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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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