•  425
    Experimenting with (Conditional) Perfection
    In Stefan Kaufmann, David Over & Ghanshyam Sharma (eds.), Conditionals: Logic, Semantics, Psychology, . forthcoming.
    Conditional perfection is the phenomenon in which conditionals are strengthened to biconditionals. In some contexts, “If A, B” is understood as if it meant “A if and only if B.” We present and discuss a series of experiments designed to test one of the most promising pragmatic accounts of conditional perfection. This is the idea that conditional perfection is a form of exhaustification—that is a strengthening to an exhaustive reading, triggered by a question that the conditional answers. If a sp…Read more
  •  48
    Reasoning About Truth in First-Order Logic
    with Claes Strannegård, Fredrik Engström, and Abdul Rahim Nizamani
    Journal of Logic, Language and Information 22 (1): 115-137. 2013.
    First, we describe a psychological experiment in which the participants were asked to determine whether sentences of first-order logic were true or false in finite graphs. Second, we define two proof systems for reasoning about truth and falsity in first-order logic. These proof systems feature explicit models of cognitive resources such as declarative memory, procedural memory, working memory, and sensory memory. Third, we describe a computer program that is used to find the smallest proofs in …Read more
  •  24
    Tracing the identity of objects
    with Sergey Blok and George Newman
    Psychological Review 113 (1): 1-30. 2006.
    This article considers how people judge the identity of objects (e.g., how people decide that a description of an object at one time, t₀, belongs to the same object as a description of it at another time, t₁). The authors propose a causal continuer model for these judgments, based on an earlier theory by Nozick (1981). According to this model, the 2 descriptions belong to the same object if (a) the object at t₁ is among those that are causally close enough to be genuine continuers of the origina…Read more
  •  21
    Sortal terms, such as table or horse, are count nouns (akin to a basic-level terms). According to some theories, the meaning of sortals provides conditions for telling objects apart (individuating objects, e.g., telling one table from a second) and for identifying objects over time (e.g., determining that a particular horse at one time is the same horse at another). A number of psychologists have proposed that sortal concepts likewise provide psychologically real conditions for individuating and…Read more
  •  15
    Lines of Thought addresses how we are able to think about abstract possibilities: How can we think about math, despite the immateriality of numbers, sets, and other mathematical entities? How are we able to think about what might have happened if history had taken a different turn? Questions like these turn up in nearly every part of cognitive science, and they are central to our human position of having only limited knowledge concerning what is or might be true.
  •  12
    Folk psychology of mental activities
    with Frederick G. Conrad
    Psychological Review 96 (2): 187-207. 1989.
    A central aspect of people's beliefs about the mind is that mental activities—for example, thinking, reasoning, and problem solving—are interrelated, with some activities being kinds or parts of others. In common-sense psychology, reasoning is a kind of thinking and reasoning is part of problem solving. People's conceptions of these mental kinds and parts can furnish clues to the ordinary meaning of these terms and to the differences between folk and scientific psychology. In this article, we us…Read more
  •  7
    Children's Understanding of the Natural Numbers’ Structure
    with Jennifer Asmuth and Emily M. Morson
    Cognitive Science 42 (6): 1945-1973. 2018.
    When young children attempt to locate numbers along a number line, they show logarithmic (or other compressive) placement. For example, the distance between “5” and “10” is larger than the distance between “75” and “80.” This has often been explained by assuming that children have a logarithmically scaled mental representation of number (e.g., Berteletti, Lucangeli, Piazza, Dehaene, & Zorzi, 2010; Siegler & Opfer, 2003). However, several investigators have questioned this argument (e.g., Barth &…Read more
  •  7
    Parts of activities: Reply to Fellbaum and Miller
    with Frederick G. Conrad
    Psychological Review 97 (4): 571-575. 1990.
    If people believe that one activity is a kind of another, they also tend to believe that the second activity is a part of the first. For example, they assert that deciding is a kind of thinking and that thinking is a part of deciding. C. Fellbaum and G. A. Miller's (see record 1991-03356-001) explanation for this phenomenon is based on the idea that people interpret part of in the domain of verbs as a type of logical entailment. Their explanation, however, suffers from at least 2 deficiencies. F…Read more