31 research outputs found
Principles of Human Learning
What are the general principles that drive human learning in different situations? I argue that much of human learning can be understood with just three principles. These are generalization, adaptation, and simplicity. To verify this conjecture, I introduce a modeling framework based on the same principles. This framework combines the idea of meta-learning -- also known as learning-to-learn -- with the minimum description length principle. The models that result from this framework capture many aspects of human learning across different domains, including decision-making, associative learning, function learning, multi-task learning, and reinforcement learning. In the context of decision-making, they explain why different heuristic decision-making strategies emerge and how appropriate strategies are selected. The same models furthermore capture order effects found in associative learning, function learning and multi-task learning. In the reinforcement learning context, they resemble individual differences between human exploration strategies and explain empirical data better than any other strategy under consideration. The proposed modeling framework -- together with its accompanying empirical evidence -- may therefore be viewed as a first step towards the identification of a minimal set of principles from which all human behavior derives
Coherent multidimensional spectroscopy in the gas phase
Recent work applying multidimentional coherent electronic spectroscopy at
dilute samples in the gas phase is reviewed. The development of refined
phase-cycling approaches with improved sensitivity has opened-up new
opportunities to probe even dilute gas-phase samples. In this context, first
results of 2-dimensional spectroscopy performed at doped helium droplets reveal
the femtosecond dynamics upon electronic excitation of cold, weakly-bound
molecules, and even the induced dynamics from the interaction with the helium
environment. Such experiments, offering well-defined conditions at low
temperatures, are potentially enabling the isolation of fundamental processes
in the excitation and charge transfer dynamics of molecular structures which so
far have been masked in complex bulk environments.Comment: Invited Review Articl
The Acquisition of Physical Knowledge in Generative Neural Networks
As children grow older, they develop an intuitive understanding of the
physical processes around them. Their physical understanding develops in
stages, moving along developmental trajectories which have been mapped out
extensively in previous empirical research. Here, we investigate how the
learning trajectories of deep generative neural networks compare to children's
developmental trajectories using physical understanding as a testbed. We
outline an approach that allows us to examine two distinct hypotheses of human
development - stochastic optimization and complexity increase. We find that
while our models are able to accurately predict a number of physical processes,
their learning trajectories under both hypotheses do not follow the
developmental trajectories of children.Comment: Published as a conference paper at ICML 202
Inducing anxiety in large language models increases exploration and bias
Large language models are transforming research on machine learning while
galvanizing public debates. Understanding not only when these models work well
and succeed but also why they fail and misbehave is of great societal
relevance. We propose to turn the lens of computational psychiatry, a framework
used to computationally describe and modify aberrant behavior, to the outputs
produced by these models. We focus on the Generative Pre-Trained Transformer
3.5 and subject it to tasks commonly studied in psychiatry. Our results show
that GPT-3.5 responds robustly to a common anxiety questionnaire, producing
higher anxiety scores than human subjects. Moreover, GPT-3.5's responses can be
predictably changed by using emotion-inducing prompts. Emotion-induction not
only influences GPT-3.5's behavior in a cognitive task measuring exploratory
decision-making but also influences its behavior in a previously-established
task measuring biases such as racism and ableism. Crucially, GPT-3.5 shows a
strong increase in biases when prompted with anxiety-inducing text. Thus, it is
likely that how prompts are communicated to large language models has a strong
influence on their behavior in applied settings. These results progress our
understanding of prompt engineering and demonstrate the usefulness of methods
taken from computational psychiatry for studying the capable algorithms to
which we increasingly delegate authority and autonomy
Coherent multidimensional spectroscopy of dilute gas-phase nanosystems
Two-dimensional electronic spectroscopy (2DES) is one of the most powerful
spectroscopic techniques, capable of attaining a nearly complete picture of a
quantum system including its couplings, quantum coherence properties and its
real-time dynamics. While successfully applied to a variety of condensed phase
samples, high precision experiments on isolated quantum systems in the gas
phase have been so far precluded by insufficient sensitivity. However, such
experiments are essential for a precise understanding of fundamental mechanisms
and to avoid misinterpretations, e.g. as for the nature of quantum coherences
in energy trans-port. Here, we solve this issue by extending 2DES to isolated
nanosystems in the gas phase prepared by helium nanodroplet isolation in a
molecular beam-type experiment. This approach uniquely provides high
flexibility in synthesizing tailored, quantum state-selected model systems of
single and many-body properties. For demonstration, we deduce a precise and
conclusive picture of the ultrafast coherent dynamics in isolated high-spin Rb2
molecules and present for the first time a dynamics study of the system-bath
interaction between a single molecule (here Rb3) and a superfluid helium
environment. The results demonstrate the unique capacity to elucidate
prototypical interactions and dynamics in tailored quantum systems and bridges
the gap to experiments in ultracold quantum science