“Vision for Action” in Young Children Aligning Multi-Featured Objects: Development and Comparison with Nonhuman Primates

Effective vision for action and effective management of concurrent spatial relations underlie skillful manipulation of objects, including hand tools, in humans. Children’s performance in object insertion tasks (fitting tasks) provides one index of the striking changes in the development of vision for action in early life. Fitting tasks also tap children’s ability to work with more than one feature of an object concurrently. We examine young children’s performance on fitting tasks in two and three dimensions and compare their performance with the previously reported performance of adult individuals of two species of nonhuman primates on similar tasks. Two, three, and four year-old children routinely aligned a bar-shaped stick and a cross-shaped stick but had difficulty aligning a tomahawk-shaped stick to a matching cut-out. Two year-olds were especially challenged by the tomahawk. Three and four year-olds occasionally held the stick several inches above the surface, comparing the stick to the surface visually, while trying to align it. The findings suggest asynchronous development in the ability to use vision to achieve alignment and to work with two and three spatial features concurrently. Using vision to align objects precisely to other objects and managing more than one spatial relation between an object and a surface are already more elaborated in two year-old humans than in other primates. The human advantage in using hand tools derives in part from this fundamental difference in the relation between vision and action between humans and other primates.     

Predisposed visual memory of shapes in quail chicks

Newly hatched chicks will spontaneously peck at conspicuous objects in their field of view, and soon learn to distinguish between edible food particles and unpleasant tasting objects. To examine whether the selective pecking is based on the ability to memorize shapes, we analyzed pecking behavior of 1- to 2-days-old quail chicks (Coturnix japonica) by using ball- and triangle-shaped beads both painted in green. Repeated presentation of dry bead (either ball or triangle) resulted in a progressively fewer number of pecks (habituation). When chicks were tested by triangle after repeated presentation of ball, chicks showed a significant increase in the number of pecks at the triangle (dishabituation). On the other hand, when tested by ball after a series of triangle presentations, pecking frequency did not increase (no dishabituation). Chicks thus distinguished the triangle as a novel object after being habituated to ball, but did not respond to the ball after triangle. A similar asymmetry was found in one-trial passive avoidance task. Chicks were pre-trained by water-coated (neutral) triangle and then trained by methylanthranilate-coated (aversive) ball. In this case, most chicks learned to avoid the ball, and half of these successful learners pecked at the triangle; they distinguished triangle from ball. When chicks were pre-trained by neutral ball and trained by aversive triangle, on the other hand, most chicks did not distinguish the ball from triangle, and showed a generalized avoidance for both beads. Chicks may be innately predisposed to memorize a limited category of shapes such as ball, and associate them with selective avoidance.     

The effects of two novel objects on the behavior of singly caged adult rhesus macaques.

Six female and six male adult rhesus macaques were given sticks and nylon balls as an attempt at simple cage enrichment. A latin square design was used to compare behavior during separate 4-week periods with each object and during a control period with no object. Frequency and duration of 15 different behaviors were recorded. Resting was the most common activity which decreased slightly in duration when the stick or nylon ball was present (P less than 0.02). The mean duration of stick use was longer than that of the nylon ball (P less than 0.01). No other behaviors changed significantly, including the frequency of abnormal behaviors such as self-abuse, stereotypic acts, and bizarre postures. Generally, these objects were used infrequently and led to few changes in the behavior of singly-caged adult rhesus macaques. However, they did appear to stimulate activity for some individuals.     

