"The meaning(s) of conditionals: Conditional probabilities, mental models, and personal utilities": Correction to Oberauer and Wilhelm (2003).

Reports an error in "The meaning(s) of conditionals: Conditional probabilities, mental models, and personal utilities" by Klaus Oberauer and Oliver Wilhelm (Journal of Experimental Psychology: Learning, Memory, and Cognition, 2003[Jul], Vol 29[4], 680-693). On page 684, Table 4, all correlations should have been identified as having a p2003-06626-018.) Five experiments were conducted to test the hypothesis that people understand conditional statements ("if p then q") as indicating a high conditional probability P(q|p). Participants estimated the probability that a given conditional is true (Experiments 1A, 1B, and 3) or judged whether a conditional was true or false (Experiments 2 and 4) given information about the frequencies of the relevant truth table cases. Judgments were strongly influenced by the ratio of pq to p?q cases, supporting the conditional probability account. In Experiments 1A, 1B, and 3, judgments were also affected by the frequency of pq cases, consistent with a version of mental model theory. Experiments 3 and 4 extended the results to thematic conditionals and showed that the pragmatic utility associated with believing a statement also affected the degree of belief in conditionals but not in logically equivalent quantified statements. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditionals and conditional probability.

The authors report 3 experiments in which participants were invited to judge the probability of statements of the form if p then q given frequency information about the cases pq, p?q, ?pq, and ?p?q (where ? = not). Three hypotheses were compared: (a) that people equate the probability with that of the material conditional, 1 - P(p?q); (b) that people assign the conditional probability, P(q/p); and (c) that people assign the conjunctive probability P(pq). The experimental evidence allowed rejection of the 1st hypothesis but provided some support for the 2nd and 3rd hypotheses. Individual difference analyses showed that half of the participants used conditional probability and that most of the remaining participants used conjunctive probability as the basis of their judgments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The negated conditional: A litmus test for the suppositional conditional?

Under the suppositional account of conditionals, when people think about a conditional assertion, "if p then q," they engage in a mental simulation in which they imagine p holds and evaluate the probability that q holds under this supposition. One implication of this account is that belief in a conditional equates to conditional probability [P(q/p)]. In this paper, the authors examine a further implication of this analysis with respect to the wide-scope negation of conditional assertions, "it is not the case that if p then q." Under the suppositional account, nothing categorically follows from the negation of a conditional, other than a second conditional, "if p then not-q." In contrast, according to the mental model theory, a negated conditional is consistent only with the determinate state of affairs, p and not-q. In 4 experiments, the authors compare the contrasting predictions that arise from each of these accounts. The findings are consistent with the suppositional theory but are incongruent with the mental model theory of conditionals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditions for the Acceptance of Deontic Conditionals.

Recent psychological research has investigated how people assess the probability of an indicative conditional. Most people give the conditional probability of q given p as the probability of if p then q. Asking about the probability of an indicative conditional, one is in effect asking about its acceptability. But on what basis are deontic conditionals judged to be acceptable or unacceptable? Using a decision theoretic analysis, we argue that a deontic conditional, of the form if p then must q or if p then may q, will be judged acceptable to the extent that the p & q possibility is preferred to the p & not-q possibility. Two experiments are reported in which this prediction was upheld. There was also evidence that the pragmatic suitability of permission rules is partly determined by evaluations of the not-p & q possibility. Implications of these results for theories of deontic reasoning are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Counterfactual and Semifactual Conditionals Prime Alternative Possibilities.

The authors examined in 3 experiments the comprehension of counterfactuals, such as "If it had rained, the plants would have bloomed," and semifactuals, such as "Even if it had rained, the plants would have bloomed," compared with indicative conditionals, "If it rained, the plants bloomed." The first experiment showed that people read the negative conjunction, "not p and not q" faster when it was primed by a counterfactual than when it was primed by an indicative conditional. They read the affirmative conjunction, "p and q" equally quickly when it was primed by either conditional. The 2nd experiment showed that people read the negated-antecedent conjunction, "not p and q" faster when it was primed by a semifactual conditional. The 3rd experiment corroborated these results in a direct comparison of counterfactuals and semifactuals. The authors discuss the implications of the results for the mental representations of different conditionals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reasoning counterfactually: Making inferences about things that didn't happen.

