The effect of experience and of dots’ density and duration on the detection of coherent motion in dogs

Abstract

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.

Dogs accurately track a moving object on a screen and anticipate its destination

“…The lower this proportion of coherently moving dots the harder is the detection of coherent motion. The lowest proportion of coherently moving dots for which dogs were capable to detect coherent motion was 0.29, a lot higher than the threshold reported for adult humans of 0.05 9,10 . Thus, coherent motion detection seems to be more efficient in humans (and other mammals including macaques, cats, and seals [11][12][13] ) than in dogs.…”

“…In Experiment 2, we fitted two models. In LMM 02, we included the predictor variables throw number (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) and the Frisbee movement condition (rewind, forward). In LMM 03, we included the predictor variables interest period number (within condition; 1-3) and the Frisbee movement condition (rewind, forward).…”

Illusion susceptibility in domestic dogs

“…In adopting this approach, three non‐illusion studies have also evaluated canine perceptual processing preferences (albeit, for some, indirectly). Two studies have evaluated global‐local precedence using a Navon’s task (Mongillo et al, 2016; Pitteri, Mongillo, Carnier, & Marinelli, 2014), while another assessed motion perception (Kanizsár et al, 2018). The two studies that specifically evaluated global‐local precedence in dogs suggests dogs may process stimuli globally; however, these two studies used the same sample of subjects, and while a global processing preference in dogs was identified, this trend was not significant (Mongillo et al, 2016; Pitteri et al, 2014).…”

“…The two studies that specifically evaluated global‐local precedence in dogs suggests dogs may process stimuli globally; however, these two studies used the same sample of subjects, and while a global processing preference in dogs was identified, this trend was not significant (Mongillo et al, 2016; Pitteri et al, 2014). In the study of motion perception, it was reported that dogs locally integrate elements (Kanizsár et al, 2018).…”

“…Originally, this explanation in dogs was reported to be unlikely as the only processing precedence study conducted on dogs observed a general preference for the global processing of stimuli (Mongillo, Pitteri, Sambugaro, Carnier, & Marinelli, 2016). However, this general preference was not statistically significant, and more recent research suggests that there is evidence for a local processing preference in dogs (Kanizsár et al, 2018).…”