Howard S. Hock

Ph.D. - Johns Hopkins University '71
Research Area: Cognitive

Contact Information:
Office: 213 Behavioral Science
Telephone: (561) 297-3363
Fax: (561) 297-2160

General Research Interests

The main focus of my research laboratory is on the perception of motion. This entails the identification of mechanisms responsible for the detection of motion as well as the neural interactions among local motion detectors that result in the formation of global motion patterns. Our experimental work, which is informed by current knowledge of visual neurophysiology, involves psychophysical studies with adult, human observers. It is generally concerned with how stable motion percepts are formed and how they evolve in time through changes in stimulation, adaptation, and effects of random fluctuations. Nonlinear dynamics, which constitutes the unifying theoretical framework for these studies, is the basis for the computational models through which we simulate our experimental results. Current projects are aimed at distinguishing the neural pathway for the processing of object motion and shape from the neural pathway for the processing of objectless motion energy, studying how the pathways interact in discriminating between the optic flow generated by the perceiver's egomotion from the actual movement of individual objects, and developing new experimental techniques for determining the perceptual organization of objects composed of multiple surfaces. Finally, we are engaged in computational projects that introduce dynamical concepts into motion detection models, investigate the role of feedback in global motion pattern formation, and establish a new approach for studying how spatial form is determined from detected motions.


Hock, H.S., & Nichols, D.F. (2012). Motion perception induced by dynamic grouping: A probe for the compositional structure of objects. Vision Research, 59, 45-63. pdf

Daniels, L.B., Nichols, D.F., Seifert, M.S., & Hock, H.S. (2012). Changes in pupil diameter entrained by cortically initiated changes in attention. Visual Neuroscience, 29, 131-142 .pdf

Azzopardi, P., & Hock, H.S. (2011). Illusory motion perception in blindsight. Proceedings of the National Academy of Sciences, 108, 876-881. pdf

Hock, H.S., Schöner, G., Brownlow S., & Taler, D. (2011). The temporal dynamics of global-to-local feedback in the formation of hierarchical motion patterns: Psychophysics and computational simulations. Attention, Perception & Psychophysics. 73, 1171-1194. pdf

Hock, H.S., & Schöner, G. (2010). A neural basis for perceptual dynamics. In V. Jirsa & R. Huys (Eds.), Nonlinear Dynamics in Human Behavior 151-177. Berlin: Springer Verlag. pdf

Hock, H.S., & Schöner, G. (2010). Measuring perceptual hysteresis with the modified method of limits: Dynamics at the threshold. Seeing and Perceiving, 23, 173-195. pdf

Hock, H.S., & Nichols, D.F. (2010). The line motion illusion: The detection of counterchanging edge and surface contrast. Journal of Experimental Psychology: Human Perception and Performance, 36, 781-79. pdf

Gilroy, L. & Hock, H.S. (2009). Simultaneity and sequence in the perception of apparent motion. Attention, Perception & Psychophysics (formerly Perception & Psychophysics), 71, 1563-1575. pdf

Hock, H.S., Schöner, G., & Gilroy, L. (2009). A counterchange mechanism for the perception of motion. Acta Psychologica, 132, 1-21. pdf

Hock, H.S., & Ploeger, A. (2006). Linking dynamical decisions at different levels of description in motion pattern formation: Psychophysics. Perception & Psychophysics, 68, 505-514. pdf

Nichols, D.F., Hock, H.S., & Schöner, G. (2006). Linking dynamical decisions at different levels of decription in motion pattern formation: Computational simulations. Perception & Psychophysics, 68, 515-533. pdf

Hock, H.S., Bukowski, l., & Nichols, D.F. Huisman, A., & Rivera, M., (2005). Dynamical vs. judgmental comparison: Hysteresis effects in motion perception. Spatial Vision, 18, 317-335. pdf

Hock, H.S., & Gilroy, L. (2005). A common mechanism for first- and second order apparent motion. Vision Research, 45, 661-675. pdf

Gilroy, L., & Hock, H.S. (2004). Multipicative non-linearity in the perception of apparent motion. Vision Research, 44, 2001-2007. pdf

Hock, H.S., Nichols, D.F., & Espinoza, J. (2004). When motion is not perceived: Evidence from adaptation and dynamical stability. Spatial Vision, 17, 235-248. pdf

Gilroy, L. & Hock, H.S. (2004). Detection of counter-changing contrast: Second-order apparent motion without post-rectification motion-energy analysis or salience mapping/feature tracking. Journal of Experimental Psychology: Human Perception and Performance, 30, 137-150. pdf

Hock, H.S., Schöner, G., & Giese, M. (2003). The dynamical foundations of motion pattern formation: Stability, selective adaptation, and perceptual continuity. Perception & Psychophysics, 65, 429-457. pdf

Hock, H.S., Park, C., & Schöner, G.. (2002). Self-organized pattern formation: Experimental dissection of motion detection and motion integration by variation of attentional spread. Vision Research, 42, 991-1003. pdf

Hock, H.S., Gilroy, L., & Harnett, G. (2002). Counter-changing luminance: A non-Fourier, non-attentional basis for the perception of single-element apparent motion. Journal of Experimental Psychology: Human Perception and Performance, 28, 93-112. pdf

Gilroy, L., Hock, H.S., & Ploeger, A., (2001). Differential activation solution to the motion correspondence problem. Perception & Psychophysics, 63, 847-861. pdf

Eastman, K, & Hock, H.S. (1999). Bistability in the perception of apparent motion: Effects of temporal asymmetry. Perception & Psychophysics, 61, 1055-1065. pdf

Hock, H.S., Balz, G.W., & Smollon, W. (1998). The effect of attentional spread on self-organized motion perception. Vision Research, 38, 3743-3758. pdf

Hock. H.S., Kogan, K., & Espinoza, J. (1997). Dynamic thresholds for the perception of single-element apparent motion: Bistability from local cooperativity. Perception & Psychophysics, 59, 1077-1088.pdf

Balz, G.W., & Hock, H.S. (1997). The effect of attentional spread on spatial resolution. Vision Research, 37, 1499-1510.pdf

Hock, H.S., Schöner, G., & Voss, A. (1997). The influence of adaptation and stochastic fluctuations on spontaneous perceptual changes for bistable stimuli. Perception & Psychophysics, 59, 509-522.pdf

Hock, H.S., Balz, G.W. & Eastman, K. (1996). Cooperative interations and the perception of motion and stationarity for directionally ambiguous apparent motion stimuli. Perception, 25, 887-900.

Hock, H.S., Schöner, G., & Hochstein, S. (1996). Perceptual stabilty and the selective adaptation of perceived and unperceived motion. Vision Reseach, 36, 3311-3323.pdf

Hock, H.S. & Eastman, K. (1995). Context effects on perceived position: Sustained and transient temporal influences on spatial interactions. Vision Research, 35, 635-646. pdf

Hock, H.S. & Balz, G.W. (1994). Spatial scale dependent in-phase and anti-phase directional biases in the perception of self-organized motion patterns.Vision Research, 34, 1843-186.

Hock, H.S., Kelso, J.A.S., & Schöner, G. (1993). Bistability and hysteresis in the perceptual organization of apparent motion. Journal of Experimental Psychology: Human Perception and Performance, 19, 63-80.pdf

Hock, H.S., Eastman, K., Stutin, C., & Field, L. (1992). Common movement and spatial separation influence the contributions of position and motion information to the detection of relative movement. Vision Research, 32, 1043-1054.