Susan M. Ravizza - US grants

We rely on the probability judgments of experts and laypeople every day. Space shuttles are launched not only on the basis of weather forecasts, but also on an engineer's subjective opinion that a part will or will not fail. Military missions and political policies are put in place using intelligence analysts' beliefs that an event will occur or has occurred. Without doubt the use of probability judgments to make decisions makes the accuracy of subjective probabilities of utmost importance. Indeed the accuracy of subjective probabilities has been well studied in the cognitive and decision sciences. Yet, an equally valuable aspect of subjective probabilities is the amount of time it takes judges to formulate their estimates. Clearly, the time a judge takes to make a probability judgment has external costs to both the judge and the decision maker. Yet, little is known about the internal time course of subjective probability judgments. Consequently, the impact these external costs have on subjective probabilities and their accuracy is not known.

In this project the Principal Investigator pursues research examining how variables external to the judge (e.g., time pressure; rewards and penalties) and internal to the judge (e.g., attention and sequential effects) impact the time course and accuracy of subjective probabilities. A general framework called Judgment Field Theory will integrate how these internal and external variables impact probability judgments. Moreover, the framework offers a cognitive account of how different descriptions of the same event (e.g., Lance Armstrong will win the race vs. Lance Armstrong won?t lose the race) change how judges evaluate the likelihood of an event occurring and how this evaluation changes as a function of time.

The broader impacts of the research are three-fold. First, the research will help in the development of methods to evaluate the accuracy of subjective probabilities. These methods can ultimately be used to improve the accuracy of judges. Second, the theoretical framework will be used in the development of an undergraduate psychological methods course curriculum that infuses a traditional methods course with techniques of cognitive modeling. Finally, a broader impact is the outreach to and integration of a diverse group of undergraduate and graduate students into cognitive science at MSU.

Working memory is the ability to store and manipulate information that is not currently present in the environment, but exists in the mind. Working memory is important to understand, because it is the foundation for reasoning, mathematics, learning a language, and other cognitive processes that involve the integration and manipulation of information stored in memory. With funding from the National Science Foundation, Dr. Susan Ravizza of the Michigan State University is investigating how people are able to keep important information active in their mind and not deplete limited memory capacity in storing unimportant information. The project focuses on two abilities that could help to determine which information gets stored in working memory. One ability directs attention to salient information in the environment, and Dr. Ravizza and her laboratory are investigating if brain activity in a region called the "temporal parietal junction" signals to orient attention to this information. Another ability gates information, and the researchers are investigating if brain activity in the basal ganglia "opens the gate" to allow important information into working memory or "closes the gate," so that irrelevant information is excluded from working memory. How these two brain components, attention and gating, work together so that working memory capacity is used effectively is being investigated as well. These studies are using functional magnetic resonance imaging (fMRI) of brain activity while people are in the process of storing and recalling information. In addition to studying healthy participants, analyses of individuals with Parkinson's disease, who have basal ganglia dysfunction, are providing further insight into the basic mechanisms of working memory performance.

This project is investigating a brain model of how information gains access to working memory through specific brain mechanisms. The research is helping to explain why unexciting information is more likely to be forgotten, and how attention to distracting information reduces memory performance. Understanding the mechanisms by which task-relevant information is stored in the presence of distracting information has increased in importance. Given that distracting information is becoming more common in environments such as the workplace, the car, and the classroom, the broader impacts of this research are likely to be significant. For example, social networking (e.g., Facebook, Twitter) during class could interfere with working memory abilities that are needed to learn in the classroom. The results of this research could suggest, for example, that strategies to improve memory should target the ability to ignore distracting information rather than trying to increase absolute storage capacity. This knowledge has potential to impact education by promoting awareness of the detrimental effects of distraction and could serve as the basis for informed policies regarding social networking in the classroom or workplace. In addition, the studies of patients with Parkinson's provide basic knowledge about the type of memory impairments experienced with basal ganglia damage.

Cognitive neuroscience research seeks to understand the basic brain mechanisms underlying cognitive and behavioral functions. While there are a variety of available research tools, the majority of these techniques are correlational, in that neural activity (or a proxy of neural activity) is measured while human subjects perform a task. Data from these techniques do not allow causal inference, which requires perturbation of the neural system. Transcranial Magnetic Stimulation (TMS) is currently the leading choice for neural perturbation in humans. With Major Research Instrumentation support from the National Science Foundation, Dr. McAuley and colleagues will purchase a TMS system to enhance research and training in cognitive neuroscience at Michigan State University. TMS can be used to produce temporary disruptions in neural activity or to stimulate the cortex in targeted brain regions. Recent developments in this technology allow image-guided TMS delivery, commonly referred to as neuronavigation. This method allows the TMS coil to be precisely positioned over a specified brain structure based on a person's neuroanatomical data obtained using magnetic resonance imaging (MRI) techniques. This capability is important because, although the structure of the brain is roughly similar across people, the exact anatomical location of neural structures can vary considerably. Targets for disruption/stimulation can be identified by selecting and highlighting the desired structure/locations with the brain. Image-guided (neuronavigated) TMS is quickly becoming a widely-used and standard technology in cognitive neuroscience research. The general value of this technology for cognitive neuroscience is that it is a non-invasive tool that can be coupled with functional and structural MRI data to make causal inferences about normal and disordered brain function that are not possible through fMRI/MRI studies alone.

The participating investigators are all active researchers in the cognitive neurosciences. The new instrumentation will transform Michigan State University's capability to conduct cutting-edge cognitive neuroscience studies that help unravel the neural bases of cognitive function in a diverse set of domains, including perception, attention, memory, cognitive control, and decision making. The acquisition will also more broadly contribute to university-wide neuroscience education and training initiatives at the graduate and undergraduate levels. As part of a new and popular undergraduate major in neuroscience, neuronavigated TMS will be included as one of the methods taught in a required core laboratory course that exposes students to a variety of different neuroscience methods. At the graduate level, the new instrumentation will strengthen introductory and advanced neuroimaging courses by providing new education and novel hands-on training and research opportunities. Michigan State University is a also leader in undergraduate research and training opportunities in STEM areas for women and underrepresented minorities, and the training opportunities created by the new instrumentation will interact synergistically with departmental, interdepartmental and university-wide initiatives. Opportunities for summer research experiences for high school students will be created through established contacts with science teachers in area high schools.