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.     

Supervisory Orientations and Salesperson Work Outcomes: The Moderating Effect of Salesperson Location

Although a growing number of companies have salespeople stationed at a site other than their supervisors' (i.e., are remotely located), relatively little attention has been paid in the literature to the differences between managing co-and remote located salespeople. Accordingly, we test the moderating effect of salesperson location on the relationships between three supervisory orientations—output, activity, and capability—and salesperson satisfaction with supervisor and performance.

The results show that salesperson location moderates the relationship between supervisory activity orientation and satisfaction such that activity orientation has a positive effect on the satisfaction of remote located salespeople, but a negative effect on the satisfaction of co-located salespeople. We find that end-results orientation is positively related to the satisfaction of co-located salespeople but not of remote located salespeople. Finally, supervisory capability orientation is positively linked to the performance of co-located salespeople but not of remote located salespeople. The results provide guidance for sales managers about how to structure their interactions with remote and proximally close salespeople.     

Validity Stability Across Entering College Cohorts: Exploring the temporal generalizability of local validity estimates

Local validity studies rely on the assumption that validity estimates from one incumbent sample approximate validity for future applicant pools. We test this assumption using SAT scores and high school grades as predictors of first year college grade point average across multiple college applicant pools for over 100 schools. We present evidence for substantial absolute and rank order consistency in validity estimates. However, this consistency is far less than perfect, resulting in potentially meaningful utility differences over time. In addition, observed fluctuations are not fully explained by sampling error alone.     

Successful or unsuccessful search for risk defusing operators: Effects on decision behaviour

In experiments with quasi-realistic risky scenarios instead of gambles, decision makers are less interested in probability information. Often, they actively search for a risk defusing operator (RDO; an action to be performed in addition to a specific alternative and expected to decrease the risk involved). Examples in daily life are insurance and vaccination. In our experiment, the central independent variable was the successful or unsuccessful RDO search. The central dependent variables were choices and information search behaviour. In order to get information about the applied heuristics, a concurrent Thinking Aloud procedure was employed in addition to the method of Active Information Search. Eighty subjects made a choice in two risky scenarios. The findings confirm that the successful search for an RDO for one of the alternatives is an excellent predictor of choice. If the subject does not search for an RDO or the search is unsuccessful, MAXIMIN was the most frequent heuristic.     

Categorization of Prototypical Stimulus Classes by Pigeons

Previous findings have demonstrated the pigeon's ability to categorize sets of schematic faces defined by a polymorphous feature rule. We present here an experiment that was conducted to evaluate the influence of the category structure determined by the distribution of features across stimulus classes. The task was a middle-value discrimination, involving a band of positive stimuli surrounded by a band of negative stimuli. Two large sets of Brunswik faces were conceptualized as variations of a standard stimulus (prototype) and occupied highly overlapping regions in the feature space. The classes could be separated in terms of a distance-from-prototype rule. Only three of five animals were successful in classification training. Analyses of both the transfer performance and of the effects of feature values on the variance of responding revealed the classical prototype effect-that is, performance determined by the overall similarity to the central tendency of the classes. A theoretical evaluation of the data examines the possibility that pigeons discriminated between the classes by virtue of a prototype-distance rule, although exemplar models offer more parsimonious accounts.