A computational model of the development of separate representations of facial identity and expression in the primate visual system

Experimental studies have provided evidence that the visual processing areas of the primate brain represent facial identity and facial expression within different subpopulations of neurons. For example, in non-human primates there is evidence that cells within the inferior temporal gyrus (TE) respond primarily to facial identity, while cells within the superior temporal sulcus (STS) respond to facial expression. More recently, it has been found that the orbitofrontal cortex (OFC) of non-human primates contains some cells that respond exclusively to changes in facial identity, while other cells respond exclusively to facial expression. How might the primate visual system develop physically separate representations of facial identity and expression given that the visual system is always exposed to simultaneous combinations of facial identity and expression during learning? In this paper, a biologically plausible neural network model, VisNet, of the ventral visual pathway is trained on a set of carefully-designed cartoon faces with different identities and expressions. The VisNet model architecture is composed of a hierarchical series of four Self-Organising Maps (SOMs), with associative learning in the feedforward synaptic connections between successive layers. During learning, the network develops separate clusters of cells that respond exclusively to either facial identity or facial expression. We interpret the performance of the network in terms of the learning properties of SOMs, which are able to exploit the statistical indendependence between facial identity and expression.     

Effects of Caregiver-Implemented Aggression Reduction Procedure on Problem Behavior of Dogs

Problem behavior of companion animals poses a threat to caregivers, other targets of problem behavior (e.g., strangers, other nonhuman animals), and those animals engaging in problem behavior. This study examined the effects of an aggression reduction procedure (ARP) on dog problem behavior. After a baseline condition showing caregivers were unsuccessful in reducing dog aggression and the behaviors preceding aggression, caregivers were trained to implement a procedure to address dog problem behavior in relatively simple contexts. Generalization programming then was used to target caregiver plan implementation and dog problem behavior in more complex contexts. The ARP effectively reduced dog aggression for all dogs. A slight reduction and increased variability in dog precursor behavior was observed when the ARP was implemented. In addition, caregivers and experts rated the goals, procedures, and effects as acceptable. Implications of these findings are discussed.     

Temperament correlates with training success in adult rhesus macaques

In recent years there has been a marked increase in awareness of issues involving the psychological well-being of nonhuman primates (NHPs) used in biomedical research. As a result, many facilities are starting to train primates to voluntarily cooperate with veterinary, husbandry, and research procedures, such as remaining still for blood draws or injections. Such training generally reduces the stress associated with these procedures, resulting in calmer animals and, ultimately, better research models. However, such training requires great investments in time, and there can be vast individual differences in training success. Some animals learn tasks quickly, while others make slower progress in training. In this study, we examined whether temperament, as measured by response to a novel food object, correlated with the amount of time it took to train 20 adult female rhesus macaques to perform a simple task. The monkeys were categorized as "exploratory" (i.e., inspected a novel object placed in the home cage within 10 sec), "moderate" (i.e., inspected the object within 10-180 sec), or "inhibited" (i.e., did not inspect the object within 3 min). We utilized positive reinforcement techniques to train the monkeys to touch a target (PVC pipe shaped like an elbow) hung on their cage. Temperament correlated with training success in this study (Pearson chi2=7.22, df=2, P=0.03). We easily trained over 75% of the animals that inspected the novel food (i.e., exploratory or moderate individuals) to touch the target. However, only 22% of the inhibited monkeys performed the task. By knowing which animals may not respond to conventional training methods, we may be able to develop alternate training techniques to address their specific needs. In addition, these results will allow us to screen monkeys to be assigned to research projects in which they will be trained, with the goal of obtaining the best candidates for those studies.     

Evidence for averaging of distance from landmarks in the domestic dog

Several studies in landmark use have shown that animals locate spatial positions by predominantly using perpendicular distance from extended surfaces over distance from individual landmarks. In the current study, I investigated whether the domestic dog encodes perpendicular distance from surfaces and whether they estimate distances from multiple cues. Dogs were first trained to locate a ball hidden at an equal and constant distance between an individual landmark and one wall (Experiment 1) or two walls (Experiment 2). On occasional unrewarded tests, the landmark was shifted laterally, perpendicularly or diagonally relative to one wall. Data revealed that the dogs largely determined where to search by averaging the distance from the walls of the room and the distance from the individual landmark. This study provides additional evidence that domestic dogs use metric properties of space to find a spatial location by use of landmarks. Although the present results are in accordance with the vector sum model, they are also consistent with current theories of spatial memory.     

