The direct perception hypothesis: perceiving the intention of another’s action hinders its precise imitation

We argue that imitation is a learning response to unintelligible actions, especially to social conventions. Various strands of evidence are converging on this conclusion, but further progress has been hampered by an outdated theory of perceptual experience. Comparative psychology continues to be premised on the doctrine that humans and nonhuman primates only perceive others’ physical ‘surface behavior’, while mental states are perceptually inaccessible. However, a growing consensus in social cognition research accepts the Direct Perception Hypothesis: primarily we see what others aim to do; we do not infer it from their motions. Indeed, physical details are overlooked – unless the action is unintelligible. On this basis we hypothesize that apes’ propensity to copy the goal of an action, rather than its precise means, is largely dependent on its perceived intelligibility. Conversely, children copy means more often than adults and apes because, uniquely, much adult human behavior is completely unintelligible to unenculturated observers due to the pervasiveness of arbitrary social conventions, as exemplified by customs, rituals, and languages. We expect the propensity to imitate to be inversely correlated with the familiarity of cultural practices, as indexed by age and/or socio-cultural competence. The Direct Perception Hypothesis thereby helps to parsimoniously explain the most important findings of imitation research, including children’s over-imitation and other species-typical and age-related variations

Why vocal production of atypical sounds in apes and its cerebral correlates have a lot to say about the origin of language

Ackermann et al. mentioned the "acquisition of species-atypical sounds" in apes without any discussions. In our commentary, we demonstrate that these atypical sounds in chimpanzees not only include laryngeal sounds but also have a major significance regarding the origins of language, if we consider looking at their context of use, their social properties, their relations with gestures, their lateralization and their neurofunctional correlates as well

Testing dogs in ape-like conditions: the effect of a barrier on dogs’ performance on the object-choice task

Recent reviews have found marked procedural and methodological differences in the testing of different taxonomic groups on the object-choice task. One such difference is the imposition of a barrier in the testing environment of nonhuman primates in the form of a cage, necessitated to ensure the experimenter’s safety. Here, we conducted two studies with domestic dogs (Canis lupus familiaris) in which we compared the performance of dogs tested from within a child’s playpen and dogs tested without this barrier present. In Study 1, in a within-subjects design, we found no effect of the barrier on dogs’ ability to use a pointing cue, but there was an increase in instances in which dogs failed to choose a cup. In Study 2, in a between-subjects design, dogs tested with a barrier failed to perform above chance, and were also more likely to fail to make a choice. When dogs tested without a barrier made an incorrect response, these were more likely to be incorrect choices than no choice errors. We discuss the implications of these differences in behavioural responses in function of the presence of a barrier and the necessity of ensuring matched conditions when comparing across species

Salecker-Wigner-Peres clock and average tunneling times

The quantum clock of Salecker-Wigner-Peres is used, by performing a post-selection of the final state, to obtain average transmission and reflection times associated to the scattering of localized wave packets by static potentials in one dimension. The behavior of these average times is studied for a gaussian wave packet, centered around a tunneling wave number, incident on a rectangular barrier and, in particular, on a double delta barrier potential. The regime of opaque barriers is investigated and the results show that the average transmission time does not saturate, showing no evidence of the Hartman effect (or its generalized version).Comment: 9 pages, 4 figure

Object-oriented Programming Laws for Annotated Java Programs

Object-oriented programming laws have been proposed in the context of languages that are not combined with a behavioral interface specification language (BISL). The strong dependence between source-code and interface specifications may cause a number of difficulties when transforming programs. In this paper we introduce a set of programming laws for object-oriented languages like Java combined with the Java Modeling Language (JML). The set of laws deals with object-oriented features taking into account their specifications. Some laws deal only with features of the specification language. These laws constitute a set of small transformations for the development of more elaborate ones like refactorings

