83 research outputs found
Voluntary Commitments Lead to Efficiency
Consider an agent (manager,artist, etc.) who has imperfect private information about his productivity. At the beginning of his career (period 1, “short run”), the agent chooses among publicly observable actions that generate imperfect signals of his productivity. The actions can be ranked according to the informativeness of the signals they generate. The market observes the agent’s action and the signal generated by it, and pays a wage equal to his expected productivity. In period 2 (the “long run”), the agent chooses between a constant payoff and a wage proportional to his true productivity, and the game ends. We show that in any equilibrium where not all types of the agent choose the same action, the average productivity of an agent choosing a less informative action is greater. However, the types choosing that action are not uniformly higher. In particular, we derive conditions for the existence of a tripartite equilibrium where low and high types pool on a less informative action while medium (on average, lower) types choose to send a more informative signal.signalling, career concerns
Usability of Humanly Computable Passwords
Reusing passwords across multiple websites is a common practice that
compromises security. Recently, Blum and Vempala have proposed password
strategies to help people calculate, in their heads, passwords for different
sites without dependence on third-party tools or external devices. Thus far,
the security and efficiency of these "mental algorithms" has been analyzed only
theoretically. But are such methods usable? We present the first usability
study of humanly computable password strategies, involving a learning phase (to
learn a password strategy), then a rehearsal phase (to login to a few
websites), and multiple follow-up tests. In our user study, with training,
participants were able to calculate a deterministic eight-character password
for an arbitrary new website in under 20 seconds
Towards optimally abstaining from prediction with OOD test examples
A common challenge across all areas of machine learning is that training data
is not distributed like test data, due to natural shifts, "blind spots," or
adversarial examples; such test examples are referred to as out-of-distribution
(OOD) test examples. We consider a model where one may abstain from predicting,
at a fixed cost. In particular, our transductive abstention algorithm takes
labeled training examples and unlabeled test examples as input, and provides
predictions with optimal prediction loss guarantees. The loss bounds match
standard generalization bounds when test examples are i.i.d. from the training
distribution, but add an additional term that is the cost of abstaining times
the statistical distance between the train and test distribution (or the
fraction of adversarial examples). For linear regression, we give a
polynomial-time algorithm based on Celis-Dennis-Tapia optimization algorithms.
For binary classification, we show how to efficiently implement it using a
proper agnostic learner (i.e., an Empirical Risk Minimizer) for the class of
interest. Our work builds on a recent abstention algorithm of Goldwasser,
Kalais, and Montasser (2020) for transductive binary classification.Comment: In NeurIPS 2021 (+spotlight), 24 page
Do Language Models Know When They're Hallucinating References?
Current state-of-the-art language models (LMs) are notorious for generating
text with "hallucinations," a primary example being book and paper references
that lack any solid basis in their training data. However, we find that many of
these fabrications can be identified using the same LM, using only black-box
queries without consulting any external resources. Consistency checks done with
direct queries about whether the generated reference title is real (inspired by
Kadavath et al. 2022, Lin et al. 2022, Manakul et al. 2023) are compared to
consistency checks with indirect queries which ask for ancillary details such
as the authors of the work. These consistency checks are found to be partially
reliable indicators of whether or not the reference is a hallucination. In
particular, we find that LMs in the GPT-series will hallucinate differing
authors of hallucinated references when queried in independent sessions, while
it will consistently identify authors of real references. This suggests that
the hallucination may be more a result of generation techniques than the
underlying representation
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