Nav: Home

Multitasking is hardest in the early morning

May 04, 2007

Multitasking seems to come easier for some and is virtually impossible for others, however new research shows that it is difficult for all in the late night and early morning.

Previous studies have shown that the time of day greatly affects human's reaction time (for a review, see Carrier & Monk, 2000). This performance decrement is constantly found during the night with its' lowest point in the early morning. This leads to the assumption that the time of day directly affects the speed of cognitive processing.

Daniel Bratzke at the University of Tuebingen wished to take these studies a bit further and figure out what makes our reaction time so slow during the wee hours. While many researchers have studied this, Bratzke focused on one of the three stages of human processing because he argues that measuring overall reaction time does not allow researchers to separate the effects of three different processing stages. Bratzke describes, for example, that the stage models of human performance assume at least three distinct processing stages: early perceptual, central decisional and late motor. He writes, "Given this widely accepted view, the question arises whether time of day affects all processing stages in general or one or more stages selectively."

There is evidence that the circadian variations in reaction time are at least partly due to changes in two of the processing stages; in the early perceptual stage for example, it takes longer to detect and identify a visual stimulus if you are tired. Likewise, manual dexterity, grip strength, and tapping, which assess motor ability, are susceptible to our circadian rhythm, with a low point in the morning and peak in the late evening.

Bratzke wished to localize the time-of-day effects on processes that occur during the central decisional stage, such as decision-making. Along with his colleagues, he hypothesized that reaction time performance decrements during the night might be associated with slowing of this central processing stage. They refer to this as the central-slowing hypothesis.

Bratzke observed six subjects during 28 hours of constant wakefulness. During this time, the subjects performed various cognitive tasks every two hours. Bratzke used a dual-task performance test (psychological refractory period paradigm) to assess the duration of the central processing stage with two stimuli introduced at different times. The results provided evidence for a circadian modulation on reaction time with a constant decrement in the late evening while reaching it's lowest point in the early morning. Importantly, dual-task interference increased in the night and early morning as well. Thus, central processing slowed down during the night, a result that supports the central-slowing hypothesis.

It is important to note that Bratzke monitored circadian phases through salivary melatonin concentration and body temperature. These biological markers of circadian phases corresponded with the decrement in reaction time, telling us that sleep deprivation was not the only moderator in the performance decrement.

These results build upon a recent study showing that even the well-practiced simple task of vehicle braking is subject to dual-task slowing. When watching the car brake in front of you while processing another stimulus concurrently the braking response can be markedly slowed down. The present results suggest that dual-task slowing as e.g. in this driving situation is influenced by the time of day with the most pronounced slowing in the early morning. Bratzke writes, "in addition to sleepiness, a combination of slowed reactions and impaired central efficiency might contribute to impaired driving performance and a higher risk for traffic accidents in the early morning."
-end-
Author Contact: Daniel Bratzke daniel.bratzke@uni-tuebingen.de

Psychological Science is ranked among the top 10 general psychology journals for impact by the Institute for Scientific Information. For a copy of the article "Central Slowing During the Night" and access to other Psychological Science research findings, please contact Catherine West at (202) 783-2077 or cwest@psychologicalscience.org.

Bratzke completed this research with within the interdisciplinary network "ClockWORK" www.clock-work.org which is funded by the Gottlieb Daimler- und Karl Benz-Stiftung.

