It's not just what we don't know: The mapping problem in the acquisition of negation.

How do learners learn what no and not mean when they are only presented with what is? Given its complexity, abstractness, and roles in logic, truth-functional negation might be a conceptual accomplishment. As a result, young children's gradual acquisition of negation words might be due to their undergoing a gradual conceptual change that is necessary to represent those words' logical meaning. However, it's also possible that linguistic expressions of negation take time to learn because of children's gradually increasing grasp of their language. To understand what no and not mean, children might first need to understand the rest of the sentences in which those words are used. We provide experimental evidence that conceptually equipped learners (adults) face the same acquisition challenges that children do when their access to linguistic information is restricted, which simulates how much language children understand at different points in acquisition. When watching a silenced video of naturalistic uses of negators by parents speaking to their children, adults could tell when the parent was prohibiting the child and struggled with inferring that negators were used to express logical negation. However, when provided with additional information about what else the parent said, guessing that the parent had expressed logical negation became easy for adults. Though our findings do not rule out that young learners also undergo conceptual change, they show that increasing understanding of language alone, with no accompanying conceptual change, can account for the gradual acquisition of negation words.

Conflict paradigms cannot reveal competence.

De Neys is right to criticize the exclusivity assumption in dual-process theories, but he misses the original sin underlying this assumption, which his working model continues to share. Conflict paradigms, in which experimenters measure how one cognitive process interferes (or does not interfere) with another, license few inferences about how the interfered-with process works on its own.

Properties of LoTs: The footprints or the bear itself?

There are two ways to understand any proposed properties of language-of-thoughts (LoTs): As diagnostic or constitutive. We argue that this choice is critical. If candidate properties are diagnostic, their homeostatic clustering requires explanation via an underlying homeostatic mechanism. If constitutive, there is no clustering, only the properties themselves. Whether deep neural networks (DNNs) are alternatives to LoTs or potential implementations turn on this choice.

The development of reasoning by exclusion in infancy.

How do humans develop the capacity to reason? In five studies, we examined infants' emerging ability to make exclusion inferences using negation, as in the disjunctive syllogism (P or Q; not P; therefore Q). Inspired by studies of non-human animals and older children, Experiments 1-3 used an exclusion task adapted from Call's (2004) 2-cup paradigm and Experiments 4-5 used an exclusion task adapted from the blicket detector paradigm (Sobel & Kirkham, 2006). In both tasks, we found failure to make exclusion inferences at 15 months, fragile success at 17 months, and robust success by 20 months of age. These data converge with some prior evidence that fails to find a capacity to represent negation in infants younger than 15 months of age and conflict with other evidence from different paradigms that suggests infants do have this capacity. We discuss three different resolutions of these conflicting data, and suggest lines of further work that might adjudicate among them.

Getting to No: Pragmatic and Semantic Factors in Two- and Three-Year-Olds' Understanding of Negation.

Although infants say "no" early, older children have difficulty understanding its truth-functional meaning. Two experiments investigate whether this difficulty stems from the infelicity of negative sentences out of the blue. In Experiment 1, given supportive discourse, 3-year-olds (N = 16) understood both affirmative and negative sentences. However, with sentence types randomized, 2-year-olds (N = 28) still failed. In Experiment 2, affirmative and negative sentences were blocked. Two-year-olds (N = 28) now succeeded, but only when affirmatives were presented first. Thus, although discourse felicity seems the primary bottleneck for 3-year-olds' understanding of negation, 2-year-olds struggle with its semantic processing. Contrary to accounts where negatives are understood via affirmatives, both sentence types were processed equally quickly, suggesting previously reported asymmetries are due to pragmatic accommodation, not semantic processing.

The logic in language: How all quantifiers are alike, but each quantifier is different.

Quantifier words like each, every, all and three are among the most abstract words in language. Unlike nouns, verbs and adjectives, the meanings of quantifiers are not related to a referent out in the world. Rather, quantifiers specify what relationships hold between the sets of entities, events and properties denoted by other words. When two quantifiers are in the same clause, they create a systematic ambiguity. "Every kid climbed a tree" could mean that there was only one tree, climbed by all, or many different trees, one per climbing kid. In the present study, participants chose a picture to indicate their preferred reading of different ambiguous sentences - those containing every, as well as the other three quantifiers. In Experiment 1, we found large systematic differences in preference, depending on the quantifier word. In Experiment 2, we then manipulated the choice of a particular reading of one sentence, and tested how this affected participants' reading preference on a subsequent target sentence. We found a priming effect for all quantifiers, but only when the prime and target sentences contained the same quantifier. For example, all-a sentences prime other all-a sentences, while each-a primes each-a, but sentences with each do not prime sentences with all or vice versa. In Experiment 3, we ask whether the lack of priming across quantifiers could be due to the two sentences sharing one fewer word. We find that changing the verb between the prime and target sentence does not reduce the priming effect. In Experiment 4, we discover one case where there is priming across quantifiers - when one number (e.g. three) is in the prime, and a different one (e.g. four) is in the target. We discuss how these findings relate to linguistic theories of quantifier meaning and what they tell us about the division of labor between conceptual content and combinatorial semantics, as well as the mental representations of quantification and of the abstract logical structure of language.

Mapping words to the world: Adults, but not children, understand how mismatching descriptions refer.

