Chimpanzees do not take into account what others can hear in a competitive situation

Chimpanzees (Pan troglodytes) know what others can and cannot see in a competitive situation. Does this reflect a general understanding the perceptions of others? In a study by Hare et al. (2000) pairs of chimpanzees competed over two pieces of food. Subordinate individuals preferred to approach food that was behind a barrier that the dominant could not see, suggesting that chimpanzees can take the visual perspective of others. We extended this paradigm to the auditory modality to investigate whether chimpanzees are sensitive to whether a competitor can hear food rewards being hidden. Results suggested that the chimpanzees did not take what the competitor had heard into account, despite being able to locate the hiding place themselves by the noise.     

Reflexively mindblind: Using theory of mind to interpret behavior requires effortful attention

People commonly interpret others’ behavior in terms of the actors’ underlying beliefs, knowledge, or other mental states, thereby using their “theory of mind.” Two experiments suggest that using one’s theory of mind is a relatively effortful process. In both experiments, people reflexively used their own knowledge and beliefs to follow a speaker’s instruction, but only effortfully used their theory of mind to take into account a speaker’s intention to interpret those instructions. In Experiment 1, people with lower working memory capacity were less effective than people with larger working memory capacity in applying their theory of mind to interpret behavior. In Experiment 2, an attention-demanding secondary task reduced people’s ability to apply their theory of mind. People appear to be reflexively mindblind, interpreting behavior in terms of the actor’s mental states only to the extent that they have the cognitive resources to do so.     

Chimpanzees really know what others can see in a competitive situation

Chimpanzee’s perspective-taking abilities are currently disputed. Here we show that in some food competition contexts, subordinate chimpanzees do take the visual perspective of dominant individuals, preferentially targeting a hidden piece of the food that the dominant cannot see over a piece that is visible to both individuals. However, the space where the animals compete is critical in determining whether subjects demonstrate this skill. We suggest that competition intensity, as mediated by these spatial factors, may play an important role in determining the strategy chimpanzees utilize in competitive contexts. Since some strategies may not require visual perspective taking in order to be successful, chimpanzees may not always demonstrate this skill. Differences in spatial arrangement may therefore account for the conflicting results of past studies.     

My face through the looking-glass: the effect of mirror reversal on reflection size estimation

People tend to grossly overestimate the size of their mirror-reflected face. Although this overestimation bias is robust, not much is known about its relationships to self-face perception. In two experiments, we investigated the overestimation bias as a function of the presentation of the own face (left–right reversed – as in a mirror – or nonreversed – as in a photograph), the identity of the seen face, and prior exposure to a real mirror. For this we developed a computerized task requiring size estimations of displayed faces. We replicated the observation that people overestimate the size of their mirror-reflected face and showed that the overestimation can be reduced following a brief mirror exposure. We also found that left–right reversal modulates the overestimation bias, depending on the perceived face’s identity. These data underline the enhanced familiarity of left–right reversed self-faces and the importance of size perception for understanding mirror reflection processing.     

Towards a common processing architecture underlying Simon and SNARC effects

It has been shown repeatedly that relatively small numbers are responded to faster with the left hand and relatively large numbers are responded to faster with the right hand. This so-called SNARC effect (Dehaene, Bossini, & Giraux, 1993) is thought to arise through activation of irrelevant spatial codes associated with the magnitude of the number. This conflict between irrelevant magnitude information and the response is conceptually similar to the well-known Simon effect. Recently, both Mapelli, Rusconi, and Umiltà (2003) and Keus and Schwarz (in press) directly compared both effects in a single task within the framework of the additive factor method (Sternberg, 1969). While Mapelli et al. found additive effects of SNARC and Simon levels, suggesting different processing stages, Keus and Schwarz found that the SNARC effect depended on the compatibility level of the Simon task leading them to propose a common origin at the response selection stage. In the present study we demonstrate in 2 experiments that the relationship between Simon and SNARC depends on the relevance of the magnitude code, thereby violating one of the core assumptions of the AFM. Instead we propose a temporal overlap model to interpret the relationship between these effects which allows to commensurate apparently divergent outcomes.     

