Suppression Task

1. Suppression Task Claudia van Kruistum December 12th, 2005

2. Questions • What is the pattern of results? • Are subjects good at reasoning, i.e. are they consistent? • Is there any influence of the experimental setup on the data? If so, what? Claudia van Kruistum

3. Materials & Methods • 4 subjects, taped on video • subject 1 & 2: 8 questions • subject 3 & 4: 10 questions • repetitition of the first two questions • explanation on first page • how it works: • subjects tick off answer(s) without intervention; • are asked for motivation; • are allowed to change answer. Claudia van Kruistum

4. Prototypical question If Mary has an essay to write, she studies late in the library. If the library is open, Mary studies late in the library. Mary has an essay to write. Which conclusion(s) can you draw? • None. • Mary has an essay to write. • Mary doesn’t have an essay to write. • Mary has textbooks to read. • Mary doesn’t have textbooks to read. • Mary studies late in the library. • Mary doesn’t study late in the library. • The library is open. • The library isn’t open. • Other, namely... Claudia van Kruistum

5. Answer patterns Claudia van Kruistum

6. Subject 1 • Very consistent • The additional conditional as a strengthening: • rq • In combination with alternative conditional: • (p s) rq Claudia van Kruistum

7. Subject 1: additional premise as strengthening If Mary has an essay to write, she studies late in the library. If the library is open, Mary studies late in the library. Mary doesn’t study late in the library. E: I’m not saying there is another conclusion. S: Yes but I’m just thinking, ehm.. [pause] No I’m sorry, I’m saying it wrong, the library is not open. E: OK. S: Because if the library were open, she would stay late in the library anyhow. E: OK. S: Whether she has an essay to write or not, that doesn’t matter. So I’m going to tick off that one as well. Yes. That’s not mutually exclusive at all. Claudia van Kruistum

8. Subject 2 • With additional premise: pq. • With alternative premise: p sq. • BUT: • Any conclusion q makes r salient as possible ab: • p sq • p • q • (p s)  rq • r • He forgets to conclude r in the first task, but corrects himself immediately after exercise. • No information about textbooks, then s. But changes this strategy. • Is inconsistent in task 6. Claudia van Kruistum

9. Subject 2: what is he doing? If Mary has an essay to write, she studies late in the library. If the library is open, Mary studies late in the library. Mary doesn’t have an essay to write. S: [long pause] I have one conclusion. E: Which conclusion is that? S: Mary doesn’t have an essay to write. E: OK. And why have you drawn that one? S: That’s what’s in the text. E: OK. Let’s go to some other conclusions. Can we say anything about textbooks? S: No, it doesn’t say a thing about textbooks. E: So? S: So I can’t draw conclusions. E: Can we say anything about her studying late in the library or not? S: No, because she doesn’t have to write an essay, but she is allowed to write one, so maybe she will. E: [pause] And then..? S: So I can’t say anything about that. E: [pause] S: She doesn’t have to write an essay, but maybe she is... it is 12 o’clock and she is still studying in the library. E: So she can have another reason to..? S: No, she may even write an essay. But she doesn’t have to do so. E: She doesn’t have to do so? S: She doesn’t have to do so, but.. that doesn’t.. it doesn’t say: She is notallowed to write an essay. E: Alright. [pause] OK. Ehm.. can we say anything about the library being open or not? S: No. E: Why not? S: It doesn’t say anything about her either being or not being in the library. Claudia van Kruistum

10. Subject 3 • Reasons to both premises separately, and from answer set to second premise: • pq, p / q • sq, q / s • p, q, s • Changes this strategy at question 6. • Now he combines the two conditionals: • Antecedent given: (pr)q • Consequent given: (pr)q • (ps)q Claudia van Kruistum

11. Subject 3: changing strategies If Mary has an essay to write, she studies late in the library. If the library is open, Mary studies late in the library. Mary doesn’t have an essay to write. E: OK. Which conclusion have you marked first of all? S: First of all, I’ve got: Mary doesn’t have an essay to write. Because: ‘Mary doesn’t have an essay to write.’ [third premise] E: Yes. S: Secondly, I’ve got: Mary doesn’t study late in the library. E: Yes. S: Because: Mary doesn’t have an essay to write, and if Mary doesn’t have an essay to write, she doesn’t study late in the library. E: Yes. S: Thirdly, I’ve got: The library isn’t open. E: Yes. S: Because if the library were open, Marie would study late in the library. [pause] E: Can you say something more about that? The last one? S: [pause] Ehm.. [long break] Well, now I’m starting to doubt. E: Why are you doubting? S: Well, Mary doesn’t have an essay to write. E: Yes. S: But that doesn’t say anything about the library. E: Yes. S: So actually eh.. I shouldn’t have ticked off that one. Claudia van Kruistum

12. Subject 4 • With additional premise: (pr) q. • With alternative premise: (ps) q. • BUT: • Refuses backward inferences up to question 6. • Then changes strategy: additional premise as strengthening. • And: any conclusion q makes r salient as possible ab. Claudia van Kruistum

13. Conclusions • Pattern of results is highly diverse. • Only 2 out of 8 - AC (additional) and DA (alternative) -get the same conclusions. • Most subjects are not consistent, i.e. they are trying to fix an interpretation. • Only one subject is completely consistent. • Something happens in task 6 for 3 subjects. • Repetition of questions reveals a change in strategy. • The given answer set influences interpretation. • Highlights information not available, e.g. if Mary will read textbooks or not. • Highlights possibility of library being closed. • Some subjects reason from premises to answer set, and from answer set back to premises. Claudia van Kruistum