Cross-situational word learning is both implicit and strategic

Cognitive Science, 2011

Cross-situational learning is a mechanism for learning the meaning of words across multiple exposures, despite exposure-by-exposure uncertainty as to the word's true meaning. We present experimental evidence showing that humans learn words effectively using cross-situational learning, even at high levels of referential uncertainty. Both overall success rates and the time taken to learn words are affected by the degree of referential uncertainty, with greater referential uncertainty leading to less reliable, slower learning. Words are also learned less successfully and more slowly if they are presented interleaved with occurrences of other words, although this effect is relatively weak. We present additional analyses of participants’ trial-by-trial behavior showing that participants make use of various cross-situational learning strategies, depending on the difficulty of the word-learning task. When referential uncertainty is low, participants generally apply a rigorous eliminative approach to cross-situational learning. When referential uncertainty is high, or exposures to different words are interleaved, participants apply a frequentist approximation to this eliminative approach. We further suggest that these two ways of exploiting cross-situational information reside on a continuum of learning strategies, underpinned by a single simple associative learning mechanism.

2010

The world offers learners a seemingly infinite number of word-to-world mappings (Quine, 1960). In order to account for how learners manage to accomplish such a difficult task, theories of word learning have proposed different tools that make the task of learning words easier. However, we propose that reducing difficulty may be detrimental-difficulty may promote long-term word learning. We tested this hypothesis in a cross-situational paradigm in which object-label mappings were ambiguous during each learning event. The three conditions of learning (2 x 2, 3 x 3, and 4 x 4) varied in the degree of difficulty. Results revealed that, although difficulty deterred immediate performance, difficulty promoted long-term performance. We suggest that theory and research should shift from focusing on in-the-moment learning to examining both immediate and long-term learning. A complete theory of word learning not only accounts for word learning in the moment and on each time scale, but also inte...

2010

The world offers learners a seemingly infinite number of word-to-world mappings (Quine, 1960). In order to account for how learners manage to accomplish such a difficult task, theories of word learning have proposed different tools that make the task of learning words easier. However, we propose that reducing difficulty may be detrimental-difficulty may promote long-term word learning. We tested this hypothesis in a cross-situational paradigm in which object-label mappings were ambiguous during each learning event. The three conditions of learning (2 x 2, 3 x 3, and 4 x 4) varied in the degree of difficulty. Results revealed that, although difficulty deterred immediate performance, difficulty promoted long-term performance. We suggest that theory and research should shift from focusing on in-the-moment learning to examining both immediate and long-term learning. A complete theory of word learning not only accounts for word learning in the moment and on each time scale, but also integrates them in order to understand how they influence each other over time.

2012

ICDL/EpiRob, 2012

Research has shown that people can learn many nouns (i.e., word-referent mappings) from a short series of ambiguous situations containing multiple word-referent pairs. Associative models assume that people accomplish such crosssituational learning by approximately tracking which words and referents co-occur. However, some researchers posit that learners hypothesize only a single referent for each word, and retain and test this hypothesis unless it is disconfirmed. To compare these two views, we fit two models to individual learning trajectories in a cross-situational word-learning task, in which each trial presents four objects and four spoken words-16 possible wordobject pairings per trial. The model that maintains a single hypothesis for each word does not fit as well as the associative model that roughly learns the co-occurrence structure of the data using competing attentional biases for familiar pairings and uncertain stimuli. We conclude that language acquisition is likely supported by memory, not sparse hypotheses.

2010

Abstract A number of modern word learning theories posit statistical processes in which knowledge is accumulated across many exposures to a word and its potential referents. Accordingly, words do not go directly from unknown to known, but rather pass through intermediate stages of partial knowledge. This work presents empirical evidence for the existence of such partial knowledge, and further demonstrates its active driving role in cross-situational word learning.

2012

Abstract 1. Both adults and young children possess powerful statistical computation capabilities—they can infer the referent of a word from highly ambiguous contexts involving many words and many referents by aggregating cross-situational statistical information across contexts. This ability has been explained by models of hypothesis testing and by models of associative learning.

Multiword units (MWUs) is a term used in the current study to broadly cover what second language acquisition (SLA) researchers refer to as collocations, conventional expressions, chunks, idioms, formulaic sequences, or other such terms, depending on their research perspective. They are ubiquitous in language and essential in both first language (L1) and second language (L2) acquisition. Although MWUs are typically learned implicitly while using language naturally in both of these types of acquisition, the current study is an investigation of whether they are acquired in implicit knowledge when they are learned explicitly in a process called deliberate paired association learning. In SLA research, it is widely accepted that explicit knowledge is developed consciously and implicit knowledge is developed subconsciously. It is also believed that there is little crossover from explicit learning to implicit knowledge. However, recent research has cast doubt on this assumption. In a series of priming experiments, Elgort (2007, 2011) demonstrated that the formal and semantic lexical representations of deliberately learned pseudowords were accessed fluently and integrated into the mental lexicon, convincing evidence that deliberately learned words are immediately acquired in implicit knowledge. The current study aimed to extend these findings to MWUs in a psycholinguistic experiment that tested for implicit knowledge gains resulting from deliberate learning. Participants’ response times (RTs) were measured in three ways, on two testing instruments. First, subconscious formal recognition processing was measured in a masked repetition priming lexical decision task. In the second instrument, a self-paced reading task, both formulaic sequencing and semantic association gains were measured. The experiment was a counterbalanced, within-subjects design; so all comparisons were between conditions on items. Results were analyzed in a repeated measures linear mixed-effects model with participants and items as crossed random effects. The dependent variable was RTs on target words. The primary independent variable was learning condition: half of the critical MWUs were learned and half of them were not. The secondary independent variable was MWU composition at two levels: literal and figurative. The masked priming lexical decision task results showed that priming effects increased especially for learned figurative MWUs, evidence that implicit knowledge gains were made on their formal and semantic lexical representations as a result of deliberate learning. Results of the self-paced reading task were analyzed from two perspectives, but were less conclusive with regard to the effects of deliberate learning. Regarding formulaic sequencing gains, literal MWUs showed the most evidence of acquisition, but this happened as a result of both incidental and deliberate learning. With regard to semantic associations, it was shown that deliberate learning had similar effects on both literal and figurative MWUs. However, a serendipitous finding from this aspect of the self-paced reading results showed clearly that literal MWUs reliably primed semantic associations and sentence processing more strongly than figurative MWUs did, both before and after deliberate learning. In sum, results revealed that the difficulties learners have with developing fluent processing of figurative MWUs can be lessened by deliberate learning. On the other hand, for literal MWUs incidental learning is adequate for incrementally developing representation strength.

Cognitive Science, 2015

Cross-situational learning is a basic mechanism that enables people to infer the correct referent for a novel word by tracking multiple hypotheses simultaneously across exposures. Previous research has shown that adults are capable of exploiting cross-situational information, but recently this gradual statistical learning mechanism has been put under debate by researchers who argue that people learn via a fast mapping procedure. We compared the performance of adult participants on a word learning task in which information was manipulated cross-situationally with the performance of simulated learning strategies. Experimental evidence indicates that adults use cross-situational learning, which appears to be a robust mechanism that facilitates word learning even under cognitively demanding circumstances.