Dissociation of mechanisms involved in dogs' oriented displacements

Factors determining spatial choice were studied in experiments conducted outdoors. Six dogs (Breton spaniel) had to choose between two paths leading to a baited feeding bowl (goal). Transparent or opaque screens were interposed between the starting-point and the goal; their arrangement was devised so as to control the length and the angular deviation or divergence of the paths. The results show that when the goal was visible (transparent screens) dogs preferred the less divergent path indicating that angular deviation was the most relevant variable. When the goal was hidden (opaque screen), they preferred the shorter path and did not take into account the angular deviation. These results suggest that two classes of mechanism underlie the selection of path in these spatial situations.     

Memory for object location and route direction in virtual large-scale space

In everyday life people have to deal with tasks such as finding a novel path to a certain goal location, finding one's way back, finding a short cut, or making a detour. In all of these tasks people acquire route knowledge. For finding the same way back they have to remember locations of objects like buildings and additionally direction changes. In three experiments using recognition tasks as well as conscious and unconscious spatial priming paradigms memory processes underlying wayfinding behaviour were investigated. Participants learned a route through a virtual environment with objects either placed at intersections (i.e., decision points) where another route could be chosen or placed along the route (non-decision points). Analyses indicate first that objects placed at decision points are recognized faster than other objects. Second, they indicate that the direction in which a route is travelled is represented only at locations that are relevant for wayfinding (e.g., decision points). The results point out the efficient way in which memory for object location and memory for route direction interact.     

Memory for object location and route direction in virtual large-scale space

In everyday life people have to deal with tasks such as finding a novel path to a certain goal location, finding one's way back, finding a short cut, or making a detour. In all of these tasks people acquire route knowledge. For finding the same way back they have to remember locations of objects like buildings and additionally direction changes. In three experiments using recognition tasks as well as conscious and unconscious spatial priming paradigms memory processes underlying wayfinding behaviour were investigated. Participants learned a route through a virtual environment with objects either placed at intersections (i.e., decision points) where another route could be chosen or placed along the route (non-decision points). Analyses indicate first that objects placed at decision points are recognized faster than other objects. Second, they indicate that the direction in which a route is travelled is represented only at locations that are relevant for wayfinding (e.g., decision points). The results point out the efficient way in which memory for object location and memory for route direction interact.     

Domestic dogs’ (Canis familiaris) choices in reference to agreement among human informants on location of food

When interacting with others, informants may offer conflicting information or information of varying accuracy. Recent research suggests that young children do not trust all informants equally and are selective in both whom they solicit for information and whose claims they support. We explored whether domestic dogs (Canis familiaris) are similarly sensitive to agreement among informants. To this end, we utilized a common human gesture, pointing, to which recent research suggests dogs are sensitive. We conducted two experiments in which an experimenter secretly hid food in one of two clear containers while the dog was distracted. Next, a small group moved to indicate the food's location using stationary points positioned above the containers. In Experiment 1, two experimenters moved to stand behind the non-baited container, while a third experimenter moved to stand behind the baited container. Then, all directed one static point at the container in front of them. Experiment 2 exactly resembled Experiment 1 with the exception that the single experimenter standing behind the baited container directed two static points at the container (one with each hand). Dogs chose the container indicated by the majority in Experiment 1 significantly more often than chance, but chose the container indicated by the minority in Experiment 2 significantly more often than chance. This suggests that the number of points, not the number of people, more strongly influenced dogs' choices.     

