20 research outputs found
Active Inverse Reward Design
Designers of AI agents often iterate on the reward function in a
trial-and-error process until they get the desired behavior, but this only
guarantees good behavior in the training environment. We propose structuring
this process as a series of queries asking the user to compare between
different reward functions. Thus we can actively select queries for maximum
informativeness about the true reward. In contrast to approaches asking the
designer for optimal behavior, this allows us to gather additional information
by eliciting preferences between suboptimal behaviors. After each query, we
need to update the posterior over the true reward function from observing the
proxy reward function chosen by the designer. The recently proposed Inverse
Reward Design (IRD) enables this. Our approach substantially outperforms IRD in
test environments. In particular, it can query the designer about
interpretable, linear reward functions and still infer non-linear ones
Explaining grokking through circuit efficiency
One of the most surprising puzzles in neural network generalisation is
grokking: a network with perfect training accuracy but poor generalisation
will, upon further training, transition to perfect generalisation. We propose
that grokking occurs when the task admits a generalising solution and a
memorising solution, where the generalising solution is slower to learn but
more efficient, producing larger logits with the same parameter norm. We
hypothesise that memorising circuits become more inefficient with larger
training datasets while generalising circuits do not, suggesting there is a
critical dataset size at which memorisation and generalisation are equally
efficient. We make and confirm four novel predictions about grokking, providing
significant evidence in favour of our explanation. Most strikingly, we
demonstrate two novel and surprising behaviours: ungrokking, in which a network
regresses from perfect to low test accuracy, and semi-grokking, in which a
network shows delayed generalisation to partial rather than perfect test
accuracy
Does Circuit Analysis Interpretability Scale? Evidence from Multiple Choice Capabilities in Chinchilla
\emph{Circuit analysis} is a promising technique for understanding the
internal mechanisms of language models. However, existing analyses are done in
small models far from the state of the art. To address this, we present a case
study of circuit analysis in the 70B Chinchilla model, aiming to test the
scalability of circuit analysis. In particular, we study multiple-choice
question answering, and investigate Chinchilla's capability to identify the
correct answer \emph{label} given knowledge of the correct answer \emph{text}.
We find that the existing techniques of logit attribution, attention pattern
visualization, and activation patching naturally scale to Chinchilla, allowing
us to identify and categorize a small set of `output nodes' (attention heads
and MLPs).
We further study the `correct letter' category of attention heads aiming to
understand the semantics of their features, with mixed results. For normal
multiple-choice question answers, we significantly compress the query, key and
value subspaces of the head without loss of performance when operating on the
answer labels for multiple-choice questions, and we show that the query and key
subspaces represent an `Nth item in an enumeration' feature to at least some
extent. However, when we attempt to use this explanation to understand the
heads' behaviour on a more general distribution including randomized answer
labels, we find that it is only a partial explanation, suggesting there is more
to learn about the operation of `correct letter' heads on multiple choice
question answering
On the Utility of Learning about Humans for Human-AI Coordination
While we would like agents that can coordinate with humans, current
algorithms such as self-play and population-based training create agents that
can coordinate with themselves. Agents that assume their partner to be optimal
or similar to them can converge to coordination protocols that fail to
understand and be understood by humans. To demonstrate this, we introduce a
simple environment that requires challenging coordination, based on the popular
game Overcooked, and learn a simple model that mimics human play. We evaluate
the performance of agents trained via self-play and population-based training.
These agents perform very well when paired with themselves, but when paired
with our human model, they are significantly worse than agents designed to play
with the human model. An experiment with a planning algorithm yields the same
conclusion, though only when the human-aware planner is given the exact human
model that it is playing with. A user study with real humans shows this pattern
as well, though less strongly. Qualitatively, we find that the gains come from
having the agent adapt to the human's gameplay. Given this result, we suggest
several approaches for designing agents that learn about humans in order to
better coordinate with them. Code is available at
https://github.com/HumanCompatibleAI/overcooked_ai.Comment: Published at NeurIPS 2019
(http://papers.nips.cc/paper/8760-on-the-utility-of-learning-about-humans-for-human-ai-coordination
The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study
AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries