Comprehension and utilisation of pointing gestures and gazing in dog–human communication in relatively complex situations

The aim of the present investigation was to study the visual communication between humans and dogs in relatively complex situations. In the present research, we have modelled more lifelike situations in contrast to previous studies which often relied on using only two potential hiding locations and direct association between the communicative signal and the signalled object. In Study 1, we have provided the dogs with four potential hiding locations, two on each side of the experimenter to see whether dogs are able to choose the correct location based on the pointing gesture. In Study 2, dogs had to rely on a sequence of pointing gestures displayed by two different experimenters. We have investigated whether dogs are able to recognise an ‘indirect signal’, that is, a pointing toward a pointer. In Study 3, we have examined whether dogs can understand indirect information about a hidden object and direct the owner to the particular location. Study 1 has revealed that dogs are unlikely to rely on extrapolating precise linear vectors along the pointing arm when relying on human pointing gestures. Instead, they rely on a simple rule of following the side of the human gesturing. If there were more targets on the same side of the human, they showed a preference for the targets closer to the human. Study 2 has shown that dogs are able to rely on indirect pointing gestures but the individual performances suggest that this skill may be restricted to a certain level of complexity. In Study 3, we have found that dogs are able to localise the hidden object by utilising indirect human signals, and they are able to convey this information to their owner.     

Does the A-not-B error in adult pet dogs indicate sensitivity to human communication?

Recent dog-infant comparisons have indicated that the experimenter's communicative signals in object hide-and-search tasks increase the probability of perseverative (A-not-B) errors in both species (Topál et al. 2009). These behaviourally similar results, however, might reflect different mechanisms in dogs and in children. Similar errors may occur if the motor response of retrieving the object during the A trials cannot be inhibited in the B trials or if the experimenter's movements and signals toward the A hiding place in the B trials ('sham-baiting') distract the dogs' attention. In order to test these hypotheses, we tested dogs similarly to Topál et al. (2009) but eliminated the motor search in the A trials and 'sham-baiting' in the B trials. We found that neither an inability to inhibit previously rewarded motor response nor insufficiencies in their working memory and/or attention skills can explain dogs' erroneous choices. Further, we replicated the finding that dogs have a strong tendency to commit the A-not-B error after ostensive-communicative hiding and demonstrated the crucial effect of socio-communicative cues as the A-not-B error diminishes when location B is ostensively enhanced. These findings further support the hypothesis that the dogs' A-not-B error may reflect a special sensitivity to human communicative cues. Such object-hiding and search tasks provide a typical case for how susceptibility to human social signals could (mis)lead domestic dogs.     

It depends on how you look at it: Scanpath comparison in multiple dimensions with MultiMatch, a vector-based approach

Eye movement sequences??or scanpaths??vary depending on the stimulus characteristics and the task (Foulsham & Underwood Journal of Vision, m>8m>(2), 6:1?C17, 2008; Land, Mennie, & Rusted, Perception, 28, 1311?C1328, 1999). Common methods for comparing scanpaths, however, are limited in their ability to capture both the spatial and temporal properties of which a scanpath consists. Here, we validated a new method for scanpath comparison based on geometric vectors, which compares scanpaths over multiple dimensions while retaining positional and sequential information (Jarodzka, Holmqvist, & Nystr?m, Symposium on Eye-Tracking Research and Applications (pp. 211?C218), 2010). ??MultiMatch?? was tested in two experiments and pitted against ScanMatch (Cristino, Math?t, Theeuwes, & Gilchrist, Behavior Research Methods, 42, 692?C700, 2010), the most comprehensive adaptation of the popular Levenshtein method. In Experiment 1, we used synthetic data, demonstrating the greater sensitivity of MultiMatch to variations in spatial position. In Experiment 2, real eye movement recordings were taken from participants viewing sequences of dots, designed to elicit scanpath pairs with commonalities known to be problematic for algorithms (e.g., when one scanpath is shifted in locus or when fixations fall on either side of an AOI boundary). The results illustrate the advantages of a multidimensional approach, revealing how two scanpaths differ. For instance, if one scanpath is the reverse copy of another, the difference is in the direction but not the positions of fixations; or if a scanpath is scaled down, the difference is in the length of the saccadic vectors but not in the overall shape. As well as having enormous potential for any task in which consistency in eye movements is important (e.g., learning), MultiMatch is particularly relevant for ??eye movements to nothing?? in mental imagery and embodiment-of-cognition research, where satisfactory scanpath comparison algorithms are lacking.     

