17 research outputs found
Building a unified model of the Optional Infinitive Stage: simulating the cross-linguistic pattern of verb-marking error in typically developing children and children with Developmental Language Disorder
Verb-marking errors are a characteristic feature of the speech of typically-developing (TD) children and are particularly prevalent in the speech of children with Developmental Language Disorder (DLD). However, both the pattern of verb-marking error in TD children and the pattern of verb-marking deficit in DLD vary across languages and interact with the semantic and syntactic properties of the language being learned. In this paper, we review work using a computational model called MOSAIC. We show how this work allows us to understand several features of the cross-linguistic data that are otherwise difficult to explain. We also show how discrepancies between the developmental data and the quantitative predictions generated by MOSAIC can be used to identify weaknesses in our current understanding and lead to further theory development; and how the resulting model (MOSAIC+) helps us understand differences in the cross-linguistic patterning of verb-marking errors in TD children and children with DLD
Neuroelectric Evidence for Cognitive Association Formation: An Event-Related Potential Investigation
Although many types of learning require associations to be formed, little is known about the brain mechanisms engaged in association formation. In the present study, we measured event-related potentials (ERPs) while participants studied pairs of semantically related words, with each word of a pair presented sequentially. To narrow in on the associative component of the signal, the ERP difference between the first and second words of a pair (Word2-Word1) was derived separately for subsequently recalled and subsequently not-recalled pairs. When the resulting difference waveforms were contrasted, a parietal positivity was observed for subsequently recalled pairs around 460 ms after the word presentation onset, followed by a positive slow wave that lasted until around 845 ms. Together these results suggest that associations formed between semantically related words are correlated with a specific neural signature that is reflected in scalp recordings over the parietal region
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Simulating the cross-linguistic pattern of optional infinitive errors in children’s declaratives and wh- questions [forthcoming]
One of the most striking features of children’s early multi-word speech is their tendency to produce non-finite verb forms in contexts in which a finite verb form is required (Optional Infinitive [OI] errors, Wexler, 1994). MOSAIC is a computational model of language learning that simulates developmental changes in the rate of OI errors across several different languages by learning compound finite constructions from the right edge of the utterance (Freudenthal, Pine & Gobet, 2006a; 2009; Freudenthal, Pine, Aguado-Orea & Gobet, 2007). However, MOSAIC currently only simulates the pattern of OI errors in declaratives, and there are important differences in the cross-linguistic patterning of OI errors in declaratives and Wh- questions. In the present study, we describe a new version of MOSAIC that learns from both the right and left edges of the utterance. Our simulations demonstrate that this new version of the model is able to capture the cross-linguistic patterning of OI errors in declaratives in English, Dutch, German and Spanish by learning from declarative input, and the cross-linguistic patterning of OI errors in Wh- questions in English, German and Spanish by learning from interrogative input. These results show that MOSAIC is able to provide an integrated account of the cross-linguistic patterning of OI errors in declaratives and Wh- questions, and provide further support for the view, instantiated in MOSAIC, that OI errors are compound-finite utterances with missing modals or auxiliaries
Simulating the cross-linguistic pattern of Optional Infinitive errors in children’s declaratives and Wh- questions
One of the most striking features of children’s early multi-word speech is their tendency to produce non-finite verb forms in contexts in which a finite verb form is required (Optional Infinitive [OI] errors, Wexler, 1994). MOSAIC is a computational model of language learning that simulates developmental changes in the rate of OI errors across several different languages by learning compound finite constructions from the right edge of the utterance (Freudenthal, Pine, Aguado-Orea, & Gobet, 2007; Freudenthal, Pine, & Gobet, 2006a, 2009). However, MOSAIC currently only simulates the pattern of OI errors in declaratives, and there are important differences in the cross-linguistic patterning of OI errors in declaratives and Wh- questions. In the present study, we describe a new version of MOSAIC that learns from both the right and left edges of the utterance. Our simulations demonstrate that this new version of the model is able to capture the cross-linguistic patterning of OI errors in declaratives in English, Dutch, German and Spanish by learning from declarative input, and the cross-linguistic patterning of OI errors in Wh- questions in English, German and Spanish by learning from interrogative input. These results show that MOSAIC is able to provide an integrated account of the cross-linguistic patterning of OI errors in declaratives and Wh- questions, and provide further support for the view, instantiated in MOSAIC, that OI errors are compound-finite utterances with missing modals or auxiliaries
Endowment effect and housing decisions
Endowment effect refers to the reported gaps between willingness to accept and willingness to pay. According to prospect theory, this effect is a result of the underweighting of opportunity costs. Given the high stake involved in a typical housing transaction, endowment effect is expected to have a significant influence on housing decisions. We develop a theoretical framework to study the presence of endowment effect and its role in housing decision-making process. Three hypotheses are derived and tested through a field experiment conducted in Beijing, China. Our empirical results show that endowment effect plays an important role in the formation of judgmental biases in housing decisions. Moreover, endowment effect interacts with housing cycles. Our study highlights the application of prospect theory in the housing market; thus, it not only extends existing theoretical and empirical works in this important sector, but also clarifies consumer behavior in the emerging property market of China
Toward a further understanding of object feature binding: a cognitive neuroscience perspective.
The aim of this thesis is to lead to a further understanding of the neural mechanisms underlying object feature binding in the human brain. The focus is on information processing and integration in the visual system and visual shortterm memory. From a review of the literature it is clear that there are three major
competing binding theories, however, none of these individually solves the binding problem satisfactorily. Thus the aim of this research is to conduct behavioural experimentation into object feature binding, paying particular attention to visual short-term memory.
