Publications of Tauzin, T.

Context-sensitive adjustment of pointing in great apes

Great apes are able to request objects from humans by pointing. It is unclear, however, whether this is an associated response to a certain set of cues (e.g. the presence and attention of a human addressee) or a communicative signal which can be adjusted to relevant aspects of the spatial and social context. In three experiments, we tested captive great apes’ flexible use of pointing gestures. We manipulated the communicative context so that the default pointing response of apes would have indicated an undesired object, either due to 1) the spatial arrangements of the target objects, 2) the perspective of the addressee or 3) the knowledge of the addressee about the target objects’ location. The results of the three experiments indicate that great apes can successfully adjust their pointing to the spatial configuration of the referent environment such as distance and location of food. However, we found no evidence that they take the perspective or the knowledge of the addressee into account when doing so. This implies that pointing in great apes is a context-sensitive, but maybe less versatile, communicative signal compared to human pointing.

The frequency of referent objects influences expectations about label length

Earlier studies suggest that word length is influenced by the linguistic context to be precise and concise at the same time. The present study investigates whether the referential-situational context can also have an effect on the expected length of words. To test this assumption a salient property of the situational context, that is, the frequency of the unfamiliar referents was varied. The participants watched pictures of novel objects in the observational phase, presented either frequently or rarely. In the test phase they saw the same pictures of objects one by one and were asked to select one of two unfamiliar labels, which – according to them – could be the name of the object displayed. The two labels provided for each object at test had either short or long orthographic length. It was hypothesized that participants will select the long label more frequently when they had to guess the name of rare objects in contrast to frequent ones. The findings supported this hypothesis. Rare objects were paired with long labels significantly more often than frequent objects, resulting in a significant difference also when contrasted to chance-level. The results were similar if abbreviated or completely different label pairs were presented to the participants in the test phase suggesting that the situational context is taken into account when language users infer word form.

Variability of signal sequences in turn-taking exchanges induces agency attribution in 10.5-mo-olds

Infants’ sensitivity to contingent reactivity as an indicator of intentional agency has been demonstrated by numerous referential gaze-following studies. Here we propose that variability of signal sequences in a turn-taking exchange provides an informative cue for infants to recognize interactions that may involve communicative information transfer between agents. Our experiment demonstrates that based on the abstract structural cue of variability of exchanged signal sequences, 10.5-mo-olds gaze-followed an entity’s subsequent object-orienting action to fixate the same object. This gaze-following effect did not depend on the specific acoustic features of the sound signals produced. However, no orientation following to target was induced when the exchanged signal sequences were identical, or when only a single entity produced the variable sound sequences. These results demonstrate infants’ early sensitivity to detect signal variability in turn-taking interactions as a relevant feature of communicative information transfer, which induces them to attribute intentional agency and communicative abilities to the participating entities. However, when no variability was present in the exchanged signals, or when the variable signal sequences were produced by a single entity alone, infants showed no evidence of attributing agency. In sum, we argue that perceiving contingent turn-taking exchange of variable signal sequences induce 10.5-mo-old preverbal infants to recognize such interactions as potentially involving communicative information transmission and attribute agency to the participating entities even if both the entities and the signals they produce are unfamiliar to them.

Communicative mind-reading in preverbal infants

Pragmatic theories of communication assume that humans evolved a species-unique inferential capacity to express and recognize intentions via communicative actions. We show that 13-month-old non-verbal infants can interpret the turn-taking exchange of variable tone sequences between unfamiliar agents as indicative of communicative transfer of goal-relevant information from a knowledgeable to a naïve agent pursuing the goal. No such inference of information transfer was drawn by the infants, however, when a) the agents exchanged fully predictable identical signal sequences, which does not enable transmission of new information, or b) when no goal-relevant contextual change was observed that would motivate its communicative transmission. These results demonstrate that young infants can recognize communicative interactions between third-party agents and possess an evolved capacity for communicative mind-reading that enables them to infer what contextually relevant information has been transmitted between the agents even without language.

The attribution of navigational- and goal-directed agency in dogs (Canis Familiaris) and human toddlers (Homo Sapiens)

Both human infants and non-human primates can recognize unfamiliar entities as instrumental agents ascribing them goals and efficiency of goal-pursuit. This competence relies on movement cues indicating distal sensitivity to the environment and choice of efficient goal-approach. While dogs’ evolved sensitivity to social cues allow them to recognize humans as communicative agents, it remains unclear whether they have also evolved a basic concept of instrumental agency. We employed a preferential object-choice procedure to test whether adult pet dogs and human toddlers can identify unfamiliar entities as agents based on different types of movement cues specifying different levels of agency. In the Navigational Agency condition, dogs preferentially chose an object that varied it’s pathway to avoid collision with obstacles over another object showing no evidence of distal sensitivity (regularly bumping into obstacles). However, in the Goal-Efficiency condition where neither objects collided with obstacles as they navigated towards a distal target, but only one of them exhibited efficient goal-approach as well, toddlers, but not dogs, showed a preference toward the efficient goal-directed agent. These findings indicate that dogs possess a limited concept of environmentally sensitive ‘navigational agency’ that they attribute to self-propelled entities capable of modifying their movement to avoid colliding with obstacles. In contrast, dogs showed no evidence of attributing the higher-level concept of ‘goal-directed instrumental agency’ based on cues of efficient goal-pursuit. Toddlers, on the other hand, demonstrated clear sensitivity to cues of efficient variability of goal-approach as the basis for differentiating, attributing, and showing preference for goal-directed instrumental agency.

Pointing as epistemic request: 12-month-olds point to receive new information

Infants start pointing systematically to objects or events around their first birthday. It has been proposed that infants point to an event in order to share their appreciation of it with others. In the current study, we tested another hypothesis, according to which infants' pointing could also serve as an epistemic request directed to the adult. Thus, infants' motivation for pointing could include the expectation that adults would provide new information about the referent. In two experiments, an adult reacted to 12-month-olds’ pointing gestures by exhibiting 'informing' or 'sharing' behavior. In response, infants pointed more frequently across trials in the informing than in the sharing condition. This suggests that the feedback that contained new information matched infants' expectations more than mere attention sharing. Such a result is consistent with the idea that not just the comprehension but also the production of early communicative signals is tuned to assist infants' learning from others.