Primate Behavior: Chimps Select Smart Tools, Monkeys Intentionally Beg

ScienceDaily (July 18, 2012) — Chimpanzees use weight to pick the best tool, and monkeys beg more when they’re paid attention to, as reported in two independent research reports published July 18 in the open access journal PLoS ONE.

In the chimp study, researchers found that the chimpanzees used weight to choose the best hammer to crack open nuts. Nut cracking is one of the most sophisticated instances of tool use in chimpanzees, and learning how to do it has been shown to be very difficult for some chimps. In work led by Cornelia Schrauf of the University of Vienna, the researchers showed that the chimps were able to choose the best tool to crack nuts based solely on the weight of the tool. Schrauf notes, “Experience clearly affected the subjects´ attentiveness to the relevant tool properties. Whereas the most skilled chimpanzee showed a preference for the most efficient hammers from the early beginning of the experiment, the unskilled individuals became selective over time.”

In another study, old world monkeys called Mangabeys were shown to modulate their begging behavior based on whether the experimenter was paying attention to them. The monkeys were trained to make “requesting gestures,” and the researchers, led by Audrey Maille of the University of Rennes 1 in France, found that the monkeys gestured more and faster when the experimenter’s body and head were facing the monkey than when they were oriented away. The monkeys did not modulate their behavior simply based on the direction of the experimenter’s gaze, though.

Maille explains, “Our study deals with…whether functional similarities may be found between human language and nonhuman primates communication. By investigating the flexibility of gestures production, we showed that old world monkeys, and not only great apes, may use communicative signals intentionally.”


Journal References:

  1. Maille A, Engelhart L, Bourjade M, Blois-Heulin C. To Beg, or Not to Beg? That Is the Question: Mangabeys Modify Their Production of Requesting Gestures in Response to Human’s Attentional States. PLoS ONE, 2012; 7 (7): e41197 DOI: 10.1371/journal.pone.0041197
  2. Schrauf C, Call J, Fuwa K, Hirata S. Do Chimpanzees Use Weight to Select Hammer Tools? PLoS ONE, 2012; 7 (7): e41044 DOI: 10.1371/journal.pone.0041044


Public Library of Science (2012, July 18). Primate behavior: Chimps select smart tools, monkeys intentionally beg. ScienceDaily. Retrieved July 19, 2012, from­ /releases/2012/07/120718192005.htm


Dopamine: A Substance With Many Messages

ScienceDaily (July 16, 2012) — Children quickly learn to avoid negative situations and seek positive ones. But humans are not the only species capable of remembering positive and negative events; even the small brain of a fruit fly has this capacity. Dopamine-containing nerve cells connected with the mushroom body of the fly brain play a role here. Scientists from the Max Planck Institute of Neurobiology in Martinsried have identified four different types of such nerve cells. Three of the nerve cell types assume various functions in mediating negative stimuli, while the fourth enables the fly to form positive memories.

From earliest childhood we learn to avoid things that harm us and seek positive experiences instead. Aversive memory is created by experiences like pricking our finger on a rose thorn, which we remember for a long time. Conversely, the smell of fresh food is positively associated with a feeling of satiety and creates a reward memory.

Hiromu Tanimoto and his colleagues at the Max Planck Institute of Neurobiology recently localised and identified the most important types of nerve cells involved in forming positive and negative memories of a fruit fly. All four nerve cell types they discovered use dopamine to communicate with other nerve cells. The dopamine signals released by these cells are received in the mushroom body, a prominent brain structure in insect brains. “It is really surprising that similar dopamine-releasing nerve cells can play such different roles,” says Tanimoto.

The scientists investigate the functions of the individual nerve cell types in two separate studies. In the process of learning avoidance strategies, the flies were presented with an odour that was associated with a negative stimulus, a foot shock. As a result, the flies learned to avoid this odour in future.

In the next round of experiments, the scientists replaced the shock with artificial activation of defined sets of nerve cells during an odour presentation. They discovered that the transient activation of these nerve cells alone is sufficient to signal aversive stimulus in the fly brain and lead to the formation of an aversive odour memory — even when no real aversive stimulus is present.

