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. (shrink)

"Under the auspices of the International Union of Psychological Science.".

The essays appearing in these two volumes are based on Keynote and State-of-the-Art Lectures delivered at the XXVth International Congress of Psychology, in Brussels, July 1992. The Brussels Congress was the latest in a series of conferences which are organized at regular intervals under the auspices of the International Union of Psychological Science, the main international organization in the field of Scientific Psychology. The first of those meetings took place in Paris in 1889. An important function of the International Congresses (...) is to promote communication between different specializations in Psychology. Speakers were therefore asked to present lectures and discussions in their own fields of study, in a way that would be accessible to fellow psychologists active in other fields. State-of-the-Art lecturers were specifically asked to prepare a tutorial review on a topic which, in the view of the Program Committee, had recently given rise to particularly important developments. These contributions are included in Volume Two. Keynote lecturers were left free to address whatever subject they felt was of greatest interest. The chapters in Volume 1 are preceded by the Presidential Address by Mark R. Rosenzweig. (shrink)

We present a meta-analytic review on the processing of negations in conditional reasoning about affirmation problems (Modus Ponens: “MP”, Affirmation of the Consequent “AC”) and denial problems (Denial of the Antecedent “DA”, and Modus Tollens “MT”). Findings correct previous generalisations about the phenomena. First, the effects of negation in the part of the conditional about which an inference is made, are not constrained to denial problems. These inferential-negation effects are also observed on AC. Second, there generally are reliable effects of (...) a negation in the clause referred to by the categorical premise, and these referred-negation effects are constrained to the logically fallacious AC and DA inferences. All findings are presented and discussed in relation to contemporary mental model (MM) and mental logic (ML) theories. It is argued that a double-negation elimination hypothesis provides a sufficient explanation of inferential-negation effects within both MM theory and ML theory, if the latter is extended by a validating search for counter examples. Both MM and ML theories adhere to a processing scheme that allows them to incorporate an account of referred-negation effects based on the thesis that counter-example frequency is modulated by the scope of a contrast class delineated by a false affirmative. We conclude that MM and ML theories provide adequate processing schemes to accommodate for the explanatory hypotheses, at least in principle. In practice, both approaches remain equivocal as regards the connectivity and interactivity with long-term memory knowledge invoked in generating, manipulating, and testing the mental representations of negative state of affairs. (shrink)

Two experiments examined the contribution of working memory (WM) to the retrieval and inhibition of background knowledge about counterexamples (alternatives and disablers, Cummins, ) during conditional reasoning. Experiment 1 presented a conditional reasoning task with everyday, causal conditionals to a group of people with high and low WM spans. High spans rejected the logically invalid AC and DA inferences to a greater extent than low spans, whereas low spans accepted the logically valid MP and MT inferences less frequently than high (...) spans. In Experiment 2, an executive-attention-demanding secondary task was imposed during the reasoning task. Findings corroborate that WM resources are used for retrieval of stored counterexamples and that people with high WM spans will use WM resources to inhibit the counterexample activation when the type of counterexample conflicts with the logical validity of the reasoning problem. (shrink)

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. (shrink)

We report two studies on the effect of implicitly versus explicitly conveying affirmation and denial problems about conditionals. Recently Evans and Handley (1999) and Schroyens et al. (1999b, 2000b) showed that implicit referencing elicits matching bias: Fewer determinate inferences are made, when the categorical premise (e.g., B) mismatches the conditional's referred clause (e.g., A). Also, the effect of implicit affirmation (B affirms not-A) is larger than the effect of implicit denial (B denies A). Schroyens et al. hypothesised that this interaction (...) is due to uncertainty in the case-wise affirmation of the contrast class of negated elements involved in implicit affirmations. In Experiment 1 we tested this hypothesis by manipulating the set size of the conditional clauses. The results confirm that binary sets, where the contrast class is a singleton, eliminate the differential effect of implicit affirmation and denial. With non-binary sets the interaction is not modulated by the scope of the contrast class (3, 5, 9 elements). Experiment 2 further investigated the role of contrast classes by using class inclusion to construct implicit affirmations (Mammal vs Mammal or Monkey) and implicit denial (No-Mammal vs Mammal or Monkey), in addition to the standard implicit problems mediated by contrast-class inclusion [(No-)Mammal/No-Mammal; Reptile; Snake). Findings indicate that class inclusion (Mammal/Monkey; Reptile/ Snake) only marginally affects performance, and is independent of the type of problem. This would suggest that the implicitness problem-type interaction is dependent on constructing contrast classes. However, the experiment failed to replicate the interaction, even on the subset of problems repeating the abstract letter/number format of Experiment 1. Moreover, with the natural binary set-sizes (vowels/consonants) the implicitness effect was eliminated entirely. (shrink)

