Correction: Two-action task,testing imitative social learning in kea (Nestor notabilis)

Social learning is an adaptive way of dealing with the complexity of life as it reduces the risk of trial-and-error learning. Depending on the type of information acquired, and associations formed, several mechanisms within the larger taxonomy of social learning can be distinguished. Imitation is one such process within this larger taxonomy, it is considered cognitively demanding and is associated with high-fidelity response matching. The present study reproduced a 2002 study conducted by Heyes and Saggerson, which successfully illustrated motor imitation in budgerigars (Melopsittacus undulatus). In our study, eighteen kea (Nestor notabilis) that observed a trained demonstrator remove a stopper from a test box (1) took less time from hopping on the box to feeding (response duration) in session one and (2) were faster in making a vertical removal response on the stopper once they hopped on the box (removal latency) in session one than non-observing control group individuals. In contrast to the budgerigars (Heyes and Saggerson, Ani Behav. 64:851–859, 2002) the present study could not find evidence of motor imitation in kea. The results do illustrate, however, that there were strong social effects on exploration rates indicating motivational and attentional shifts. Furthermore, the results may suggest a propensity toward emulation in contrast to motor imitation or alternatively selectivity in the application of imitation.

     

The IAT is sensitive to the perceived accuracy of newly learned associations

Three experiments tested whether the Implicit Association Test (IAT) is sensitive to the perceived accuracy of newly learned associations. In experiment 1, participants learned to associate positive or negative attributes with two novel groups. Participants in one condition were told that the attributes accurately described the groups; in a second condition, prior to learning, they were made aware that the attributes were randomly assigned to the groups. Participants were given an IAT and an explicit measure testing attitudes towards the two groups. When the participants were told that the attributes were accurate, their IAT performance and explicit measure responses indicated a preference for the more positively described group but when the attributes were known to be arbitrary, preferences were reduced according to both measures. Experiment 2 replicated these results and demonstrated that the associations were learned even in the random condition. Experiment 3 included a condition that placed “not” before each attribute, which demonstrated that people can incorporate a negative modifier into a learned association. Explicit attitudes and the IAT showed reversed preferences in this negation condition. These experiments imply that the IAT is sensitive to the perceived accuracy of learned associations. Copyright © 2011 John Wiley & Sons, Ltd.     

Cognitive control in number magnitude processing: evidence from eye-tracking

The unit-decade compatibility effect describes longer response times and higher error rates for incompatible (e.g., 37_52) than compatible (e.g., 42_57) number comparisons. Recent research indicated that the effect depends on the percentage of same-decade filler items. In the present study, we further examined this relationship by recording participants’ eye-fixation behaviour. In four conditions, participants had to compare item sets with different filler item types (i.e., same-decade and same-unit filler items) and different numbers of same-decade filler items (i.e., 25, 50, and 75 %). We found a weaker unit-decade compatibility effect with most fixations on tens in the condition with same-unit filler items. Moreover, the compatibility effect increased with the percentage of same-decade filler items which was accompanied by less fixations on tens and more fixations on units. Thus, our study provides first eye-tracking evidence for the influence of cognitive control in number processing.     

Framing of Decisions: Effect on Active and Passive Risk Avoidance

Decision makers intending to avoid risk in a decision situation can choose a less risky alternative (passive risk avoidance) or intervene actively in an alternative applying a risk‐defusing action (active risk avoidance). In Experiment 1 (64 participants), we compared active and passive risk defusing in two framing conditions. In the negative frame, in the uncertain alternative, a change to the worse was possible; in the positive frame, a change to an improvement was possible. Each participant decided in both framing conditions. As expected, active risk avoidance behavior for preventing a negative outcome (i.e., in the negative frame) was more likely than for promoting a positive one (i.e., in the positive frame). If decision makers did not or could not actively defuse the risk, they chose in correspondence to the classical pattern: risk avoidance in the positive frame and risk seeking in the negative one. We replicated the latter result in a second experiment (32 participants). The classical framing pattern in passive risk avoidance in both experiments is remarkable, because participants were not presented or did not search for exact probabilities. Copyright © 2014 John Wiley & Sons, Ltd.     

Dogs’ use of the solidity principle: revisited

A wealth of comparative data has been accumulated over the past decades on how animals acquire and use information about the physical world. Domestic dogs have typically performed comparably poorly in physical cognition tasks, though in a recent study Kundey et al. (Anim Cogn 13:497–505, 2010) challenged this view and concluded that dogs understand that objects cannot pass through solid barriers. However, the eight subjects in the study of Kundey et al. may have solved the task with the help of perceptual cues, which had not been controlled for. Here, we tested dogs with a similar task that excluded these cues. In addition, unlike the set-up of Kundey et al., our set-up allowed the subjects to observe the effect of the solid barrier. Nevertheless, all 28 subjects failed to solve this task spontaneously and showed no evidence of learning across 50 trials. Our results therefore call into question the earlier suggestion that dogs have, or can acquire, an understanding of the solidity principle.     