The scientists were also able to demonstrate that the three types of nerves cells that are responsible for the memory of punishment fulfil different functions. A major difference here is the stability of the induced memories. One of the cell types is responsible for the long-lasting memory, while memories formed by other dopamine cells are short-lived. “Punishing events induce aversive memories with different stabilities by combining distinct dopamine cells in the fly brain” explains Tanimoto.

The same method was employed to demonstrate that another set of dopamine cells signals reward to form positive odour memory. When these cells were artificially activated, the flies remembered the smell and tried to get to the source of the odour even in the absence of sugar reward. The scientists proved that specific dopamine neurons also play a key role in this process.

The messenger substance dopamine is not only significant for fruit flies and other insects. Particularly, it is also needed for reward-based learning in humans. These new discoveries suggest that functional diversity of dopamine is a highly conserved mechanism in brains.


Journal References:

1. Chang Liu, Pierre-Yves Plaçais, Nobuhiro Yamagata, Barret D. Pfeiffer, Yoshinori Aso, Anja B. Friedrich, Igor Siwanowicz, Gerald M. Rubin, Thomas Preat, Hiromu Tanimoto. A subset of dopamine neurons signals reward for odour memory in Drosophila. Nature, 2012; DOI: 10.1038/nature11304

2. Yoshinori Aso, Andrea Herb, Maite Ogueta, Igor Siwanowicz, Thomas Templier, Anja B. Friedrich, Kei Ito, Henrike Scholz, Hiromu Tanimoto. Three Dopamine Pathways Induce Aversive Odor Memories with Different Stability. PLoS Genetics, 2012; 8 (7): e1002768 DOI: 10.1371/journal.pgen.1002768


Max-Planck-Gesellschaft (2012, July 16). Dopamine: A substance with many messages. ScienceDaily. Retrieved July 19, 2012, from­ /releases/2012/07/120718131355.htm



Researcher Calls for Global Action On Pandemic of Physical Inactivity

ScienceDaily (July 18, 2012) — The high prevalence and consequences of physical inactivity should be recognized as a global pandemic, according to a new publication by Harold W. Kohl, III, Ph.D., professor of epidemiology at The University of Texas School of Public Health, part of The University of Texas Health Science Center at Houston (UTHealth).


“Physical inactivity continues to be undervalued among people who can make a difference despite evidence of its health benefits and the evident cost burden posed by present levels of physical inactivity globally,” said Kohl, who is also with the Michael & Susan Dell Center for Healthy Living at the UT School of Public Health.

The paper is the fifth and final paper in The Lancet “Series on Physical Activity” published this week and outlines key strategies and resources needed to make physical activity a global public health priority. “This series emphasizes the need to focus on population physical activity levels as an outcome, not just decreasing obesity,” said Kohl, professor of kinesiology at The University of Texas at Austin.

The health burden of physical inactivity is substantial, according to Kohl. “Although regular physical activity is critical for weight control, it is equally or more important for lowering risk of many different chronic diseases such as heart disease, some cancers, osteoporosis and diabetes.”

According to Kohl, research on physical activity needs to be its own priority within public health research of non-communicable diseases.

Globally nearly one-third of persons 15 and over were insufficiently active in 2008 and approximately 3.2 million deaths each year are attributable to insufficient physical activity, according to the World Health Organization. In 2008, the prevalence of insufficient physical activity was highest in the Americas and Eastern Mediterranean regions.

In the paper, the researchers argue for increased prioritizing of physical activity across multiple sectors of influence including health, transportation, sports, education and business. “This issue is of particular importance in countries with low-to-middle incomes, where rapid economic and social changes are likely to reduce the domestic, work and transport-related physical activity demands of daily life,” said Kohl. “Improved understanding of what works best in these nations will be key to developing national policies and action plans.

Kohl recommends a multi-sector and systems-wide approach to physical activity promotion to increase population levels of activity worldwide rather than efforts focused on individual health. “Traditional approaches, where responsibility for change has resided with the health sector, will not be sufficient,” said Kohl. “Improvements must happen at every level including planning and policy, leadership and advocacy and workforce training.”

In 2008, 25.4 percent of U.S. adults reported no leisure time physical activity, according to the Centers for Disease Control and Prevention (CDC). County estimates of leisure-time physical inactivity range from 10.1 percent to 43 percent in the United States. These rates reflect adults who report no physical activity or exercise other than at their regular job.

