Acute psychosocial stress weakens the sense of agency in healthy adults

Figures & data

Figure 1. Schematic illustration of the procedure. Saliva cortisol (SC) was collected five times at baseline, before the TSST, and after the TSST 0 min/15 min/30 min. Note: Heart rate (HR) and electrodermal activity (EDA) were recorded eight times for 5 min at baseline, before the TSST, throughout the preparation/speech/arithmetic, and at 0min/15 min/30 min after the TSST manipulation. Two interval estimation tasks were performed before and after the TSST, respectively. H&E: Heart rate (HR) and electrodermal activity (EDA), HR_base(baseline), HR_bef (before TSST), HR_pre(preparation), HR_spe(speech), HR_Air(Arithmetic), HR_0min(TSST_0min), HR_15min(TSST_15min), HR_30min(TSST_30min), SC: Salivary cortisol; TSST: Trier Social Stress Test.

An illustration of timeline that salivary cortisol, heart rate, and electrodermal activity were measured.

Figure 2. Illustration the paper version of SAM. Note: (a,b) Adapted version of the Self-Assessment Model for potency and arousal ratings. Valence and arousal were rated on a 9-point Likert scale, (a) for emotional pleasantness, where 1 represents the sadness and 9 represents the happiness, and (b) for emotional arousal, where 1 represents the calmness and 9 represents excitement.

Ten pictures were divided into a and b groups. The first five pictures from the saddest to the happiest, representing the mood for a; the last five pictures from the calmest to about to explode, representing the degree of arousal for b.

Figure 3. Diagram of the interval estimation process. Note: A fixation cross appears at the center of screen. The participant presses "Z" for left or "M" for right on the keyboard (voluntary condition) or hears a sound of key beep (involuntary condition). The fixation cross disappears followed by a fixed time interval with a feedback tone "left" or "right." The participant was asked to report the time interval by clicking on a 0–1000 ms timeline.

The experiment contained voluntary condition and involuntary condition. For the voluntary condition, participant was asked to estimate the temporal interval between disappearance of fixation cross which caused by voluntary action and the appearance of feedback tone. As for the involuntary condition, the only difference from voluntary condition was that the fixation cross was passively disappeared.

Figure 4. Results of physiological indicators across both groups and times. Note: A represents the results of HR (BPM), B represents the results of SCL, C represents the results of NS.SCRs, and D represents the results of SC (nmol/L). where *represents p < 0.05, **represents p < 0.01. Error bars represent SEM.

Here are four plots A, B, C, and D. A represents the results of HR (BPM). There is a significant increase in HR (eg., HRspe, HRAri, and HR0min) occurring after TSST in the experimental group. B represents the results of SCL. A significant increase in SCL during the mental arithmetic of TSST in the experimental group is observed. C represents the results of NS.SCRs. A significant difference is found in two groups during the preparation phase, with the experimental group being higher than the control group. D represents the results of SC (nmol/L). A significant difference between the two groups 15 minutes after the end of TSST is reported.

Table 1. Means and standard deviations for HR(BPM) in two groups and the simple effects of group.

	Experimental group	Control group	F (1,32)	p	${\eta }_p^2$
Baseline	74.27 (6.61)	74.22 (11.89)	0.00	0.99	0.00
TSST before	72.00 (6.23)	71.09 (11.42)	0.08	0.77	0.00
Preparation	75.81 (7.34)	70.28 (8.92)	3.89	0.06	0.11
Speech	97.61 (15.81)	77.64 (8.66)	20.87	0.00**	0.40
Mental arithmetic	98.01 (14.02)	70.11 (9.13)	47.24	0.00**	0.60
TSST 0 min	86.96 (14.91)	71.60 (9.15)	13.09	0.00*	0.29
TSST 15 min	72.10 (8.10)	68.47 (8.88)	1.55	0.22	0.05
TSST 30 min	71.29 (7.57)	67.34 (9.50)	1.79	0.19	0.05

*Represents p < 0.05, **represents p < 0.01.