The authors investigated the relationship between reasoners' understanding of subjunctive conditionals (e.g., if p had happened, then q would have happened) and the inferences they were prepared to endorse. Reasoners who made a counterfactual interpretation of subjunctive statements (i.e., they judged the statement to imply that p and q did not happen) endorsed different inferences than those who did not. Those who made a counterfactual interpretation were more likely to (a)judge the situation in which p and q occurred to be inconsistent with the conditional statement and (b) make negative inferences such as modus tollens (i.e., – q therefore – p ). These findings occurred with familiar and unfamiliar content, affirmative and negative conditionals, and conditional and biconditional relations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditionals: A theory of meaning, pragmatics, and inference.

The authors outline a theory of conditionals of the form If A then C and If A then possibly C. The 2 sorts of conditional have separate core meanings that refer to sets of possibilities. Knowledge, pragmatics, and semantics can modulate these meanings. Modulation can add information about temporal and other relations between antecedent and consequent. It can also prevent the construction of possibilities to yield 10 distinct sets of possibilities to which conditionals can refer. The mental representation of a conditional normally makes explicit only the possibilities in which its antecedent is true, yielding other possibilities implicitly. Reasoners tend to focus on the explicit possibilities. The theory predicts the major phenomena of understanding and reasoning with conditionals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditional reasoning with inducements and advice

In an earlier study of conditional reasoning, Newstead et al. [Newstead, S.E., Ellis, C.E., Evans, J.St.B.T., Dennis, I., (1997). Conditional reasoning with realistic material. Thinking and Reasoning 3, 49-96] found that people drew more inferences from conditionals framed as inducements (threats and promises) than from conditionals phrased as advice (tips and warnings). The present study was designed to test the hypothesis that this difference arose from the fact that the speaker of an inducement is normally seen to have control over the consequent event whereas the giver of advice does not. In the experiment reported here, inducement and advice conditionals were constructed in brief contexts such that in either case the speaker could be seen to have high or low control. Participants drew many more conditional inferences of all kinds for high control than for low control conditionals in either context. A second finding of interest was that participants drew many more forward (antecedent to consequent) inferences than backward inferences with these kinds of realistic conditionals.     

How does feature-based attention affect visual processing?

Five experiments are reported from which it is concluded that attending on the basis of a stimulus feature (e.g., red) does not directly affect the sensory quality of stimuli that possess that feature. Feature-based attention was manipulated in a visual search task by providing information about the probability that the target would possess a given feature (e.g., "The target has a 1.0 probability of being red when present.") Feature-based attention failed to aid performance under "data-limited" conditions (i.e., those under which performance was primarily affected by the quality of the stimulus) but did affect performance under conditions that were not data limited (Experiments 1-3). If attending to a feature had affected the sensory quality of stimuli, performance should have been aided under all conditions. Experiments 4 and 5 provided converging support for this conclusion.     

Conditional reasoning, causality, and the structure of semantic memory: strength of association as a predictive factor for content effects

Available evidence indicates that responses to conditional inferences using concrete causal premises is affected by the relative number of available alternate causes (Cummins, D.D., 1995. Memory and Cognition 23 (5), 646-658). We propose that another important factor that may influence the kinds of inferences made to causal conditionals is the relative strength of association between such causes and the consequent term. We present a study with adult participants that examines the effect of strength of association on performance on a conditional reasoning task using causal premises for which there exist one highly associated potential cause for the given consequent term. We predicted that adults would produce a greater proportion of biconditional responses to invalid forms with strongly associated premises than weakly associated ones, while valid forms would not be affected by strength of association. The results are consistent with this hypothesis.     

