Abstract
In natural vision, shifts in spatial attention are associated with shifts of gaze. Computational models of such overt attention typically use the concept of a saliency map: Normalized maps of center-surround differences are computed for individual stimulus features and added linearly to obtain the saliency map. Although the predictions of such models correlate with fixated locations better than chance, their mechanistic assumptions are less well investigated. Here, we tested one key assumption: Do the effects of different features add linearly or according to a max-type of interaction? We measured the eye position of observers viewing natural stimuli whose luminance contrast and/or color contrast (saturation) increased gradually toward one side. We found that these feature gradients biased fixations toward regions of high contrasts. When two contrast gradients (color and luminance) were superimposed, linear summation of their individual effects predicted their combined effect. This demonstrated that the interaction of color and luminance contrast with respect to human overt attention is—irrespective of the precise model—consistent with the assumption of linearity, but not with a max-type interaction of these features.
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Bacon, W. F., & Egeth, H. E. (1997). Goal-directed guidance of attention: Evidence from conjunctive visual search. Journal of Experimental Psychology: Human Perception & Performance, 23, 948–961.
Baddeley, R. J., & Tatler, B. W. (2006). High frequency edges (but not contrast) predict where we fixate: A Bayesian system identification analysis. Vision Research, 46, 2824–2833. doi:10.1016/j.visres.2006.02.024
Benjamini, Y., & Hochberg, Y. (1995). Controlling the false discovery rate: A practical and powerful approach to multiple testing. Journal of the Royal Statistical Society: Series B, 57, 289–300. Available at www.jstor.org/stable/2346101.
Brainard, D. H. (1997). The Psychophysics Toolbox. Spatial Vision, 10, 433–436. doi:10.1163/156856897X00357
Buswell, G. T. (1935). How people look at pictures: A study of the psychology of perception in art. Chicago: University of Chicago Press.
Cerf, M., Harel, J., Einhäuser, W., & Koch, C. (2008). Predicting human gaze using low-level saliency combined with face detection. Advances in Neural Information Processing, 20, 241–248.
Cornelissen, F. W., Peters, E. M., & Palmer, J. (2002). The Eye-link Toolbox: Eye tracking with MATLAB and the Psychophysics Toolbox. Behavior Research Methods, Instruments, & Computers, 34, 613–617.
Derrington, A. M., Krauskopf, J., & Lennie, P. (1984). Chromatic mechanisms in lateral geniculate nucleus of macaque. Journal of Physiology, 357, 241–265.
Einhäuser, W., & König, P. (2003). Does luminance-contrast contribute to a saliency map for overt visual attention? European Journal of Neuroscience, 17, 1089–1097. doi:10.1046/j.1460-9568.2003.02508.x
Einhäuser, W., Kruse, W., Hoffmann, K.-P., & König, P. (2006). Differences of monkey and human overt attention under natural conditions. Vision Research, 46, 1194–1209. doi:10.1016/j.visres.2005.08.032
Einhäuser, W., Rutishauser, U., Frady, E. P., Nadler, S., König, P., & Koch, C. (2006). The relation of phase noise and luminance contrast to overt attention in complex visual stimuli. Journal of Vision, 6, 1148–1158. doi:10.1167/6.11.1
Einhäuser, W., Rutishauser, U., & Koch, C. (2008). Task-demands can immediately reverse the effects of sensory-driven saliency in complex visual stimuli. Journal of Vision, 8(2, Art. 2), 1–19. doi:10.1167/8.2.2
Einhäuser, W., Spain, M., & Perona, P. (2008). Objects predict fixations better than early saliency. Journal of Vision, 8(14, Art. 18), 1–26. doi:10.1167/8.14.18
Elazary, L., & Itti, L. (2008). Interesting objects are visually salient. Journal of Vision, 8, 1–15. doi:10.1167/8.3.3
Foulsham, T., & Underwood, G. (2008). What can saliency models predict about eye movements? Spatial and sequential aspects of fixations during encoding and recognition. Journal of Vision, 8(2, Art. 6), 1–17. doi:10.1167/8.2.6
Gao, D., Mahadevan, V., & Vasconcelos, N. (2008). On the plausibility of the discriminant center—surround hypothesis for visual saliency. Journal of Vision, 8(7, Art. 13), 1–18. doi:10.1167/8.7.13
Golz, J., & MacLeod, D. I. A. (2002). Influence of scene statistics on colour constancy. Nature, 415, 637–640. doi:10.1038/415637a
Gottlieb, J. P., Kusunoki, M., & Goldberg, M. E. (1998). The representation of visual salience in monkey parietal cortex. Nature, 391, 481–484. doi:10.1038/35135
Henderson, J. M., Brockmole, J. R., Castelhano, M. S., & Mack, M. (2007). Visual saliency does not account for eye movements during visual search in real-world scenes. In R. van Gompel, M. Fischer, W. Murray, & R. Hill (Eds.), Eye movement research: Insights into mind and brain (pp. 537–562). Amsterdam: Elsevier.
