Program in Neuroscience

About

My research consists of three topic areas that are highly inter-related. In collaboration with Geoff Loftus, I have addressed the temporal aspects of information processing tasks such as character identification and binocular information acquisition. This work has produced 6 peer-reviewed articles in major journals. More recently I have expanded my research focus to look at how the information that is acquired by these early perceptual mechanisms is processed in memory tasks. Several research projects have addressed the nature of the representation of perceptual information, and the use of this information in recognition and metacognitive tasks. This research line has produced 4 articles and book chapters, with several other articles under review.

Mathematical Modeling of Visual Information Processing

The processing of a perceptual stimulus is not instantaneous. The sensory response tends to be extended in time, and the nature of this temporal delay affects how the stimulus is processed. This research line uses quantitative models to address the interactions between lower-level sensory processes and higher-level perceptual and information processing mechanisms. We measure the temporal properties of the sensory response, which are signatures of the underlying neural pathways that subserve the processing of a particular task. In this research line I have addressed the processes that underlie character recognition, binocular summation, localization and identification, and temporal inhibition.

Articles based on this research appear in The Psychological Review, Journal of Experimental Psychology: Human Perception and Performance, Perception & Psychophysics, and Vision Research. A seventh article is accepted pending revision at The Journal of Mathematical Psychology.

Visual Mechanisms Associated with Face Perception

Information that is acquired by the early sensory and perceptual mechanisms studied in the previous research area must be stored and later matched with other stimuli to enable recognition. Vision researchers attempting to understand how the visual system encodes visual information have typically used relatively simple stimuli such as sine-wave gratings or gaussian patches. These findings may not reveal how those initial representations are combined by higher-order visual processing mechanism that are responsible for more complex stimuli such as faces. My research investigates the visual mechanisms that are involved in complex pattern perception. We have been most interested in how faces are represented in memory, and what features are included in this representation. In conjunction with my graduate student Anne Arici, we have developed quantitative models that account for different aspects of face recognition data.

Articles describing this research are published in Psychological Science and Journal of Experimental Psychology: Learning Memory & Cognition.

Confidence and Accuracy in Eyewitness Testimony

Jurors often believe, and are often explicitly told by judges, that confident eyewitnesses are more accurate than unconfident eyewitnesses. However, a very small to nil correlation between an eyewitness' confidence and accuracy is often reported in the literature. Motivated by this applied area, I am conducting a series of experiments looking at the basic calibration issues underlying memory performance and a subject's ability to monitor and report their confidence in the accuracy of their memory reports.

We find that confidence is not just important for eyewitness identification; other aspects of confidence can affect the recognition response. As a result, this topic area is intrinsically tied to the previous area.

An article describing the first experiments in this research line has been resubmitted to Psychonomic Bulletin & Review, and Anne Arici's first year project also addresses this topic.