Imagine that you are imprisoned in a tunnel that opens out onto a precipice two paces to your left, and a pit of vipers two paces to your right. To torment you, your evil captor forces you to take a series of steps to the left and right. You need to devise a series that will allow you to avoid the hazards — if you take a step to the right, for example, you’ll want your second step to be to the left, to avoid falling off the cliff. You might try alternating right and left steps, but here’s the catch: You have to list your planned steps ahead of time, and your captor might have you take every second step on your list (starting at the second step), or every third step (starting at the third), or some other skip-counting sequence. Is there a list of steps that will keep you alive, no matter what sequence your captor chooses?

In this brainteaser, devised by the mathematics popularizer James Grime, you can plan a list of 11 steps that protects you from death. But if you try to add a 12th step, you are doomed: Your captor will inevitably be able to find some skip-counting sequence that will plunge you over the cliff or into the viper pit.

Around 1932, Erdős asked, in essence, what if the precipice and pit of vipers are three paces away instead of two? What if they are N paces away? Can you escape death for an infinite number of steps? The answer, Erdős conjectured, was no — no matter how far away the precipice and viper pit are, you can’t elude them forever.

But for more than 80 years, mathematicians made no progress on proving Erdős’ discrepancy conjecture (so named because the distance from the center of the tunnel is known as the discrepancy).

{ Quanta | Continue reading }

We review recent evidence revealing that the mere willingness to engage analytic reasoning as a means to override intuitive “gut feelings” is a meaningful predictor of key psychological outcomes in diverse areas of everyday life. For example, those with a more analytic thinking style are more skeptical about religious, paranormal, and conspiratorial concepts. In addition, analytic thinking relates to having less traditional moral values, making less emotional or disgust-based moral judgments, and being less cooperative and more rationally self-interested in social dilemmas. Analytic thinkers are even less likely to offload thinking to smartphone technology and may be more creative.

{ SSRN | Continue reading }

oil on canvas { Alberto Giacometti, Portrait of Pierre Josse, 1961 }

My brain tumor introduced itself to me on a grainy MRI, in the summer of 2009, when I was 28 years old. […]

Over time I would lose my memory—almost completely—of things that happened just moments before, and become unable to recall events that happened days and years earlier. […]

Through persistence, luck, and maybe something more, an incredible medical procedure returned my mind and memories to me almost all at once. I became the man who remembered events I had never experienced, due to my amnesia. The man who forgot which member of his family had died while he was sick, only to have that memory, like hundreds of others, come flooding back. The memories came back out of order, with flashbacks mystically presenting themselves in ways that left me both excited and frightened.

{ Quartz | Continue reading }

People with a certain type of gene are more deeply affected by their life experiences, a new study has revealed.

The findings challenge traditional thinking about depression, showing what might be considered a risk gene for depression in one context, may actually be beneficial in another.

Researchers at the University of Melbourne were interested in why some, but not all adults who have experienced sexual or physical abuse as children go on to develop long-term depression. […]

Those with the s/s genotype (23%) who had experienced sexual or physical abuse as a child were more likely to experience ongoing severe depressive symptoms in middle age. But, conversely, those with this same genotype but no history of abuse were happier than the rest of the population.

{ EurekAlert | Continue reading }

An influential theory about the malleability of memory comes under scrutiny in a new paper in the Journal of Neuroscience.

The ‘reconsolidation’ hypothesis holds that when a memory is recalled, its molecular trace in the brain becomes plastic. On this view, a reactivated memory has to be ‘saved’ or consolidated all over again in order for it to be stored.

A drug that blocks memory formation (‘amnestic’) will, therefore, not just block new memories but will also cause reactivated memories to be forgotten, by preventing reconsolidation.

This theory has generated a great deal of research interest and has led to speculation that blocking reconsolidation could be used as a tool to ‘wipe’ human memories.

However, Gisquet-Verrier et al. propose that amnestic drugs don’t in fact block reconsolidation, but instead add an additional element to a reactivated memory trace. This additional element is a memory of the amnestic itself – essentially, ‘how it feels’ to be intoxicated with that drug.

In other words, the proposal is that amnestics tag memories with ‘amnestic-intoxication’ which makes these memories less accessible due to the phenomenon of state dependent recall. This predicts that the memories could be retrieved by giving another dose of the amnestic.

So, Gisquet-Verrier et al. are saying that (sometimes) an ‘amnestic’ drug can actually improve memory.

{ Neuroskeptic | Continue reading }

related { Kids can remember tomorrow what they forgot today }

Sensitive new telescopes now permit astronomers to detect the waste heat that is expected to be a signature of advanced alien civilisations that can harness enormous energies on the scale of the stellar output of their own galaxy. Professor Michael Garrett has used radio observations of candidate galaxies to show that such advanced civilisations are very rare or entirely absent from the local Universe.