Horwitz, G. D., & Newsome, W. T. (1999). Separate signals for target selection and movement specification in the superior colliculus. Science, 284, 1158–1161. doi:10.1126/science.284.5417.1158
Itti, L. (2005). Quantifying the contribution of low-level saliency to human eye movements in dynamic scenes. Visual Cognition, 12, 1093–1123.
Itti, L., & Baldi, P. (2005). A principled approach to detecting surprising events in video. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR) (pp. 631–637). Los Alamitos, CA: IEEE Computer Society Press.
Itti, L., & Koch, C. (2000). A saliency-based search mechanism for overt and covert shifts of visual attention. Vision Research, 40, 1489–1506. doi:10.1016/S0042-6989(99)00163-7
James, W. (1890). Principles of psychology. New York: Holt.
Koch, C., & Ullman, S. (1985). Shifts in selective visual attention: Towards the underlying neural circuitry. Human Neurobiology, 4, 219–227.
Krieger, G., Rentschler, I., Hauske, G., Schill, K., & Zetzsche, C. (2000). Object and scene analysis by saccadic eye-movements: An investigation with higher-order statistics. Spatial Vision, 13, 201–214. doi:10.1163/156856800741216
Kustov, A. A., & Robinson, D. L. (1996). Shared neural control of attentional shifts and eye movements. Nature, 384, 74–77. doi:10.1038/384074a0
Land, M. F., & Hayhoe, M. (2001). In what ways do eye movements contribute to everyday activities? Vision Research, 41, 3559–3565. doi:10.1016/S0042-6989(01)00102-X
Lewis, A., & Zhaoping, L. (2005). Saliency from natural scene statistics. Abstract Viewer/Itinerary Planner (Program No. 821.11). Washington, DC: Society for Neuroscience.
Li, Z. (2002). A saliency map in primary visual cortex. Trends in Cognitive Sciences, 6, 9–16. doi:10.1016/S1364-6613(00)01817-9
Mannan, S. K., Ruddock, K. H., & Wooding, D. S. (1996). The relationship between the locations of spatial features and those of fixations made during visual examination of briefly presented images. Spatial Vision, 10, 165–188. doi:10.1163/156856896X00123
Mannan, S. K., Ruddock, K. H., & Wooding, D. S. (1997). Fixation patterns made during brief examination of two-dimensional images. Perception, 26, 1059–1072.
Mazer, J. A., & Gallant, J. L. (2003). Goal-related activity in V4 during free viewing visual search: Evidence for a ventral stream visual salience map. Neuron, 40, 1241–1250. doi:10.1016/S0896-6273(03)00764-5
McPeek, R. M., & Keller, E. L. (2002). Superior colliculus activity related to concurrent processing of saccade goals in a visual search task. Journal of Neurophysiology, 87, 1805–1815.
Michelson, A. A. (1927). Studies in optics. Chicago: University of Chicago Press.
Morrone, M. C., Denti, V., & Spinelli, D. (2002). Color and luminance contrasts attract independent attention. Current Biology, 12, 1134–1137. doi:10.1016/S0960-9822(02)00921-1
Najemnik, J., & Geisler, W. S. (2005). Optimal eye movement strategies in visual search. Nature, 434, 387–391. doi:10.1038/nature03390
Navalpakkam, V., & Itti, L. (2005). Modeling the influence of task on attention. Vision Research, 45, 205–231. doi:10.1016/j.visres.2004.07.042
Nothdurft, H. (2000). Salience from feature contrast: Additivity across dimensions. Vision Research, 40, 1183–1201. doi:10.1016/ S0042-6989(00)00031-6
Oliva, A., Torralba, A., Castelhano, M. S., & Henderson, J. M. (2003). Top-down control of visual attention in object detection. IEEE Proceedings of the International Conference on Image Processing, 1, 253–256.
Parkhurst, D., Law, K., & Niebur, E. (2002). Modeling the role of salience in the allocation of overt visual attention. Vision Research, 42, 107–123. doi:10.1016/S0042-6989(01)00250-4
Parkhurst, D., & Niebur, E. (2004). Texture contrast attracts overt visual attention in natural scenes. European Journal of Neuroscience, 19, 783–789. doi:10.1111/j.0953-816X.2003.03183.x
Peli, E. (1997). In search of a contrast metric: Matching the perceived contrast of Gabor patches at different phases and bandwidths. Vision Research, 37, 3217–3224. doi:10.1016/S0042-6989(96)00262-3
Pelli, D. G. (1997). The Video Toolbox software for visual psychophysics: Transforming numbers into movies. Spatial Vision, 10, 437–442. doi:10.1163/156856897X00366
Peters, R. J., Iyer, A., Itti, L., & Koch, C. (2005). Components of bottom-up gaze allocation in natural images. Vision Research, 45, 2397–2416. doi:10.1016/j.visres.2005.03.019
Pomplun, M. (2006). Saccadic selectivity in complex visual search displays. Vision Research, 46, 1886–1900. doi:10.1016/j.visres.2005.12.003
Posner, M. I., & Petersen, S. E. (1990). The attention system of the human brain. Annual Review of Neuroscience, 13, 25–42. doi:10.1146/ annurev.ne.13.030190.000325
Privitera, C. M., Fujita, T., Chernyak, D., & Stark, L. W. (2005). On the discriminability of hROIs, human visually selected regionsof-interest. Biological Cybernetics, 93, 141–152. doi:10.1007/s00422-005-0586-7
Privitera, C. M., & Stark, L. W. (2000). Algorithms for defining visual regions-of-interest: Comparison with eye fixations. IEEE Transactions on Pattern Analysis & Machine Intelligence, 22, 970–982.