Association for Psychological Science

Related Circadian Rhythm Articles:

Japanese children learn to write through rhythm
How do we learn to write? A Japanese study looked at the development of writing skills in Japanese first-grade students, and revealed aspects of handwriting development that have been largely neglected in research carried out in Latin alphabet communities.
How circadian clocks communicate with each other
Multiple biological clocks control the daily rhythms of physiology and behavior in animals and humans.
Your brain's got rhythm
Salk scientists create synthetic brain systems called 'circuitoids' to better understand dysfunctional movements in Parkinson's, ALS and other diseases.
The rhythm that makes memories permanent
Every time we learn something new, the memory does not only need to be acquired, it also needs to be stabilized in a process called memory consolidation.
Rhythm of breathing affects memory and fear
Scientists have discovered for the first time that the rhythm of breathing creates electrical activity in the human brain that enhances emotional judgments and memory recall.
How the liver dances to a day/night rhythm
Following the day-night cycle, the liver has its own metabolic rhythm.
Technology brings new precision to study of circadian rhythm in individual cells
A new technology may help scientists better understand how an individual cell synchronizes its biological clock with other cells.
Feeling the rhythm
The Circadian Rhythms investigation examines whether long-term spaceflight throws off circadian rhythm in astronauts and the role of factors such as irregular light and dark cycles, microgravity induced changes in body composition, and reduced physical activity.
Fat tissue shows a robust circadian rhythm in a dish
In The Journal of the Federation of American Societies for Experimental Biology: Demonstrating that human subcutaneous adipose tissue shows a circadian rhythm in insulin sensitivity in a dish.
Powering up the circadian rhythm
Salk team first to discover protein that controls the strength of body's circadian rhythms.

Related Circadian Rhythm Reading:

Circadian Rhythms: A Very Short Introduction (Very Short Introductions)
by Russell Foster (Author), Leon Kreitzman (Author)

The earth's daily rotation affects just about every living creature. From dawn through to dusk, there are changes in light, temperature, humidity, and rainfall. However, these changes are regular, rhythmic and, therefore, predictable. Thus, the near 24 hour circadian rhythm is innate: a genetically programmed clock that essentially ticks of its own accord.

This Very Short Introduction explains how organisms can "know" the time and reveals what we now understand of the nature and operation of chronobiological processes. Covering variables such as light, the metabolism, human... View Details


Rhythms of Life: The Biological Clocks that Control the Daily Lives of Every Living Thing
by Russell G. Foster (Author), Leon Kreitzman (Author)

Why can’t teenagers get out of bed in the morning? How do bees tell the time? Why do some plants open and close their flowers at the same time each day? Why do so many people suffer the misery of jet lag? In this fascinating book, Russell Foster and Leon Kreitzman explain the significance of the biological clock, showing how it has played an essential role in evolution and why it continues to play a vitally important role in all living organisms.

The authors tell us that biological clocks are embedded in our genes and reset at sunrise and sunset each day to link astronomical time... View Details


Reset Your Inner Clock: The Drug-Free Way to Your Best-Ever Sleep, Mood, and Energy
by Michael Terman Ph.D. (Author), Ian McMahan Ph.D. (Author)

Sleep problems and depressed mood go hand in hand, forming a frustrating cycle. Michael Terman has analyzed the brain functions that feed these disorders. In Reset Your Inner Clock, he reveals the heart of his findings, a powerful program that recalibrates our internal clocks--our exquisitely designed sensitivity to the timing and brightness of light exposure. He shows how these need to be tuned to the modern demands of a 24/7 society.

Beginning with a questionnaire that pinpoints the problem areas, Terman helps readers decipher when their natural internal night begins and... View Details


Circadian Rhythms: Below Our Awareness
by Choice PH

Circadian rhythms are physical, mental and behavioral changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in an organism's environment. They are found in most living things, including animals, plants and many tiny microbes.

Circadian rhythms are not the same thing as biological clocks, but they are closely related. In this eBook we discuss how our biological clocks drive our circadian rhythm and how circadian rhythms affect our sleep patterns. View Details


Sleep, Circadian Rhythms, and Metabolism: The Rhythm of Life
by William Olds (Editor)

This title includes a number of Open Access chapters.

Providing a nuanced study of the connections between sleep, circadian rhythms, and metabolis, this informative book examines how circadian actions affect the liver and adipose tissue, the brain, and metabolism. This important book introduces the reader to circadian rhythms in the body and the external cues that set them, discusses on a molecular and organ level how disrupting these clocks results in metabolic and sleep disorders, and looks at the clinical applications of circadian rhythms, with a focus on sleep.

