Ideal Time of Day for Risky Decision Making: Evidence from the Balloon Analogue Risk Task

Figures & data

Table 1 The Averaging Results of Sleep Dairy from Two Weeks Preceding the Study

	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6	Day7
Sleeping time	23:54 ± 0.39	23:52 ± 0.39	23:54 ± 0.33	23.46 ± 0.43	23:45 ± 0.33	23:48 ± 0.40	23:50 ± 0.36
Waking time	7:46 ± 0.64	7:48 ± 0.62	7:44 ± 0.61	7:45 ± 0.60	7:50 ± 0.57	7:45 ± 0.56	7:46 ± 0.50
Sleep duration (h)	7.87 ± 0.55	7.93 ± 0.51	7.85 ± 0.59	7.98 ± 0.54	8.07 ± 0.57	7.96 ± 0.57	7.93 ± 0.45
	Day 8	Day 9	Day 10	Day 11	Day 12	Day 13	Day14
Sleeping time	23:53 ± 0.37	23:54 ± 0.39	23:49 ± 0.40	23:53 ± 0.44	23:49 ± 0.38	23:49 ± 0.46	23:49 ± 0.36
Waking time	7:51 ± 0.52	7:47 ± 0.50	7:45 ± 0.51	7:49 ± 0.50	7:52 ± 0.52	7:38 ± 0.44	7:43 ± 0.51
Sleep duration (h)	7.96 ± 0.57	7.88 ± 0.47	7.92 ± 0.51	7.93 ± 0.52	8.05 ± 0.47	7.83 ± 0.52	7.90 ± 0.38

Note: Mean ± SD.

Figure 1 Balloon Analogue Risk Task (BART).

Figure 2 Go/no-go Task (GNG) task.

Note: The order of task 1 and task 2 was counter-balanced between different participants and sessions.

Figure 3 Psychomotor Vigilance Task (PVT) task.

Figure 4 Experimental design and procedure.

Table 2 Descriptive Statistics

	Morning (M ± SD)	Afternoon (M ± SD)	t-value	p-value	Cohen’s d
BART
Adjusted average number of pumps on unexploded balloons	6.06 ± 1.16	6.42 ± 1.41	−2.135*	0.042	−0.404
Number of explosions (Loss number)	17.36 ± 3.73	16.89 ± 4.62	0.762	0.453	0.144
Total gains	164.00 ± 18.10	174.29 ± 13.85	−2.871**	0.008	−0.543
Negative feedback	5.79 ± 1.56	6.24 ± 1.68	−2.741*	0.011	−0.518
Positive feedback	6.23 ± 1.09	6.48 ± 1.36	−1.208	0.237	−0.228
Go no-go
Go trials reaction time (ms)	393.54 ± 36.44	391.25 ± 36.02	0.067	0.947	0.013
Go trials hit rate	0.98 ± 0.04	0.99 ± 0.02	−0.554	0.584	−0.105
No-go trials false alarm rate	0.13 ± 0.09	0.18 ± 0.10	−2.989**	0.006	−0.565
D prime	3.53 ± 0.59	3.30 ± 0.57	1.977	0.058	0.374
Sleepiness and vigilance
Sleepiness	4.93 ± 1.21	5.39 ± 0.88	−1.904	0.068	−0.360
PVT reaction time (ms)	332.13 ± 21.61	334.14 ± 25.04	−0.577	0.569	−0.109
PVT lapses	2.75 ± 2.46	3.25 ± 4.06	−1.070	0.294	−0.202

Note: *p<0.05, **p<0.01.

Figure 5 Time-of-day effect on Balloon Analogue Risk Task (BART). (A) The adjusted average number of pumps on unexploded balloons, (B) The total gains, (C) The adjusted average number of pumps after negative feedback. *p<0.05, **p<0.01.

Figure 6 Time-of-day effect on No-go trials false rate which reflects the level of inhibitory control in Go/no-go task. **p<0.01.

Table 3 The Correlation Between the Time-of-Day Effects on Risky Decision Making and Inhibitory Control

Variables (Delta Scores)	1	2	3	4	5	6	7
1. Adjusted average pumps	1
2. Explosions	0.727***	1
3.Total gains	0.209	−0.468**	1
4.Positive feedback	0.929***	0.735***	0.093
5.Negative feedback	0.803***	0.543**	0.245
6.No-go false alarm rate	−0.044	−0.017	0.012	0.072	−0.429*	1
7.D prime	0.033	−0.168	0.287	0.241	0.498**	0.490**	1

Notes: The table showed no relationship between the change of BART (1–5) and other indexes (6–7) variation. Delta score = “index score in the afternoon” minus “index score in the morning”; Adjusted average pumps = Adjusted average number of pumps on unexploded balloons, Explosions = Number of explosions, Negative feedback = Average number of pumps after exploded balloons, Positive feedback =Average number of pumps after the unexploded balloon. *p<0.05, **p<0.01, ***p<0.001.