Incidental memory in dogs (Canis familiaris): adaptive behavioral solution at an unexpected memory test

Memory processing in nonhuman animals has been typically tested in situations where the animals are repeatedly trained to retrieve their memory trace, such as delayed matching to sample, serial probe recognition, etc. In contrast, how they utilize incidentally formed memory traces is not well investigated except in rodents. We examined whether domestic dogs could solve an unexpected test based on a single past experience. In Experiment 1, leashed dogs were led to 4 open, baited containers and allowed to eat from 2 of them (Exposure phase). After a walk outside for more than 10?min, during which time the containers were replaced with new identical ones, the dogs were unexpectedly returned to the site and unleashed for free exploration (test phase). Eleven out of 12 dogs first visited one of the containers from which they had not eaten. In Experiment 2, two containers had food in them, one had a nonedible object, and the last one was empty. Dogs visited all 4 containers and were allowed to eat one of the food rewards in the Exposure phase. In the test phase, unleashed dogs first visited the previously baited container from which they had not eaten significantly more often than chance. These results demonstrate that in an unexpected, test dogs may retrieve “what” and “where” information about seen (now invisible) items from incidental memory formed during a single past experience.     

An account of human “impulsivity” on self-control tasks

Three experiments examined the effects of economic constraint (time restriction—trials restriction) on adult humans' performance on concurrent chained schedules of reinforcement in which terminal links differed both in reward size and pre-reward delay levels. In the first, terminal links offered a long delay (20, 30, 40, 50 sec) followed by 2 points, or a short delay (10 sec) followed by 1 point. Initial links consisted of the same variable interval schedules for each alternative. Subjects showed a conditional sensitivity to increases in delay. Under a time constraint, there was an increasing preference for the smaller reward as the delay to the larger reward was increased, whereas under a trials constraint subjects were totally insensitive to such changes. In the second experiment, this finding was replicated using long and short periods of video game playing as large and small rewards. In the third experiment terminal link parameters remained constant (2 points after 15 sec, or 1 point immediately), but initial link parameters were manipulated (either VI 1-sec, 8-sec, or 20-sec) so that the higher relative rate of reward shifted from being associated with the small reward to being associated with the large reward. Again subjects chose differently under the two constraints. Subjects under the time constraint exhibited a preference for the small reward at all levels of initial link, but under the trials constraint subjects preferred the large reward. Subjects in the time constraint condition thus exhibited a maladaptive insensitivity to changes in the initial link duration. These findings are interpreted as supporting a miscalculation rather than a discounting interpretation of human performance on “self-control” tasks.     

Cognitive reference points

Two methods were used to test the hypothesis that natural categories (such as colors, line orientations, and numbers) have reference point stimuli (such as focal colors, vertical and horizontal lines, and numbers that are multiples of 10) in relation to which other stimuli of the category are judged. In Experiment I, subjects placed pairs of stimuli into sentence frames consisting of linguistic “hedges” such as “— is essentially—.” Results were that the supposed reference stimuli were most often placed in the second (reference) slot. In Experiment II, the subject placed a stimulus in physical space to represent his feeling of the psychological distance of that stimulus from another spatially fixed stimulus. Results showed that, when supposed reference stimuli were fixed, other stimuli were placed closer to them than vice versa. The results have substantive implications for the understanding of internal structure of categories and methodological implications for the mapping of reference points, quantification of linguistic intuitions, and the assumption of symmetry in psychological distance judgments.     

Amygdala and “emotional” modulation of the relative use of multiple memory systems

The basolateral amygdala modulates the cognitive and habit memory processes mediated by the hippocampus and caudate nucleus, respectively. The present experiments used a plus-maze task that can be acquired using either hippocampus-dependent “place” learning or caudate-dependent “response” learning to examine whether peripheral or intra-basolateral amygdala injection of anxiogenic drugs would bias rats towards the use of a particular memory system. In Experiment 1, adult male Long–Evans rats were trained to swim from the same start point to an escape platform located in a consistent goal arm, and received pre-training peripheral injections of the α₂-adrenoceptor antagonists yohimbine (2.5 or 5.0 mg/kg), RS 79948-197 (0.05, 0.1, or 0.2 mg/kg), or vehicle. On a drug-free probe trial from a novel start point administered 24 h following acquisition, vehicle treated rats predominantly displayed hippocampus-dependent place learning, whereas rats previously treated with yohimbine (2.5, 5.0 mg/kg) or RS 79948-197 (0.1 mg/kg) predominantly displayed caudate-dependent response learning. In Experiment 2, rats receiving pre-training intra-basolateral amygdala infusions of RS 79948-197 (0.1 μg/0.5 μl) also predominantly displayed response learning on a drug-free probe trial. The findings indicate (1) peripheral injections of anxiogenic drugs can influence the relative use of multiple memory systems in a manner that favors caudate-dependent habit learning over hippocampus-dependent cognitive learning, and (2) intra-basolateral amygdala infusion of anxiogenic drugs is sufficient to produce this modulatory influence of emotional state on the use of multiple memory systems.     

