An accumulation of action potentials is behind Venus Flytraps’ “decision” to keep closed and start producing digestive enzymes once their trap sensors are triggered, scientists at Universität Würzburg have found.
“The carnivorous plant Dionaea muscipula, also known as Venus flytrap, can count how often it has been touched by an insect visiting its capture organ in order to trap and consume the animal prey,” said Rainer Hedrich of Universität Würzburg in Germany.
The researchers wanted to understand how Venus Fly traps decide to close and how they decide they have something to digest. After all, the researchers noted, closing their traps around an object and filling with digestive enzymes is biologically costly, and sometimes their sensors are triggered by stimuli that are not prey at all — “false alarms.”
The researchers sought to test this by implanting artificial sensors in a Venus Flytrap. The sensors are thin spikes that stick out of the inside of the plant’s interior walls. They then flicked the sensors to cause the plant to close. When the scientists continually flicked the sensors, the plant became excited and began to produce the acidic digestive bath that fills their closed lobes.
By means of accumulated action potentials, the plant understands that what it has caught is in fact a struggling insect. It also understands the size of the insect by the number of the sensors it triggers.
“The number of action potentials informs [the plant] about the size and nutrient content of the struggling prey,” Hedrich said. “This allows the Venus flytrap to balance the cost and benefit of hunting.”
To eat, the scientists concluded, a Venus Flytrap requires at least five contacts with its sensors. The second trigger closes the plant, the third and further triggers activate touch hormones and begin the production of digestive enzymes, and the fifth begins the uptake of nutrients.
The report, “The Venus Flytrap Dionaea muscipula Counts Prey-Induced Action Potentials to Induce Sodium Uptake,” was completed by Böhm and Scherzer et al, and was published in the journal Current Biology.
By Andy Stern
When political parties reverse their policy stance, their supporters immediately switch their opinions too
At least a significant portion of their supporters, according to U of Aarhus researchers.
When two competing political parties in Denmark reversed their policy stance on an issue — suddenly they both supported reducing unemployment benefits — their voters immediately moved their opinions by around 15% into line with their party.
The same thing happened when one of these parties shifted from opposing to supporting ending Denmark’s early retirement.
The researchers were studying how public opinion is formed. Their recent paper sheds light on how much influence political parties have over their supporters, according to the researchers, who surveyed their panel of subjects in five successive waves between 2010 and 2011. They studied the same group of party supporters before, during and after a policy reversal.
“We can see that [the] welfare programs were actually quite popular … and many of the voters of the center-right party were in favor of these welfare programs,” commented one of the researchers, Rune Slothuus. “Nevertheless, we can see that they reversed their opinion from supporting these welfare programs to opposing these welfare programs.”
“I was surprised to see the parties appeared this powerful in shaping opinions,” Slothuus said. “Our findings suggest that partisan leaders can indeed lead citizens’ opinions in the real world, even in situations where the stakes are real and the economic consequences tangible.”
The researchers pondered Western democracy in light of their findings: “If citizens just blindly follow their party without thinking much about it, that should lead to some concern about the mechanisms in our democracy. Because how can partisan elites represent citizens’ views if the views of citizens are shaped by the very same elites who are supposed to represent them?”
Source: How Political Parties Shape Public Opinion in the Real World. Rune Slothuus and Martin Bisgaard. First published: 04 November 2020 https://doi.org/10.1111/ajps.12550
The brain listens for things it is trying to predict
The brain interprets sounds as they contrast with its expectations; it recognizes patterns of sounds faster when they’re in line with what it is predicting it will hear, but it only encodes sounds when they contrast with expectations, according to Technische U researchers.
The researchers showed this by monitoring the two principal nuclei of the subcortical pathway responsible for auditory processing: the inferior colliculus and the medial geniculate body, as their subjects listened to patterns of sounds which the researches modified so that sometimes they would hear an expected sound pattern, and other times something unexpected.