Bee-eaters (<Emphasis Type="Italic">Merops orientalis</Emphasis>) respond to what a predator can see

Two sets of experiments are reported that show that the small green bee-eater (Merops orientalis, a small tropical bird) can appreciate what a predator can or cannot see. Bee-eaters avoid entering the nest in the presence of a potential nest predator. In the first set of experiments bee-eaters entered the nest more frequently when the predator was unable to see the nest from its position, as compared to an approximately equidistant position from which the nest could be seen. In the second set of experiments bee-eaters entered the nest more frequently when the predator was looking away from the nest. The angle of gaze from the nest was associated significantly positively with the probability of entering the nest whereas the angle from the bird was not. Birds showed considerable flexibility as well as individual variation in the possible methods of judging the predator's position and direction of gaze. Electronic Publication     

Chimpanzees deceive a human competitor by hiding

There is little experimental evidence that any non-human species is capable of purposefully attempting to manipulate the psychological states of others deceptively (e.g., manipulating what another sees). We show here that chimpanzees, one of humans' two closest primate relatives, sometimes attempt to actively conceal things from others. Specifically, when competing with a human in three novel tests, eight chimpanzees, from their first trials, chose to approach a contested food item via a route hidden from the human's view (sometimes using a circuitous path to do so). These findings not only corroborate previous work showing that chimpanzees know what others can and cannot see, but also suggest that when competing for food chimpanzees are skillful at manipulating, to their own advantage, whether others can or cannot see them.     

How are bodies special? Effects of body features on spatial reasoning

Embodied views of cognition argue that cognitive processes are influenced by bodily experience. This implies that when people make spatial judgments about human bodies, they bring to bear embodied knowledge that affects spatial reasoning performance. Here, we examined the specific contribution to spatial reasoning of visual features associated with the human body. We used two different tasks to elicit distinct visuospatial transformations: object-based transformations, as elicited in typical mental rotation tasks, and perspective transformations, used in tasks in which people deliberately adopt the egocentric perspective of another person. Body features facilitated performance in both tasks. This result suggests that observers are particularly sensitive to the presence of a human head and body, and that these features allow observers to quickly recognize and encode the spatial configuration of a figure. Contrary to prior reports, this facilitation was not related to the transformation component of task performance. These results suggest that body features facilitate task components other than spatial transformation, including the encoding of stimulus orientation.     

Experience in integrative negotiations: What needs to be learned?

In this research we focus on the roles of experience and understanding in fostering integrative negotiation performance. We report on two experiments in which we distinguish between understanding opponents’ general priorities among issues versus understanding their specific gains for particular offers. Although experience enhanced integrative performance even in the absence of understanding, we found that understanding the specific gains had an incremental effect on performance. We conclude that while generally acknowledging opponents’ interests is not sufficient, the additional inferential step of assessing their specific gains throughout the negotiation process is advantageous.     

Imitative learning from a third-party interaction: relations with self-recognition and perspective taking

Young children’s ability to learn something new from a third-party interaction may be related to the ability to imagine themselves in the third-party interaction. This imaginative ability presupposes an understanding of self-other equivalence, which is manifested in an objective understanding of the self and an understanding of others’ subjective perspectives. The current study measured imitative learning of a novel action seen only in a third-party interaction, mirror self-recognition, and perspective taking in a group of 48 18- to 20-month-olds. Patterns of performance suggest that understanding self-other equivalence is related to third-party learning.     

Give them what they want: The benefits of explicitness in gift exchange

Five studies show that gift recipients are more appreciative of gifts they explicitly request than those they do not. In contrast, gift givers assume that both solicited and unsolicited gifts will be equally appreciated. At the root of this dilemma is a difference of opinion about what purchasing an unsolicited gift signals: gift givers expect unsolicited gifts will be considered more thoughtful and considerate by their intended recipients than is actually the case (,  and ). In our final two studies, we highlight two boundary conditions for this effect: identifying a specific gift and using money as a gift. When gift recipients request one specific gift, rather than providing a list of possible gifts, givers become more willing to purchase the requested gift (Study 4). Further, although givers believe that recipients do not appreciate receiving money as much as receiving a solicited gift, recipients feel the opposite about these two gift options (Study 5).     

Role of motor processes in extrinsically encoding mental transformations

Previous research has shown that imagined perspective rotations elicit spatial and low-level cortical motor areas of the brain when participants rely on knowledge of their physical body, or body percept (Wraga, Flynn, Boyle, & Evans, 2010). The current study used functional magnetic resonance imaging (fMRI) to investigate whether recruitment of the body percept would activate low-level cortical motor areas of the brain within other classes of mental transformations. Participants performed imagined object and perspective rotations of three-dimensional Shephard-Metzler (1971) stimuli. For each task, participants used button presses serving as virtual pointers to locate a prescribed portion of the stimuli with respect to their "right" and "left." We found low-level cortical motor activation (M1) for both mental transformations; however, the degree to which such activation related to participants' performance differed, as well as the recruitment of additional nonmotoric strategies. The results are discussed in terms of recent hypotheses regarding the role of the body percept in extrinsically encoded mental transformations.