... View Details


Circadian Rhythm
by Mr. Robert Scott Morris (Author), Mr. R. Scott Morris (Author)

Circadian Rhythm is the name of a boat that was the vehicle for many summers of rollicking good times for a group of blue-collar yachtsmen. This book describes these adventures and provides the reader with a glimpse of the champagne life style on a beer budget. The intrepid crew of Circadian Rhythm could barely make the month's payment on the boat, but still managed to bang heads with the "blue-bloods" of the New England sailing world and come out ahead. This book is for the arm chair sailor and active sailor who enjoy a good yarn with a few chuckles mixed in. View Details


You Are Getting Sleepy: Lifestyle-Based Solutions for Insomnia
by Paul Glovinsky PhD (Author), Arthur Spielman PhD (Author)

For readers enticed by Arianna Huffington's The Sleep Revolution but looking for the medical evidence to support its claims, two doctors have incorporated the latest research into a guide designed to help insomniacs get sleepy.

"For insomniacs who don't want a cosmetic solution, this guide digs deeper, and is likely to get better, more permanent results." ―Kirkus Reviews on The Insomnia Answer

Good sleep is an elusive goal: the harder you try to fall asleep, the less likely you are to be successful. Insomnia is stoked by different habits,... View Details


Circadian Medicine
by Christopher S. Colwell (Author)

Circadian rhythms, the biological oscillations based around our 24-hour clock, have a profound effect on human physiology and healthy cellular function. Circadian Rhythms: Health and Disease is a wide-ranging foundational text that provides students and researchers with valuable information on the molecular and genetic underpinnings of circadian rhythms and looks at the impacts of disruption in our biological clocks in health and disease.

Circadian Rhythms opens with chapters that lay the fundamental groundwork on circadian rhythm biology. Section II looks at the... View Details


Chronotherapy: Resetting Your Inner Clock to Boost Mood, Alertness, and Quality Sleep
by Michael Terman Ph.D. (Author), Ian McMahan Ph.D. (Author)

An enlightened approach to insomnia, depressed mood, fatigue, and other sleep-related problems of everyday life, harnessing the power of light therapy to reset the natural clock.

Sleep problems and depressed mood often go hand in hand, forming a frustrating cycle. Michael Terman, PhD, has devoted his career to studying the brain functions that feed these disorders. His discoveries in chronotherapy have been widely recognized as game-changers by the medical establishment, and his 2010 New York Times op-ed, “Sleeping (or Not) by the Wrong Clock,” shot to number one on... View Details


The Circadian Prescription: Get in Step with Your Body's Natural Rhythms
by Sidney MacDonald Baker (Author), Karen Baar (Author)

Provides a dietary and lifestyle program designed to enhance the body's natural rhythms for optimum health, offering a ten-point program to improve sleep, prevent or treat disease, increase energy, enhance mental abilities, and achieve ideal weight. 25,000 first printing. View Details

Best Science Podcasts 2017

We have hand picked the best science podcasts for 2017. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Simple Solutions
Sometimes, the best solutions to complex problems are simple. But simple doesn't always mean easy. This hour, TED speakers describe the innovation and hard work that goes into achieving simplicity. Guests include designer Mileha Soneji, chef Sam Kass, sleep researcher Wendy Troxel, public health advocate Myriam Sidibe, and engineer Amos Winter.
Now Playing: Science for the People

#448 Pavlov (Rebroadcast)
This week, we're learning about the life and work of a groundbreaking physiologist whose work on learning and instinct is familiar worldwide, and almost universally misunderstood. We'll spend the hour with Daniel Todes, Ph.D, Professor of History of Medicine at The Johns Hopkins University, discussing his book "Ivan Pavlov: A Russian Life in Science."