Rao, R. P. N., Zelinsky, G. J., Hayhoe, M. M., & Ballard, D. H. (2002). Eye movements in iconic visual search. Vision Research, 42, 1447–1463. doi:10.1016/S0042-6989(02)00040-8
Reinagel, P., & Zador, A. (1999). Natural scene statistics at the centre of gaze. Network: Computation in Neural Systems, 10, 341–350.
Rizzolatti, G., Raggio, L., Dascola, I., & Umiltà, C. (1987). Reorienting attention across the horizontal and vertical meridians: Evidence in favor of a premotor theory of attention. Neuropsychologia, 25, 31–40.
Robinson, D. L., & Petersen, S. E. (1992). The pulvinar and visual salience. Trends in Neurosciences, 15, 127–132. doi:10.1016/0166-2236(92)90354-B
Spalek, T. M., & Hammad, S. (2005). The left-to-right bias in inhibition of return is due to the direction of reading. Psychological Science, 16, 15–18. doi:10.1111/j.0956-7976.2005.00774.x
Steinwender, J., & König, P. (2007, August). Context dependency of overt attention in natural scenes. Poster presented at the 14th European Conference on Eye Movements, Potsdam.
Tatler, B. W. (2007). The central fixation bias in scene viewing: Selecting an optimal viewing position independently of motor biases and image feature distributions. Journal of Vision, 7(14, Art. 4), 1–17. doi:10.1167/7.14.4
Tatler, B. W., Baddeley, R. J., & Gilchrist, I. D. (2005). Visual correlates of fixation selection: Effects of scale and time. Vision Research, 45, 643–659. doi:10.1016/j.visres.2004.09.017
Thompson, K. G., Bichot, N. P., & Schall, J. D. (1997). Dissociation of visual discrimination from saccade programming in macaque frontal eye field. Journal of Neurophysiology, 77, 1046–1050.
Torralba, A. (2003). Modeling global scene factors in attention. Journal of the Optical Society of America A, 20, 1407–1418. doi:10.1364/JOSAA.20.001407
Torralba, A., Oliva, A., Castelhano, M. S., & Henderson, J. M. (2006). Contextual guidance of eye movements and attention in real-world scenes: The role of global features in object search. Psychological Review, 113, 766–786.
Treisman, A. M., & Gelade, G. (1980). A feature-integration theory of attention. Cognitive Psychology, 12, 97–136. doi:10.1016/0010-0285(80)90005-5
Vincent, B. T., Troscianko, T., & Gilchrist, I. D. (2007). Investigating a space-variant weighted salience account of visual selection. Vision Research, 47, 1809–1820. doi:10.1016/j.visres.2007.02.014
Wolfe, J. M., Butcher, S. J., Lee, C., & Hyle, M. (2003). Changing your mind: On the contributions of top-down and bottom-up guidance in visual search for feature singletons. Journal of Experimental Psychology: Human Perception & Performance, 29, 483–502.
Wolfe, J. M., Cave, K. R., & Franzel, S. L. (1989). Guided search: An alternative to the feature integration model of visual search. Journal of Experimental Psychology: Human Perception & Performance, 15, 419–433.
Yarbus, A. L. (1967). Eye movements and vision (B. Haigh, Trans.). New York: Plenum.
Zhang, L., Tong, M. H., Marks, T. K., Shan, H., & Cottrell, G. W. (2008). SUN: A Bayesian framework for saliency using natural statistics. Journal of Vision, 8(7, Art. 32), 1–20. doi:10.1167/8.7.32
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The work was supported financially by Deutsche Forschungsgemeinschaft Research Training Group 885—NeuroAct (to B.M.tH. and W.E.), the German Academic Exchange Service (to S.E.), and by IST-027268-POP (Perception On Purpose; to P.K.).
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Engmann, S., Hart, B.M.’., Sieren, T. et al. Saliency on a natural scene background: Effects of color and luminance contrast add linearly. Attention, Perception, & Psychophysics 71, 1337–1352 (2009). https://doi.org/10.3758/APP.71.6.1337
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DOI: https://doi.org/10.3758/APP.71.6.1337