“Gift Giving” by Wild Bottle nose Dolphins (Tursiops sp.) to Humans at a Wild Dolphin Provisioning Program,Tangalooma, Australia

ABSTRACT

While there is increasing interest in the impact of animal interactions upon children's wellbeing and attitudes, there has been less attention paid to the specific characteristics of the animals that attract and engage children. We used a within-subjects design to explore how differences in animal features (such as their animacy, size, and texture) impacted upon pre-school children's social and emotional responses. This study examined pre-schoolers' interactions with two animal-like robots (Teksta and Scoozie), two insect types (stick insects and hissing cockroaches) and a dog (Teasel, a West Highland Terrier). Nineteen preschool participants aged 35–57 months were videoed while interacting with the experimenter, a peer, and each stimulus (presented individually). We used both verbal and nonverbal behaviors to evaluate interactions and emotional responses to the stimuli and found that these two measures could be incongruent, highlighting the need for systematic approaches to evaluating children's interactions with animals. We categorized the content of children's dialogues in relation to psychological and biological attributes of each stimulus and their distinctions between living and non-living stimuli; the majority of comments were biological, with psychological terms largely reserved for the dog and mammal-like robot only. Comments relating to living qualities revealed ambiguity towards attributes that denote differences between living and non-living creatures. We used a range of nonverbal measures, including willingness to approach and touch stimuli, rates of self-touching, facial expressions of emotion, and touch to others. Insects (hissing cockroaches and stick insects) received the most negative verbal and nonverbal responses. The mammal-like robot (rounded, fluffy body shape, large eyes, and sympathetic sounds) was viewed much more positively than its metallic counterpart, as was the real dog. We propose that these interactions provide information on how children perceive animals and a platform for the examination of human socio-emotional and cognitive development more generally. The children engaged in social referencing to the adult experimenter rather than familiar peers when uncertain about the stimuli presented, suggesting that caregivers have a primary role in shaping children's responses to animals.     

Shift in the intrinsic excitability of medial prefrontal cortex neurons following training in impulse control and cued-responding tasks

Impulse control is an executive process that allows animals to inhibit their actions until an appropriate time. Previously, we reported that learning a simple response inhibition task increases AMPA currents at excitatory synapses in the prelimbic region of the medial prefrontal cortex (mPFC). Here, we examined whether modifications to intrinsic excitability occurred alongside the synaptic changes. To that end, we trained rats to obtain a food reward in a response inhibition task by withhold responding on a lever until they were signaled to respond. We then measured excitability, using whole-cell patch clamp recordings in brain slices, by quantifying action potentials generated by the injection of depolarizing current steps. Training in this task depressed the excitability of layer V pyramidal neurons of the prelimbic, but not infralimbic, region of the mPFC relative to behavioral controls. This decrease in maximum spiking frequency was significantly correlated with performance on the final session of the task. This change in intrinsic excitability may represent a homeostatic mechanism counterbalancing increased excitatory synaptic inputs onto those neurons in trained rats. Interestingly, subjects trained with a cue that predicted imminent reward availability had increased excitability in infralimbic, but not the prelimbic, pyramidal neurons. This dissociation suggests that both prelimbic and infralimbic neurons are involved in directing action, but specialized for different types of information, inhibitory or anticipatory, respectively.     

Men and women exhibit a differential bias for processing movement versus objects

Sex differences in many spatial and verbal tasks appear to reflect an inherent low-level processing bias for movement in males and objects in females. We explored this potential movement/object bias in men and women using a computer task that measured targeting performance and/or color recognition. The targeting task showed a ball moving vertically towards a horizontal line. Before reaching the line, the ball disappeared behind a masking screen, requiring the participant to imagine the movement vector and identify the intersection point. For the color recognition task, the ball briefly changed color before disappearing beneath the mask and participants were required only to identify the color shade. Results showed that targeting accuracy for slow and fast moving balls was significantly better in males compared to females. No sex difference was observed for color shade recognition. We also studied a third, dual attention task comprised of the first two, where the moving ball briefly changed color randomly just before passing beneath the masking screen. When the ball changed color, participants were required only to identify the color shade. If the ball didn't change color, participants estimated the intersection point. Participants in this dual attention condition were first tested with the targeting and color tasks alone and showed results that were similar to the previous groups tested on a single task. However, under the dual attention condition, male accuracy in targeting, as well as color shade recognition, declined significantly compared to their performance when the tasks were tested alone. No significant changes were found in female performance. Finally, reaction times for targeting and color choices in both sexes correlated highly with ball speed, but not accuracy. Overall, these results provide evidence of a sex-related bias in processing objects versus movement, which may reflect sex differences in bottom up versus top-down analytical strategies.     

