anticipation/controlling motivation (n = 18). Results Participants who anticipated future self-control depletion conserved resources on the second task by completing fewer words on a Stroop task compared to controls. Participants who received autonomy-supportive instructions performed significantly better than controls on a third task (endurance handgrip squeeze), but worse than controls on the fourth task (another endurance handgrip squeeze). There were no significant interactions between anticipation and motivation (p > .05). Conclusions Results support previous findings reflecting conservation and motivation effects on self-control strength. This was the first study to show that autonomy-supportive instructions may assist self-control performance in the short term but ultimately depletes self-control strength and impairs performance in the long term.
We investigate the effects of anticipation and motivation on self-control. • Anticipation of future self-control demands leads to resource conservation. • Motivation leads to better initial self-control but worse performance later on.
نتیجه گیری انگلیسی
Results Demographics and covariate checks One-way ANOVAs revealed no significant differences between conditions on age and number of hours of exercise per week (p > .05). The distributions of men and women, as well as, the distributions of lifting weights for exercise, were evaluated using contingency tables and no significant differences (p > .05) were found between conditions. On average participants in the sample engaged in moderate-vigorous physical activity on 2.02 (SD = 1.16) days/week. Univariate factorial ANOVAs 2 (autonomy-supportive motivation/controlling motivation) × 2 (anticipation/no anticipation) were computed comparing scores for: perceived physical exertion (RPE), perceived mental exertion (RPME), BMIS, and trait self control (SCS). With the exception of SCS, no significant differences (p > .05) were found between conditions. There was a significant effect for SCS, F(3,68) = 5.89, p = .02. Post-hoc tests (Tukey's HSD) showed the anticipation/autonomy-supportive motivation condition scored lower on SCS than the other three conditions, which did not differ from one another. This finding provided an indication that the randomization procedure was not successful for creating equivalent groups based on the SCS score; therefore, SCS was included as a covariate in tests of the main hypotheses. Main analyses The first hypothesis, that the participants who were provided with anticipatory information about future self-control expenditure would conserve self-control strength on an initial self-control task and, in doing so, perform worse than controls on a later self-control task, was evaluated by comparing performance scores for the modified Stroop task and both the raw and residualized change in muscular endurance scores from Trial 1 to Trial 2. In previous research residualized change scores rather than raw change scores have been used to determine physical performance effects of self-control depletion (Bray et al., 2008, Bray et al., 2011, Graham and Bray, 2012 and Tice et al., 2007). Residualized change scores control for individual differences in strength as well as the negative correlation between baseline scores and raw change scores, as individuals that hold longer muscular contractions tend to have larger trial-to-trial changes. Residualized change scores were calculated by regressing the Trial 2 contraction duration on the Trial 1 contraction duration (Cohen, Cohen, Aiken, & West, 2003). Prior to those analyses, a one-way ANOVA of the scores on the anticipation manipulation check items was computed. Results showed participants in the condition that received instructions to anticipate further self-control depletion scored higher on both items: “How much energy were you trying to conserve for the last endurance trial?”, F(1,70) = 10.51, p < .01, and the item “How important was it for you to conserve your energy for the last endurance trial?”, F(1,70) = 9.42, p < .01. Descriptive statistics summarizing the Stroop task performance and the Trial 1 to Trial 2 raw and residualized handgrip endurance change scores for the anticipation and no anticipation conditions are presented in Tables 1 and 2, respectively. To test hypothesis 1, one-way ANCOVAs were computed on the Stroop scores (words completed and errors made) co-varying for SCS. The two groups were found to differ significantly, F(1,69) = 9.63, p = .003, with the anticipation group completing fewer words during the 5-min task. The distribution of scores representing the number of Stroop errors was not normal and was transformed using a square root function. Analyses of those scores also showed a significant effect, F(1,69) = 64.75, p < .001, with the anticipation condition exhibiting a greater number of errors than the no anticipation group. Contrary to the hypothesis, the anticipation and no anticipation groups did not differ on handgrip self-control performance (p > .05) in analyses of either the raw or residualized change scores. Table 1. Stroop task and two-item scores between the anticipation and no anticipation conditions co-varying for SCS scores. Variables Anticipation M (SD) No anticipation M (SD) p d Stroop Words completed 244.56 (53.16) 284.25 (45.05) .003 0.80 Stroop Errors made (raw values) 17.11 (6.48) 7.22 (6.78) <.001 1.47 Stroop Errors made (SQRT Transformed) 4.05 (0.84) 2.45 (0.84) <.001 1.90 Conservation manipulation checks “How much energy were you trying to conserve for the final endurance trial?” 