Tag Archives: Tiredness

Bar neon sign.

Ignoring distractions or temptation is harder when you’re tired, stressed, or trying to remember something

Stress, tiredness, and general cognitive strain make it much harder for us to ignore signals in the environment for something rewarding — such as bright neon signs for fast food joints.

Bar neon sign.

Neon lights and ads are such tempting cues.
Image via Pixabay.

We all have impulses we’d like to have a better handle on. Some of you might be trying to diet, quit smoking, or kick some other habit; good luck. New research says that tiredness, stress, or any other drain on your mental resources can make it harder for you to resist tempting cues and thus make good on your decision. The team says that trying to hold information in our memory also produces this effect, the first time this link has been demonstrated.

Self-control

“We knew already that participants find it hard to ignore cues that signal a large reward,” says study lead Dr. Poppy Watson at UNSW.

“We have a set of control resources that are guiding us and helping us suppress these unwanted signals of reward. But when those resources are taxed, these become more and more difficult to ignore.”

Researchers refer to the cognitive processes that allow us to pay attention, organize our life, focus, or regulate our emotions as ‘executive control’. It wasn’t yet clear whether our ability or inability to ignore reward cues (i.e. temptation) was related to executive control or a separate ability, but the present research suggests that the former is true: executive control processes are employed to keep us from distractions or temptations. However, the findings also show that these resources are limited.

“Now that we have evidence that executive control processes are playing an important role in suppressing attention towards unwanted signals of reward, we can begin to look at the possibility of strengthening executive control as a possible treatment avenue for situations like addiction,” says Dr. Watson.

For the study, the team had participants look at a screen on which various shapes — including a colorful circle — were being displayed. Their task was to locate and look at a diamond shape on the screen, and if successful, they’d be given money. However, if they looked at the colored circle — which played the part of the distraction/temptation — they wouldn’t receive money. To make things even harder, participants were told that the presence of a blue circle on-screen meant that they’d be paid more if they successfully completed the diamond task than if an orange circle was shown.

The team tracked where each participant was looking using eye-tracking technology. The team ran a low-memory load and a high-memory load version of the experiment. In the high-memory load version, the participants were also asked to memorize a sequence of numbers while performing the larger task. This set-up was used to further draw from the participants’ cognitive resources and to see how this impacted their ability to perform the diamond task.

Hot Dogs.

Image via Pixabay.

“Study participants found it really difficult to stop themselves from looking at cues that represented the level of reward — the coloured circles — even though they were paid to try and ignore them,” Dr. Watson says.

“Crucially, the circles became harder to ignore when people were asked to also memorize numbers: under high memory load, participants looked at the coloured circle associated with the high reward around 50% of the time, even though this was entirely counterproductive.”

The findings suggest that people need access to either full or at least a sizeable chunk of their cognitive control processes to successfully block distractions or temptations from the environment. This mechanism, ironically, seems to make it harder to ignore cues regarding habits or behaviors you want to change — because you’re paying attention to changing them specifically. This might also explain why people find it harder to focus on dieting or beating an addiction if they are under a lot of stress.

“There’s this strong known link between where your attention is and what you eventually do, so if you find it hard to focus your attention away from reward cues, it’s even harder to act accordingly,” says Dr. Watson. “Constant worrying or stress is the equivalent to the high-memory load scenario of our experiment, impacting on people’s ability to use their executive control resources in a way that’s helping them manage unwanted cues in the environment.”

The team wants to see if executive control can be strengthened and if that can be used in the context of drug rehabilitation.

The paper “Capture and Control: Working Memory Modulates Attentional Capture by Reward-Related Stimuli” has been published in the journal Psychological Science.

Driver sleeping.

Your car’s vibrations are making you a lousier driver — by lulling you to sleep

Just 15 minutes in a car makes us sleepier, affecting our ability to drive. After 30 minutes, this effect has a “significant impact on your ability to stay concentrated and alert,” researchers warn.

Driver sleeping.

Image via Pexels.

According to a new paper published by researchers from RMIT University in Melbourne, Australia, cars themselves may be a significant threat against our ability to drive safely — some 20% of fatal car accidents today involve driver fatigue, they explain, and, according to their research, the vibrations we experience in cars makes us sleepier, posing a major risk for motorists everywhere.

Snooze cruise

“We know 1 in 5 Australians have fallen asleep at the wheel and we know that drowsy driving is a significant issue for road safety,” said Professor Stephen Robinson, paper co-author. “When you’re tired, it doesn’t take much to start nodding off and we’ve found that the gentle vibrations made by car seats as you drive can lull your brain and body.

The team worked with 15 volunteers who were placed in a virtual driving simulator. The test pitted each participant against a monotonous, two-lane highway. It wasn’t the actual driving experience that was central to this experiment, however — what the team wanted to see was what effect car vibrations have on the volunteers’ alertness levels.

The simulator was installed on a platform that could vibrate on different frequencies. Each volunteer was tested twice, using the same 60-minute driving scenario, once with vibrations at low frequencies (4-7 Hz, the same range you’d experience in a car) and once with no vibrations (as a control test).

To gauge participants’ alertness, the team monitored their heartbeat. The researchers explain that tiredness induced by vibration makes it harder, both psychologically and physiologically, for people to perform mental tasks. In order to compensate, the body’s sympathetic nervous system alters the rate with which our hearts beat. So, by looking at each volunteer’s heart rate variability (HRV), researchers were able to gain an objective measure of how drowsy they were feeling as the test progressed.

Driving simulator.

The simulator rig used in the study.
Image credits RMIT University.

During the vibrating test, volunteers started showing signs of drowsiness roughly 15 minutes in. By the 30 minute mark, they showed significant drowsiness and required substantial effort to maintain alertness and cognitive performance. The effect was progressively stronger as the test drew on, peaking at 60 minutes.

Co-author Mohammad Fard, an Associate Professor at RMIT, said that the results warrant further research into the effect of these vibrations on people. One of the first areas that should be investigated is whether their effect is consistent across different demographics, he adds — as the current experiment used a relatively tiny sample size.

“We want to study a larger cohort, particularly to investigate how age may affect someone’s vulnerability to vibration-induced drowsiness as well as the impact of health problems such as sleep apnea,” he said. “Our research also suggests that vibrations at some frequencies may have the opposite effect and help keep people awake.

“So we also want to examine a wider range of frequencies, to inform car designs that could potentially harness those ‘good vibrations’.”

“To improve road safety, we hope that future car seat designs can build in features that disrupt this lulling effect and fight vibration-induced sleepiness,” added Robinson.

The paper “The Effects of Physical Vibration on Heart Rate Variability as a Measure of Drowsiness,” has been published in the journal Ergonomics.