The effect of experience and of dots’ density and duration on the detection of coherent motion in dogs
Knowledge about the mechanisms underlying canine vision is far from being exhaustive, especially that concerning post-retinal elaboration. One aspect that has received little attention is motion perception, and in spite of the common belief that dogs are extremely apt at detecting moving stimuli, there is no scientific support for such an assumption. In fact, we recently showed that dogs have higher thresholds than humans for coherent motion detection (Kanizsar et al. in Sci Rep UK 7:11259, 2017). This term refers to the ability of the visual system to perceive several units moving in the same direction, as one coherently moving global unit. Coherent motion perception is commonly investigated using random dot displays, containing variable proportions of coherently moving dots. Here, we investigated the relative contribution of local and global integration mechanisms for coherent motion perception, and changes in detection thresholds as a result of repeated exposure to the experimental stimuli. Dogs who had been involved in the previous study were given a conditioned discrimination task, in which we systematically manipulated dot density and duration and, eventually, re-assessed our subjects’ threshold after extensive exposure to the stimuli. Decreasing dot duration impacted on dogs’ accuracy in detecting coherent motion only at very low duration values, revealing the efficacy of local integration mechanisms. Density impacted on dogs’ accuracy in a linear fashion, indicating less efficient global integration. There was limited evidence of improvement in the re-assessment but, with an average threshold at re-assessment of 29%, dogs’ ability to detect coherent motion remains much poorer than that of humans.
KeywordsCoherent motion Dot density Dot lifetime Perceptual learning Dog
We are very grateful to the student Giulia Madumali Zotti for helping with the experiments and to Dr. Carlo Poltronieri for his technical assistance. The study was funded by the University of Padova (to LM, 2016 - prot. DOR1673431). Dr. Orsolya Kanizár was supported by a PhD grant funded by the University of Padova.
Compliance with ethical standards
None of the authors of this paper has any financial or personal relationship with other people or organizations which might inappropriately influence or bias its content.
Human and animal rights
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.
- Aguirre GK, Komáromy AM, Cideciyan AV, Brainard DH, Aleman TS, Roman AJ, Avants BB, Gee JC, Korczykowski M, Hauswirth WW, Acland GM (2007) Canine and human visual cortex intact and responsive despite early retinal blindness from RPE65 mutation. PLoS Med 4:e230. https://doi.org/10.1371/journal.pmed.0040230 CrossRefPubMedPubMedCentralGoogle Scholar
- Bertenthal BI, Pinto J (1994) Global processing of biological motions. Psychol Sci 5:221–225. https://doi.org/10.1111/j.1467-9280.1994.tb00504.x CrossRefGoogle Scholar
- Blanke O, Brooks A, Mercier M, Spinelli L, Adriani M, Lavanchy L, Safran AB, Landis T (2007) Distinct mechanisms of form-from-motion perception in human extrastriate cortex. Neuropsychol 45:644–653. https://doi.org/10.1016/j.neuropsychologia.2006.07.019 CrossRefGoogle Scholar
- Djavadian RL, Harutiunian-Kozak BA (1987) Retinotopic organization of the lateral suprasylvian area of the cat. Acta Neurobiol Exp 43:251–262Google Scholar
- Fahle M, Henkle-Fahle S (1996) Interobserver variance in perceptual performance and learning. Invest Ophth Vis Sci 37:869–877Google Scholar
- Miller PE, Murphy CJ (1995) Vision in dogs. J Am Vet Med Assoc 15:1623–1634Google Scholar
- Prins N, Kingdom FAA (2009) Palamedes: matlab routines for analyzing psychophysical data. http://www.palamedestoolbox.org. Accessed 12 Sept 2017
- Williams D, Brannan J (1994) Spatial integration of local motion signals. In: Smith A, Snowden R (eds) Visual detection of motion. Academic Press, London, pp 291–303Google Scholar
- Wurtz RH, Kandel ER (2000) Perception of motion, depth and form. In: Kandel ER, Schwarts JH, Jessel TM (eds) Principles of neural science, 4th edn. McGraw-Hill, New York, pp 548–571Google Scholar