On the planet Kyron, in a faraway galaxy, there are four kinds of unisex humanoids:

A TWE is a Kyronian who is born a child and remains a child throughout its lifetime.

A NEL is a Kyronian who is born an adult and remains an adult throughout its lifetime.

A BIT is a Kyronian who is born a child and becomes an adult.

A DEK is a Kyronian who is born an adult and becomes a child.

Your task will be to analyze two pieces of information given to you about a particular Kyronian, and to decide whether these two pieces of information describe a TWE, NEL, BIT, or DEK. The two pieces of information will be a description of the Kyronian in the year of its birth, 1979,

and a description of the Kyronian 21 years later, in the year 2000. The description of the Kyronian in the year 1979 will appear on the left and the description of the Kyronian in the year 2000 will appear to the right. Each description may take either of two forms. The description may be verbal, consisting of any of the words TWE,nel,BIT,OR dek; or the description may be a symbol, consisting of either

the symbol + (child)

the symbol & (adult)

the symbol I (inconsistent)

In order to make these judgements, you need to know two additional facts. First, when a kyronian is first born, it is not possible to distinguish a TWE from a BIT, or a NEL from a DEK. The reason for this is that at birth, Both a TWE and a BIT appear to be children, and both a NEL and a DEK appear to be adults. It is only after one has an opportunity to see what effect, if any, the aging process has had, that one can distinguish a TWE from a BIT, or a NEL from a DEK. Second, after 21 years, it is possible to make these distinctions, because a BIT has changed from a child to an adult, and a DEK has changed from an adult to a child. A TWE and a nel look exactly as they did at birth. The kinds of judgements you will be making are of four types:

1. The first category of judgement involves two symbols. You will be presented first with a symbol for a Kyronian at birth in 1979, then the symbol for the same Kyronian in the year 2000, and finally with three alternative verbal descriptions. Your task will be to judge which of the three verbal descriptions correctly identifies the kind of Kyronian depicted in the symbols. For example, you might be presented with the following problem:

& + D NEL BIT
The correct answer to this problem is DEK, because the symbols depict a Kyronian who was born an adult and became a child.

2. The second category of judgement involves a verbal description of a Kyronian at birth in 1979, And a symbol of the same Kyronian 21 years later in the year 2000. Your task is to judge which of the three verbal descriptions correctly identifies the kind of Kyronian depicted in the verbal description and the symbol. There is one important thing for you to realize in this kind of problem. Since it is not possible to tell at birth whether the individual is a TWE or a BIT, on the one hand (since both appear as children), or a NEL or a DEK, on the other (since both appear as adults), the verbal description for 1979 can be counted on only to identify correctly the physical appearance of the Kyronian; it may or may not correctly predict the appearance of the same Kyronian 21 years later. It is simply not possible, in 1979, to know what the Kyronian will look like 21 years later. Thus, if you are told that the Kyronian is a TWE, you can be assured that that Kyronian appears to be a child; you cannot be certain that 21 years later the Kyronian will still appear to be a child; if the Kyronian is actually a BIT, it will appear to be an adult. Similarly, if you are told the Kyronian is a BIT, You cannot be sure it is not actually a TWE.The same principle applies to NEL and DEK. If you are told that the Kyronian appears to be a NEL or a DEK in 1979, You can be sure only that the Kyronian appears to be an adult. You cannot be sure of what the Kyronian will look like in the year 2000. To summarize, the verbal description in 1979 will always correctly describe the Kyronian's physical appearance in 1979, but it may or may not correctly predict the Kyronian's physical appearance in 2000. Consider two

examples:NEL & NEL BIT DEK
The correct answer is NEL, since the Kyronian appears to be an adult in 1979, and appears to be an adult in 2000 as well. NEL thus correctly predicted the Kyronian's physical appearance in 2000.