MizarMode—an integrated proof assistance tool for the Mizar way of formalizing mathematics

The Emacs authoring environment for Mizar (MizarMode) is today the authoring tool of choice for many (probably the majority of) Mizar authors. This article describes the MizarMode and focuses on the proof assistance functions and tools available in it.

We start with the explanation of the design principles behind the Mizar system, and show how these design principles—mainly the concentration on simple and intuitive human-oriented proofs—have helped Mizar in developing and maintaining a very large body of formalized mathematics.

Mizar is a non-programmable and non-tactical verifier: the proofs are developed in the traditional “write—compile—correct” software programming loop. While this method is in the beginning more laborious than the methods employed in tactical and programmable proof assistants, it makes the “proof code” in the long-run more readable, maintainable and reusable. This seems to be a crucial factor for a long-term and large-scale formalization effort.

MizarMode has been designed with the aim to facilitate this kind of proof development by a number of “code-generating”, “code-browsing” and “code-searching” methods, and tools programmed or integrated within it. These methods and tools now include, e.g., the automated generation of proof skeletons, semantic browsing of the articles and abstracts, structured viewing, proof advice using trained machine learning tools like the Mizar Proof Advisor, deductive tools like MoMM, etc. We give an overview of these proof-assistance tools and their integration in the MizarMode, and also discuss some emerging and future extensions such as integration of external theorem proving assistance.     

Why do dogs (<Emphasis Type="Italic">Canis familiaris</Emphasis>) select the empty container in an observational learning task?

Many argue that dogs show unique susceptibility to human communicative signals that make them suitable for being engaged in complex co-operation with humans. It has also been revealed that socially provided information is particularly effective in influencing the behaviour of dogs even when the human’s action demonstration conveys inefficient or mistaken solution of task. It is unclear, however, how the communicative nature of the demonstration context and the presence of the human demonstrator affect the dogs’ object-choice behaviour in observational learning situations. In order to unfold the effects of these factors, 76 adult pet dogs could observe a communicative or a non-communicative demonstration in which the human retrieved a tennis ball from under an opaque container while manipulating another distant and obviously empty (transparent) one. Subjects were then allowed to choose either in the presence of the demonstrator or after she left the room. Results showed a significant main effect of the demonstration context (presence or absence of the human’s communicative signals), and we also found some evidence for the response-modifying effect of the presence of the human demonstrator during the dogs’ choice. That is, dogs predominantly chose the baited container, but if the demonstration context was communicative and the human was present during the dogs’ choice, subjects’ tendency to select the baited container has been reduced. In agreement with the studies showing sensitivity to human’s communicative signals in dogs, these findings point to a special form of social influence in observational learning situations when it comes to learning about causally opaque and less efficient (compared to what comes natural to the dog) action demonstrations.     

Delayed matching by fornix-transected monkeys: The sample, the push and the bait

In the acquisition event of ordinary delayed matching to sample the monkey sees a sample, displaces it, and finds a food reward underneath; subsequently the retention test consists of a choice between that sample and a distractor, and the strength of the memory laid down by the acquisition event may be assessed by the correctness of choice at the retention test. The present experiments varied the acquisition events and examined the effect of those variations on normal and fornix-transected monkeys' memory. One variation was to proceed as normally but never to bait the sample at acquisition; this variation allowed assessment of the role of the food reward in ordinary matching. Another was to present the sample, baited and to be displaced, as normally, but to present also the distractor, baited but not requiring to be displaced, in a second acquisition event; this “push-match” variation allowed assessment of memory for the displacement. The main result from normal monkeys was that matching to unbaited samples was learned much faster than matching to baited samples. Following fornix transection, final performance levels in matching to baited and to unbaited samples were unimpaired but push-match showed a permanent deficit. These results support earlier indications that fornix-transected monkeys have normal sensory memory but are deficient in the memory of instrumental responses.     