Table 2. Means and standard deviations for SCL in two groups and the simple effects of group.

	Experimental group	Control group	F (1,32)	p	${\eta }_p^2$
Baseline	0.18 (0.13)	0.19 (0.12)	0.10	0.75	0.00
TSST before	0.24 (0.17)	0.36 (0.17)	4.23	0.04*	0.12
Preparation	0.44 (0.18)	0.41 (0.16)	0.37	0.55	0.01
Speech	0.50 (0.13)	0.42 (0.19)	2.05	0.16	0.06
Mental arithmetic	0.52 (0.11)	0.38 (0.14)	10.49	0.00*	0.25
TSST 0 min	0.51 (0.11)	0.43 (0.21)	1.74	0.20	0.05
TSST 15 min	0.42 (0.21)	0.44 (0.20)	0.07	0.80	0.00
TSST 30 min	0.46 (0.17)	0.44 (0.24)	0.05	0.82	0.00

*Represents p < 0.05, **represents p < 0.01.

Table 3. Means and standard deviations for NS.SCRs in two groups and the simple effects of group.

	Experimental group	Control group	F (1,32)	p	${\eta }_p^2$
Baseline	8.00 (6.61)	7.41 (9.75)	0.03	0.86	0.00
TSST before	7.12 (8.03)	8.18 (7.82)	0.15	0.70	0.00
Preparation	21.76 (12.41)	11.18 (9.05)	8.07	0.00*	0.20
Speech	19.47 (15.30)	16.29 (16.04)	0.35	0.56	0.01
Mental arithmetic	15.29 (15.88)	9.29 (9.33)	1.80	0.19	0.05
TSST 0 min	15.65 (11.51)	13.12 (11.13)	0.42	0.52	0.01
TSST 15 min	14.41 (13.83)	11.12 (7.56)	0.74	0.40	0.02
TSST 30 min	112.65 (10.44)	14.59 (14.59)	0.20	0.66	0.00

*Represents p < 0.05, **represents p < 0.01.

Table 4. Means and standard deviations for SC in two groups and the simple effects of group.

	Experimental group	Control group	F (1, 32)	p	${\eta }_p^2$
Baseline	0.83 (0.25)	0.73 (0.23)	1.38	0.25	0.04
TSST before	1.19 (0.32)	1.19 (0.35)	0.008	0.99	0.00
TSST 0 min	2.09 (0.85)	2.06 (0.72)	0.01	0.93	0.00
TSST 15 min	1.64 (0.35)	1.31 (0.36)	7.04	0.01*	0.18
TSST 30 min	1.09 (0.30)	1.14 (0.24)	0.30	0.59	0.01

*Represents p < 0.05, **represents p < 0.01.

Figure 5. Paired t-test for reported time between voluntary and involuntary conditions. It shows that the reported interval for the voluntary condition is significantly shorter than that for the involuntary condition, p < 0.05.

Paired t-test charts of reported interval for all participants in the two different conditions, showed that the reported time in the voluntary condition was significantly shorter than that in the involuntary condition, p < 0.05.

Table 5. The reported intervals for the two groups with different conditions.

		Experimental group		Control group
		Mean	SD	Mean	SD
Pretest	Voluntary condition	364.52	83.97	368.04	77.64
	Involuntary condition	406.18	79.32	379.72	82.20
posttest	Voluntary condition	384.80	85.05	379.62	104.74
	Involuntary condition	402.65	86.72	405.21	97.04

Figure 6. Temporal binding scores for experimental and control groups. Temporal binding scores of the pretest was significantly greater than posttest in the experimental group, while there was no difference in the control group.

Temporal binding scores for the two groups. The temporal binding scores of the experimental group in posttest were significantly lower than the scores in pretest , p < 0.05. There was no difference in the control group.

Data availability statement

All raw data obtained in this experiment including questionnaires, physiological measurements and time estimates, and data used for statistical analysis in the article (excluding excluded data), are publicly available on the figshare website: https://doi.org/10.6084/m9.figshare.21758537.v2.