Strategies during complex conditional inferences

In certain contexts reasoners reject instances of the valid Modus Ponens and Modus Tollens inference form in conditional arguments. Byrne (1989) observed this suppression effect when a conditional premise is accompanied by a conditional containing an additional requirement. In an earlier study, Rumain, Connell, and Braine (1983) observed suppression of the invalid inferences “the denial of the antecedent” and “the affirmation of the consequent” when a conditional premise is accompanied by a conditional containing an alternative requirement. Here we present three experiments showing that the results of Byrne (1989) and Rumain et al. (1983) are influenced by the answer procedure. When reasoners have to evaluate answer alternatives that only deal with the inferences that can be made with respect to the first conditional, then suppression is observed (Experiment 1). However, when reasoners are also given answer alternatives about the second conditional (Experiment 2) no suppression is observed. Moreover, contrary to the hypothesis of Byrne (1989), at least some of the reasoners do not combine the information of the two conditionals and do not give a conclusion based on the combined premise. Instead, we hypothesise that some of the reasoners have reasoned in two stages. In the first stage, they form a putative conclusion on the basis of the first conditional and the categorical premise, and in the second stage, they amend the putative conclusion in the light of the information in the second premise. This hypothesis was confirmed in Experiment 3. Finally, the results are discussed with respect to the mental model theory and reasoning research in general.     

Strategies in temporal reasoning

Researchers currently working on relational reasoning typically argue that mental model theory (MMT) is a better account than the inference rule approach (IRA). They predict and observe that determinate (or one-model) problems are easier than indeterminate (or two-model) problems, whereas according to them, IRA should lead to the opposite prediction. However, the predictions attributed to IRA are based on a mistaken argument. The IRA is generally presented in such a way that inference rules only deal with determinate relations and not with indeterminate ones. However, (a) there is no reason to presuppose that a rule-based procedure could not deal with indeterminate relations, and (b) applying a rule-based procedure to indeterminate relations should result in greater difficulty. Hence, none of the recent articles devoted to relational reasoning currently presents a conclusive case for discarding IRA by using the well-known determinate vs indeterminate problems comparison.     

A dual-process specification of causal conditional reasoning

There are two accounts describing causal conditional reasoning: the probabilistic and the mental models account. According to the probabilistic account, the tendency to accept a conclusion is related to the probability by which cause and effect covary. According to the mental models account, the tendency to accept a conclusion relates to the availability of counterexamples. These two accounts are brought together in a dual-process theory: It is argued that the probabilistic reasoning process can be considered as a heuristic process whereas the mental models account can be seen as its analytic counterpart. Experiment 1 showed that the two processes differ on a temporal dimension: The variation in fast responses was best predicted by the variation in likelihood information, while the variation in slow responses was best predicted by variation in counterexample information. Experiments 2 and 3 validate the override principle: The likelihood conclusion can be overwritten when specific counterexamples are retrieved in time. In Experiment 2 both accounts were compared based on their difference in input. In Experiment 3 we used a verbal protocol analysis to validate the dual-process idea at the output level. The data of the three experiments provide converging support for framing the two reasoning accounts in a dual-process theory.     

Truth table tasks: The relevance of irrelevant

Two types of truth table tasks are used investigating mental representations of conditionals: a possibilities-based and a truth-based one. In possibilities tasks, participants indicate whether a situation is possible or impossible according to the conditional rule. In truth tasks participants evaluate whether a situation makes the rule true or false, or is irrelevant with respect to the truth of the rule. Comparing the two-option version of the possibilities task with the truth task in Experiment 1, the possibilities task yields logical answer patterns whereas the truth task yields defective patterns. Adding the irrelevant option to the possibilities task in Experiment 2 leads to a considerable amount of defective patterns in the possibilities task, but still to more logical patterns in the possibilities task than in the truth task. Experiment 3 shows that directionality matters since rule-to-situation tasks yield more logical answer patterns than do situation-to-rule tasks. We conclude that both task types are not comparable as such since wording, number of options and directionality influence the results.     

The Role of Organization in the Learning of a Sensori-Motor Task

Two experiments investigated the ability of five- and six-month-old Guatemalan infants to discriminate human faces visually and to associate faces and voices differing in age and sex. The 32 infants in Experiment I discriminated between photographs of a man, a woman, and a seven-year-old boy. They did not, however, discriminate between photographs of two men, two women, or of two seven-year-old boys. The 24 infants in Experiment II were presented three different pairs of photographs of faces. One pair consisted of a man and a woman, another of a woman and a child, and the third of a man and a child. Voices appropriate to each pair of photographs accompanied the presentation of the visual stimulus. Looking at the woman and child seemed to be influenced by the presentation of a woman's voice and a boy's voice. Appropriate voices did not alter looking behavior with regard to the woman and man or the man and child.     

The Consequences of Ignoring Variability in Measurement Occasions Within Data Collection Waves in Latent Growth Models

In longitudinal data collection, it is common that each wave of collection spans several months. However, researchers using latent growth models commonly ignore variability in data collection occasions within a wave. In this study, we investigated the consequences of ignoring within-wave variability in measurement occasions using a Monte Carlo simulation and an empirical study. The results of the simulation study showed that ignoring heterogeneity resulted in biased estimates for some parameters, especially when heterogeneity was large and assessment dates had a skewed distribution. Models constructed on person-specific time points yielded precise estimates and more adequate model fit. In the empirical study, we demonstrated different time coding strategies with a subsample taken from Early Childhood Longitudinal Study Kindergarten Cohort.     

The Mechanisms Involved in the Behavior of White Rats on the Inclined Plane

Semantic tasks, such as lexical decision making and word recognition, have not produced a mood priming effect. Earlier studies have been criticized because they included (a) mood induction techniques that required instruction to feel the mood, and (b) the use of overleamed tasks that did not require controlled processing. In this pair of experiments, the authors attempted to address these criticisms. However, the results of this study did not demonstrate a mood priming effect for happy and sad subjects who appraised sentence content as being happy or sad. The results of this study supported the dissociation of semantic and episodic memory.     

Some Changing Aspects of the Self-Concept of Pubescent Males

Fifty Ss initially rated themselves and a friend on intelligence. Ss were then divided into High and Low Acceptance groups using a self-ideal discrepancy. It was predicted that the High Acceptance group would generally rate themselves higher on the self-concept measures than would the Low Acceptance group. Further, and most importantly, it was predicted that the High group would rate their friend's intelligence as similar to their own, while the Low group would rate their friend higher than themselves and, therefore, closer to their ideal. The predictions were generally supported, although the High group failed to exhibit the expected trait similarity. It was concluded that a trait complementarity model was most appropriate for interpreting the results of both groups.     

The archetypal interpretation of fairy tales: Bluebeard

Evil has its divine depths, into which it is irreverent to look.