The behavioural experiment was designed and conducted using a within-subjects delayed responset ask comprising a battery of sixty-four composite objects each with three features and four dimensions in each of three conditions (spatial, temporal and spatio-temporal).Findings from the experiment,which focus on spatial and temporal aspects of object feature binding and feature proximity on
binding errors, support the spatial theories on object feature binding, in addition we propose that temporal theories and convergence, through hierarchical feature
analysis, are also involved. Because spatial properties have a dedicated processing neural stream, and temporal properties rely on limited capacity memory systems, memories for sequential information would likely be more
difficult to accuratelyr ecall. Our study supports other studies which suggest that both spatial and temporal coherence to differing degrees,may be involved in
object feature binding. Traditionally, these theories have purported to provide individual solutions, but this thesis proposes a novel unified theory of object feature binding in which hierarchical feature analysis, spatial attention and temporal synchrony each plays a role. It is further proposed that binding takes place in visual short-term memory through concerted and integrated information
processing in distributed cortical areas. A cognitive model detailing this integrated proposal is given. Next, the cognitive model is used to inform the design and suggested implementation of a computational model which would be
able to test the theory put forward in this thesis. In order to verify the model, future work is needed to implement the computational model.Thus it is argued
that this doctoral thesis provides valuable experimental evidence concerning spatio-temporal aspects of the binding problem and as such is an additional building block in the quest for a solution to the object feature binding problem
Toward a further understanding of object feature binding : a cognitive neuroscience perspective
The aim of this thesis is to lead to a further understanding of the neural mechanisms underlying object feature binding in the human brain. The focus is on information processing and integration in the visual system and visual shortterm memory. From a review of the literature it is clear that there are three major competing binding theories, however, none of these individually solves the binding problem satisfactorily. Thus the aim of this research is to conduct behavioural experimentation into object feature binding, paying particular attention to visual short-term memory. The behavioural experiment was designed and conducted using a within-subjects delayed responset ask comprising a battery of sixty-four composite objects each with three features and four dimensions in each of three conditions (spatial, temporal and spatio-temporal).Findings from the experiment,which focus on spatial and temporal aspects of object feature binding and feature proximity on binding errors, support the spatial theories on object feature binding, in addition we propose that temporal theories and convergence, through hierarchical feature analysis, are also involved. Because spatial properties have a dedicated processing neural stream, and temporal properties rely on limited capacity memory systems, memories for sequential information would likely be more difficult to accuratelyr ecall. Our study supports other studies which suggest that both spatial and temporal coherence to differing degrees,may be involved in object feature binding. Traditionally, these theories have purported to provide individual solutions, but this thesis proposes a novel unified theory of object feature binding in which hierarchical feature analysis, spatial attention and temporal synchrony each plays a role. It is further proposed that binding takes place in visual short-term memory through concerted and integrated information processing in distributed cortical areas. A cognitive model detailing this integrated proposal is given. Next, the cognitive model is used to inform the design and suggested implementation of a computational model which would be able to test the theory put forward in this thesis. In order to verify the model, future work is needed to implement the computational model.Thus it is argued that this doctoral thesis provides valuable experimental evidence concerning spatio-temporal aspects of the binding problem and as such is an additional building block in the quest for a solution to the object feature binding problem.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Constraining the function of CA1 in associative memory models of the hippocampus
Institute for Adaptive and Neural ComputationCA1 is the main source of afferents from the hippocampus, but the function of
CA1 and its perforant path (PP) input remains unclear. In this thesis, Marr’s model
of the hippocampus is used to investigate previously hypothesized functions, and also
to investigate some of Marr’s unexplored theoretical ideas. The last part of the thesis
explains the excitatory responses to PP activity in vivo, despite inhibitory responses in
vitro.
Quantitative support for the idea of CA1 as a relay of information from CA3 to the
neocortex and subiculum is provided by constraining Marr’s model to experimental
data. Using the same approach, the much smaller capacity of the PP input by comparison
implies it is not a one-shot learning network. In turn, it is argued that the
entorhinal-CA1 connections cannot operate as a short-term memory network through
reverberating activity.
The PP input to CA1 has been hypothesized to control the activity of CA1 pyramidal
cells. Marr suggested an algorithm for self-organising the output activity during
pattern storage. Analytic calculations show a greater capacity for self-organised patterns
than random patterns for low connectivities and high loads, confirmed in simulations
over a broader parameter range. This superior performance is maintained in the
absence of complex thresholding mechanisms, normally required to maintain performance
levels in the sparsely connected networks. These results provide computational
motivation for CA3 to establish patterns of CA1 activity without involvement from the
PP input.
The recent report of CA1 place cell activity with CA3 lesioned (Brun et al., 2002.
Science, 296(5576):2243-6) is investigated using an integrate-and-fire neuron model
of the entorhinal-CA1 network. CA1 place field activity is learnt, despite a completely
inhibitory response to the stimulation of entorhinal afferents. In the model, this is
achieved using N-methyl-D-asparate receptors to mediate a significant proportion of
the excitatory response. Place field learning occurs over a broad parameter space. It is
proposed that differences between similar contexts are slowly learnt in the PP and as a
result are amplified in CA1. This would provide improved spatial memory in similar
but different contexts