Joshua K. Hartshorne

When Does Cognitive Functioning Peak? The Asynchronous Rise and Fall of Different Cognitive Abilities Across the Life Span

Understanding how and when cognitive change occurs over the life span is a prerequisite for understanding normal and abnormal development and aging. Most studies of cognitive change are constrained, however, in their ability to detect subtle, but theoretically informative life-span changes, as they rely on either comparing broad age groups or sparse sampling across the age range. Here, we present convergent evidence from 48,537 online participants and a comprehensive analysis of normative data from standardized IQ and memory tests. Our results reveal considerable heterogeneity in when cognitive abilities peak: Some abilities peak and begin to decline around high school graduation; some abilities plateau in early adulthood, beginning to decline in subjects’ 30s; and still others do not peak until subjects reach their 40s or later. These findings motivate a nuanced theory of maturation and age-related decline, in which multiple, dissociable factors differentially affect different domains of cognition.

Response to Comment on "Estimating the reproducibility of psychological science"

Gilbert et al. conclude that evidence from the Open Science Collaboration’s Reproducibility Project: Psychology indicates high reproducibility, given the study methodology. Their very optimistic assessment is limited by statistical misconceptions and by causal inferences from selectively interpreted, correlational data. Using the Reproducibility Project: Psychology data, both optimistic and pessimistic conclusions about reproducibility are possible, and neither are yet warranted.

Visual Working Memory Capacity and Proactive Interference

Background Visual working memory capacity is extremely limited and appears to be relatively immune to practice effects or the use of explicit strategies. The recent discovery that visual working memory tasks, like verbal working memory tasks, are subject to proactive interference, coupled with the fact that typical visual working memory tasks are particularly conducive to proactive interference, suggests that visual working memory capacity may be systematically under-estimated. Methodology/Principal Findings Working memory capacity was probed behaviorally in adult humans both in laboratory settings and via the Internet. Several experiments show that although the effect of proactive interference on visual working memory is significant and can last over several trials, it only changes the capacity estimate by about 15%. Conclusions/Significance This study further confirms the sharp limitations on visual working memory capacity, both in absolute terms and relative to verbal working memory. It is suggested that future research take these limitations into account in understanding differences across a variety of tasks between human adults, prelinguistic infants and nonlinguistic animals.

Tracking Replicability As a Method of Post-Publication Open Evaluation

Recent reports have suggested that many published results are unreliable. To increase the reliability and accuracy of published papers, multiple changes have been proposed, such as changes in statistical methods. We support such reforms. However, we believe that the incentive structure of scientific publishing must change for such reforms to be successful. Under the current system, the quality of individual scientists is judged on the basis of their number of publications and citations, with journals similarly judged via numbers of citations. Neither of these measures takes into account the replicability of the published findings, as false or controversial results are often particularly widely cited. We propose tracking replications as a means of post-publication evaluation, both to help researchers identify reliable findings and to incentivize the publication of reliable results. Tracking replications requires a database linking published studies that replicate one another. As any such database is limited by the number of replication attempts published, we propose establishing an open-access journal dedicated to publishing replication attempts. Data quality of both the database and the affiliated journal would be ensured through a combination of crowd-sourcing and peer review. As reports in the database are aggregated, ultimately it will be possible to calculate replicability scores, which may be used alongside citation counts to evaluate the quality of work published in individual journals. In this paper, we lay out a detailed description of how this system could be implemented, including mechanisms for compiling the information, ensuring data quality, and incentivizing the research community to participate.

Verb argument structure predicts implicit causality: The advantages of finer-grained semantics

While the referent of a nonreflexive pronoun clearly depends on context, the nature of these contextual restrictions is controversial. The present study seeks to characterise one representation that guides pronoun resolution. Our focus is an effect known as “implicit causality”. In causal dependant clauses, the preferred referent of a pronoun varies systematically with the verb in the main clause (contrast Sally frightened Mary because she … with Sally feared Mary because she…). A number of researchers have tried to explain and predict such biases with reference to semantic classes of verbs. However, such studies have focused on a small number of specially selected verbs. In Experiment 1, we find that existing taxonomies perform near chance at predicting pronoun-resolution bias on a large set of representative verbs. However, a more fine-grained taxonomy recently proposed in the linguistics literature does significantly better. In Experiment 2, we tested all 264 verbs in two of the narrowly defined verb classes from this new taxonomy, finding that pronoun-resolution biases were categorically different. These findings suggest that the semantic structure of verbs tightly constrains the interpretation of pronouns in causal sentences, raising challenges for theories which posit that implicit causality biases reflect world knowledge or arbitrary lexical features.

