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1.1 root 1: .\" @(#)p2 6.1 (Berkeley) 5/23/86
2: .\"
3: .NH
4: Educational Assumptions and Design.
5: .PP
6: First, the way to teach people how to do something
7: is to have them do it. Scripts should
8: not contain long pieces of explanation; they should
9: instead frequently ask the student to do some task.
10: So teaching is always by example: the typical
11: script fragment shows a small example of some
12: technique and then asks the
13: user to either repeat that example or
14: produce a variation on it.
15: All are intended to be easy enough that most students will get most questions
16: right, reinforcing the desired behavior.
17: .PP
18: Most lessons fall into one of three types.
19: The simplest presents a lesson and asks for a yes or no
20: answer to a question.
21: The student is given a chance to experiment before replying.
22: The script checks for the correct reply.
23: Problems of this form are sparingly used.
24: .PP
25: The second type asks for a word or number as an answer.
26: For example a lesson on files might say
27: .IP
28: .I
29: How many files are there in the current directory?
30: Type ``answer N'', where N is the number of files.
31: .R
32: .LP
33: The student is expected to respond (perhaps after experimenting) with
34: .LP
35: .I
36: answer 17
37: .R
38: .LP
39: or whatever.
40: Surprisingly often, however, the idea of a substitutable argument
41: (i.e., replacing
42: .I
43: N
44: .R
45: by
46: 17)
47: is difficult for non-programmer students,
48: so the first few such lessons need real care.
49: .PP
50: The third type of lesson is open-ended \(em
51: a task is set for the student,
52: appropriate parts of the input or output are monitored,
53: and the student types
54: .ul
55: ready
56: when the task is done.
57: Figure 1 shows a sample dialog that illustrates the last of these, using two
58: lessons about the
59: .I cat
60: (concatenate, i.e., print) command taken
61: from early in the script that teaches
62: file handling.
63: Most
64: .I learn
65: lessons are of this form.
66: .KF
67: .TS
68: box, center;
69: c.
70: T{
71: Figure 1: Sample dialog from basic files script
72: .sp
73: (Student responses
74: in italics; `$' is the prompt)
75: .nf
76: .sp
77: A file can be printed on your terminal
78: by using the "cat" command. Just say
79: "cat file" where "file" is the file name.
80: For example, there is a file named
81: "food" in this directory. List it
82: by saying "cat food"; then type "ready".
83: $ \fIcat food\fR
84: this is the file
85: named food.
86: $ \fIready\fR
87:
88: Good. Lesson 3.3a (1)
89:
90: Of course, you can print any file with "cat".
91: In particular, it is common to first use
92: "ls" to find the name of a file and then "cat"
93: to print it. Note the difference between
94: "ls", which tells you the name of the file,
95: and "cat", which tells you the contents.
96: One file in the current directory is named for
97: a President. Print the file, then type "ready".
98: $ \fIcat President\fR
99: cat: can't open President
100: $ \fIready\fR
101:
102: Sorry, that's not right. Do you want to try again? \fIyes\fR
103: Try the problem again.
104: $ \fIls\fR
105: \&.ocopy
106: X1
107: roosevelt
108: $ \fIcat roosevelt\fR
109: this file is named roosevelt
110: and contains three lines of
111: text.
112: $ \fIready\fR
113:
114: Good. Lesson 3.3b (0)
115:
116: The "cat" command can also print several files
117: at once. In fact, it is named "cat" as an abbreviation
118: for "concatenate"....
119: .fi
120: T}
121: .TE
122: .sp
123: .KE
124: .PP
125: After each correct response the computer congratulates
126: the student and indicates the lesson number that
127: has just been completed, permitting the student
128: to restart the script after that lesson.
129: If the answer is wrong, the student
130: is offered a chance to repeat the lesson.
131: The ``speed'' rating of the student (explained in
132: section 5) is given after the lesson number when the lesson is completed successfully; it is
133: printed only for the aid of script authors checking
134: out possible errors in the lessons.
135: .br
136: .PP
137: It is assumed that there is no foolproof way
138: to determine if the student truly ``understands''
139: what he or she is doing;
140: accordingly,
141: the current
142: .I
143: learn
144: .R
145: scripts
146: only measure performance, not comprehension.
