Schreckstoff is a chemical cocktail that fish release from their skin after an injury. Fish perceive the risk of a predator nearby when they sense the chemical in water, and they display an alarm behaviour called a “startle” event. We have an update on it from Iain Couzin (University of Konstanz), who was looking for a behavioural possibility that does not exist when you look at individual animals.

An increase in startle rates is not an indication that individual fish are more receptive to sensory cues in a setting. The best predictor of a startle event is how the individuals are positioned with respect to one another and how far apart they are. Just by changing the structure of the group, by coming closer together, the strength of the social connectivity among the individuals can be increased. And this allows them to respond effectively and rapidly to changes in their environment — as a collective.

Intelligence doesn’t always reside in our brains, in the individual animal, Couzin said, “intelligence can also be encoded in the hidden network of communication between us.”

SNEAK PEEK

1. Sound fact: One

Sounds deemed intolerable are mainly between 40Hz and 80 Hz. It is the range of frequencies used by human screams, including those of babies. Machine-made alarms use the same frequencies — to maximise the chances of getting attention. Who explained this?

1. Dr Luc Arnal (UNIGE’s Faculty of Medicine)

2. Sound fact: Two

When a sound is played into your ear, the sound propagates and is reflected and absorbed by the ear canal. All of this produces a unique signature that can be identified by devices. Who modified wireless earbuds to authenticate smartphone users via the unique signature?

2. Computer scientist Zhanpeng Jin (University at Buffalo)

3. Loyalty above all

A ghastly crime is committed. The family and friends of the perpetrator did nothing to stop it. This is not as uncommon as it sounds. Loyalty is so powerful a motivator that, in certain circumstances, it can “override other virtues like honesty”. Who demonstrated it in a study?

3. US Army research psychologist Walter Sowden

4. An update on cats

Cats are aloof and independent. Yes, seemingly but not really. Like dogs, cats display social flexibility in regard to their attachments with people. Who found evidence that “cats are securely attached to their owner and use them as a source of security in a novel environment?

4. Kristyn Vitale (Oregon State University)

5. Just for a change

If you are an introvert, force yourself to be an extravert. You’ll be happier. Changing one’s social behaviour is an achievable goal for many people. That is the suggestion of a study asking people to act like extraverts for a prolonged period. Who conducted the study?

5. UC Riverside researcher Sonja Lyubomirsky

6. Pilgrims in danger

Islam follows a lunar calendar, and so the dates for Hajj change. For five to seven years at a time, the pilgrimage falls over summer. As soon as 2020, summer temperatures around Mecca could exceed the extreme danger heat-stress threshold. Who announced this?

6. Civil & environmental engineer Elfatih Eltahir (MIT)

7. Supreme killersl

We are just one among over 35,000 species of terrestrial vertebrates that share Earth’s surface resources, but 28 percent of animal deaths are caused by us — directly! This “disproportionately huge effect” doesn’t include deaths due to habitat destruction. Who did the stats?

7. Jerrold L. Belant (SUNY College of ESF, Syracuse)

8. Just missed it!

Some athletes feel a rapid drop in performance in high stress moments, like scoring a goal. It is caused by one-way signals from the brain’s emotion circuit to the movement circuit. Who found and presented it as a whole new paradigm for testing psychiatric disorders?

8. Molecular neurobiologist Xin Jin (Salk Institute)

9. Put in sequences

People perceive claims using words that follow the alphabetic order (like “Advil kills pain”) as more trustworthy than claims using words that don’t do so (like ‘Vufferil Eases Pain). Who observed the brain’s dependence on familiar sequences in organising its database?

9. Dan King (University of Texas Rio Grande Valley)

QUIZ No. 922

1. Who estimated that mountain regions contain more than 85% of the world’s species?

– Carsten Rahbek
– Wallace Smith Broecker
– Selwyn G. Blaylock

1. Carsten Rahbek

2. Who discovered that cancers can hijack our body’s natural wound-healing response?

– Andrew C. Dudleyo
– Charles Brenton Huggins
– Sean C. Senechal

2. Andrew C. Dudleyo

3. Snowfalls on silicone surfaces produce a charge. Who made a device to capture it?

– George H. Heilmeier
– Marie Van Brittan Brown
– Richard B. Kaner

3. Richard B. Kaner

4. “What do I know?” Which illustrious philosopher is known for this sceptical remark?

– Blaise Pascal
– Jean-Jacques Rousseau
– Michel de Montaigne

4. Michel de Montaigne

5. Who did a collection of African folk tales to create an outlet for traditional African art?

– Bernard Binlin Dadie
– Marie-Christine Koundja
– Ketty Nivyabandi

5. Bernard Binlin Dadie