“The response to physical inactivity has been incomplete, unfocused, understaffed and underfunded compared with other risk factors for non-communicable diseases,” said Kohl. “This has put physical activity in reverse gear compared with population trends and advances in tobacco and alcohol control and diet.”

Kohl said Texas is one of a few states that have a plan to promote physical activity, Active Texas 2020. He led the development of the plan with the Governor’s Advisory Council on Physical Fitness. The Active Texas plan includes strategies and ideas that can be used by communities throughout the state.

“Physical education in schools is still one of the most effective means promoting physical activity, particularly among children,” said Kohl. Texas Education Code requires elementary school students to receive at least 30 minutes of daily physical activity and 225 minutes of physical activity per two weeks for four of six semesters for middle school students.

Kohl was recently appointed to lead the Institute of Medicine’s committee on Physical Activity and Physical Education in the School Environment. He is on the President’s Council of Fitness, Sports & Nutrition Science Board. Kohl also led development of the 2008 U.S. Physical Activity Guidelines.


Journal Reference:

  1. Harold W Kohl, Cora Lynn Craig, Estelle Victoria Lambert, Shigeru Inoue, Jasem Ramadan Alkandari, Grit Leetongin, Sonja Kahlmeier. The pandemic of physical inactivity: global action for public health. The Lancet, 2012; DOI: 10.1016/S0140-6736(12)60898-8


University of Texas Health Science Center at Houston (2012, July 18). Researcher calls for global action on pandemic of physical inactivity. ScienceDaily. Retrieved July 19, 2012, from­ /releases/2012/07/120718112055.htm

Do Dolphins Think Nonlinearly?

ScienceDaily (July 18, 2012) — Research from the University of Southampton, which examines how dolphins might process their sonar signals, could provide a new system for human-made sonar to detect targets, such as sea mines, in bubbly water.

When hunting prey, dolphins have been observed to blow ‘bubble nets’ around schools of fish, which force the fish to cluster together, making them easier for the dolphins to pick off. However, such bubble nets would confound the best human-made sonar because the strong scattering by the bubbles generates ‘clutter’ in the sonar image, which cannot be distinguished from the true target.

Taking a dolphin’s sonar and characterising it from an engineering perspective, it is not superior to the best human-made sonar. Therefore, in blowing bubble nets, dolphins are either ‘blinding’ their echolocation sense when hunting or they have a facility absent in human-made sonar.

The study by Professor Tim Leighton, from the University’s Institute of Sound and Vibration Research (ISVR), and colleagues examined whether there is a way by which dolphins might process their sonar signals to distinguish between targets and clutter in bubbly water.

In the study, published in Proceedings of the Royal Society A, Professor Leighton along with Professor Paul White and student Gim Hwa Chua used echolocation pulses of a type that dolphins emit, but processed them using nonlinear mathematics instead of the standard way of processing sonar returns. This Biased Pulse Summation Sonar (BiaPSS) reduced the effect of clutter by relying on the variation in click amplitude, such as that which occurs when a dolphin emits a sequence of clicks.

Professor Leighton says: “We know that dolphins emit sequences of clicks and the amplitude of each click can vary from one to the next, so that not all the clicks are the same loudness. We asked, what if this variation in amplitude was not coincidental, but instead was key to distinguishing fish from bubbles.

“These clicks were shown to identify targets when processed using nonlinear mathematics, raising the question of whether dolphins also benefit from such mathematics. The variation in amplitude of these clicks is the key: it produces changes in the echoes which can identify the target (fish) in the bubble net, where human-made sonar does not work.

“Although this does not conclusively prove that dolphins do use such nonlinear processing, it demonstrates that humans can detect and classify targets in bubbly water using dolphin-like sonar pulses, raising intriguing possibilities for dolphin sonar when they make bubble nets.”

BiaPSS was shown to be effective in distinguishing targets from the clutter generated by bubbles in the ‘field of view’ of the sonar. One such target is a sea mine, which is relatively simple to purchase, and inexpensive (around $1,000 each) compared to the financial damage (let alone injury and loss of life) that they cause (for example $96 million repair to USS Samuel B Roberts; $24 million repair to USS Princeton; $3.6 million to USS Tripoli).

