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  • Ramscar Lab 16:29 on 01.10.2016 Permalink
    Tags: , , Decision Making, Learning,   

    Exploratory Decision-Making as a Function of Lifelong Experience, Not Cognitive Decline 

    Our latest aging study has just been published in the Journal of Experimental Psychology: General. The paper reports work done with Nate Blanco, Kirsten Smayda and Todd Maddox at the University of Texas, Austin, Bradley Love (University College London) and Ross Otto (New York University). It helps illustrate just how important computational models are to our understanding of changes in behavior across the adult lifespan, showing why it makes no sense to talk about processing declines in the absence of models of what is being processed, and how.

    Here’s the abstract:

    Older adults perform worse than younger adults in some complex decision-making scenarios, which is commonly attributed to age-related declines in striatal and frontostriatal processing. Recently, this popular account has been challenged by work that considered how older adults’ performance may differ as a function of greater knowledge and experience, and by work showing that, in some cases, older adults outperform younger adults in complex decision-making tasks. In light of this controversy, we examined the performance of older and younger adults in an exploratory choice task that is amenable to model-based analyses and ostensibly not reliant on prior knowledge. Exploration is a critical aspect of decision-making poorly understood across the life span. Across 2 experiments, we addressed (a) how older and younger adults differ in exploratory choice and (b) to what extent observed differences reflect processing capacity declines. Model-based analyses suggested that the strategies used by the 2 groups were qualitatively different, resulting in relatively worse performance for older adults in 1 decision- making environment but equal performance in another. Little evidence was found that differences in processing capacity drove performance differences. Rather the results suggested that older adults’ performance might result from applying a strategy that may have been shaped by their wealth of real-word decision-making experience. While this strategy is likely to be effective in the real world, it is ill suited to some decision environments. These results underscore the importance of taking into account effects of experience in aging studies, even for tasks that do not obviously tap past experiences.

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  • Ramscar Lab 20:12 on 01.13.2014 Permalink
    Tags: , , , Learning,   

    Ageing research goes to press 

    We are pleased to announce that Topics in Cognitive Science has just released our extended article The myth of cognitive decline: Non-linear dynamics of lifelong learning, with a companion introduction to the research by Profs Wayne Gray and Thomas Hills, who ask: Does cognition deteriorate with age or is it enhanced by experience?

    Abstract for “The Myth of Cognitive Decline”

    As adults age, their performance on many psychometric tests changes systematically, a finding that is widely taken to reveal that cognitive information-processing capacities decline across adulthood. Contrary to this, we suggest that older adults’ changing performance reflects memory search demands, which escalate as experience grows. A series of simulations show how the performance patterns observed across adulthood emerge naturally in learning models as they acquire knowledge. The simulations correctly identify greater variation in the cognitive performance of older adults, and successfully predict that older adults will show greater sensitivity to fine-grained differences in the properties of test stimuli than younger adults. Our results indicate that older adults’ performance on cognitive tests reflects the predictable consequences of learning on information-processing, and not cognitive decline. We consider the implications of this for our scientific and cultural understanding of aging.

    You can check out some of the press at Language Log, The New York Times, National GeographicThe Telegraph, The Independent, Psychology Today (in Fulfillment at Any Age Statistical Life), The Daily Mail, Forbes, The Huffington Post, The National Post, The Times of India, and Gawker. Or listen to the radio segment on the BBC’s World Service. There’s also a lively comment thread over at Reddit Science.

     
  • Ramscar Lab 20:32 on 12.13.2013 Permalink
    Tags: Learning, , , Overregularization, ,   

    The many curious cases of mouses 

    Error and expectation in language learning: The curious absence of ‘mouses’ in adult speech has just come out in Language, and opens, enticingly enough, with a quote from the Silver Blaze:

    Gregory: “Is there any other point to which you would wish to draw my attention?”

    Holmes: “To the curious incident of the dog in the nighttime”.

    Gregory: “The dog did nothing in the nighttime”.

    Holmes: “That was the curious incident”.

    –Sir Arthur Conan Doyle

    For more puzzles on learning, morphology, and negative evidence, we turn to the abstract:

    As children learn their mother tongues, they make systematic errors. For example, English speaking children regularly say “mouses” rather than “mice”. Because children’s errors aren’t explicitly corrected, it has been argued that children could never learn to make the transition to adult language based on the evidence available to them, and thus that learning even simple aspects of grammar is logically impossible without recourse to innate, language specific constraints. Here, we examine the role children’s expectations play in language learning, and present a model of plural noun learning that generates a surprising prediction: At a given point in learning, exposure to regular plurals (e.g. rats) can decrease children’s tendency to overregularize irregular plurals (e.g. mouses). Intriguingly, the model predicts that the same exposure should have the opposite effect earlier in learning. Consistent with this, we show that testing memory for items with regular plural labels contributes to a decrease in irregular plural overregularization in six-year-olds, but an increase in four-year-olds. Our model and results suggest that children’s overregularization errors both arise and resolve themselves as a consequence of the distribution of error in the linguistic environment, and that far from presenting a logical puzzle for learning, they are inevitable consequences of it.

