Picture-object recognition in pigeons: evidence of representational insight in a visual categorization task using a complementary information procedure

Success in tasks requiring categorization of pictorial stimuli does not prove that a subject understands what the pictures stand for. The ability to achieve representational insight is by no means a trivial one because it exceeds mere detection of 2-D features present in both the pictorial images and their referents. So far, evidence for such an ability in nonhuman species is weak and inconclusive. Here, the authors report evidence of representational insight in pigeons. After being trained on pictures of incomplete human figures, the birds responded significantly more to pictures of the previously missing parts than to nonrepresentative stimuli, which demonstrates that they actually recognized the pictures' representational content.     

Gaze behavior in analytical and holistic face processing

We conducted two experiments examining children's and adults' gaze behavior when processing faces analytically (focusing on a single feature) or holistically (comparing the overall similarity of the faces). Children 6-8 and 9-10 years of age and adults were instructed to assign schematically drawn faces in Experiment 1 and photos of real faces in Experiment 2 to two categories. The categories were constructed so as to allow either an analytical or holistic categorization of the faces. During all trials, gaze behavior was recorded from stimulus onset until reaction. The location and duration of the fixations used were analyzed. Whereas the holistic processors fixated the whole area of the eyes and nose most and longest independently of age, analytical processors showed a more feature-specific gaze behavior, focusing their fixations upon the particular feature used for subsequent processing. Thus, differences in analytical and holistic face processing can be detected early in gaze behavior-that is, at the visual encoding stage.     

Confusion and compensation in visual perception: effects of spatiotemporal proximity and selective attention

The authors investigated spatial, temporal, and attentional manipulations in a short-term repetition priming paradigm. Brief primes produced a strong preference to choose the primed alternative, whereas long primes had the opposite effect. However, a 2nd brief presentation of a long prime produced a preference for the primed word despite the long total prime duration. These surprising results are explained by a computational model that posits the offsetting components of source confusion (prime features are confused with target features) and discounting (evidence from primed features is discounted). The authors obtained compelling evidence for these components by showing how they can cooperate or compete through different manipulations of prime salience. The model allows for dissociations between prime salience and the magnitude of priming, thereby providing a unified account of "subliminal" and "supraliminal" priming.     

Preschoolers' and adults' reliance on object shape and object function for lexical extension.

We investigated the developmental progression of reliance on object function versus object shape to extend novel words. In 3 experiments, 3-year-olds, 5-year-olds, and adults were presented with sets of objects consisting of a target, a same-shape/different-function match, a different-shape/same-function match, and a distracter. In Experiments 1 and 2, function was emphasized during the word learning phase and participants were given direct experience with the functions of target and test objects. In Experiment 3, function was emphasized both during the learning phase and when requesting a referent of the novel labels. Across all 3 experiments, 3- and 5-year-olds focused on shape while adults focused on function when extending the novel words. These results suggest a developmental change in the consideration of shape and function in lexical extension.     

Evidence of heterospecific referential communication from domestic horses (<Emphasis Type="Italic">Equus caballus</Emphasis>) to humans

Referential communication occurs when a sender elaborates its gestures to direct the attention of a recipient to its role in pursuit of the desired goal, e.g. by pointing or showing an object, thereby informing the recipient what it wants. If the gesture is successful, the sender and the recipient focus their attention simultaneously on a third entity, the target. Here we investigated the ability of domestic horses (Equus caballus) to communicate referentially with a human observer about the location of a desired target, a bucket of food out of reach. In order to test six operational criteria of referential communication, we manipulated the recipient’s (experimenter) attentional state in four experimental conditions: frontally oriented, backward oriented, walking away from the arena and frontally oriented with other helpers present in the arena. The rate of gaze alternation was higher in the frontally oriented condition than in all the others. The horses appeared to use both indicative (pointing) and non-indicative (nods and shakes) head gestures in the relevant test conditions. Horses also elaborated their communication by switching from a visual to a tactile signal and demonstrated perseverance in their communication. The results of the tests revealed that horses used referential gestures to manipulate the attention of a human recipient so to obtain an unreachable resource. These are the first such findings in an ungulate species.     

Training the equidistant principle of number line spacing

The characteristics of effective numerical trainings are still under scientific debate. Given the importance of number line estimation due to the strong relation between task performance and arithmetic abilities, the current study aimed at training one important number line characteristic: the equidistant spacing of adjacent numbers. Following an embodied training approach, second-graders were trained using a randomized crossover design to divide a presented line into different numbers of equal segments by walking the line with equally spaced steps. Performance was recorded, and feedback as to the correct equidistant spacing was provided using the Kinect sensor system. Training effects were compared to a control training with no involvement of task-specific whole-body movements. Results indicated more pronounced specific training effects after the embodied training. Moreover, transfer effects to number line estimation and arithmetic performance were partially observed. In particular, differential training effects for bounded versus unbounded number line estimation corroborate the assumption that not only bodily experiences but also the need for a flexible adaption of the perspective on the training material might influence training success. Hence, more pronounced training effects of the embodied training might stem from different cognitive processes involved.     

Investigating emotional contagion in dogs (<Emphasis Type="Italic">Canis familiaris</Emphasis>) to emotional sounds of humans and conspecifics

Emotional contagion, a basic component of empathy defined as emotional state-matching between individuals, has previously been shown in dogs even upon solely hearing negative emotional sounds of humans or conspecifics. The current investigation further sheds light on this phenomenon by directly contrasting emotional sounds of both species (humans and dogs) as well as opposed valences (positive and negative) to gain insights into intra- and interspecies empathy as well as differences between positively and negatively valenced sounds. Different types of sounds were played back to measure the influence of three dimensions on the dogs’ behavioural response. We found that dogs behaved differently after hearing non-emotional sounds of their environment compared to emotional sounds of humans and conspecifics (“Emotionality” dimension), but the subjects responded similarly to human and conspecific sounds (“Species” dimension). However, dogs expressed more freezing behaviour after conspecific sounds, independent of the valence. Comparing positively with negatively valenced sounds of both species (“Valence” dimension), we found that, independent of the species from which the sound originated, dogs expressed more behavioural indicators for arousal and negatively valenced states after hearing negative emotional sounds. This response pattern indicates emotional state-matching or emotional contagion for negative sounds of humans and conspecifics. It furthermore indicates that dogs recognized the different valences of the emotional sounds, which is a promising finding for future studies on empathy for positive emotional states in dogs.