Professor Leighton adds: “There are still questions to answer. For one thing, dolphins would have to use a frequency, when they enter bubbly water, which is sufficiently low that they can hear up to frequencies twice as high in pitch. Until measurements are taken of wild dolphin sonar as they hunt in bubbly water, these questions will remain unanswered. What we have shown is that it is not impossible to distinguish targets in bubbly water using the same sort of pulses that dolphins use.”

The authors previously proposed a form of sonar signal (TWIPS: Twin Inverted Pulse Sonar) that could work in bubble clouds, consisting of pairs of pulses that were identical except that one was inverted with respect to the other, that could detect targets in bubbly water if the signal processing were to make use of nonlinear mathematics. However, while these TWIPS pulses were successful, there was no conclusive evidence that the types of pulses devised for that study are used by any type of dolphin.


Journal Reference:

  1. T. G. Leighton, G. H. Chua And P. R. White. Do dolphins benefit from nonlinear mathematics when processing their sonar returns? Proceedings of the Royal Society A, 2012 DOI: 10.1098/rspa.2012.0247


University of Southampton (2012, July 18). Do dolphins think nonlinearly?. ScienceDaily. Retrieved July 19, 2012, from­ /releases/2012/07/120718090627.htm

Actions Don’t Always Speak Louder Than Words, at Least, Not When It Comes to Forgiveness

ScienceDaily (July 18, 2012) — People are more likely to show forgiving behavior if they receive restitution, but they are more prone to report they have forgiven if they get an apology, according to Baylor University research published in the Journal of Positive Psychology.

The study underscores the importance of both restitution and apology and of using multiple measures for forgiveness, including behavior, said Jo-Ann Tsang, Ph.D., an associate professor of psychology and neuroscience in Baylor’s College of Arts & Sciences.

“One of the main reasons for using behavioral measures in addition to self-reporting by individuals is that they can make themselves look better by only self-reporting, although they don’t necessarily intend to lie,” she said. “And it may be that ‘I forgive you’ is a more conscious feeling if they receive an apology.”

In the study, 136 undergraduate psychology students were stationed in individual cubicles and told that raffle tickets for a $50 gift card would be given out in three rounds, with 10 tickets per round to be divided between a participant and a unknown “partner.” They also were told they might receive a note from the partner.

In the first round, participants were given only two of the 10 tickets split between them and their partners; in the second, they got nine. Some were told the distributions were made by the partner; others were told it was by chance.

Some participants received an apology note from their partners on the second round, saying, “Sorry about that first round. I got carried away, and I feel really bad that I did that.” Some participants also received raffle tickets back from their partners in the second round, a form of restitution. In the last round, the participants were given the chance to be in charge of distributions themselves.

Researchers examined the links between apology, restitution, empathy and forgiveness, measuring forgiveness in two ways: Through behavior (how many raffle tickets participants gave to their partners on the third round); and self-reporting on a questionnaire, with participants telling how highly they rated their motivation to forgive.

Researchers wrote that “making amends can facilitative forgiveness, but not all amends can fully compensate for offenses.” Apology may be needed to repair damage fully, but it may be a “silent forgiveness,” while restitution without apology may lead to a “hollow forgiveness” in which the offenders are treated better but not necessarily forgiven.

“The results suggest that if transgressors seek both psychological and interpersonal forgiveness from their victims, they must pair their apologies with restitution,” they wrote. “Apparently, actions and words speak loudest in concert.”


Journal Reference:

  1. Robert D. Carlisle, Jo-Ann Tsang, Nadia Y. Ahmad, Everett L. Worthington, Charlotte vanOyen Witvliet, Nathaniel Wade. Do actions speak louder than words? Differential effects of apology and restitution on behavioral and self-report measures of forgiveness. The Journal of Positive Psychology, 2012; 7 (4): 294 DOI: 10.1080/17439760.2012.690444


Baylor University (2012, July 18). Actions don’t always speak louder than words, at least, not when it comes to forgiveness. ScienceDaily. Retrieved July 19, 2012, from­ /releases/2012/07/120718090551.htm