Tunneling Time in the Landau-Zener Model

We give a general definition for the tunneling time in the Landau-Zener model. This definition allows us to compute numerically the Landau-Zener tunneling time at any sweeping rate without ambiguity. We have also obtained analytical results in both the adiabatic limit and the sudden limit. Whenever applicable, our results are compared to previous results and they are in good agreement.Comment: 7pages, 9 figure

Are chimpanzees really so poor at understanding imperative pointing? Some new data and an alternative view of canine and ape social cognition

There is considerable interest in comparative research on different species’ abilities to respond to human communicative cues such as gaze and pointing. It has been reported that some canines perform significantly better than monkeys and apes on tasks requiring the comprehension of either declarative or imperative pointing and these differences have been attributed to domestication in dogs. Here we tested a sample of chimpanzees on a task requiring comprehension of an imperative request and show that, though there are considerable individual differences, the performance by the apes rival those reported in pet dogs. We suggest that small differences in methodology can have a pronounced influence on performance on these types of tasks. We further suggest that basic differences in subject sampling, subject recruitment and rearing experiences have resulted in a skewed representation of canine abilities compared to those of monkeys and apes

Apes communicate about absent and displaced objects: methodology matters

Displaced reference is the ability to refer to an item that has been moved (displaced) in space and/or time, and has been called one of the true hallmarks of referential communication. Several studies suggest that nonhuman primates have this capability, but a recent experiment concluded that in a specific situation (absent entities) human infants display displaced reference but chimpanzees do not. Here we show that chimpanzees and bonobos of diverse rearing histories are capable of displaced reference to absent and displaced objects. It is likely that some of the conflicting findings from animal cognition studies are due to relatively minor methodological differences, but are compounded by interpretation errors. Comparative studies are of great importance in elucidating the evolution of human cognition, however, greater care must be taken with methodology and interpretation for these studies to accurately reflect species differences

The effects of changes in the referential problem space of infants and toddlers (homo sapiens): implications for cross-species comparisons

Recent reviews have highlighted the tendency in the comparative literature to make claims about species’ relative evolutionarily adaptive histories based on studies comparing different species tested with procedurally and methodologically different protocols. One particularly contentious area is the use of the Object Choice Task (OCT), used to measure an individual’s ability to use referential cues, which is a core attribute of joint attention. We tested human children with versions of the OCT that have been previously used with dogs and nonhuman primates to see if manipulating the set-up would lead to behavioral changes. In Study 1, we compared the responses of 18-month-olds and 36-month-olds when tested with and without a barrier. The presence of a barrier between the child and the reward did not suppress performance but did elicit more communicative behavior. Moreover, the barrier had a greater facilitating effect on the younger children, who displayed more communicative behavior in comparison with older children, who more frequently reached through the barrier in acts of direct prehension. In Study 2, we compared the behavior of 36-month-olds when the reward was within reaching distance (proximal) and when it was out of reach (distal). The children used index-finger points significantly more in the distal condition and grabbed more in the proximal condition, showing that they were making spatial judgements about the accessibility of the reward rather than just grabbing per se. We discuss the implications of these within-species differences in behavioral responses for cross-species comparisons

Systematics of the snub-nosed monkey: rhinopithecus

This paper will explore and summarize some of the published evidence for the systematic relationships of the colobine monkeys in the poorly known genus, Rhinopithecus. Rhinopithecus comprises four allopatric colobine species (or subspecies, see Groves, 1970, and below) that share a distinctive, turquoise-colored face and nose, the nose being characterized by a sharply upturned superior border with accessory flaps of skin, on the lateral nasal borders, that partially cover the nasal openings (Dollman, 1912; Milne-Edwards, 1870, 1872 [cited in Szalay & Delson, 1979]; Thomas, 1903). Their ecology and distribution will be briefly reviewed and an account of the history of their proposed taxonomic relations will be presented. Some locomotor characteristics of these monkeys will be (very briefly) evaluated to elucidate the relative primitiveness or specialization of these distinctive monkeys with respect to the eucatarrhine condition and other fossil and living forms