Attribute Framing and Goal Framing Effects in Health Decisions

Levin, Schneider, and Gaeth (LSG, 1998) have distinguished among three types of framing—risky choice, attribute, and goal framing—to reconcile conflicting findings in the literature. In the research reported here, we focus on attribute and goal framing. LSG propose that positive frames should be more effective than negative frames in the context of attribute framing, and negative frames should be more effective than positive frames in the context of goal framing. We test this framework by manipulating frame valence (positive vs negative) and frame type (attribute vs goal) in a unified context with common procedures. We also argue that the nature of effects in a goal-framing context may depend on the extent to which the research topic has “intrinsic self-relevance” to the population. In the context of medical decision making, we operationalize low intrinsic self-relevance by using student subjects and high intrinsic self-relevance by using patients. As expected, we find complete support for the LSG framework under low intrinsic self-relevance and modified support for the LSG framework under high intrinsic self-relevance. Overall, our research appears to confirm and extend the LSG framework.     

Point of view in personal memories

A structural aspect of personal memories was examined in four studies. In some memories, one has the perspective of an observer, seeing oneself “from the outside.” In other memories, one sees the scene from one's own perspective; the field of view in such memories corresponds to that of the original situation. The existence of “observer” and “field” memories was confirmed in Study 1, using a recall questionnaire. In Study 2, the similarity structure of a specified set of eight to-be-recalled situations was established: the significant dimensions were “emotionality” and “self-awareness.” Study 3 related these dimensions to the observer-field distinction; situations involving a high degree of emotion and selfawareness were most likely to be recalled with an observer perspective. Recall set was varied in Study 4: a focus on feelings (as opposed to objective circumstances) produced relatively more field memories. Studies 3 and 4 also showed that events reported as more recent tend to be recalled in the field mode. Thus a qualitative characteristic of personal memories—the perspective from which they are experienced—is apparently related to characteristics of the original event, to the individual's purpose in recalling that event, and to the reported recall interval.     

Directional learning,but no spatial mapping by rats performing a navigational task in an inverted orientation

Previous studies have identified neurons throughout the rat limbic system that fire as a function of the animal’s head direction (HD). This HD signal is particularly robust when rats locomote in the horizontal and vertical planes, but is severely attenuated when locomoting upside-down (Calton & Taube, 2005). Given the hypothesis that the HD signal represents an animal’s sense of directional heading, we evaluated whether rats could accurately navigate in an inverted (upside-down) orientation. The task required the animals to find an escape hole while locomoting inverted on a circular platform suspended from the ceiling. In Experiment 1, Long-Evans rats were trained to navigate to the escape hole by locomoting from either one or four start points. Interestingly, no animals from the 4-start point group reached criterion, even after 29 days of training. Animals in the 1-start point group reached criterion after about six training sessions. In Experiment 2, probe tests revealed that animals navigating from either 1- or 2-start points utilized distal visual landmarks for accurate orientation. However, subsequent probe tests revealed that their performance was markedly attenuated when navigating to the escape hole from a novel start point. This absence of flexibility while navigating upside-down was confirmed in Experiment 3 where we show that the rats do not learn to reach a place, but instead learn separate trajectories to the target hole(s). Based on these results we argue that inverted navigation primarily involves a simple directional strategy based on visual landmarks.     

