HENRY

This week in Science - The inappropriate use and protrayal of Chimpanzees:

In 2005, a survey (see the table, left side) was conducted at the Regenstein Center for African Apes (RCAA) at the Lincoln Park Zoo (Chicago, IL). (…) The final question of the survey asked respondents to select which of three great ape species (chimpanzees, gorillas, and orangutans) were considered endangered in the wild. Of those choices, 95% of respondents thought gorillas were endangered, 91% thought orangutans were endangered, but only 66% believed chimpanzees to be endangered. (…) Respondents were informed that, in fact, all three great apes were classified as endangered and then asked for a reason why they thought a particular ape was not considered in this category. No prompting with answers was provided, and all responses were recorded by the interviewer. Of the 250 respondents who were willing to provide explanations for their choice, the most common reason for the category chosen (35%) was that chimpanzees were commonly seen on television, advertisements, and movies and, therefore, must not be in jeopardy.

National Geographic & the world’s 25 most endangered primates.

This week’s Science is a special issue on social cognition, and has a bundle of fun little articles (all of which are subscription only), starting with a review of “Social Components of Fitness in Primate Groups” by Joan Silk:

There is much interest in the evolutionary forces that favored the evolution of large brains in the primate order. The social brain hypothesis posits that selection has favored larger brains and more complex cognitive capacities as a means to cope with the challenges of social life. The hypothesis is supported by evidence that shows that group size is linked to various measures of brain size. But it has not been clear how cognitive complexity confers fitness advantages on individuals. Research in the field and laboratory shows that sophisticated social cognition underlies social behavior in primate groups. Moreover, a growing body of evidence suggests that the quality of social relationships has measurable fitness consequences for individuals.

This is followed by Herrmann et al’s “Humans Have Evolved Specialized Skills of Social Cognition: The Cultural Intelligence Hypothesis“, where they test the idea that one of the reasons that humans are smart is because we’ve developed a special set of cognitive skills for handling social tasks:

Humans have many cognitive skills not possessed by their nearest primate relatives. The cultural intelligence hypothesis argues that this is mainly due to a species-specific set of social-cognitive skills, emerging early in ontogeny, for participating and exchanging knowledge in cultural groups. We tested this hypothesis by giving a comprehensive battery of cognitive tests to large numbers of two of humans’ closest primate relatives, chimpanzees and orangutans, as well as to 2.5-year-old human children before literacy and schooling. Supporting the cultural intelligence hypothesis and contradicting the hypothesis that humans simply have more “general intelligence,” we found that the children and chimpanzees had very similar cognitive skills for dealing with the physical world but that the children had more sophisticated cognitive skills than either of the ape species for dealing with the social world.

Next up is another paper by Robin Dunbar and Susanne Shultz on Evolution in the Social Brain (henry covered their previous paper too):

The evolution of unusually large brains in some groups of animals, notably primates, has long been a puzzle. Although early explanations tended to emphasize the brain’s role in sensory or technical competence (foraging skills, innovations, and way-finding), the balance of evidence now clearly favors the suggestion that it was the computational demands of living in large, complex societies that selected for large brains. However, recent analyses suggest that it may have been the particular demands of the more intense forms of pairbonding that was the critical factor that triggered this evolutionary development. This may explain why primate sociality seems to be so different from that found in most other birds and mammals: Primate sociality is based on bonded relationships of a kind that are found only in pairbonds in other taxa.

Heading right down the cognitive path is Prospection: Experiencing the Future by Gilbert and Wilson, who review some recent work on “mental time travel”:

All animals can predict the hedonic consequences of events they’ve experienced before. But humans can predict the hedonic consequences of events they’ve never experienced by simulating those events in their minds. Scientists are beginning to understand how the brain simulates future events, how it uses those simulations to predict an event’s hedonic consequences, and why these predictions so often go awry.

David Premack reviews the differences between animal and human cognition in “Human and animal cognition: Continuity and discontinuity” (doi). Abstract only:

Microscopic study of the human brain has revealed neural structures, enhanced wiring, and forms of connectivity among nerve cells not found in any animal, challenging the view that the human brain is simply an enlarged chimpanzee brain. On the other hand, cognitive studies have found animals to have abilities once thought unique to the human. This suggests a disparity between brain and mind. The suggestion is misleading. Cognitive research has not kept pace with neural research.

Neural findings are based on microscopic study of the brain and are primarily cellular. Because cognition cannot be studied microscopically, we need to refine the study of cognition by using a different approach. In examining claims of similarity between animals and humans, one must ask: What are the dissimilarities? This approach prevents confusing similarity with equivalence. We follow this approach in examining eight cognitive cases—teaching, short-term memory, causal reasoning, planning, deception, transitive inference, theory of mind, and language—and find, in all cases, that similarities between animal and human abilities are small, dissimilarities large. There is no disparity between brain and mind.

Update: That would be David Premack not Daniel Premack. My apologies!

Erica Cartmill and Richard Byrne announce in today’s Current Biology, that Orangutans Modify Their Gestural Signaling According to Their Audience’s Comprehension (doi:10.1016/j.cub.2007.06.069):

When people are not fully understood, they persist with attempts to communicate, elaborating their speech in order to better convey their meaning. We investigated whether captive orangutans (Pongo pygmaeus and Pongo abelii) would use analogous communicative strategies in signaling to a human experimenter, and whether they could distinguish different degrees of misunderstanding.

To do this, the Orangutans were offered two types of food - one which they really like, and one which is less tasty, and were given the one they gestured for. All the gestures were directed towards the tasty food, whilst the experimenter sat silently for 30 seconds, before giving the orangutan some food.

Some of the time, the experimenter gave the apes all of the tasty food they wanted, so that the gestural communication was successful: the orang communicated that they wanted the tasty food, and received the tasty food too. In other cases, the experimenter gave out a mix of half the tasty food, and half the less-tasty food (partially successful communication), or gave them all the disliked food (a complete failure to communicate effectively).

The types of gestures from the orangutans were quite varied:

The fascinating thing here, is that the Orangs responded differently to each condition. Once they communicated successfully, and gotten the food, the gestures stopped almost completely. In contrast, when they were partially successful, they tended to repeat the original gesture, but when communication was unsuccessful (and they got the yuck-food), they changed to a different gesture.

These results suggest that the Orangutans are actively monitoring their gestures with regard to their effectiveness at communicating: if the gesture only partially worked, they repeated it (stupid humans), or if it completely failed, they tried a different gesture.

The authors conclude that:

Although the communication sequences of the orangutans are perhaps not as sophisticated, they nonetheless accomplish the same objectives. By maximizing efficiency at searching for an understood signal and homing in on those that achieve partial success, orangutans are able to overcome misunderstandings. In the absence of a shared lexicon, one way of arriving at a shared meaning is to adopt a charades-like strategy, transmitting not only the content of the intended message but also a signal indicating how well you have been understood.

If the recipient can use this information, then the signaler and recipient will be able to arrive at a common understanding much faster. This strategy offers one possible pathway toward constructing a shared lexicon from learned or ritualized signals. Investigations into the structures of intentional communication by apes may therefore provide insight into the prelinguistic devices that helped construct the very earliest forms of hominid language.