A timely study in the journal Human Factors suggests why texting while driving is riskier than talking on a cell phone or with another passenger. Human factors/ergonomics researchers at the University of Utah found that texters in a driving simulator had more crashes, responded more slowly to brake lights on cars in front of them, and showed impairment in forward and lateral control than did drivers who talked on a cell phone while driving or drove without texting.

Researchers Frank Drews and colleagues found evidence that attention patterns differ for drivers who text versus those who converse on a cell phone. In the latter case, the researchers say, "drivers apparently attempt to divide attention between a phone conversation and driving, adjusting the processing priority of the two activities depending on task demands." But texting requires drivers to switch their attention from one task to the other. When such attention-switching occurs as drivers compose, read, or receive a text, their overall reaction times are substantially slower than when they're engaged in a phone conversation. The type of texting activity also appears to make a difference; in this study, reading messages affected braking times more than did composing them.

The hazards of texting while driving continue to receive broad national and international attention as accident rates attributed to this practice increase. As a result, a growing number of U.S. cities and states, as well as Canadian provinces, ban texting while operating a vehicle. Drews et al. noted that according to CTIA (www.ctia.org), more than 1 trillion text messages were sent in 2008 in the United States alone. To find why and how much drivers are impaired during texting, the researchers engaged 20 men and 20 women between the ages of 19 and 23 in both a single task (straight driving) and a dual task (driving and texting) in a high-fidelity simulator. The participants, experienced texters with an average of 4.75 years of driving experience, received and sent messages while the researchers observed their brake onset time, following distance, lane maintenance, and collisions.

The crash risk attributable to texting is substantial. One possible explanation is that drivers who text tend to decrease their minimum following distance and also experience delayed reaction time. For example, in the Drews et al. study, drivers' median reaction time increased by 30 percent when they were texting and 9 percent when they talked on the phone, compared with their performance in a driving-only condition.

Religious people tend to use their own beliefs as a guide in thinking about what God believes, but are less constrained when reasoning about other people's beliefs, according to new study published in the Nov. 30 early edition of the Proceedings of the National Academy of Sciences.

Nicholas Epley, professor of behavioral science at the University of Chicago's Booth School of Business, led the research, which included a series of survey and neuroimaging studies to examine the extent to which people's own beliefs guide their predictions about God's beliefs. The findings of Epley and his co-authors at Australia's Monash University and UChicago extend existing work in psychology showing that people are often egocentric when they infer other people's beliefs.

The PNAS paper reports the results of seven separate studies. The first four include surveys of Boston rail commuters, UChicago undergraduate students and a nationally representative database of online respondents in the United States. In these surveys, participants reported their own belief about an issue, their estimated God's belief, along with a variety of others, including Microsoft founder Bill Gates, Major League Baseball's Barry Bonds, President George W. Bush, and an average American.

Two other studies directly manipulated people's own beliefs and found that inferences about God's beliefs tracked their own beliefs. Study participants were asked, for example, to write and deliver a speech that supported or opposed the death penalty in front of a video camera. Their beliefs were surveyed both before and after the speech.

The final study involved functional magnetic resonance imaging to measure the neural activity of test subjects as they reasoned about their own beliefs versus those of God or another person. The data demonstrated that reasoning about God's beliefs activated many of the same regions that become active when people reasoned about their own beliefs.

The researchers noted that people often set their moral compasses according to what they presume to be God's standards. "The central feature of a compass, however, is that it points north no matter what direction a person is facing," they conclude. "This research suggests that, unlike an actual compass, inferences about God's beliefs may instead point people further in whatever direction they are already facing."

But the research in no way denies the possibility that God's presumed beliefs also may provide guidance in situations where people are uncertain of their own beliefs, the co-authors noted.

A study in the Dec.1 issue of the journal Sleep shows that short, unpleasant, dreamlike mental activity occurs during sleepwalking and sleep terrors episodes, suggesting that people with these sleep disorders may be acting out dreamlike thoughts.

Results show that 71 percent of participants reported at least one incident of dreamlike mental content associated with an episode of sleepwalking or sleep terrors, and the action in the dreamlike thoughts corresponded with the observed behavior. A total of 106 reports of dreamlike mental activity were collected; the mental content was brief, with 95 percent of the reports involving a single visual scene. These dreamlike thoughts were frequently unpleasant, with 84 percent involving apprehension, fear or terror; 54 percent involving misfortune, in which injury, mishap or adversity occurred through chance or environmental circumstances; and 24 percent involving aggression, with the dreamer always being the victim. Compared with healthy controls, patients with sleepwalking and sleep terrors reported more severe daytime sleepiness and had four times as many arousals from slow-wave sleep.

Principal investigator Isabelle Arnulf, MD, PhD, neurologist and head of the sleep disorders unit at Unité des Pathologies du Sommeil at Hôpital Pitié-Salpêtrière in Paris, France, said that it has been widely believed that dreams do not occur during sleepwalking and sleep terrors events. However, previous studies focused mostly on children rather than adults.

"The results are surprising, as it is commonly reported that sleepwalkers and patients with sleep terrors do not remember dreaming," said Arnulf. "Adults involved in the study who experienced sleepwalking and sleep terrors were less confused during the episode than children, making it easier to express their dream mentations."

According to the AASM, sleepwalking and sleep terrors typically occur during arousals from slow-wave sleep and are classified as "parasomnias," which are undesirable events or experiences that occur during entry into sleep, within sleep or during arousals from sleep. Sleepwalking occurs when a person gets out of bed and walks around with an altered state of consciousness and impaired judgment. An episode of sleep terrors occurs when a person sits up in bed with a look of intense fear, often making a cry or piercing scream.

Forty-three patients with severe, frequent, dangerous or disturbing episodes of sleepwalking or sleep terrors participated in the study and were matched with 25 healthy control subjects. The mean age of patients was 26 years with a range from 11 to 72 years, and 46 percent were male. Five patients suffered exclusively from sleep terrors, eight subjects suffered from sleepwalking only and 30 experienced both sleepwalking and sleep terrors.

Data were gathered retrospectively by interview, so that the dreamlike thoughts that were collected covered a lifetime span for each patient. Thirty-eight patients (88 percent) were able to reliably answer questions about their mental content during the sleepwalking and sleep terrors episodes. Sleep also was monitored during one night in a laboratory.

For a long time rapid eye movement (REM) sleep has been considered to be the neurobiological basis of dreaming, the authors noted. Although complex mental activity has been reported in non-REM sleep during slow-wave sleep, the extent to which the reported dreamlike thoughts may be described as "dreaming" is still debated.

The authors suggested that the brief, dreamlike activity occurring during sleepwalking and sleep terrors could be either the terminal part of a longer dream that is forgotten at the time of arousal, or a short mental creation elicited before or just at the time of arousal.