Ricerc@Sapienza

Study Objectives: To evaluate the effects of total and partial sleep deprivation on reflection
impulsivity and risk-taking in tasks requiring deliberative decision-making processes.
Participants and Methods: Seventy-four healthy young adults were selected to participate
in two independent experiments, each consisting of a crossover design. In Experiment 1, 32
participants were tested after one night of regular sleep (RS), and after one night of total
sleep deprivation (TSD). In Experiment 2, 42 participants were tested following five nights
of RS and after five nights of partial sleep deprivation (PSD), implying five hours of sleep
per night. In both the experiments, two deliberative decision-making tasks were administered,
involving different decision-making constructs. The Mosaic Task (MT) assessed
reflection impulsivity, the tendency to gather information before making a decision. The
Columbia Card Task cold version (CCTc) evaluated risk-taking propensity in a dynamic
environment.
Results: Unlike TSD, PSD led to an increment of reflection impulsivity and risk-taking.
Nevertheless, analyses taking into account the individuals’ baseline (RS) performance
showed consistent results between the two experimental sleep manipulations. Participants
who gathered more information to make decisions in the MT when well-rested, then relied on
less evidence under sleep loss, and more cautious participants in the CCTc tended to make
riskier decisions.
Conclusion: Results pointed to differential consequences of sleep deprivation depending on
the habitual way to respond during decision-making involving deliberative reasoning processes.
Results were interpreted according to a putative interaction between sleep loss effect
and individual difference factors.