{ Astron | Continue reading }

Health has been identified as an important variable involved in mate choice. Unhealthy organisms are generally less able to provide reproductively important resources to partners and offspring and are more likely to pass on communicable disease.

Research on human mate preferences has shown that both men and women prefer healthy mates. Yet to date, little research has examined how health relates to one’s own mating experiences. In the present study, 164 participants (87 women) who were currently in heterosexual romantic relationships completed measures of frequency and severity of health problems, anticipated partner infidelity, and intensity of jealousy felt in their current relationship. […]

[I]ndividuals who believe they are in poor health are also likely to perceive themselves to be at a mating disadvantage. Results indicated that self-reported poor health, in terms of both frequency and severity of health symptoms, predicted a greater perception that one’s partner would commit an infidelity as well as increased romantic jealousy. Anticipated partner infidelity mediated the links between health problems and jealousy, suggesting that unhealthy individuals perceive their partners as being more likely to mate with an intrasexual (same-sex) rival, in turn facilitating jealousy.

{ Evolutionary Psychology | PDF }

The ratio between the body circumference at the waist and the hips (or WHR) is a secondary sexual trait that is unique to humans and is well known to influence men’s mate preferences. Because a woman’s WHR also provides information about her age, health and fertility, men’s preference concerning this physical feature may possibly be a cognitive adaptation selected in the human lineage. […]

We analyzed the WHR of women considered as ideally beautiful who were depicted in western artworks from 500 BCE to the present. These vestiges of the past feminine ideal were then compared to more recent symbols of beauty: Playboy models and winners of several Miss pageants from 1920 to 2014. We found that the ideal WHR has changed over time in western societies: it was constant during almost a millennium in antiquity (from 500 BCE to 400 CE) and has decreased from the 15th century to the present. Then, based on Playboy models and Miss pageants winners, this decrease appears to slow down or even reverse during the second half of the 20th century.

The universality of an ideal WHR is thus challenged, and historical changes in western societies could have caused these variations in men’s preferences.

{ PLOS | Continue reading }

A new study from Duke University finds that adolescents ages 10 to 16 can be more analytical in their economic choices than many slightly older young adults. […]

Scott Huettel, a professor of psychology and neuroscience at Duke: “The new results point to the idea that we should not think of adolescents as being irrational. What’s different about them is they don’t use simple rules as effectively.”

Such simple rules are the mental shortcuts people take in decision-making—often to their benefit—as they age and gain more experience. Most adults apply the “don’t drink and drive” rule, for example, to avoid getting in a car with someone who’s been drinking. In contrast, teens may more carefully weigh this decision.

“Adolescents are going to be more likely to use cost-benefit analysis than the (simple rules) that adults use.” […]

Other research has shown that adolescents aren’t necessarily more risk-seeking but that they are more sensitive to good outcomes compared with adults.

{ Science Beta | Continue reading }

photo { Vasantha Yogananthan }

In daily life, we frequently encounter false claims in the form of consumer advertisements, political propaganda, and rumors. Repetition may be one way that insidious misconceptions, such as the belief that vitamin C prevents the common cold, enter our knowledge base. Research on the illusory truth effect demonstrates that repeated statements are easier to process, and subsequently perceived to be more truthful, than new statements.

The prevailing assumption in the literature has been that knowledge constrains this effect (i.e., repeating the statement “The Atlantic Ocean is the largest ocean on Earth” will not make you believe it). We tested this assumption. […]

Contrary to prior suppositions, illusory truth effects occurred even when participants knew better. […] Participants demonstrated knowledge neglect, or the failure to rely on stored knowledge, in the face of fluent processing experiences.

{ Journal of Experimental Psychology | Continue reading }

Animals eject fluids for waste elimination, communication, and defense from predators. These diverse systems all rely on the fundamental principles of fluid mechanics, which we use to predict urination duration across a wide range of mammals. […]

Using high-speed videography and flow-rate measurement obtained at Zoo Atlanta, we discover that all mammals above 3 kg in weight empty their bladders over nearly constant duration of 21 s. […]

Smaller mammals are challenged during urination by high viscous and capillary forces that limit their urine to single drops.

{ PNAS | Continue reading }

collage { imp kerr }

You see a man at the grocery store. Is that the fellow you went to college with or just a guy who looks like him? One tiny spot in the brain has the answer.

Neuroscientists have identified the part of the hippocampus that creates and processes this type of memory, furthering our understanding of how the mind works, and what’s going wrong when it doesn’t.

{ Lunatic Laboratories | Continue reading }

An experiment was carried out in a French bar. A waitress briefly touched (or not) the forearm of a patron when asking him/her what he/she want to drink. Results show that touch increases tipping behavior although giving a tip to a waitress in a bar is unusual in France. The familiarity of tactile contact in France was used to explain our results.

