Department of Psychology
University of California Santa Barbara
Santa Barbara, CA 93106
droll at psych dot ucsb dot edu
Curriculum Vita (PDF download)
About
I'm currently a postdoc in the Psychology Department at the University of California Santa Barbara, working in the Vision & Image Understanding lab with Miguel Eckstein . I completed my Ph.D. in Brain and Cognitive Science from the University of Rochester in August 2005 under the mentorship of Mary Hayhoe. My research interests include eye movements, visual attention and working memory.Research Interests
Scenes are typically composed of a complex array of stimuli and our brain is fundamentally limited in its capacity to process and store this information. What guides the selection process? There is growing evidence to suggest that the visual system is exquisitely sensitive to the demands of the task, selectively processing the information necessary to fulfill an immediate goal. The sequence of eye movements during ordinary behavior may be the outcome of a continuous sequence of decisions, perpetually guiding the eye to areas in a scene expected to contain relevant information. During a single fixation, the brain can further bias the processing of low-level features through the use of visual attention. The degree to which the acquired scene information is judged to be relevant to the goals of the ongoing task may have consequences on whether or not this information is retained in working memory. In addition to task goals, the encoding and retention of visual information may also be guided by another top-down influence; the prior knowledge, or expectations, of one’s environment.Thus, my research tests the hypothesis that what visual information is chosen for encoding and retention depends upon both immediate task goals and the accumulated prior knowledge of scene context. I test this hypothesis in two ways. First, by examining the sequence of eye movements made during naturalistic tasks, or in more traditional experimental paradigms such as visual search. Second, by occasionally making changes to objects within a scene, and examining the ways in which these changes influence an observer’s perception, or judgments, of the scene.
Projects
Gaze Control While Walking in Real-World EnvironmentsThe vast majority of research on eye movements is performed while viewing synthetic images on computer monitors while performing contrived tasks. It is not known if performance in these laboratory tasks extends to an understanding of human behavior in the context of real-world interactions. We are currently developing a set of experiments to assess where people direct their gaze as they perform an everyday activity of walking around a building. Where do people choose to look? How might where they choose to look influence what objects they remember?
|
Learning Statistics of Cue Validity and Reward to Direct Gaze and Visual Attention
Visual attention has traditionally been considered to enhance sensory processing, or to serve as a filter, for attended stimuli. It is also possible to consider visual attention as an act of decision-making, reflecting a process of selection. The process of selection is often difficult when there is external variability in the sensory signal and internal noise. To resolve this ambiguity, observers may incorporate other information in their decision, such as their prior expectation that the sensory signal was generated from the stimulus relevant to the task. How do observers learn how to weigh the evidence for a sensory signal? How does the magnitude of reward influence this reinforcement? Preliminary results in a visual search task suggest that observers direct their gaze towards regions (or cues) in the scene likely to contain the target, and also cues associated with reward.
 |
These experiments are created using the Matlab Psychophysics Toolbox and Eyelink (SR Research) eye tracker in collaboration with Miguel Eckstein, Craig Abbey, and Binh Pham at UC Santa Barbara. |
The Role of Task Context on Visual Attention and Working Memory
Little is known regarding what visual information is selected and retained when guiding behavior. My research tests the hypothesis that acquisition and retention of visual information is governed by task relevance. Preliminary data suggests that immediate task demands govern the precise composition of visual working memory, the contents of which may be aggregates of task relevant features. For more, see Sorting Bricks in Virtual Reality
 |
These experiments were performed in the Virtual Reality Lab in the Department of Computer Science at the University of Rochester in collaboration with Mary Hayhoe. |
Influencing Allocation of Gaze and Visual Attention by Learning Environmental Probabilities
When attempting to identify an object change in a scene, can visual attention and gaze be guided by learned expectations of the scene? Such learned knowledge may include the frequency with which a particular object is expected to change, and also the frequency that the object has a particular feature. Preliminary results suggest that subjects can form these estimates from the statistical structure of the envirnment and use this information to improve performance in change detection.
 |
These experiments are created using Matlab Psychophysics and Eyelink Toolboxes in collaboration with Krista Gigone and Mary Hayhoe at the University of Rochester. |
Publications
JOURNAL ARTICLESDroll, J.A, Gigone, K. & Hayhoe, M.M.(2007) Learning where to direct gaze during change detection. Journal of Vision, 7(14):6, 1-12,http://journalofvision.org/7/14/6/, doi:10.1167/7.14.6.
