The cosmic oddball that's 67 million light-years away has a puzzling shape. Breakthroughs, discoveries, and DIY tips sent every weekday. What does it look like in your mind? Chances are, it's a swirling circle of galactic energy . A galaxy is often described as one of a few broadly defined shapes--elliptical, spiral, or lenticular--as described by the Hubble sequence .

Breakthroughs, discoveries, and DIY tips sent every weekday. Even a century after Edward Hubble confirmed its existence, astronomers learn new details about the Andromeda galaxy that help us better understand our cosmic neighborhood and the wider universe. Earlier this week, NASA released its latest detailed images of the Milky Way's spiral sibling, as well an ethereal sonification of its energy wavelengths. Attaining an outside view of the Milky Way galaxy is a bit like trying to examine the entire planet from your backyard--that is to say, it's impossible from humanity's current vantage point. The next best option for astronomers is gazing at similar nearby spiral galaxies, the closest of which is Messier 31.

Position bias has proven to be a prevalent issue of modern language models (LMs), where the models prioritize content based on its position within the given context. This bias often leads to unexpected model failures and hurts performance, robustness, and reliability across various applications. Our mechanistic analysis attributes the position bias to two components employed in nearly all state-of-the-art LMs: causal attention and relative positional encodings. Specifically, we find that causal attention generally causes models to favor distant content, while relative positional encodings like RoPE Su et al. (2024) prefer nearby ones based on the analysis of retrieval-augmented question answering (QA). Further, our empirical study on object detection reveals that position bias is also present in vision-language models (VLMs). Based on the above analyses, we propose to eliminate position bias caused by different input segment orders (e.g., options in LM-as-a-judge, retrieved documents in QA) in a training-free zero-shot manner. Our method changes the causal attention to bidirectional attention between segments and utilizes model attention values to decide the relative orders of segments instead of using the order provided in input prompts, therefore enabling Position-INvariant inferencE (PINE) at the segment level. By eliminating position bias, models achieve better performance and reliability in downstream tasks where position bias widely exists, such as LM-as-a-judge and retrieval-augmented QA. Notably, PINE is especially useful when adapting LMs for evaluating reasoning pairs: it consistently provides 8 to 10 percentage points performance gains in most cases, and makes Llama-3-70B-Instruct perform even better than GPT-4-0125-preview on the RewardBench reasoning subset.

Among the more modern anxieties of parents today is how virtual assistants will train their children to act. The fear is that kids who habitually order Amazon's Alexa to read them a story or command Google's Assistant to tell them a joke are learning to communicate not as polite, considerate citizens, but as demanding little twerps. This worry has become so widespread that Amazon and Google both announced this week that their voice assistants can now encourage kids to punctuate their requests with "please." The version of Alexa that inhabits the new Echo Dot Kids Edition will thank children for "asking so nicely." Google Assistant's forthcoming Pretty Please feature will remind kids to "say the magic word" before complying with their wishes.

It's been four years since Canadian studio Bioware seemingly closed out its science fiction RPG series Mass Effect with one of the most controversial (or as some put it, "disappointing") endings in video game history. Next March, however, the beloved series is returning, with a brand-new cast and setting, and some interesting new design features. Coming two years after the developer's acclaimed Dragon Age: Inquisition, it's likely Andromeda will draw on a lot of the ideas and systems from that game, as well as from the Mass Effect canon. But what do we actually know about the next title? Mass Effect has often been beautiful, but it's never looked so much like an actual, modern-day sci-fi movie as Andromeda does in the trailers.