Computational levels and conditional inference: Reply to Schroyens and Schaeken (2003).

This article is a reply to W. Schroyens and W. Schaeken's (2003; see record 2002-08431-014) critique of M. Oaksford, N. Chater, and J. Larkin's (2000; see record 2000-08540-005) conditional probability model (CP) of conditional inference. It is argued that their meta-analysis does not falsify CP because the evidence may bear on more than one computational level of explanation. Moreover, it is argued that CP provides a rational account of more of the data than W. Schroyens and W. Schaeken's mental models theory. Other points are also addressed. It is suggested that W. Schroyens and W. Schaeken's model and CP converge on the importance of probabilistic prior knowledge in conditional inference. This is consistent with the normative literature, which (like CP) treats conditionals in terms of subjective conditional probabilities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cytogenetic studies of epithelial ovarian carcinoma

We performed cytogenetic studies of 36 human epithelial ovarian carcinomas using in situ culture and robotic harvest. We obtained analyzable metaphases of all 36 tumors (100%). One or more chromosomally abnormal clones were observed in 80% of tumors. Common clonal chromosome gains (each occurring in six or more cases) included +1, +2, +3, +6, +7, +9, and +12. Common clonal chromosome losses (occurring in 12 or more cases) included -X, -4, -8, -11, -13, -15, -17, and -22. Common clonal structural abnormalities (occurring in four or more cases) involved regions 1p36, 1q32, 1q42, 3p13-->p26, 3q26-->q29, 7p22, 9q34, 11p13-p15, 17q21-->q23, 19p13.3, and 19q13.3. Trisomy 12 was noted as the sole anomaly in three of five borderline and grade 1 tumors. Two grade 2 tumors contained i(1q), -14, -15 and -22. The results suggest that the pathogenesis of borderline and low-grade tumors may differ from that of higher grade tumors. Two high-grade tumors had an apparent translocation between 17q21 and 19p13.3, two chromosome regions believed to be critical to ovarian carcinogenesis.     

Conditional reasoning in children.

Conditional reasoning ability is analyzed in the context of Piaget's logical operational system. It is argued that facility in concrete operations is necessary and sufficient for competence in the simple syllogistic forms, though dealing with conditional statements in certain more complex contexts requires formal operations. Data from 3 studies are presented in support of these assertions. Using a total of 120 Ss in Grades 1–5, results of Exps I and II show that presentation of statements in a concrete conversational context elicited substantially more correct conditional reasoning than has been found in earlier studies. Results of Exp III, which used a total of 154 Ss in Grades 2, 4, 6, and 8, indicate that a distinction is drawn between comprehension that p (not p) entails the possibility of q (given If p, then q) and comprehension that q entails the possibility of p. The former is less difficult than the latter, and only the latter requires concrete operations. A methodological implication of these studies is that in the assessment of logical competence, results depend heavily on the exact manner of presentation, as well as on the specific logical operation being assessed. Implications for the theory of formal operations and for the study of traditional syllogistic reasoning are also discussed. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Theories of Conditional Reasoning: A Developmental Examination of Competing Hypotheses.

Children and adolescents were presented with problems that contained deontic (i.e., if action p is taken, then precondition q must be met) or causal (i.e., if event p occurs, then event q will transpire) conditionals and that varied in the ease with which alternative antecedents could be activated. Results showed that inferences were linked to the availability of alternative antecedents and the generation of "disabling" conditions (claims that the conditionals were false under specific circumstances). Age-related developments were found only on problems involving indeterminate inferences. Correlations among inferences differed for children and adolescents. The findings provide stronger support for domain-general theories than for domain-specific theories of reasoning and suggest, under some conditions, age-related changes in the roles of implicit and explicit processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of Y3 receptor-mediated synaptic inhibition by chimeric neuropeptide Y-peptide YY peptides in the rat brainstem

