{"id":2702,"date":"2016-08-31T17:49:04","date_gmt":"2016-08-31T15:49:04","guid":{"rendered":"http:\/\/cognitionandculture.local\/?p=2702"},"modified":"2023-07-24T14:15:07","modified_gmt":"2023-07-24T12:15:07","slug":"could-preschoolers-learn-to-reason-deductively","status":"publish","type":"post","link":"https:\/\/cognitionandculture.local\/blogs\/pierre-jacob\/could-preschoolers-learn-to-reason-deductively\/","title":{"rendered":"Could preschoolers learn to reason deductively?"},"content":{"rendered":"
Conceptual change or change of conception?<\/em><\/p>\n One basic issue raised by the study of both the history of science and human ontogenetic cognitive development is that of conceptual change: when should a change be interpreted as a conceptual<\/em> change rather than as a change of conception<\/em> (or belief<\/em>)? This question has been at the heart of Susan Carey\u2019s developmental investigations from the very beginning. In her monumental (2009) book, The Origin of Concepts<\/em>, she advocates a view of human ontogenetic cognitive development that rests on what she and Liz Spelke call core<\/em> cognitive capacities and that involves rather sharp conceptual discontinuities. As she has stressed over the years, her acceptance of discontinuities in cognitive development bears some affinities to moderate versions of Thomas Kuhn\u2019s famous view of the incommensurability between scientific paradigms in the history of science. In the past, she has argued for example that human infants lack fundamental biological concepts and that nai\u0308ve biology is constructed in the course of development by the cross-fertilization of basic core<\/em> physical and psychological concepts and conceptions.<\/p>\n Quinean Bootstrapping<\/em><\/p>\n In her (2009) book, she offers a completely innovative account of how children may learn entirely new concepts (e.g. the concept integer<\/em>), which are not part of human infants\u2019 innate core cognitive resources. At the heart of her proposal is the process that she herself calls Quinean bootstrapping<\/em>, in reference to a couple of influential metaphors used by the philosopher Willard Van Orman Quine to capture the puzzling character of the scientific enterprise, one of which he borrowed from the logical positivist Otto Neurath: scientists try to fix their boat while at sea. Quine\u2019s other metaphor is that of \u201cscrambling up a chimney supporting oneself by pressing against the sides one is building as one goes along\u201d (Carey, 2009, p. 306). Carey\u2019s non-metaphorical approach to bootstrapping involves two fundamental stages. First, it involves the construction or selection of some relevant set of explicit symbolic placeholders<\/em>. The second process is the process of interpreting<\/em> the placeholders through some non-deductive (or non-demonstrative) process, including e.g. abduction, thought experimentation, limiting case analyses and analogical mapping (Carey, 2009, pp. 306-307).<\/p>\n As Carey (2009, p. 419) notes, these two stages seem well illustrated by an example from the philosopher Ned Block (1986) where he describes what he went through when he took his first physics course and was introduced to such terms as \u201cenergy, momentum, acceleration, and mass.\u201d These terms were placeholders, whose meanings he could not immediately map onto familiar concepts already available to him. What he could do instead is learn how to map them onto one another (e.g. \u201cmass\u201d time \u201cacceleration\u201d equals \u201cforce\u201d). Later he was able to integrate them more fully within his broader conceptual repertoire.<\/p>\n As much experimental evidence (from Carey and colleagues) strongly suggests, human infants\u2019 core cognitive resources do not include the concept integer<\/em>. Instead, what is available to human infants (and to non-human animals as well) are two separate core systems of representations: an object-file<\/em> system and an analog magnitude system<\/em>. While the former underlies the precise representations of sets of cardinality limited to 3 or 4 individuals, the latter underlies the approximate representations of sets of larger cardinality. Neither is sufficient for representing e.g. the concept 7. In her book, Carey argues that children bootstrap their way to the concept integer<\/em> from these two core numerical systems of representation via various placeholders from their native tongue. Among these placeholders are natural language quantifiers (e.g. the English singular-plural marker and such English expressions as \u201csome\u201d and \u201call\u201d). Children further memorize the count list \u201cOne, two, three, …\u201d (up to \u201cten\u201d) more\u00a0or less as they would sing \u201ceeny, meeny, miny, moe.\u201d Only when they recognize that the list is ordered by the successor function can they interpret it numerically.