Cognitive Science Colloquium
All meetings take place on Thursdays, 3.30-5.30 pm in Bioscience Research Building 1103, unless otherwise noted.
February 4 — Robert Nosofsky (Psychological and Brain Sciences, Indiana University).
Title: Exemplar Model Accounts of Relations and Dissociations Between Categorization and Recognition
Abstract: In this talk I provide an overview of an exemplar-based evidence-accumulation model of categorization and recognition decision making and its applications to empirical data, including its accounts of intriguing dissociations that have been demonstrated between categorization and recognition memory. According to Nosofsky and Palmeri’s (1997, 2015) exemplar-based random-walk model, people represent categories by storing individual exemplars in memory. Presentation of a test item causes the exemplars to be retrieved. The retrieved exemplars drive an evidence-accumulation process that leads to both categorization and recognition decisions. In the first part of my talk, I illustrate applications of the model to predicting the time course of decision making in tasks of both categorization and recognition.
Whereas the exemplar model presumes that categorization and recognition are mediated by the same memory representations and decision processes, this idea has been strongly challenged by results from the cognitive neuroscience literature. For example, behavioral studies have demonstrated intriguing dissociations in which amnesic subjects, despite having severely impaired old-new recognition memory, perform at normal levels in categorization tasks involving the same kinds of stimuli. In addition, neuroimaging studies reveal that different parts of the brain are activated when observers engage in categorization versus recognition tasks. These findings suggest, in contrast to the fundamental assumption of the exemplar model, that separate memory systems may mediate categorization and recognition. In the second part of my talk, I describe how I have attempted to address these challenges.
February 18 — Nancy Kanwisher (Brain and Cognitive Sciences, MIT).
Title: Functional specificity in the human brain
Abstract: Over the last two decades, functional MRI has provided extensive evidence that some regions of the human brain are engaged very specifically in single mental processes. Yet, the idea of functional specificity in the brain is often described as old-fashioned, something that sophisticated modern neuroscientists have moved beyond. I will argue that many of these critiques result from misconceptions and confusions, and that in fact the evidence for functional specificity is stronger than ever. I will illustrate the case with data from classic examples (e.g. face processing) as well as newer areas of investigation (high-level audition). I will also consider the question of which mental functions get their own private patch of real estate in the brain and why.
February 25 — Justin Halberda (Psychological and Brain Sciences, Johns Hopkins University) – Note: in BPS 1208.
Title: An interface between vision, numerical cognition, and word meanings
Abstract: Whereas limits of visual processing are interesting in their own right, these limits take on a deeper meaning where vision integrates with other cognitive systems. It is at this point that limits within vision become limits that can affect the whole of cognition. I present evidence for one such case: an interface between vision, numerical cognition and the semantics of quantifier terms. The goal is to highlight a case where non-visual cognition (lexical meanings) interfaces with vision and visual limits (tracking multiple sets) constrain later cognition.
March 3 — Reiko Mazuka (Psychology, RIKEN Brain Institute, Japan).
Learning to become a native listener of Japanese
Abstract: The goal of our research is identify the processes by which human infants with no prior linguistic knowledge and highly limited cognitive skills acquire the ability to understand and manipulate highly complex language systems in a short time and without explicit instruction. The talk will present results from studies that investigated how Japanese infants learn certain characteristics of Japanese phonology, knowledge of which is considered prerequisite for the acquisition of abstract, symbolic properties of language. One distinctive characteristics of Japanese phonology, for example, is duration-based vowel distinction, which can be used for both lexical differentiation (obasan vs obaasan) and for phrasal/prosodic differentiation (dakara vs dakaraaa). How do babies learn that lexical and prosodic information systems are different, and how do they determine whether a given long or short vowel is being used lexically or prosodically? Our studies compare babies' behavioral responses with speech input provided by their environment, computational acquisition models, and brain imaging studies. The talk will discuss results from these and related studies, highlighting the unique opportunities that Japanese language properties provide to disentangle fundamental questions pertaining to acquisition.
March 10 — Nicholas Turk-Browne (Psychology, Princeton University).