What is implicit causality

In causal dependent clauses, the preferred referent of a pronoun varies systematically with the verb in the main clause (contrast Sally frightens Mary because she … with Sally loves Mary because she …). This “implicit causality” phenomenon is understood to reflect intuitions about who caused the event. Researchers have debated whether these intuitions are based on linguistic structure or instead a function of high-level, non-linguistic cognition. Two lines of evidence support the latter conclusion: implicit causality is related to a broad social judgement task, and it is affected by general knowledge about the participants in the event. On closer inspection, neither of these claims have been established. Eight new experiments find that (a) the relationship between implicit causality and the social judgement task is tenuous, and (b) previously employed event-participant manipulations have minimal to no effect on implicit causality. These findings support an account on which implicit causality is driven primarily by linguistic structure and only minimally by general knowledge and non-linguistic cognition.

The neural computation of scalar implicature

Language comprehension involves not only constructing the literal meaning of a sentence but also going beyond the literal meaning to infer what was meant but not said. One widely studied test case is scalar implicature: The inference that, e.g., Sally ate some of the cookies implies she did not eat all of them. Research is mixed on whether this is due to a rote, grammaticalised procedure or instead a complex, contextualised inference. We find that in sentences like If Sally ate some of the cookies, then the rest are on the counter, that the rest triggers a late, sustained positivity relative to Sally ate some of the cookies, and the rest are on the counter. This is consistent with behavioural results and linguistic theory suggesting that the former sentence does not trigger a scalar implicature. This motivates a view on which scalar implicature is contextualised but dependent on grammatical structure.

The Causes and Consequences Explicit in Verbs

Interpretation of a pronoun in one clause can be systematically affected by the verb in the previous clause. Compare Archibald angered Bartholomew because he … (he = Archibald) with Archibald criticised Bartholomew because he … (he = Bartholomew). While it is clear that meaning plays a critical role, it is unclear whether that meaning is directly encoded in the verb or, alternatively, inferred from world knowledge. We report evidence favouring the former account. We elicited pronoun biases for 502 verbs from seven Levin verb classes in two discourse contexts (implicit causality and implicit consequentiality), showing that in both contexts, verb class reliably predicts pronoun bias. These results confirm and extend recent findings about implicit causality and represent the first such study for implicit consequentiality. We discuss these findings in the context of recent work in semantics, and also develop a new, probabilistic generative account of pronoun interpretation.

Love Is Hard to Understand: The Relationship between Transitivity and Caused Events in the Acquisition of Emotion Verbs.

Famously, dog bites man is trivia whereas man bites dog is news. This illustrates not just a fact about the world but about language: to know who did what to whom, we must correctly identify the mapping between semantic role and syntactic position. These mappings are typically predictable, and previous work demonstrates that young children are sensitive to these patterns and so could use them in acquisition. However, there is only limited and mixed evidence that children do use this information to guide acquisition outside of the laboratory. We find that children understand emotion verbs which follow the canonical CAUSE-VERB-PATIENT pattern (Mary frightened/delighted John) earlier than those which do not (Mary feared/liked John), despite the latters higher frequency, suggesting childrens generalization of the mapping between causativity and transitivity is broad and active in acquisition.

Are Implicit Causality Pronoun Resolution Biases Consistent Across Languages and Cultures

The referent of a nonreflexive pronoun depends on context, but the nature of these contextual restrictions is controversial. For instance, in causal dependent clauses, the preferred referent of a pronoun varies systematically with the verb in the main clause (Sally frightens Mary because she … vs. Sally loves Mary because she …). Several theories claim that verbs with similar meanings across languages should show similar pronoun resolution effects, but these claims run contrary to recent analyses on which much of linguistic and nonlinguistic cognition is susceptible to cross-cultural variation, and in fact there is little data in the literature to decide the question one way or another. Analysis of data in eight languages representing four historically unrelated language families reveals consistent pronoun resolution biases for emotion verbs, suggesting that the information upon which implicit causality pronoun resolution biases are derived is stable across languages and cultures.