{ International Journal of Hospitality Management | Continue reading }

still { Ingmar Bergman, The Passion of Anna, 1969 }

“Despite the common belief that remembering our mistakes will help us make better decisions in the present,” says the study’s lead author, “we actually find that thinking about our failures at self-control leads us to repeat them and indulge in the present, so it’s not helpful at all.”

{ EurekAlert | Continue reading }

Criminal investigations often use photographic evidence to identify suspects. Here we combined robust face perception and high-resolution photography to mine face photographs for hidden information. By zooming in on high-resolution face photographs, we were able to recover images of unseen bystanders from reflections in the subjects’ eyes.

To establish whether these bystanders could be identified from the reflection images, we presented them as stimuli in a face matching task (Experiment 1). Accuracy in the face matching task was well above chance (50%), despite the unpromising source of the stimuli. […] In a test of spontaneous recognition (Experiment 2), observers could reliably name a familiar face from an eye reflection image.

For crimes in which the victims are photographed (e.g., hostage taking, child sex abuse), reflections in the eyes of the photographic subject could help to identify perpetrators.

{ PLOS | Continue reading }

A mezuzah is a small case affixed to the doorframe of each room in Jewish homes and workplaces which contains a tiny scroll of parchment inscribed with a prayer. It is customary for religious Jews to touch the mezuzah every time they pass through a door and kiss the fingers that touched it. However, kissing the mezuzah has also become customary for many secular Jews who think of the mezuzah as a good luck charm.

In view of a recent revelation that kissing the mezuzah entails a health hazard, the present paper inquires whether it also has some observable benefit. In an experiment conducted among non-religious mezuzah-kissing economics and business students confronted with a logic-problem exam, some were allowed to kiss the mezuzah before taking the exam, whereas the others were asked not to do so or could not do so because it had been removed from the room doorframe. The experiment revealed that participants who did not kiss the mezuzah performed worse than those who kissed it, and that the stronger is one’s belief in the mezuzah’s luck-enhancing properties, the better he performs when he kisses it but the worse he performs when he does not.

{ Journal of Economic Behavior & Organization | Continue reading }

We meta-analyzed the effects of sexual media, violent media, sexual ads, and violent ads on the advertising outcomes of brand memory, brand attitudes, and buying intentions. The meta-analysis included 53 experiments involving 8,489 participants.

Analyses found that brands advertised in violent media content were remembered less often, evaluated less favorably, and less likely to be purchased than brands advertised in nonviolent, nonsexual media. Brands advertised using sexual ads were evaluated less favorably than brands advertised using nonviolent, nonsexual ads. There were no significant effects of sexual media on memory or buying intentions. There were no significant effects of sexual or violent ads on memory or buying intentions.

As intensity of sexual ad content increased, memory, attitudes, and buying intentions decreased.

When media content and ad content were congruent (e.g., violent ad in a violent program), memory improved and buying intentions increased.

Violence and sex never helped and often hurt ad effectiveness.

{ Psychological Bulletin/American Psychological Association | PDF }

related { Allegation that ad-serving companies deliberately slow down web pages to maximise profit }

We present participants with coherent and incoherent narratives

When presented to coherent narratives participants remember plots

When presented to incoherent narratives participants remember facts

Plot formation modulate activity in the Default Mode Network of the brain

{ NeuroImage | Continue reading }

New research finds that sarcasm is far more nuanced, and actually offers some important, overlooked psychological and organizational benefits.

“To create or decode sarcasm, both the expressers and recipients of sarcasm need to overcome the contradiction (i.e., psychological distance) between the literal and actual meanings of the sarcastic expressions. This is a process that activates and is facilitated by abstraction, which in turn promotes creative thinking” […]

“Those in the sarcasm conditions subsequently performed better on creativity tasks than those in the sincere conditions or the control condition. This suggests that sarcasm has the potential to catalyze creativity in everyone. That being said, although not the focus of our research, it is possible that naturally creative people are also more likely to use sarcasm, making it an outcome instead of [a] cause in this relationship.” […]

“While most previous research seems to suggest that sarcasm is detrimental to effective communication because it is perceived to be more contemptuous than sincerity, we found that, unlike sarcasm between parties who distrust each other, sarcasm between individuals who share a trusting relationship does not generate more contempt than sincerity”

{ Harvard Gazette | Continue reading }

art { Broomberg & Chanarin }

Two options for dealing with climate change — reducing greenhouse gas emissions through a global agreement, and geoengineering proposals such as injecting sulfur into the stratosphere — tend to dominate current thinking. But there is a “third way” that is almost entirely neglected in political negotiations and public debate. It involves capturing carbon dioxide from the atmosphere and storing it or using it to create things we need.

{ NY Times | Continue reading }