The role of prediction in learned predictiveness.

Learning permits even relatively uninteresting stimuli to capture attention if they are established as predictors of important outcomes. Associative theories explain this "learned predictiveness" effect by positing that attention is a function of the relative strength of the association between stimuli and outcomes. In three experiments we show that this explanation is incomplete: learned overt visual-attention is not a function of the relative strength of the association between stimuli and an outcome. In three experiments, human participants were exposed to triplets of stimuli that comprised (a) a target (that defined correct responding), (b) a stimulus that was perfectly correlated with the presentation of the target, and (c) a stimulus that was uncorrelated with the presentation of the target. Participants' knowledge of the associative relationship between the correlated or uncorrelated stimuli and the target was always good. However, eye-tracking revealed that an attentional bias toward the correlated stimulus only developed when it and target-relevant responding preceded the target stimulus. We propose a framework in which attentional changes are modulated during learning as a function the relative strength of the association between stimuli and the task-relevant response, rather than an association between stimuli and the task-relevant outcome. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Dogs fail to recognize a human pointing gesture in two-dimensional depictions of motion cues.

Few studies have investigated biological motion perception in dogs and it remains unknown whether dogs recognise the biological identity of two-dimensional animations of human motion cues. To test this, we assessed the dogs' (N = 32) responses to point-light displays of a human performing a pointing gesture towards one of two pots. At the start of the experiment the demonstrator was a real-life person, but over the course of the test dogs were presented with two-dimensional figurative representations of pointing gestures in which visual information was progressively removed until only the isolated motion cues remained. Dogs' accuracy was above chance level only with real-life and black-and-white videos, but not with the silhouette or the point-light figure. Dogs' accuracy during these conditions was significantly lower than in the real-life condition. This result could not be explained by trial order since dogs' performance was still not higher than chance when only the point-light figure condition was presented after the initial demonstration. The results imply that dogs are unable to recognise humans in two-dimensional depictions of human motion cues only. In spite of extensive exposure to human movement, dogs need more perceptual cues to detect equivalence between human two-dimensional animations and the represented living entity.

I know a dog when I see one: dogs (Canis familiaris) recognize dogs from videos.

Several aspects of dogs' visual and social cognition have been explored using bi-dimensional representations of other dogs. It remains unclear, however, if dogs do recognize as dogs the stimuli depicted in such representations, especially with regard to videos. To test this, 32 pet dogs took part in a cross-modal violation of expectancy experiment, during which dogs were shown videos of either a dog and that of an unfamiliar animal, paired with either the sound of a dog barking or of an unfamiliar vocalization. While stimuli were being presented, dogs paid higher attention to the exit region of the presentation area, when the visual stimulus represented a dog than when it represented an unfamiliar species. After exposure to the stimuli, dogs' attention to different parts of the presentation area depended on the specific combination of visual and auditory stimuli. Of relevance, dogs paid less attention to the central part of the presentation area and more to the entrance area after being exposed to the barking and dog video pair, than when either was paired with an unfamiliar stimulus. These results indicate dogs were surprised by the latter pairings, not by the former, and were interested in where the barking and dog pair came from, implying recognition of the two stimuli as belonging to a conspecific. The study represents the first demonstration that dogs can recognize other conspecifics in videos.

Do Domestic Dogs (Canis lupus familiaris) Perceive Numerosity Illusions?

Recent studies have showed that domestic dogs are only scantly susceptible to visual illusions, suggesting that the perceptual mechanisms might be different in humans and dogs. However, to date, none of these studies have utilized illusions that are linked to quantity discrimination. In the current study, we tested whether dogs are susceptible to a linear version of the Solitaire illusion, a robust numerosity illusion experienced by most humans. In the first experiment, we tested dogs' ability to discriminate items in a 0.67 and 0.75 numerical ratio. The results showed that dogs' quantity discrimination abilities fall in between these two ratios. In Experiment 2, we presented the dogs with the Solitaire illusion pattern using a spontaneous procedure. No evidence supporting any numerosity misperception was found. This conclusion was replicated in Experiment 3, where we manipulated dogs' initial experience with the stimuli and their contrast with the background. The lack of dogs' susceptibility to the Solitaire illusion suggests that numerical estimation of dogs is not influenced by the spatial arrangement of the items to be enumerated. In view of the existing evidence, the effect may be extended to dogs' quantitative abilities at large.