Serial conditional discrimination and temporal bisection in rats selectively lesioned in the dentate gyrus

In positive serial conditional discrimination, animals respond during a target stimulus when it is preceded by a feature stimulus, but they do not respond when the same target stimulus is presented alone. Moreover, the feature and target stimuli are separated from each other by an empty interval. The present work aimed to investigate if two durations (4 or 16 s) of the same feature stimulus (light) could modulate the operant responses of rats to different levers (A and B) during a 5-s target stimulus (tone). In the present study, lever A was associated with the 4-s light, and lever B was associated with the 16-s light. A 5-s empty interval was included between the light and the tone. In the same training procedure, the rats were also presented with the 5-s tone without the preceding light stimuli. In these trials, the responses were not reinforced. We evaluated the hippocampal involvement of these behavioral processes by selectively lesioning the dentate gyrus with colchicine. Once trained, the rats were submitted to a test using probe trials without reinforcement. They were presented with intermediate durations of the feature stimulus (light) to obtain a temporal bisection curve recorded during the exposure to the target stimuli. The rats from both groups learned to respond with high rates during tones preceded by light and with low rates during tones presented alone, which indicated acquisition of the serial conditional discrimination. The rats were able to discriminate between the 4- and 16-s lights by correctly choosing lever A or B. In the test, the temporal bisection curves from both experimental groups showed a bisection point at the arithmetic mean between 4 and 16 s. Such processes were not impaired by the dentate gyrus lesion. Thus, our results showed that different durations of a feature stimulus could result in conditional properties. However, this processing did not appear to depend on the dentate gyrus alone.     

Rigorous Training of Dogs Leads to High Accuracy in Human Scent Matching-To-Sample Performance

Human scent identification is based on a matching-to-sample task in which trained dogs are required to compare a scent sample collected from an object found at a crime scene to that of a suspect. Based on dogs’ greater olfactory ability to detect and process odours, this method has been used in forensic investigations to identify the odour of a suspect at a crime scene. The excellent reliability and reproducibility of the method largely depend on rigor in dog training. The present study describes the various steps of training that lead to high sensitivity scores, with dogs matching samples with 90% efficiency when the complexity of the scents presented during the task in the sample is similar to that presented in the in lineups, and specificity reaching a ceiling, with no false alarms in human scent matching-to-sample tasks. This high level of accuracy ensures reliable results in judicial human scent identification tests. Also, our data should convince law enforcement authorities to use these results as official forensic evidence when dogs are trained appropriately.     

Female but not male dogs respond to a size constancy violation

Differences between sexes in cognitive processes are widespread in humans and permeate many, if not most, cognitive domains. In animal cognition research, however, possible sex differences are still often neglected. Here, we provide striking evidence for a sex-specific response in an object permanence task in domestic dogs (Canis familiaris). Female dogs responded with significantly increased looking times to a violation of expectancy--a ball 'magically' changing size while temporarily occluded. By contrast, male dogs, irrespective of their neuter status, did not respond to the size constancy violation. These results indicate that sex differences in basic cognitive processes may extend to mammals in general, and call for increased consideration of possible sex effects when analysing and interpreting data in animal cognition.     

