Actual Lecture 5

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1
What is the core idea behind 'rational analysis' in cognitive science?
It treats people as approximately optimal machines that adapt to their environment and tasks in the best possible way.
2
In rational analysis, how is learning typically modeled as an optimal process?
Learning is modeled via Bayesian update, using Bayes' rule to optimally revise beliefs based on evidence.
3
What kind of models are based on probability theory and are widely used to describe learning, reasoning, and memory in cognitive science?
Probabilistic cognitive models, with Bayesian models being a very important subclass.
4
According to rational theory, behavior is assumed to implement optimal relations between _____ and cognitive processes.
environment structure
5
In the 'auxiliary fronting' example, what is the naive rule a child might infer to form a question like "Is the man smiling?"
Move the verb to the beginning of the sentence.
6
Given the declarative "The man who is tall is smiling," what ungrammatical question does the 'closest-verb' rule produce?
*Is the man who tall is smiling?
7
Given the declarative "The man who is tall is smiling," what grammatical question does the 'structurally highest' rule produce?
Is the man who is tall smiling?
8
The 'poverty of the stimulus' argument points out that children converge on the structurally-based rule for question formation without hearing direct _____ that the linear rule is wrong.
evidence
9
What is the classical conclusion from generative grammar regarding the 'poverty of the stimulus'?
Children are endowed with a universal grammar that privileges hierarchical structure over linear order.
10
How does unbounded recursion (e.g., "I know that he knows that she knows...") present a 'poverty of the stimulus' problem?
Children generalize to potentially unbounded recursion despite rarely encountering deeply recursive sentences in their input.
11
In formal language theory, a language is defined as a set of _____ over some alphabet.
strings
12
Given an alphabet {\$a,b\$}, what is the language \$L_1 = \{a^n b^m \mid n, m e 1\}\$?
The set of all strings with one or more 'a's followed by one or more 'b's.
13
For a base set \$X = \{\text{abc}\}\$, the _____ is the set of all finite concatenations, including the empty string \$\epsilon\$.
Kleene star (\$X^*\$)
14
The formal language \$L_0 = a^n N\$ can be used to model what natural language construction?
A sequence of any number of adjectives ('a') followed by a noun ('N').
15
The formal language \$L = \{a^n b^n \mid n \in \mathbb{N}\}\$ is often used to model what type of grammatical construction?
Center embedding, where the number of opening elements (e.g., nouns) must match closing elements (e.g., verbs).
16
What is the general formula for conditional probability, \$P(A|B)\$?
\$P(A|B) = \frac{P(A \cap B)}{P(B)}\$, for \$P(B) > 0\$.
17
A _____ is a function from a sample space of possible events to a set of real numbers.
random variable
18
What type of function is used to describe the probability distribution of a discrete random variable?
A probability mass function (PMF).
19
What type of function is used to describe the probability distribution of a continuous random variable?
A probability density function (PDF).
20
A continuous random variable \$X\$ that follows a normal distribution is denoted by what notation?
\$X \sim N(\mu, \sigma^2)\$
21
What is the probability mass function for a geometric distribution, \$P(X=k)\$?
\$P(X=k) = \alpha(1-\alpha)^{k-1}\$, for \$k=1,2,3,\dots\$
22
A geometric distribution is typically interpreted as the probability that the first success in a series of independent trials occurs on the _____-th trial.
k
23
What is the formula for Bayes' rule, expressing \$P(H|E)\$?
\$P(H|E) = \frac{P(E|H)P(H)}{P(E)}\$
24
In Bayes' rule, the term \$P(H|E)\$ is known as the _____ probability.
posterior
25
In Bayes' rule, the term \$P(H)\$ is known as the _____ probability.
prior
26
In Bayes' rule, the term \$P(E|H)\$ is known as the _____.
likelihood
27
The term \$P(E)\$ in Bayes' rule is the marginal likelihood, which acts as a _____.
normalizing constant
28
How is the evidence term \$P(E)\$ calculated as a sum over all possible hypotheses \$H_i\$?
\$P(E) = \sum_i P(E|H_i)P(H_i)\$
29
What is the proportional form of Bayes' rule, often used for comparing hypotheses?
\$P(H|E) \propto P(E|H)P(H)\$
30
The 'reverse-engineering' approach in Bayesian cognitive modeling works backward from observed behavior to infer the _____ and _____ that make that behavior optimal.
priors and likelihoods
31
What is the central claim of Fodor's Language of Thought (LOT) hypothesis?
Humans possess basic conceptual primitives and logical operations that combine compositionally to form complex concepts.
32
In the Bayesian LOT framework, how is learning modeled?
Learning is modeled as applying Bayes' rule over a hypothesis space defined by the Language of Thought.
33
In the LOT for strings, what is the `plus(S, c)` or `\$S \oplus c\$` operation?
It adds character 'c' to the end of string 'S'.
34
In the LOT for strings, what does the `rest(S)` operation return?
It returns all characters of string 'S' except for the first one.
35
The LOT program \$F_0 = \text{if}(\text{flip}(1/3), \epsilon, F_0 \oplus a)\$ generates what formal language?
The set of all positive-length sequences of 'a', i.e., \$\{a, aa, aaa, ...\}\$.
36
The LOT program \$F_0 = \text{if}(\text{flip}(1/3), \epsilon, F_0 \oplus a)\$ assigns probabilities to strings that follow what named distribution?
A geometric distribution.
37
In the LOT framework, how is the prior probability \$P(H)\$ of a hypothesis (a program) calculated?
It's approximated as \$p^m\$, where \$m\$ is the number of primitives used and \$p\$ is the prior probability of a single primitive.
38
Assigning lower prior probability to hypotheses that require more primitives implements a _____ penalty.
complexity
39
The complexity penalty in the LOT prior is analogous to what principle from information theory?
The Minimum Description Length (MDL) principle.
40
In Bayesian learning, what happens to a hypothesis if it assigns a likelihood of 0 to an observed piece of data?
Its posterior probability becomes 0, and it is effectively eliminated from consideration.
41
In a learning model, _____ is the proportion of strings the model correctly accepts out of all true language strings.
recall
42
In a learning model, _____ is the proportion of strings the model classifies as 'in the language' that truly belong to it.
precision
43
The _____ score is the harmonic mean of precision and recall.
F1
44
The Bayesian LOT model learns languages like \$a^n\$ and \$a^n b^n\$ well but struggles with which computationally harder language involving three symbols?
\$a^n b^n c^n\$
45
The Bayesian model's difficulty in learning a language with a fixed, small number of embeddings (e.g., 'up to 4') suggests that fully _____ rules may be simpler to encode in LOT.
recursive
46
How does the Bayesian LOT framework model the developmental trajectory of number word learning in children?
Posterior probability mass shifts sequentially from one-knower, to two-knower, and eventually to a general counting principle (CP-knower) hypothesis.
47
In the number learning model, grasping a general, recursive counting principle corresponds to the _____ hypothesis gaining the most posterior probability.
CP-knower
48
In the 'wudsy' experiments, what was the learning task for human participants?
To infer the meaning (the concept) of the novel word 'wudsy' from labeled examples of objects.
49
In the LOT for concepts model, how are complex concepts like "blue and circle" represented?
They are represented as Boolean formulas (e.g., 'blue \$\land\$ circle') over primitive predicates for properties like color and shape.
50
According to Marr's levels of analysis, Bayesian models of cognition are typically considered to be explanations at the _____ level.
computational

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