Dogs (Canis familiaris) recognise our faces in photographs: implications for existing and future research.

Dogs are an ideal species to investigate phylogenetic and ontogenetic factors contributing to face recognition. Previous research has found that dogs can recognise their owner using visual information about the person's face, presented live. However, a thorough investigation of face processing mechanisms requires the use of graphical representations and it currently remains unclear whether dogs are able to spontaneously recognise human faces in photographs. To test this, pet dogs (N = 60) were briefly separated from their owners and, to achieve reunion, they needed to select the location indicated by a photograph of their owner's face, rather than that of an unfamiliar person concurrently presented. Photographs were taken under optimal and suboptimal (non-frontally oriented and unevenly illuminated faces) conditions. Results revealed that dogs approached their owner significantly above chance level when presented with photos taken under optimal conditions. Further analysis revealed no difference in the probability of choosing the owner between the optimal and suboptimal conditions. Dogs were more likely to choose the owner if they directed a higher percentage of looking time towards the owner's photograph compared to the stranger's one. In addition, the longer the total viewing time of both photos, the higher the probability that dogs chose the stranger. A main effect of dogs' sex was also obtained, with a higher probability of male dogs choosing the owner's photograph. This study provides direct evidence that dogs are able to recognise their owner's face from photographs. The results imply that motion and three-dimensional information is not necessary for recognition. The findings also support the ecological valence of such stimuli and increase the validity of previous investigations into dog cognition that used two-dimensional representations of faces. The effects of attention may reflect differences at the individual level in attraction towards novel faces or in the recruitment of different face processing mechanisms.

Local Dot Motion, Not Global Configuration, Determines Dogs' Preference for Point-Light Displays.

Visual perception remains an understudied area of dog cognition, particularly the perception of biological motion where the small amount of previous research has created an unclear impression regarding dogs' visual preference towards different types of point-light displays. To date, no thorough investigation has been conducted regarding which aspects of the motion contained in point-light displays attract dogs. To test this, pet dogs (N = 48) were presented with pairs of point-light displays with systematic manipulation of motion features (i.e., upright or inverted orientation, coherent or scrambled configuration, human or dog species). Results revealed a significant effect of inversion, with dogs directing significantly longer looking time towards upright than inverted dog point-light displays; no effect was found for scrambling or the scrambling-inversion interaction. No looking time bias was found when dogs were presented with human point-light displays, regardless of their orientation or configuration. The results of the current study imply that dogs' visual preference is driven by the motion of individual dots in accordance with gravity, rather than the point-light display's global arrangement, regardless their long exposure to human motion.

Development of a Spatial Discount Task to Measure Impulsive Choices in Dogs.

Impulsive choices reflect an individual's tendency to prefer a smaller immediate reward over a larger delayed one. Here, we have developed a behavioural test which can be easily applied to assess impulsive choices in dogs. Dogs were trained to associate one of two equidistant locations with a larger food amount when a smaller amount was presented in the other location, then the smaller amount was placed systematically closer to the dog. Choices of the smaller amount, as a function of distance, were considered a measure of the dog's tendency to make impulsive choices. All dogs (N = 48) passed the learning phase and completed the entire assessment in under 1 h. Choice of the smaller food amount increased as this was placed closer to the dog. Choices were independent from food motivation, past training, and speed of learning the training phase; supporting the specificity of the procedure. Females showed a higher probability of making impulsive choices, in agreement with analogue sex differences found in human and rodent studies, and supporting the external validity of our assessment. Overall, the findings support the practical applicability and represent a first indication of the validity of this method, making it suitable for investigations into impulsivity in dogs.

Learned changes in outcome associability.

When a cue reliably predicts an outcome, the associability of that cue will change. Associative theories of learning propose this change will persist even when the same cue is paired with a different outcome. These theories, however, do not extend the same privilege to an outcome; an outcome's learning history is deemed to have no bearing on subsequent new learning involving that outcome. Two experiments were conducted which sought to investigate this assumption inherent in these theories using a serial letter-prediction task. In both experiments, participants were exposed, in Stage 1, to a predictable outcome ('X') and an unpredictable outcome ('Z'). In Stage 2, participants were exposed to the same outcomes preceded by novel cues which were equally predictive of both outcomes. Both experiments revealed that participants' learning towards the previously predictable outcome was more rapid in Stage 2 than the previously unpredicted outcome. The implications of these results for theories of associative learning are discussed.