Heterogeneity impairs numerical matching but not numerical ordering in preschool children

Do preschool children appreciate numerical value as an abstract property of a set of objects? We tested the influence of stimulus features such as size, shape, and color on preschool children's developing nonverbal numerical abilities. Children between 3 and 5 years of age were tested on their ability to estimate number when the sizes, shapes, and colors of the elements in an array were varied (heterogeneous condition) versus when they did not vary (homogeneous condition). One group of children was tested on an ordinal task in which the goal was to select the smaller of two arrays while another group of children was tested on a match‐to‐sample task in which the goal was to choose one of two visual arrays that matched the sample in number. Children performed above chance on both homogeneous and heterogeneous stimuli in both tasks. However, while children showed no impairment on heterogeneous relative to homogeneous arrays in the ordering task, performance was impaired by heterogeneity in the matching task. We suggest that nonverbal numerical abstraction occurs early in development, but specific task objectives may prevent children from engaging in numerical abstraction.     

“The grammar of action”: Sequence and syntax in children's copying

Progressions when copying shapes can be regarded as forming a path, with choices to be made at points along the path. Paths can be described in terms of rules that specify what to do at the start (e.g., start at the top rather than the bottom, with a vertical rather than a horizontal stroke) and in general (e.g., draw with a continuous line rather than a broken pattern). Such rules describe consistencies in the paths children and adults follow. They also allow us to describe age changes in terms of hierarchies of shifting rules, design differences in terms of conflict between rules, and errors (left-right reversals) in terms of the need to amend the usual rules. The results point to the advantages of treating graphic behavior as syntactic behavior and to the feasibility of using graphic tasks for the analysis of patterned or rule-governed activity.     

An analysis of response,direction, and place learning in an open field and T maze

Rats were trained to locate food in a response, direction, or place problem on an open field located at 2 positions. In Experiment 1, both the response and direction groups solved the problem. The place group failed to solve the task in approximately 300 trials. Experiment 2 demonstrated that rats need distinguishable start points to solve a place problem when neither a response nor a direction solution is available. Findings from Experiment 3 suggest that a combination of path traveled and distinct cues help to differentiate start points. Experiment 4 replicated the findings using a T maze. These results suggest "place" solutions are difficult for rats. The data are discussed with respect to conditional learning and modern spatial mapping theory.     

Discrimination of “W” and “V” shapes by goldfish

Goldfish were trained to discriminate between “W” and “V” shapes; different groups were trained with the shapes in different orientations. Transfer tests were given after training and the following conclusions were drawn. Animals learned to discriminate between the training shapes by detecting the difference in the number of points present in each; they learned the difference in the relative number of points rather than the absolute number present in each shape; the subjects transferred well to pairs of shapes bearing points facing in different directions from those on the training shapes; knobs were treated as practically equivalent to points; animals relied more heavily on differences at the tops of the shapes than on differences in the bottom halves.     

Counselling and careers education in the united states: Some current trends

The author visited the United States in May/June 1972 with a grant from the US Department of State under their Leaders and Specialists Programme. He visited nine major cities and met nearly a hundred people in the guidance and counselling field, including some of the leading figures. This paper identifies some of the main current trends in American guidance work — notably the reevaluation of the counsellor's role and the push for “career education” — and examines their implications for guidance work in Britain.     

Creativity and Sex Composition: An Experimental Illustration

An experiment is reported in which the effect of sex composition on the creativity of brainstorming groups is investigated. It was hypothesized that mixed sex groups would be more creative than either homogeneous male or homogeneous female groups. Fifteen groups, consisting of four members each two males and two females; four females; four males, took part in the experiment. The experimenter noted the number of ideas generated per person, as well as the different associations with these ideas, and the number of different angles from which the task was approached. After finishing the exercise, subjects completed a post-experimental questionnaire. Results show that heterogeneous groups produced more creative outcomes than homogeneous groups. Also, they rated their process more positively. These findings are discussed in relation to the type of task used, and in relation to the general notion that heterogeneous groups are likely to produce more creative outcomes yet suffer from more process problems as compared to homogeneous groups.