Archival material from primary and metastatic renal clear cell carcinomas of 25 patients was studied by comparative genomic hybridization. Copy number changes of entire chromosomes or chromosomal subregions were detected in 22 primary and 21 metastatic tumors. Copy number changes affected the following chromosomes in at least 20% of the 25 primary tumors (minimal common region given in parentheses): gains were noted for chromosomes 1 (1q21-->q23), 5 (5q31-->q34), 7 (7p), 8 (8q), 16 (16p), 17 (17q12-->qter), 19, and 22 (22q12-->qter); losses were revealed for chromosomes 3 (3p21-->pter), 8 (8p23-->pter), 14(14q21-->qter), and Y. The same chromosomal regions that were involved in primary renal clear cell carcinomas were also found in the respective metastatic tumors but with strikingly different frequencies for a few regions. Metastatic tumors showed a significantly higher frequency of complete or partial gains of the long arm of chromosome 1, in particular at 1q21-->q23 than primary tumors (16 cases versus 6 cases; P < 0.005). These data suggest a correlation of metastatic events in renal clear cell carcinomas with an increase in the copy number of genes located at 1q, in particular at 1q21-->q23. In contrast, the entire or partial loss of the short arm of chromosome 3 was significantly less frequent in metastatic tumors (8 cases versus 15 cases; P < 0.025). The validity of 1q and 3p copy number changes detected by comparative genomic hybridization was confirmed by interphase cytogenetics with region-specific yeast artificial chromosomes to paraffin-embedded tumor tissue sections.     

Putting Ifs to Work: Goal-Based Relevance in Conditional Directives.

Conditional directives are used by speakers to instruct hearers which actions are to be taken should certain events occur. The authors demonstrate that conditional directives are distinct from indicative conditionals in which speakers predict what is likely to be observed should certain events occur. The 1st set of experiments shows that goal structure determines what information speakers will select to test whether conditional directives have been followed but that these selections do not reflect their interpretations of the deontic necessity and sufficiency of the conditional relation. The 2nd set of experiments shows that formulations of conditional directives differ in how clearly speakers consider them to express their situation-specific intentions and that hearers accurately perceive what speakers intend them to do as a result of these formulations. The authors' findings illustrate a form of social rationality common in everyday interaction, which broadens normative conceptions of conditionals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Consequential Conditionals: Invited and Suppressed Inferences From Valued Outcomes.

Consequential conditionals are defined as "if P then Q" statements, where P is an action, and Q a predicted outcome of this action, which is either desirable or undesirable to the agent. Experiment 1 shows that desirable (viz. undesirable) outcomes invite an inference to the truth (viz. falsity) of their antecedent. Experiment 2 shows that the more extreme the outcome is, the stronger the invited inference is. Experiment 3 shows that modus ponens from premises "If A then C, A" can be suppressed with the introduction of a consequential conditional, "If C then Q," where Q is an undesirable outcome. Experiment 4 shows that the more undesirable Q is, the larger the suppression is. The authors discuss how these results can enrich current approaches of conditional inference on the basis of mental models, complementary necessary conditions, and conditional probabilities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Economical and biological efficiencies of beef cattle differing in level of milk production

Thirty-three osteosarcomas (OS) were analyzed cytogenetically. Clonal chromosome changes were detected in 17 cases. Six tumors had chromosome numbers in the diploid range, 6 in the triploid range, 1 in the tetraploid range and 1 in the pentaploid range, while 3 tumors had multiple clones with different ploidy levels. Including the present 17 tumors, a total of 27 OS with clonal aberrations have been reported. The recognizable structural rearrangements in these 27 tumors clustered to chromosome arms 1p, 1q, 3p, 3q, 7q, 11p, 17p and 22q. Chromosome bands 1q11, 1q21, 1q42 and 7q11 were the most frequently rearranged, and the most common numerical rearrangements were -3, -10, -13 and -15. Supernumerary ring chromosomes, in 2 tumors as the sole change, were found in all 3 parosteal OS, which is in agreement with the findings in 1 previously reported parosteal OS. The association between ring formation and parosteal morphology represents the first cytogenetic-morphologic entity among OS.