Niki Pfeifer

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Nonmonotonic logics allow—contrary to classical (monotone) logics— for withdrawing conclusions in the light of new evidence. Nonmonotonic reasoning is often claimed to mimic human common sense reasoning. Only a few studies, though, have investigated this claim empirically. system p is a central, broadly accepted nonmonotonic reasoning system that proposes(More)
An important field of probability logic is the investigation of inference rules that propagate point probabilities or, more generally, interval probabilities from premises to conclusions. Conditional probability logic (CPL) interprets the common sense expressions of the form “if . . . , then . . . ” by conditional probabilities and not by the probability of(More)
Interiors of buildings are often represented as two-dimensional spaces with attributes attached to them. Examples can be found everywhere, from architectural design plans to maps showing evacuation routes in emergency cases. Most of the navigation programs use primarily 2D plans for visualization and communication. Some exceptions are historical buildings(More)
The modus ponens (A → B, A ∴ B) is, along with modus tollens and the two logically not valid counterparts denying the antecedent (A → B,¬A ∴ ¬B) and affirming the consequent, the argument form that was most often investigated in the psychology of human reasoning. The present contribution reports the results of three experiments on the probabilistic versions(More)
Nonmonotonic conditionals (A |∼ B) are formalizations of common sense expressions of the form “if A, normally B”. The nonmonotonic conditional is interpreted by a “high” coherent conditional probability, P (B|A) > .5. Two important properties are closely related to the nonmonotonic conditional: First, A |∼ B allows for exceptions. Second, the rules of the(More)
Nonmonotonic reasoning is often claimed to mimic human common sense reasoning. Unfortunately, though, only a few studies investigated this claim empirically. In the present study four psychological experiments are reported that investigate three rules of System P, namely the AND, the Left Logical Equivalence LLE, and the OR Rule. The actual inferences of(More)
Traditionally, syllogisms are arguments with two premises and one conclusion which are constructed by propositions of the form “All... are...” and “At least one... is...” and their respective negated versions. Unfortunately, the practical use of traditional syllogisms is quite restricted. On the one hand, the “All...” propositions are too strict, since a(More)
We take coherence based probability logic as the basic reference theory to model human deductive reasoning. The conditional and probabilistic argument forms are explored. We give a brief overview of recent developments of combining logic and probability in psychology. A study on conditional inferences illustrates our approach. First steps towards a process(More)