Dogs learn to solve the support problem based on perceptual cues

Numerous recent studies have investigated how animals solve means-end tasks and unraveled considerable variation in strategies used by different species. Domestic dogs (Canis familiaris) have typically performed comparably poorly in physical cognition tasks, but a recent study showed that they can solve the on–off condition of the support problem, where they are confronted with two boards, one with a reward placed on it and the other with a reward placed next to it. To explore which strategies dogs use to solve this task, we first tested 37 dogs with the on–off condition tested previously and then tested subjects that passed this condition with three transfer tasks. For the contact condition, the inaccessible reward was touching the second board. For the perceptual containment condition, the inaccessible reward was surrounded on three sides by the second board, but not supported by it, whereas for the gap condition, discontinuous boards were used. Unlike in the previous study, our subjects did not perform above chance level in the initial trials of the on–off condition, but 13 subjects learned to solve it. Their performance in the transfer tasks suggests that dogs can learn to solve the support problem based on perceptual cues, that they can quickly adopt new cues when old ones become unreliable, but also that some apparently inherent preferences are hard to overcome. Our study contributes to accumulating evidence demonstrating that animals typically rely on a variety of perceptual cues to solve physical cognition tasks, without developing an understanding of the underlying causal structure.     

Representational insight in pigeons: comparing subjects with and without real-life experience

Understanding the relation between objects and their pictures at a level beyond mere feature discrimination is by no means a trivial cognitive ability, and support of this is still weak in nonhuman species. Here, we report evidence of representational insight in pigeons. Responding to pictures of human body parts was compared in birds that had extensive pre-experience with live humans and in birds that had never seen any human heads. In a two-alternative forced-choice procedure the pigeons were trained to discriminate between pictures of either handless or headless humans and nonhumans. On test, the birds had to choose (i) between body parts they had already seen in training and the parts that had been missing, (ii) between previously seen parts and arbitrary skin patches, and (iii) between previously missing parts and skin patches. Only the pigeons that lacked experience with real heads and were trained with pictures of headless humans failed to show a significant preference for pictures of missing parts (i.e., heads) over arbitrary skin patches. This demonstrates the importance of individual experience with the real 3D-referents of pictures for classification of the latter and is thereby evidence of representational insight.     

Dogs’ attention towards humans depends on their relationship, not only on social familiarity

Both in humans and non-human animals, it has been shown that individuals attend more to those they have previously interacted with and/or they are more closely associated with than to unfamiliar individuals. Whether this preference is mediated by mere social familiarity based on exposure or by the specific relationship between the two individuals, however, remains unclear. The domestic dog is an interesting subject in this line of research as it lives in the human environment and regularly interacts with numerous humans, yet it often has a particularly close relationship with its owner. Therefore, we investigated how long dogs (Canis familiaris) would attend to the actions of two familiar humans and one unfamiliar experimenter, while varying whether dogs had a close relationship with only one or both familiar humans. Our data provide evidence that social familiarity by itself cannot account for dogs’ increased attention towards their owners since they only attended more to those familiar humans with whom they also had a close relationship.     

How to solve a mechanical problem: the relevance of visible and unobservable functionality for kea

Animals sometimes succeed quickly in solving a mechanical problem that is a modification of one they have previously learnt to solve. However, they may do so by attending to the visible features of the relevant physical dimension without knowing its causal functionality, if that is not directly perceivable. This kind of problem solving can be tested by simultaneously offering two mechanical devices with the same visual features but different inherent appropriateness for problem solving. Here, we provide data collected by following this procedure for the first time in a bird species. Captive kea, Nestor notabilis, a parrot species highly interested in the affordances of objects, were offered a mechanical problem in which they had to remove a baited tube from one of two upright poles where removal was blocked at the end of one pole but not the other. With extended but not with restricted exploration of a baseline apparatus, the kea immediately succeeded in removing the tube from an apparatus that had modified pole ends when they were able to visually observe (without touching) that one of these ends would block tube removal but the other would not. However, when the kea were allowed to explore two poles that had a removable and a fixed obstruction where the difference in function was not visible, they preferred the removable one during unbaited exploration but failed afterwards to push a tube to the end of the pole with the loose structure during subsequent baited test trials. Thus, in spite of the speed with which the kea learnt the tasks, there was no indication that they understood the underlying unobservable causal structure of the problem.