SCXT 350

 

Exam #1

 

 

 

 

 

Name ___________________________________

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Friday, February 26

100 pts.

 

 

The story so far.

 

A central (perhaps the central) commitment of Cognitive Science is to the idea that intelligent activity, language, cognition, perception and the like is computational or algorithmetic in nature. 

 

 

1.         (10 pts.)           Give a definition of an algorithm together with an example.  What is the connection between an algorithm and a computer program?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Descartes had an opinion on this topic.  While he was thinking of automata, we can rephrase his deliberation in terms of computer programs.  He said that, while it was conceivable that we could construct a mechanical dog that could fool us, it would not be possible to construct a person.

 

2.         (10 pts.)           Descartes promised us two reasons why we would not be fooled by an automaton, and then (in the segment we read gave us one.  What was it?

 

 

 

 

 

 

 

 

 

 

 

 

The conversation now shifts, many years later, to Turing, who considered the question “Can machines think?”, and proposed what is now known as the Turing Test.

 

3.         (10 pts.)           Give a description of the Turing test as Turing proposed it.  It would help to draw a diagram.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.         (5 pts.)             Turing’s paper can be viewed as a response to Descartes in that if a computer program were to pass the Turing Test, it would do something Descartes though impossible.  What was that?

 

 

 

Back to computers and algorithms for a bit. 

 

5.         (10 pts.)           What is the Turing-Church hypothesis, and what role does it play in the statement that “cognition is computable?”

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6.         (15 pts.)           To understand what computable might mean, we need some examples.  We begin with the notion of a computer.  In talking about computers, we sketched an “architectural view” of a computer, labeling an ALU, control unit, memory, input-output, and long-term storage.  Reproduce that sketch, and give brief definitions of the control unit, ALU, and memory.  A full credit response would do more than simply saying what the letters in ALU stood for.

 

 

 

7.         (10 pts.)           In exploring the idea of a computer further, we listed five things that a computer could do.  List these, with brief explanations.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8.         (5 pts. each).  Finally, in order to understand what computers can and can not do, it is important to learn something of a programming language.  Please answer the following questions in LISP:

 

a.         Write (3 + 2) / (7 – 6) in LISP

 

 

 

 

 

 

                                    (continued on next page)

 

                                    (continuation of problem 8)

 

 

Without using first, second, third, etc., write expressions which will retrieve

 

b,         The first item in the list lst

 

 

 

 

c.         The second item in the list lst

 

 

 

 

 

d.         Using defun, write a function average which will take two numbers and return their average.  For example (average 4 6) should return 5.

 

 

 

 

 

 

 

9.         (10 pts.)           Finally, David Marr proposed that if we wanted to think of cognition as information processing, we needed to provide explanations at several levels.  List, and briefly describe, Marr’s three levels of explanation.