DEK & DEK NEL BIT
The correct answer is again NEL, since the Kyronian appears to be an adult in both 1979 and 2000. In this example, DEK failed to predict correctly the physical appearance of the Kyronian in 2000 .As always, however, the description of physical appearance was correct for 1979.

3. The third category of judgement involves a symbol for a Kyronian in the year 1979, followed by a verbal description of the same Kyronian in the year 2000. Your task is to indicate which of the two symbols correctly describes the physical appearance of the Kyronian in the year 2000. Watch out for the case in which the verbal description of the Kyronian in the year 2000 is inconsistent with the symbol of the Kyronian in the year 1979. In this event you choose as your answer the letter "I". An inconsistency represents an important situation---a contradiction of terms. Consider two example problems:+

TWE & + I

Here the correct answer is + , since the Kyronian was born as a child and remained a child throughout its lifetime. Note that the verbal description is consistent with the symbol.&

BIT + & I

In this example, the correct answer is I . The symbol depicts an adult Kyronian in 1979, But a bit born in 1979 as a child. Since this situation is impossible, The symbol and verbal description are inconsistent.

4. The forth category of judgement involves two verbal descriptions of a Kyronian, one in 1979 and another in 2000. The verbal descriptions are followed by two alternative symbols and the letter I . Your task is to select the symbol that correctly depicts in 2000 the Kyronian described in the two verbal descriptions, or else to indicate that the two verbal descriptions are inconsistent with each other (I). There are two important things for your to realize in this kind of problem, First, remember that verbal descriptions in 1979 always accurately represent the physical appearance of the Kyronian in 1979, but may or may not accurately predict the Kyronian's physical appearance in 2000. Second, it is possible for two verbal descriptions to be inconsistent. Two verbal descriptions are inconsistent if one describes a Kyronian being born as an adult, and the other describes the Kyronian being born as a child, or visa versa. This not simply a case of misprediction; it is an impossibility. Consider some examples of this kind of problem:DEK

DEK & I +

In this case the correct answer is obviously + , since in 2000 a DEK appears to be a child.TWE BIT I

+ &

Here, the correct answer is & . The first term describes a Kyronian who was born a child; it incorrectly predicts that the Kyronian will remain a child. In fact, the second term shows that the child becomes an adult.NEL TWE &

+ I

Here, the correct answer is I , because the term describes a Kyronian born an adult, and the second term describes a Kyronian born as a child. This is impossible, and hence the two verbal descriptions are inconsistent. Like the sample problem above, the problems that follow are in two parts. The left side contains two pieces of information from 1979 and from 2000. The right side consists of three pieces of response choices. If the evidence from 2000 is a symbol, The response choice are verbal descriptions. If the evidence from 2000 is a verbal description, the response choices will be symbols plus a letter "I" (representing a response of "Inconsistent"). Answers appear at the end of the chapter.

A B C
1. & DEK + I &
2. & TWE + I &
3. + & TWE BIT NEL
4. BIT + BIT DEK TWE
5. TWE + BIT TWE NEL
6. + DEK & + I
7. + BIT & + I
8. BIT BIT + I &
9. & NEL + I &
10. + NEL & I +
11. BIT DEK & I +
12. TWE BIT & + I
13. + + NEL DEK TWE
14. DEK & BIT NEL TWE
15. & + NEL TWE DEK
16. NEL & NEL BIT DEK
17. NEL NEL & I +
18. BIT NEL I + &
19. DEK + NEL DEK BIT
20. NEL BIT I + &
21. NEL TWE & + I
22. NEL + DEK TWE BIT
23. + TWE & + I
24. BIT TWE & + I
25. TWE & DEK NEL BIT
26. BIT & BIT TWE DEK
27. & & NEL TWE DEK
28. NEL DEK & + I
29. DEK NEL I + &
30. DEK TWE & I +
31. DEK DEK + & I
32. & BIT & I +
33. TWE DEK + & I
34. TWE NEL + & I
35. DEK BIT + & I
36. TWE TWE & I +