Large language models (LLMs) now give reasoning before answering, excelling in tasks like multiple-choice question answering (MCQA). Yet, a concern is that LLMs do not solve MCQs as intended, as work finds LLMs sans reasoning succeed in MCQA without using the question, i.e., choices-only. Such partial-input success is often deemed problematic, but reasoning traces could reveal if these strategies are truly shallow in choices-only settings. To study these strategies, reasoning LLMs solve MCQs in full and choices-only inputs; test-time reasoning often boosts accuracy on full and in choices-only half the time. While possibly due to shallow shortcuts, choices-only success is barely affected by the length of reasoning traces, and after finding traces pass faithfulness tests, we show they use less problematic strategies like inferring missing questions. In all, we challenge claims that partial-input success is always a flaw, so we discuss how reasoning traces could separate problematic data from less problematic reasoning.

At first glance at this creature, you'd be forgiven for mistaking it for a sparkly pair of fake eyelashes. But the creature is very much real and was discovered at the junction of three tectonic plates in the Pacific Ocean. Researchers from the Schmidt Ocean Institute spotted the animal while using an underwater robot to scour the seabed. The animal is a polychaete - a class of marine worms, more widely known as bristle worms. 'To describe this polychaete, one simply must use jazz hands -- it is the only way to capture this deep-sea worm's dazzle!' the experts said in an Instagram post about the polychaete.

From Cornwall and Wales to Essex, Blackpool and the Norfolk coast, Britain has experienced a flurry of earthquakes in the past month. The biggest – a 3.8 magnitude tremor that struck Wales on February 24 – sparked panic as locals reported their beds started to move and walls shook. One resident in the small Welsh town of Abertillery not far from the epicentre said the quake was so noticeable'it felt like the roof was falling off'. The Welsh quake was preceded by several more including a 1.5 magnitude quake in Cornwall and a 3.8 magnitude event off the coast of Great Yarmouth. Here's all you need to know about the British tremors – including whether recent tectonic activity suggests a'big one' is soon to hit parts of the country.

Less than two weeks after the tragic earthquake that has killed more than 40,000 people in Turkey and Syria, another shake has rocked New Zealand. Wednesday's'widely felt' tremor, around magnitude 6, jolted both New Zealand's islands, although thankfully there's been no immediate reports of damage or injury. Earthquakes are happening all the time, from the ones too small to even be noticed to the devastating high magnitude quakes that lead to thousands of fatalities. But its occurrence so soon after the disaster in Turkey and Syria begs the question - could they be linked? Here, MailOnline takes a closer look at today's event and whether it's related to the catastrophic tremor in the Middle East last week.

A new model claims to predict when and where the next major earthquake may strike - just days after a 7.8 magnitude quake rocked Turkey and Syria, killing at least 19,000 people. Developed by a team of seismologists and statisticians at Northwestern University, the model takes into account previous earthquakes' specific order and timing rather than just relying on the average time between past earthquakes. This method also explains why earthquakes tend to come in clusters. The team found that faults have'long-term memory,' which means an earthquake did not release all the strain that built up on the fault over time, so some remains after a big earthquake and can cause another. Seismologists have traditionally assumed that big earthquakes on faults are relatively regular and that the next quake will occur after approximately the same amount of time as the previous two.

Scientists have discovered a hidden layer of Earth, which sits 100 miles below the surface and covers at least 44 percent of the planet. This previously unknown region of molten rock is part of the asthenosphere, located under tectonic plates in the upper mantle, which forms a soft boundary that allows the solid rock slabs to move. While the discovery is significant, it shatters long-held theories that molten rocks influence the asthenosphere's viscosity. Junlin Hua, with the University of Texas, Austin, said in a statement: 'When we think about something melting, we intuitively think that the melt must play a big role in the material's viscosity. 'But what we found is that even where the melt fraction is quite high, its effect on mantle flow is very minor.'

A strange'swarm' of small earthquakes in California that lasted nearly four years was triggered by fluid spilling into the fault system from underground reservoirs, scientists say. The naturally occurring injection of underground fluid drove the earthquake swarm near Cahuilla in Southern California, which occurred in bursts around the region from early 2016 to late 2019. US scientists have made their conclusions based on earthquake detection algorithms that catalogued more than 22,000 individual seismic events that made up the'swarm'. Using machine learning to plot the location, depth and size of the tremors, the researchers generated a 3D representation of the underlying fault zone. The results suggested dynamic pressure changes from natural fluid injections deep below the surface largely controlled the prolonged evolution of the Cahuilla swarm.