Statistical learning in mind and brain
Abstract: The environment is highly stable over time. Not only do we repeatedly encounter the same people, places, and objects, but they also tend to appear in regular sequences and configurations. These regularities are extracted rapidly and often without effort or awareness, resulting in higher-order knowledge of words, events, and scenes. Based on behavioral studies, I will suggest that this kind of statistical learning has widespread consequences for the mind, including showing that it distorts the perception of ensemble features such as numerosity, and that it commands attention to locations and features with structure. Based on neuroimaging, patient, and computational studies, I will then suggest that the medial temporal lobe memory system helps implement this kind of statistical learning in the brain, including showing that the hippocampus learns structure by shaping the representational space for objects to mirror both simple and complex regularities. These studies reveal the deep and broad ways in which statistical learning interacts with other aspects of cognition.
March 24 — Liina Pylkkänen (Linguistics & Psychology, NYU).
Title: Semantic composition within the integrative hub architecture of the brain: A view from MEG
Abstract: An important goal for the cognitive neuroscience of syntax and semantics is to move beyond general notions of “integration” when characterizing the combinatory system of language. My lab has studied the brain basis of combinatory operations for about a decade now, taking the results of formal semantics within theoretical linguistics as the model that fundamentally guides the experimentation. This work has revealed a shared combinatory network between comprehension and production comprising at least of the left anterior temporal lobe (LATL) and the ventromedial prefrontal cortex (vmPFC). In the first part of this talk, I will focus on our current understanding of the role of the LATL in combinatory processing. In the second part of the talk, I will zoom out, and consider the “hub-architecture” of the brain more generally. Across many domains of cognition, including “resting state cognition,” a relatively consistent set of highly connected network hubs keeps emerging. These include the areas implicated for composition in our work (LATL and vmPFC), but also others, such as the angular gyrus and the medial parietal cortex. In the second half of the talk, I will show recent results pertaining to the roles of the latter two in language processing. The overall picture that emerges is that when we look for the brain basis of combinatory processing in language, we find the same hubs that are implicated for integrative processing in many domains.
March 31 — Arie Kruglanski (Psychology, University of Maryland). – Note: in BPS 1208.
The economics of mental energy
Abstract: Natural scientists agree that energy is one of the most fundamental pre-requisites of life, and that none of life’s functions, from the minutely molecular to the vastly molar can be performed without a source of energy. The concept of energy is also quite popular in everyday discourse and one often hears references to “feeling energized”, “lacking energy” or trying to boost it through imbibing various “energy drinks.” It is somewhat surprising, therefore, that the science of psychology paid the concept of energy rather scant attention. In this talk, I will describe our attempt at taking energy seriously and incorporating it as a central element in our theory of motivated cognition. I will discuss how the present theory integrates prior notions (e.g. dual systems theories) and how it affords new insights into fundamental psychological phenomena (such as wishful thinking).
April 14 — Pawan Sinha (Brain and Cognitive Sciences, MIT).
Learning to see late in childhood
Abstract: The hope inherent in pursuing basic research is that sometime in the future the work will prove beneficial to society. This fruition can often take many years. However, in some instances, even the conduct of basic research can yield tangible societal benefits. I shall describe an effort that perhaps fits in this category. Named 'Project Prakash', this initiative provides sight to blind children on the one hand and helps address questions regarding brain plasticity and learning on the other. Through a combination of behavioral and brain-imaging studies, the effort has provided evidence of visual learning late in childhood and has illuminated some of the processes that might underlie such learning.
April 28 — Kalina Christoff (Psychology, University of British Columbia).
Title: Mind wandering as spontaneous thought: A dynamic framework
Abstract: Mind-wandering has recently come to occupy a central position in cognitive psychology and neuroscience. Most theories and research so far have examined it in terms task-unrelated or stimulus-independent mental contents that occur at particular moments of time. A defining feature of mind-wandering, however, are its dynamics: how thought moves over time. In this talk, I will introduce a dynamic framework for understanding mind-wandering and its neural basis. I propose that mind-wandering is best understood as a member of a larger family of spontaneous thought processes – a family that also includes creative thought and dreaming. I will distinguish between two types of constraints on thought – deliberate and automatic – that can reduce thought’s spontaneous movement. Within this framework, fluctuations between spontaneous, automatic, and deliberate modes of thinking correspond to changing interactions among large-scale brain networks. Finally, the framework situates spontaneous thought within a broader conceptual space that allows its comparison to goal-directed thought, as well as to clinical disorders that make thought excessively constrained – such as in rumination and anxiety, or excessively variable – such as in ADHD.