Droll, J.A & Hayhoe, M.M.(2007) Trade-offs between gaze and working memory use. Journal of Experimental Psychology: Human Perception and Performance, 33(6), 1352-1365.
Droll, J.A., Hayhoe, M.M., Triesch, J., & Sullivan, B. (2005) Task demands control acquisition and storage of visual information. Journal of Experimental Psychology: Human Perception and Performance. 31(6):1416-1438.
Bisley J.W., Zaksas D., Droll J., Pasternak, T. (2003) Activity of MT neurons during a memory for motion task. Journal of Neurophysiology 90:2752-2757.
BOOK CHAPTERS
Hayhoe, M.M., Droll, J.A., Mennie, N. (2007) Learning where to look. In R. van Gompel, M. Fischer,
CONFERENCE TALKS
Droll, J.A., Pham, B.T., Abbey, C.K.,
Eckstein,
M.P. (2007) Gaze control and perceptual decisions are modulated by
learned
expected reward. Vision Sciences Society Meeting Abstracts, 7.
Droll, J.A., Pham, B.T., Abbey, C.K.,
Eckstein,
M.P. (2006) Implicit, but not explicit, measures of learning cue
validity
during visual search require task feedback. Society for Neuroscience
Abstracts,
32.
Droll J., Hayhoe, M., Triesch, J., Sullivan, B. (2004) Working memory for object features is influenced by scene context. Vision Sciences Society Meeting Abstracts, 4.
Droll J., Hayhoe, M., Triesch, J., Sullivan, B. (2003) Attention is not enough: Task micro-structure determines visual information acquisition. Society for Neuroscience Abstracts, 29.
Droll J., Hayhoe, M., Triesch, J., Sullivan, B. (2003) Influence of task demands on object representations. European Conference on Visual Perception Abstracts, 26.
Droll J., Hayhoe, M., Triesch, J., Sullivan, B. (2003) Task relevance of object features modulates the content of visual memory. Vision Sciences Society Meeting Abstracts, 3.
CONFERENCE POSTERS
Droll,
J.A. and Eckstein, M.P. (2007) Understanding visual change perception
in
unconstrained environments using eye tracking. IC Postdoctoral Research
Fellowship Colloquium.
Droll,
J.A., Pham, B.T., Abbey, C.K., Eckstein, M.P. (2006) Learning
predictive cues
to optimize visual search. Vision Sciences Society Meeting, 6.
Gigone, K.M., Droll,
J.A., Hayhoe, M.M.
(2006)
Gaze patterns in search reflect learnt environmental probabilities and
rewards.
Vision Sciences Society Meeting, 6.
Chajka,
K., Hayhoe, M.M., Sullivan, B.T., Pelz, J., Mennie, N., Droll, J.A.
(2006)
Predictive eye movements in squash. Vision
Sciences Society Meeting, 6.
Robinson, A.E.,
Triesch, J., Hayhoe,
M.M., Droll,
J.A., Sullivan, B.T. (2006) Change blindness during multiple
interactions with
a single object. Vision Sciences Society Meeting, 6.
Droll, J.A. Hayhoe, M.M, Sullivan, B.T. (2004) Task demands control acquisition and maintenance of visual information. Object Perception, Attention & Memory Meeting Abstracts, 12.
(OPAM 2005 poster - powerpoint)
Droll, J.A. Hayhoe, M.M, Sullivan, B.T. (2004) Gaze and hand movements indicate acquisition of new object features. Society for Neuroscience Abstracts, 30.
Droll J.A., Zaksas D., Bisley J.W., Pasternak, T. (2001) MT neurons respond to remote visual motion stimuli used in a working memory task. Society for Neuroscience Abstracts, 27.
Droll J.A., Bisley J.W., Pasternak, T. (2001) Activity in MT neurons during a memory for visual motion task. European Conference on Visual Perception Abstracts, 24
Droll J.A., Bisley J.W., Pasternak, T. (2001) The delay activity of some MT neurons may signal the remembered direction of motion. Vision Sciences Society Meeting Abstracts, 1.
Droll J.A., Bisley J.W., Pasternak, T (2000) Delay activity in area MT neurons during a visual working memory task. Society for Neuroscience Abstracts, 26.
Droll J.A., Bisley J.W., Pasternak, T. (2000) Delay activity in area MT neurons during a visual working memory task. IOVS Suppl. (abstracts), 41,4.