     
  • Ramscar Lab 20:47 on 08.01.2013 Permalink
    Tags: Cognitive Maturation, , Learning, Lexicon,   

    New Articles on Learning and Development 

    This summer, we have two new papers coming out on early learning and development.

    In Child Development, there’s an article on Dual routes to cognitive flexibility, which explores how three-year olds engage in flexible, goal-oriented behavior, in the absence of a mature prefrontal cortex.

    Cognitive control, the ability to align our actions with goals or context, is largely absent in children under four. How then are preschoolers able to tailor their behavior to best match the situation? Learning may provide an alternative route to context-sensitive responding. This study investigated this hypothesis in the Dimensional Change Card Sort (DCCS), a classic test of cognitive control that most under-fours fail. A training intervention based on learning theoretic principles proved highly effective: Three-year-olds who learned about DCCS rules and game contexts in a card-labeling task, subsequently transferred this knowledge to sorting in the DCCS, passing at more than 3 times the rate of controls (N = 47). This surprising finding reveals much about the nature of the developing mind.

    Then over at Psychological Science, we make a case for why Children value informativity over logic in early word learning, and why that may confer distinct advantages over adult strategies.

    The question of how children learn the meanings of words has long puzzled philosophers and psychologists. As Quine famously pointed out, simply hearing a word in context reveals next to nothing about its meaning. How then do children learn to understand and use words correctly? Here, we show how learning theory can offer an elegant solution to this seemingly intractable puzzle in language acquisition. From it, we derived formal predictions about word learning in situations of Quinean ambiguity, and subsequently tested our predictions on toddlers, undergraduates, and developmental psychologists. The toddlers’ performance was consistent both with our predictions and with the workings of implicit mechanisms that can facilitate the learning of meaningful lexical systems. Adults adopted a markedly different and likely suboptimal strategy. These results suggest one explanation for why early word learning can appear baffling: Adult intuitions may be a poor source of insight into how children learn.

     
  • Ramscar Lab 12:21 on 04.22.2013 Permalink
    Tags: Communication, Information Theory, , Learning, Processing, Production   

    Opinion Piece in Frontiers 

    Frontiers in Language Sciences has just published our commentary on the research question “Does Language Production Shape Language Form and Comprehension?” posed by Prof Maryellen MacDonald. Both her original article and our reply are open access.

     
  • Ramscar Lab 15:27 on 10.17.2011 Permalink
    Tags: , Learning, ,   

    Looking for the PLoS Paper on Number Learning? 

    Looking for our award-winning PLoS One paper on how children learn numbers? In the last month, roughly half of Google searchers that stumbled onto this page were doing just that. We’ll save you the trouble of browsing further: find it here!

    Although number words are common in everyday speech, learning their meanings is an arduous, drawn-out process for most children, and the source of this delay has long been the subject of inquiry. Children begin by identifying the few small numerosities that can be named without counting, and this has prompted further debate over whether there is a specific, capacity-limited system for representing these small sets, or whether smaller and larger sets are both represented by the same system. Here we present a formal, computational analysis of number learning that offers a possible solution to both puzzles. This analysis indicates that once the environment and the representational demands of the task of learning to identify sets are taken into consideration, a continuous system for learning, representing and discriminating set-sizes can give rise to effective discontinuities in processing. At the same time, our simulations illustrate how typical prenominal linguistic constructions (“there are three balls”) structure information in a way that is largely unhelpful for discrimination learning, while suggesting that postnominal constructions (“balls, there are three”) will facilitate such learning. A training-experiment with three-year olds confirms these predictions, demonstrating that rapid, significant gains in numerical understanding and competence are possible given appropriately structured postnominal input. Our simulations and results reveal how discrimination learning tunes children’s systems for representing small sets, and how its capacity-limits result naturally out of a mixture of the learning environment and the increasingly complex task of discriminating and representing ever-larger number sets. They also explain why children benefit so little from the training that parents and educators usually provide. Given the efficacy of our intervention, the ease with which it can be implemented, and the large body of research showing how early numerical ability predicts later educational outcomes, this simple discovery may have far-reaching consequences.

     
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