Disturbances by dog barking increase vigilance in coots Fulica atra

Animals frequently interrupt their activity to look up and to scan their surrounding environment for potential predators (vigilance). As vigilance and other activities are often mutually exclusive, such behaviours are at the expense of feeding, sleeping or preening. Authors of many wildlife disturbance studies found that people with free-running dogs provoked the most pronounced disturbances (e.g. greater flushing distances and more birds affected). However, dogs on leash may also negatively affect wild animals, and barking dogs may lead to an increase in vigilance. In this study, I tested this hypothesis in coots (Fulica atra) using three different playback procedures: (1) dog barks, (2) conspecific coot alarm calls and (3) chaffinch song. The trials were conducted in spring and autumn 2005 at three study sites in southwestern Germany. During the dog playbacks, vigilance increased significantly from 17 to 28%. This increase in vigilance is comparable to the presence of a natural predator. As expected, vigilance also increased significantly during conspecific coot alarm calls but not during playbacks of the chaffinch song control. Two main findings result from the study: (1) coots respond to acoustic traits of dogs and may be able to acoustically recognise this predator and (2) this increase in vigilance might have implications for conservation, especially when considering buffer zones around sensitive areas.     

Visual Cues Given by Humans Are Not Sufficient for Asian Elephants (Elephas maximus) to Find Hidden Food

Recent research suggests that domesticated species – due to artificial selection by humans for specific, preferred behavioral traits – are better than wild animals at responding to visual cues given by humans about the location of hidden food. \Although this seems to be supported by studies on a range of domesticated (including dogs, goats and horses) and wild (including wolves and chimpanzees) animals, there is also evidence that exposure to humans positively influences the ability of both wild and domesticated animals to follow these same cues. Here, we test the performance of Asian elephants (Elephas maximus) on an object choice task that provides them with visual-only cues given by humans about the location of hidden food. Captive elephants are interesting candidates for investigating how both domestication and human exposure may impact cue-following as they represent a non-domesticated species with almost constant human interaction. As a group, the elephants (n = 7) in our study were unable to follow pointing, body orientation or a combination of both as honest signals of food location. They were, however, able to follow vocal commands with which they were already familiar in a novel context, suggesting the elephants are able to follow cues if they are sufficiently salient. Although the elephants’ inability to follow the visual cues provides partial support for the domestication hypothesis, an alternative explanation is that elephants may rely more heavily on other sensory modalities, specifically olfaction and audition. Further research will be needed to rule out this alternative explanation.     

The modulation of corticospinal excitability during motor imagery of actions with objects

We investigated whether corticospinal excitability during motor imagery of actions (the power or the pincer grip) with objects was influenced by actually touching objects (tactile input) and by the congruency of posture with the imagined action (proprioceptive input). Corticospinal excitability was assessed by monitoring motor evoked potentials (MEPs) in the first dorsal interosseous following transcranial magnetic stimulation over the motor cortex. MEPs were recorded during imagery of the power grip of a larger-sized ball (7 cm) or the pincer grip of a smaller-sized ball (3 cm)--with or without passively holding the larger-sized ball with the holding posture or the smaller-sized ball with the pinching posture. During imagery of the power grip, MEPs amplitude was increased only while the actual posture was the same as the imagined action (the holding posture). On the other hand, during imagery of the pincer grip while touching the ball, MEPs amplitude was enhanced in both postures. To examine the pure effect of touching (tactile input), we recorded MEPs during imagery of the power and pincer grip while touching various areas of an open palm with a flat foam pad. The MEPs amplitude was not affected by the palmer touching. These findings suggest that corticospinal excitability during imagery with an object is modulated by actually touching an object through the combination of tactile and proprioceptive inputs.     