Branching time, indeterminism and tense logic

This paper deals with the historical and philosophical background of the introduction of the notion of branching time in philosophical logic as it is revealed in the hitherto unpublished mail-correspondence between Saul Kripke and A.N. Prior in the late 1950s. The paper reveals that the idea was first suggested by Saul Kripke in a letter to A.N. Prior, dated September 3, 1958, and it is shown how the elaboration of the idea in the course of the correspondence was intimately intervowen with considerations of how to represent indeterminism and of the adequacy of tensed logic in light of special relativity. The correspondence underpins the point that Prior??s later development of branching time may be understood as a crucial part of his attempt at the formulating a conceptual framework integrating basic human notions of time and free choice.     

Right-hemispheric cortical contributions to language ability in healthy adults

In this study we investigated the correlation between individual linguistic ability based on performance levels and their engagement of typical and atypical language areas in the brain. Eighteen healthy subjects between 21 and 64 years participated in language ability tests, and subsequent functional MRI scans measuring brain activity in response to a sentence completion and a word fluency task. Performance in both reading and high-level language tests correlated positively with increased right-hemispheric activation in the inferior frontal gyrus (specifically Brodmann area 47), the dorsolateral prefrontal cortex (DLPFC), and the medial temporal gyrus (Brodmann area 21). In contrast, we found a negative correlation between performance and left-hemispheric DLPFC activation.Our findings indicate that the right lateral frontal and right temporal regions positively modulate aspects of language ability.     

Time- and space-order effects in timed discrimination of brightness and size of paired visual stimuli

Despite the importance of both response probability and response time for testing models of choice, there is a dearth of chronometric studies examining systematic asymmetries that occur over time- and space-orders in the method of paired comparisons. In this study, systematic asymmetries in discriminating the magnitude of paired visual stimuli are examined by way of log odds ratios of binary responses as well as by signed response speed. Hierarchical Bayesian modeling is used to map response probabilities and response speed onto constituent psychological process, and processing capacity is also assessed using response time distribution hazard functions. The findings include characteristic order effects that change systematically in magnitude and direction with changes in the magnitude and separation of the stimuli. After Hellstr?m (1979, 2000), sensation weighting (SW) model analyses show that such order effects are reflected in the weighted accumulation of noisy information about the difference between stimulus values over time, and interindividual differences in weightings asymmetries are related to the relative processing capacity of participants. An account of SW based on the use of reference level information and maximization of signal-to-noise ratios is posited, which finds support from theoretically driven analyses of behavioral data.     

Instruction-in-Interaction: The Teaching and Learning of a Manual Skill

This study takes an interest in instructions and instructed actions in the context of manual skills. The analysis focuses on a video recorded episode where a teacher demonstrates how to crochet chain stitches, requests a group of students to reproduce her actions, and then repeatedly corrects the attempts of one of the students. The initial request, and the students’ responses to it, could be seen as preliminary to the series of corrective sequences that come next: the request and the following attempts make it possible for the teacher to launch instructional sequences specifically designed and addressed to the students who need further guidance. In the interaction between the teacher and the novice student, the reasoned character of the instructed actions is not explained so much as installed and tuned. The materiality of the project makes it possible for the two parties to methodically and meticulously adjust their actions in accordance with each other, and towards the gradual realization of the aimed-for results. In connection to this, a number of issues pertaining to the reproducibility and recognizability of manual skills are raised: how instructions-in-interaction orient towards the progression of the skill rather than the interaction itself; how attempts by and mistakes of the instructed party provide grounds for further instruction; and, consequently, how instructions in the form of corrections build on the instructor’s continuous assessments of the instructed actions.