3.08 (1.89) 1.86 (1.24) .002 0.76 “How important was it for you to conserve your energy for the final endurance trial?” 3.19 (2.07) 1.92 (1.40) .003 0.72 Note: M = mean, SD = standard deviation, d = effect size. Table options Table 2. Raw change and unstandardized residualized change scores for endurance trial 1–2 and trial 2–3 by autonomy-supportive motivation/controlling motivation and anticipation/no anticipation conditions (adjusted for SCS scores). Variable Anticipation M (SD) No anticipation M (SD) Trial 1–Trial 2 Raw Δ −6.03 (20.19) −8.78 (21.89) Trial 2–Trial 3 Raw Δ −16.28 (16.18) −14.31 (11.98) Trial 1–Trial 2 Residualized Δ 0.90 (17.10) −0.35 (15.20) Trial 2–Trial 3 Residualized Δ −1.00 (13.49) 1.00 (10.23) Autonomy-supportive motivation M (SD) Controlling motivation M (SD) Trial 1–Trial 2 Raw Δ 2.87 (17.84) −18.26 (18.55) Trial 2–Trial 3 Raw Δ −19.57 (13.37) −10.77 (13.75) Trial 1–Trial 2 Residualized Δ 4.87 (13.57) −4.58 (17.23) Trial 2–Trial 3 Residualized Δ −4.40 (11.22) 4.65 (10.98) Autonomy-supportive motivation Controlling motivation Anticipation No anticipation Anticipation No anticipation Trial 1–Trial 2 Raw Δ 6.00 (14.40) −0.44 (20.80) −19.47 (17.18) −17.11 (20.18) Trial 2–Trial 3 Raw Δ −22.89 (16.00) −16.06 (9.06) −8.88 (13.21) −12.56 (14.38) Trial 1–Trial 2 Residualized Δ 6.45 (12.69) 3.20 (14.62) −5.30 (19.50) −3.89 (15.33) Trial 2–Trial 3 Residualized Δ −7.64 (12.12) −0.98 (9.32) 6.42 (11.05) 2.97 (10.97) Note: M = mean, SD = standard deviation. Table options Hypotheses 2 and 3 about the main effect of motivation and the interactive effects of anticipation and motivation were evaluated using both raw and residualized handgrip endurance change scores from Trial 1 to Trial 2 (see Table 2 for descriptive statistics). The prediction of hypothesis 2 was that individuals who received autonomy-supportive instructions would perform better on Trial 2 (less change from Trial 1) compared to individuals who received controlling motivation instructions. A 2 (autonomy-supportive motivation/controlling motivation) × 2 (anticipation/no anticipation) univariate ANCOVA (co-varying for SCS) of the raw change scores revealed a main effect for motivation, F(1,67) = 6.28, p < .001 (d = 1.16). A 2 × 2 ANCOVA of the residualized change scores also revealed a main effect for motivation F(1,67) = 6.64, p = .012 (d = 0.61). Thus, in both analyses participants in the autonomy-supportive motivation conditions showed less deterioration in performance from Trial 1 to Trial 2 compared to the controlling motivation conditions. Hypothesis 3: that participants who conserved resources and received autonomy-supportive instructions would exhibit superior performance compared to participants in the other conditions was evaluated using the interaction term from the 2 × 2 ANCOVA analyses. Contrary to predictions, the anticipation by motivation interaction was not significant (p > .05) in the analyses of either the raw or residualized change scores. Hypothesis 4: that participants who received autonomy-supportive instructions prior to Trial 2 would perform worse than those who received controlling motivation instructions on a subsequent challenge of their self-control strength was evaluated using both raw and residualized handgrip endurance change scores from Trial 2 to Trial 3 (see Table 2 for descriptive statistics). For the raw change scores, a 2 (autonomy-supportive motivation/controlling motivation) × 2 (anticipation/no anticipation) univariate ANCOVA (co-varying for SCS) revealed a main effect for motivation, F(1,67) = 3.28, p = .006 (d = 0.65). A 2 (autonomy-supportive motivation/controlling motivation) × 2 (anticipation/no anticipation) univariate ANCOVA (co-varying for SCS) of the residualized change scores revealed a main effect for motivation, F(1,67) = 12.16, p = .001 (d = 0.82). Thus, in both analyses participants in the autonomy-supportive motivation conditions showed larger deteriorations in performance from Trial 2 to Trial 3 compared to the controlling motivation conditions. Neither the main effect for anticipation nor the interaction was significant (p > .05) in either analysis.