Inan earlier paper on this topic, ‘Eupatridai, Archons, and Areopagus,'3I was primarily concerned to recover the views of Aristotle, as expressed in the ‘Αθ. πολ., on such elements of Attic Society as Eupatridai, Gennetai, etc. I sought to establish that to him at least these two were not identical: that, more precisely, he recorded two stages of development—(a) ‘Ion’: in whose day the whole body of Athenians was composed of Gennetai, whileEupatridaihad not yet been created.(b) ‘Theseus’: who created the Eupatridai—distinguishing (...) them, as a Third Estate, from those two Estates (Georgoi and Demiourgoi) which had hitherto, since Ion, composed the body of Athenians. (shrink)

This paper describes how to ethically conduct research with Black populations at the intersection of COVID-19 and the Black Lives Matter movement. We highlight the issues of historical mistrust in the USA and how this may impact Black populations’ participation in COVID-19 vaccination trials. We provide recommendations for researchers to ethically engage Black populations in research considering the current context. Our recommendations include understanding the impact of ongoing trauma, acknowledging historical context, ensuring diverse research teams and engaging in open and (...) honest conversations with Black populations to better address their needs. The core of our recommendation is recognising the impact of trauma in our research and health care practices. (shrink)

In an earlier paper on this topic, ‘Eupatridai, Archons, and Areopagus,'3 I was primarily concerned to recover the views of Aristotle, as expressed in the ‘Αθ. πολ., on such elements of Attic Society as Eupatridai, Gennetai, etc. I sought to establish that to him at least these two were not identical: that, more precisely, he recorded two stages of development— ‘Ion’: in whose day the whole body of Athenians was composed of Gennetai, while Eupatridai had not yet been created. ‘Theseus’: (...) who created the Eupatridai—distinguishing them, as a Third Estate, from those two Estates which had hitherto, since Ion, composed the body of Athenians. (shrink)

The purpose of this paper is to put forward the hypothesis that the author of ‘Herodes περ πολιτας is Kritias. The speech bears Herodes’ name: did Herodes' well-known interest in Kritias amount to the transcription of a whole speech? The speech concerns Thessalian affairs at approximately the time when Kritias was in Thessaly: is it exactly the time? and is the tone what we would expect Kritias' tone to be? We have much description of Kritias' prose style, and a few (...) verbatim fragments: does the style of this speech correspond? (shrink)

This famous decree, which is the earliest Athenian decree preserved on stone, is printed e.g. by Hiller in IG. i. no. i, and with a materially different text by Tod in SGHI. no. II. A small new fragment was published in Hesperia, vii. 264. Restorations continue to differ widely and fundamentally. In Hesperia, x. 301–7, Meritt has discussed recent suggestions, and has submitted his own text on p. 307; on p. 305 is a drawing by Raubitschek of the whole monument (...) on the basis of Meritt's text. (shrink)

The Spartan Rhetra quoted by Plutarch in Lyc. vi. 2 consists of some thirty-seven words in an archaic Dorian or near-Dorian dialect: Plutarch says it was an oracle, and that later an extra clause was added by the kings Polydoros and Theopompos; he quotes this ‘added clause’ in vi. 8. I believe this Rhetra was not an oracle but an act of the Spartan Ekklesia; and I suspect that the ‘added clause’ was not added, but is an integral part of (...) the original act. But for our first objective this opinion matters less than Plutarch's opinion. Our first objective must be to recover Plutarch's text : and to do that, we must understand his interpretation. (shrink)

Plutarch concludes his chapter on the Rhetra with six lines of Tyrtaios: φοβου κοςσαντες Πυθωνθεν οκαδ' νεικαν1 μαντεας τε θεο κα τελεντ' πεα ρχειν μν βουλῦς θεοτιμτους βασιλας οσι μλει Σπρτας μερεσσα πλις πρεσβτας τε γροντας, πειτα δ δημτας νδρας πθεαις τραις ντααπαμειβομνους. These lines are quoted to confirm Plutarch's statement, that the Kings who added the last clause to the Rhetra ‘persuaded the city [to accept this addition] on the grounds that it was part of the God's command'. On (...) Plutarch's view, the two Kings added an extra clause to an oracle, and justified their action by alleging that Delphi had authorized the clause. It is not immediately obvious how Tyrtaios’ lines confirm this view. The Delphic utterance whose substance is given in lines 3–6 approximately paraphrases parts of Clauses I and I I, but where is Clause III? The burden has to be borne by the one word εθεαις: ‘the Kings and gerontes shall initiate business, the demos shall reply with undistorted rhetrai’ or ‘shall respond to the rhetrai without distorting them’. If εθεαις is given enough weight, the oracle which Tyrtaios quotes may be held to forbid the ‘excessive amendment’ against which Clause III was aimed. (shrink)