147: If the student can perform a given task, that is deemed to be ``learning.''
148: .[
149: skinner teaching 1961
150: .]
151: .PP
152: The main point of using the computer is that what the student
153: does is checked for correctness immediately.
154: Unlike many CAI scripts, however, these scripts provide
155: few facilities for dealing with wrong answers.
156: In practice, if most of the answers are not right the script is
157: a failure; the universal solution to student error is to provide
158: a new, easier script.
159: Anticipating possible wrong answers is an endless job, and it is really
160: easier as well as better to provide a simpler script.
161: .PP
162: Along with this goes the assumption that
163: anything can be taught to anybody if it can
164: be broken into sufficiently small pieces. Anything
165: not absorbed in a single chunk is just subdivided.
166: .PP
167: To avoid boring the faster students,
168: however,
169: an effort is made in the files and editor scripts to provide
170: three tracks of different difficulty.
171: The fastest sequence of lessons
172: is aimed at roughly the bulk and speed of a typical tutorial
173: manual and should be adequate for review and for
174: well-prepared students.
175: The next track is intended for most users and is roughly
176: twice as long. Typically, for example, the fast track
177: might present an idea and ask for a variation on the
178: example shown; the normal track will first
179: ask the student to repeat the example that was shown
180: before attempting a variation.
181: The third and slowest track, which is often
182: three or four times the length of the fast track,
183: is intended to be adequate for anyone.
184: (The lessons of Figure 1 are from the third track.)
185: The multiple tracks also mean that a student repeating a course is unlikely
186: to hit the same series of lessons; this makes it profitable for a shaky
187: user to back up and try again, and many students have done so.
188: .PP
189: The tracks are not completely distinct, however.
190: Depending on the number of correct answers the student has given for the
191: last few lessons, the program may switch tracks.
192: The driver is actually capable of following
193: an arbitrary directed graph of lesson sequences, as discussed in section 5.
194: Some more structured arrangement, however, is used in all current scripts
195: to aid the script writer in organizing the material into lessons.
196: It is sufficiently difficult
197: to write lessons
198: that the three-track theory
199: is not followed very closely
200: except in
201: the files and editor scripts.
202: Accordingly,
203: in some cases, the fast track is produced merely by skipping
204: lessons from the slower track.
205: In others, there is essentially only one track.
206: .PP
207: The main reason for using the
208: .I
209: learn
210: .R
211: program rather than
212: simply writing the same material as a workbook
213: is not the selection of tracks, but
214: actual hands-on experience.
215: Learning by doing
216: is much more effective
217: than pencil and paper exercises.
218: .PP
219: .I Learn
220: also provides a mechanical check on performance.
221: The first version in fact would not let
222: the student proceed unless it
223: received correct answers to the questions
224: it set and it would not tell a student the right answer.
225: This somewhat Draconian approach has been moderated
226: in version 2.
227: Lessons are sometimes badly worded or even just plain wrong;
228: in such cases,
229: the student has no recourse.
230: But if a student is simply unable to complete one lesson,
231: that should not prevent access to the rest.
232: Accordingly, the current version of
233: .I learn
234: allows the student to skip
235: a lesson that he cannot pass;
236: a ``no'' answer to the ``Do you want to try again?''
237: question in Figure 1 will pass to the next lesson.
238: It is still true that
239: .I learn
240: will not tell the student the right answer.
241: .PP
242: Of course, there are valid objections to the
243: assumptions above.
244: In particular, some students may object to
245: not understanding
246: what they are doing;
247: and the procedure of smashing everything into small pieces may provoke
248: the retort ``you can't cross a ditch in two jumps.''
249: Since writing CAI scripts is considerably
250: more tedious than ordinary manuals, however, it is safe
251: to assume that there will always be alternatives to the
252: scripts as a way of learning.
253: In fact, for a reference manual of 3 or 4 pages it would
254: not be surprising to have a tutorial manual of 20 pages
255: and a (multi-track) script of 100 pages. Thus the reference manual
256: will exist long before the scripts.
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