Passage 9
Sedentary behavior (defined as an energy expenditure of <1.5 METs while lying,
sitting, or reclining, while awake can be detrimental for cognitive performance,
whereas acute physical activity breaks may elicit positive effects. One of the main
underlying mechanisms driving the acute physical activity-induced improvements
on cognitive performance is assumed to be changes in cerebral blood flow driven by
neural activation. Previous research findings have demonstrated that a single bout of
physical activity (about 10–20 min) can increase such task-related cerebral blood
flow, with coinciding improvements in prefrontal cortex-dependent cognitive tasks.
However, decreases in task-related cerebral blood flow after an exercise bout with
concomitant enhancement in cognitive performance has also been observed.
In this randomized crossover study, the effects of frequent, short physical activity
breaks during prolonged sitting on cognitive task-related activation of the prefrontal
cortex were investigated. The effects on working memory, psychological factors,
and blood glucose were also examined, and whether arterial stiffness moderated
prefrontal cortex activation. Thirteen subjects (mean age 50.5 years; eight men)
underwent three 3-h sitting conditions, interrupted every 30-min by a different 3-min
break on separate, randomized-ordered days: seated social interactions (SOCIAL),
walking (WALK), or simple resistance activities (SRA). Arterial stiffness was assessed
at baseline. Before and after each 3-h condition, psychological factors (stress, mood,
sleepiness, and alertness) were assessed through questionnaires and functional nearinfrared spectroscopy (fNIRS) was used to measure changes in prefrontal oxygenated
hemoglobin (Oxy-Hb), indicative of cortical activation, while performing working
memory tasks [1- (baseline), 2-, and 3-back]. Blood glucose levels were continuously
measured throughout the conditions.
Results revealed no significant changes in Oxy-Hb during the 2-back compared
with the 1-back test in any condition, and no time-by-condition interactions. During
the 3-back test, there was a significant decrease in Oxy-Hb compared with the
1-back after the WALK condition in the right prefrontal cortex, but there were no
time-by-condition interactions, although 3-back reaction time improved only in the
WALK condition. Mood and alertness improved after the WALK condition, which was
significantly different from the SOCIAL condition. Arterial stiffness moderated the
effects, such that changes in Oxy-Hb were significantly different between WALK and
SOCIAL conditions only among those with low arterial stiffness. Blood glucose during
the interventions did not differ between conditions. Thus, breaking up prolonged
sitting with frequent, short physical activity breaks may reduce right prefrontal
cortex activation, with improvements in some aspects of working memory, mood,
and alertness.
Interrupting prolonged sitting, with frequent, short walking breaks decreased taskrelated right prefrontal cortex activation as measured by Oxy-Hb during a high load
working memory task. Still, frequent, short walking breaks also enhanced working
memory performance, suggesting that physical activity breaks during prolonged
sitting may help preserve or even improve neural efficiency. Of further importance,
alertness and positive mood were enhanced by frequent, short walking breaks
compared with prolonged sitting. While more experimental scrutiny is needed to
clarify the physiological mechanisms underlying such improved neural efficiency,
frequent, short walking breaks may be recommended in middle-aged adults to
support psychological well-being during extended periods of sitting and cognitive
performance on mentally demanding tasks.
Frequent, Short Physical Activity Breaks Reduce Prefrontal Cortex Activation but
Preserve Working Memory in Middle-Aged Adults: ABBaH Study. Adapted from
Heiland et al. (2021).
Which of the following are true statements regarding the process of problemsolving?
A) Heuristics are rarely applied in day-to-day problem solving when it comes
to basic, everyday tasks or concerns
B) The presence of biases often impact problem-solving in only subtle ways,
and can be exacerbated by group dynamics or the presence of observers
C) The presence of observers or partners, as well as membership in a group,
has little influence on problem-solving patterns and outcomes
D) Problem solving is unaffected by belief perseverance
Correct answer is B
When it comes to problem-solving, people often tend to take shortcuts, adopt
heuristics, and rely on biases and assumptions rather than carefully, thoroughly, and
thoughtfully considering the nuances of the situation at hand. This phenomenon
can be explained by a variety of psychological and sociological phenomena.
Answer B is correct because the presence of biases often impact problem-solving
in only subtle ways, and can be exacerbated by group dynamics or the presence
of observers. Although human beings may prefer to think that they are unaffected
by biases, can identify biases when they arise, or are able to identify where their
patterns of thinking or problem-solving are erroneous, this is often not the case.
People sometimes act under the influence of biases without knowing they are doing
so. Furthermore, the presence of others–whether they be observers, partners,
or group members–has profound and powerful influences on how people solve
problems and on the eventual outcomes that arise as a result. Groupthink and
group polarization are examples of these, as is the Hawthorne effect, which arises
when people alter their behavior because they are being observed in a study- or
research-type setting. If they were alone, they would act differently.
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