Source: Alejandro Tabas, Glad Mihai, Stefan Kiebel, Robert Trampel, Katharina von Kriegstein. Abstract rules drive adaptation in the subcortical sensory pathway. eLife, 2020; 9 DOI: 10.7554/eLife.64501
We have a particular way of understanding a room
When several research subjects were instructed to explore an empty room, and when they were instead seated in a chair and watched someone else explore the room, their brain waves followed a certain pattern, as recorded by a backpack hooked up to record their brain waves, eye movements, and paths. It didn’t matter if they were walking or watching someone else, according to UC researchers led by Dr Matthias Stangl.
The researchers also tested what happened when subjects searched for a hidden spot, or watched someone else do so, and found that brain waves flowed more strongly when they had a goal and hunted for something.
Source: Matthias Stangl, Uros Topalovic, Cory S. Inman, Sonja Hiller, Diane Villaroman, Zahra M. Aghajan, Leonardo Christov-Moore, Nicholas R. Hasulak, Vikram R. Rao, Casey H. Halpern, Dawn Eliashiv, Itzhak Fried, Nanthia Suthana. Boundary-anchored neural mechanisms of location-encoding for self and others. Nature, 2020; DOI: 10.1038/s41586-020-03073-y
Extroverts and introverts use different vocabularies
Extroverts use ‘positive emotion’ and ‘social process’ words more often than introverts, according to new research conducted at Nanyang Technological U.
‘Love,’ ‘happy,’ and ‘blessed’ indicate pleasant emotions, and ‘beautiful’ and ‘nice’ indicate positivity or optimism, and are among the words found to be used more often by extroverts. So too are ‘meet,’ ‘share,’ and ‘talk,’ which are about socializing. Extroverts use personal pronouns — except ‘I’ — more too, another indication of sociability.
The correlation, however, was small, and the researchers think that stronger linguistic indicators need to be found to achieve their general goal, which is improving machine learning approaches to targeting consumer marketing.
Source: Jiayu Chen, Lin Qiu, Moon-Ho Ringo Ho. A meta-analysis of linguistic markers of extraversion: Positive emotion and social process words. Journal of Research in Personality, 2020; 89: 104035 DOI: 10.1016/j.jrp.2020.104035
WhatsApp is changing today - Users must give the app permission to send their private data to Facebook or lose account
WhatsApp was bought by Facebook in 2014, but has thrived while promoting itself as a privacy-respecting messaging app that now has 1.5b monthly active users. This week, though, WhatApp sent out an update to users’ phones that they must ‘consent’ to a new policy or lose access.
Whatsapp will now share more of your data, including your IP address (your location) and phone number, your account registration information, your transaction data, and service-related data, interactions on WhatsApp, and other data collected based on your consent, with Facebook’s other companies. Facebook has been working towards more closely integrating Facebook, WhatsApp, Instagram and Messenger.
Users who do not agree to ‘consent’ to the new policy will see their WhatsApp account become inaccessible until they do ‘consent.’ These accounts will remain dormant for 120 days after which they will be ‘deleted.’
The biggest change to the user policy, which many people ignored and clicked ‘agree’ to, thinking it was just another unimportant app update message, now reads,
‘We collect information about your activity on our Services, like service-related, diagnostic, and performance information. This includes information about your activity (including how you use our Services, your Services settings, how you interact with others using our Services (including when you interact with a business), and the time, frequency, and duration of your activities and interactions), log files, and diagnostic, crash, website, and performance logs and reports. This also includes information about when you registered to use our Services; the features you use like our messaging, calling, Status, groups (including group name, group picture, group description), payments or business features; profile photo, “about” information; whether you are online, when you last used our Services (your “last seen”); and when you last updated your “about” information.’
Notably, Elon Musk tweeted on the news, saying that WhatsApp users should switch to Signal, one of several popular privacy-focused messaging apps similar to WhatsApp.
The data sharing policy change doesn’t affect people in Europe due to GDPR data protection regulations.