<\/p>\n Fodorian skepticism<\/em><\/p>\n While Carey\u2019s bootstrapping account of children\u2019s concept of integer<\/em> is a major contribution, it faces a pair of challenges: what counts as a genuinely novel<\/em> concept? And how could the interpretation<\/em> stage of the placeholders work in accordance with the requirement that the conceptual output be entirely novel<\/em>? As Carey is well aware, this pair of challenges can be traced back to Jerry Fodor\u2019s notorious skepticism<\/em>, first expressed in his (1975) argument for the language of thought (recently echoed by Rey, 2014). In a nutshell, Fodor\u2019s skeptical argument about conceptual change rests on the fundamental assumption that learning a new concept consists in forming a hypothesis about its content and testing it. To take a famous example from Nelson Goodman, in order to learn the new placeholder \u201cgrue,\u201d one must form and test the hypothesis that something is grue<\/em> if and only if it is green<\/em> before August\u00a031 2016 or blue<\/em> thereafter. Fodor\u2019s point is that not unless one already possesses all the conceptual ingredients necessary to represent the right side of the biconditional could one learn the meaning of the new placeholder \u201cgrue.\u201d While the placeholder \u201cgrue\u201d may incontrovertibly be a new predicate, the question arises: to what extent is its content, i.e., the concept grue<\/em>, a novel<\/em> concept? All approaches to cognitive development that accept conceptual discontinuities are open to Fodor\u2019s skepticism. In response, Carey (2009, 2014) explicitly rejects Fodor\u2019s identification between learning a concept and the process of hypothesis formation and confirmation.<\/p>\n Logical concepts<\/em><\/p>\n Since the publication of her (2009) opus, Susan Carey has turned her attention to a novel and fundamental topic of investigation: do human children learn general, i.e. domain- independent<\/em>, logical<\/em> concepts such as negation<\/em>, conjunction<\/em> and disjunction<\/em>? This in particular is the topic of one of her recent papers with Shilpa Mody published in Cognition<\/em>, in which they investigate the ability of preschoolers to deductively reason in accordance with the disjunctive syllogism: Reasoning by exclusion<\/em><\/p>\n Mody and Carey report the results of two studies. The goal of the first study was to find out whether 23-month-olds can reason by exclusion<\/em>, as required in their cups task, in which they are motivated to find a ball that was placed in one of two cups A and B, but toddlers could not see which one because the cups were occluded by a screen when the experimenter hid the ball. After the screen was removed, the toddlers were shown that one cup (e.g. A) was empty. Finally the toddlers were asked to find the ball. A large majority of 23-month-olds turned out to pass this task and therefore to be able to reason by exclusion (as older children have been shown to). While success in this task requires the ability to reason by exclusion, one fundamental question is whether the ability to reason deductively in accordance with the disjunctive syllogism is a necessary condition for being able to reason by exclusion.<\/p>\n As Mody and Carey rightly observe, success in this task alone cannot demonstrate that toddlers reason deductively in accordance with the disjunctive syllogism, which requires them at least to make use of logical negation and to represent the disjunctive premise, i.e. to form a single representation of a pair of possible locations for the ball. Instead of using disjunction<\/em>,\u00a0they may, for example, represent each location separately<\/em>, in accordance with what Mody and Carey call the \u201cmaybe A, maybe B\u201d interpretation. In which case, upon discovering that cup A is empty, they should hold the belief that the ball is in B with subjective probability less than 1. Instead of using domain-general logical negation<\/em>, they may, according to Mody and Carey (p. 46), form domain-specific thoughts representing emptiness<\/em>, rather than thoughts \u201cgeneralizable to other situations involving negation.\u201d However and paradoxically, it is not entirely clear whether there could be domain-specific<\/em> thoughts about emptiness in general<\/em>, i.e. thoughts that could represent emptiness without specifying some relevant property or other (e.g. a ball), whose presence would make the thought false.<\/p>\n
\nA OR B,
\nNOT A,
\nTHEREFORE B.
\nA valid piece of deductive (or demonstrative) reasoning is such that if the premises are true, so is the conclusion. In a nutshell, the broad question is: at what developmental stage are preschoolers sensitive to the logical properties of representations considered in the abstract<\/em>?<\/p>\n