How do children learn to connect expressions (e.g., "that red apple") to the real-world objects they refer to? The dominant view in developmental psychology is that children rely on descriptive information, "red" and "apple." In contrast, linguistic theories of the adult language attribute primacy to grammatical elements: words such as "that" or "another" first establish the status of potential referents within the discourse context (old or new) before descriptions can factor in. These theories predict that reference can succeed even when the description does not match the referent. We explored this novel prediction in adults and children. Over four experiments, we found that (a) adults relied on the articles to identify the referent, even when the description did not fit, consistent with grammar-first accounts; (b) consistent with description-first accounts, and unlike adults, 3- to 5-year-old children prioritized the descriptions provided by nouns and adjectives, despite being sensitive to grammatical information. This suggests that children connect expressions to referents differently from adults. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Expressing fear enhances sensory acquisition.

It has been proposed that facial expression production originates in sensory regulation. Here we demonstrate that facial expressions of fear are configured to enhance sensory acquisition. A statistical model of expression appearance revealed that fear and disgust expressions have opposite shape and surface reflectance features. We hypothesized that this reflects a fundamental antagonism serving to augment versus diminish sensory exposure. In keeping with this hypothesis, when subjects posed expressions of fear, they had a subjectively larger visual field, faster eye movements during target localization and an increase in nasal volume and air velocity during inspiration. The opposite pattern was found for disgust. Fear may therefore work to enhance perception, whereas disgust dampens it. These convergent results provide support for the Darwinian hypothesis that facial expressions are not arbitrary configurations for social communication, but rather, expressions may have originated in altering the sensory interface with the physical world.

Counting and the ontogenetic origins of exact equality.

Humans are unique in their capacity to both represent number exactly and to express these representations symbolically. This correlation has prompted debate regarding whether symbolic number systems are necessary to represent large exact number. Previous work addressing this question in innumerate adults and semi-numerate children has been limited by conflicting results and differing methodologies, and has not yielded a clear answer. We address this debate by adapting methods used with innumerate populations (a "set-matching" task) for 3- to 5-year-old US children at varying stages of symbolic number acquisition. In five studies we find that children's ability to match sets exactly is related not simply to knowing the meanings of a few number words, but also to understanding how counting is used to generate sets (i.e., the cardinal principle). However, while children were more likely to match sets after acquiring the cardinal principle, they nevertheless demonstrated failures, compatible with the hypothesis that the ability to reason about exact equality emerges sometime later. These findings provide important data on the origin of exact number concepts, and point to knowledge of a counting system, rather than number language in general, as a key ingredient in the ability to reason about large exact number.

Problems and Mysteries of the Many Languages of Thought.

"What is the structure of thought?" is as central a question as any in cognitive science. A classic answer to this question has appealed to a Language of Thought (LoT). We point to emerging research from disparate branches of the field that supports the LoT hypothesis, but also uncovers diversity in LoTs across cognitive systems, stages of development, and species. Our letter formulates open research questions for cognitive science concerning the varieties of rules and representations that underwrite various LoT-based systems and how these variations can help researchers taxonomize cognitive systems.

Contrast and entailment: Abstract logical relations constrain how 2- and 3-year-old children interpret unknown numbers.

Do children understand how different numbers are related before they associate them with specific cardinalities? We explored how children rely on two abstract relations - contrast and entailment - to reason about the meanings of 'unknown' number words. Previous studies argue that, because children give variable amounts when asked to give an unknown number, all unknown numbers begin with an existential meaning akin to some. In Experiment 1, we tested an alternative hypothesis, that because numbers belong to a scale of contrasting alternatives, children assign them a meaning distinct from some. In the "Don't Give-a-Number task", children were shown three kinds of fruit (apples, bananas, strawberries), and asked to not give either some or a number of one kind (e.g. Give everything, but not [some/five] bananas). While children tended to give zero bananas when asked to not give some, they gave positive amounts when asked to not give numbers. This suggests that contrast - plus knowledge of a number's membership in a count list - enables children to differentiate the meanings of unknown number words from the meaning of some. Experiment 2 tested whether children's interpretation of unknown numbers is further constrained by understanding numerical entailment relations - that if someone, e.g. has three, they thereby also have two, but if they do not have three, they also do not have four. On critical trials, children saw two characters with different quantities of fish, two apart (e.g. 2 vs. 4), and were asked about the number in-between - who either has or doesn't have, e.g. three. Children picked the larger quantity for the affirmative, and the smaller for the negative prompts even when all the numbers were unknown, suggesting that they understood that, whatever three means, a larger quantity is more likely to contain that many, and a smaller quantity is more likely not to. We conclude by discussing how contrast and entailment could help children scaffold the exact meanings of unknown number words.

Infants' representations of others' goals: representing approach over avoidance.

Goals fall into two broad types--approach and avoidance. Research on infants' early goal understanding has focused only on approach goals, usually assuming that infants will encode an ambiguous display where an actor picks one object over another as the actor wanting to approach the former rather than avoid the latter. We investigated infants' understanding of approach and avoidance separately by presenting 7-month-olds with a hand either consistently approaching, or consistently avoiding, an object. Infants dishabituated to a disruption of the consistent approach pattern, but not of the consistent avoidance pattern. In the second experiment, we show that 14-month-olds, who have a richer understanding of goals, still do not dishabituate when a hand first reaches to and picks up an object it has consistently avoided before. A third experiment found that 7-month-olds successfully dishabituated to the first motion of a previously stationary object when all the objects moved on their own with no hand present, ruling out several low-level interpretations of infants' failure to dishabituate to the violations of the avoidance pattern in Experiments 1 and 2. We conclude that infants do not represent avoidance from the same type of evidence they can use to represent approach.