Wild-Born Orangutans (Pongo abelii) Engage in Triadic Interactions During Play

It has long been held that triadic interactions, or interactions between individuals that include shared perception and goals concerning an outside entity, require elaborate cognitive processes such as joint attention. With their connection to shared intentionality, triadic interactions have been a key topic of interest for developmental and evolutionary psychologists, notably when making comparisons between humans and other ape species. There is good evidence that chimpanzees and bonobos engage in triadic interactions; however, convincing evidence for orangutans are more limited and so far have been found only in the context of feeding. I engaged 11 wild-born sanctuary orangutans through the medium of a stick, allowing them to decide how to use the object and how to interact with me. The participating orangutans developed idiosyncratic ways of using the stick and engaging with me during the activity, and six of them alternated their gaze between the stick and me. When I interrupted the activity, the participating orangutans displayed more numerous and different behaviors than before the interruption to actively reengage me in the game. Much like human infants, they appeared more interested in the social interaction than in the stick. These findings confirm that triadic interactions occur in nonenculturated orangutans and are consistent with studies of other nonhuman great ape species, which also show triadic interactions, suggesting that joint attention and potentially shared intentionality may have an early origin in our evolutionary history.     

Attention to uninformative features expressed by pigeons in a duration matching-to-sample task

Pigeons were trained on a matching-to-sample task in which they had to respond to a different choice stimulus following the same durations (2 or 10 s) of two different signals. The duration signals consisted of a white light presented from the ceiling and a red light presented from the front wall. Subsequent test performance indicated that matching accuracy declined (1) when the set of choice stimuli following a duration signal differed from the set presented during training, and (2) when the color or location of the duration signal was changed from values used during training. These results are discussed in terms of attention to uninformative features of a visual stimulus.     

Do Domestic Dogs Understand Human Actions as Goal-Directed?

Understanding of other’s actions as goal-directed is considered a fundamental ability underlying cognitive and social development in human infants. A number of studies using the habituation-dishabituation paradigm have shown that the ability to discern intentional relations, in terms of goal-directedness of an action towards an object, appears around 5 months of age. The question of whether non-human species can perceive other’s actions as goal-directed has been more controversial, however there is mounting evidence that at least some primates species do. Recently domestic dogs have been shown to be particularly sensitive to human communicative cues and more so in cooperative and intentional contexts. Furthermore, they have been shown to imitate selectively. Taken together these results suggest that dogs may perceive others'' actions as goal-directed, however no study has investigated this issue directly. In the current study, adopting an infant habituation-dishabituation paradigm, we investigated whether dogs attribute intentions to an animate (a human) but not an inanimate (a black box) agent interacting with an object. Following an habituation phase in which the agent interacted always with one of two objects, two sets of 3 trials were presented: new side trials (in which the agent interacted with the same object as in the habituation trial but placed in a novel location) and new goal trials (in which the agent interacted with the other object placed in the old location). Dogs showed a similar pattern of response to that shown in infants, looking longer in the new goal than new side trials when they saw the human agent interact with the object. No such difference emerging with the inanimate agent (the black box). Results provide the first evidence that a non-primate species can perceive another individual’s actions as goal-directed. We discuss results in terms of the prevailing mentalisitic and non-mentalistic hypotheses regarding goal-attribution.     

What experimental experience affects dogs’ comprehension of human communicative actions?

Studies of dogs report that individuals reliably respond to the goal-directed communicative actions (e.g., pointing) of human experimenters. All of these studies use some version of a multi-trial approach, thereby allowing for the possibility of rapid learning within an experimental session. The experiments reported here ask whether dogs can respond correctly to a communicative action based on only a single presentation, thereby eliminating the possibility of learning within the experimental context. We tested 173 dogs. For each dog reaching our test criteria, we used a single presentation of six different goal-directed actions within a session, asking whether they correctly follow to a target goal (container with concealed food) a (1) distal hand point, (2) step toward one container, (3) hand point to one container followed by step toward the other, (4) step toward one container and point to the other, (5) distal foot point with the experimenter's hands free, and (6) distal foot point with the experimenter's hands occupied. Given only a single presentation, dogs selected the correct container when the experimenter hand pointed, foot pointed with hands occupied, or stepped closer to the target container, but failed on the other actions, despite using the same method. The fact that dogs correctly followed foot pointing with hands occupied, but not hands free, suggests that they are sensitive to environmental constraints, and use this information to infer rational, goal-directed action. We discuss these results in light of the role of experience in recognizing communicative gestures, as well as the significance of coding criteria for studies of canine competence.