In his theory of evolution, Darwin recognized that the conditions of life play a role in the generation of hereditary variations, as well as in their selection. However, as evolutionary theory was developed further, heredity became identified with genetics, and variation was seen in terms of combinations of randomly generated gene mutations. We argue that this view is now changing, because it is clear that a notion of hereditary variation that is based solely on randomly varying genes that are unaffected (...) by developmental conditions is an inadequate basis for evolutionary theories. Such a view not only fails to provide satisfying explanations of many evolutionary phenomena, it also makes assumptions that are not consistent with the data that are emerging from disciplines ranging from molecular biology to cultural studies. These data show that the genome is far more responsive to the environment than previously thought, and that not all transmissible variation is underlain by genetic differences. In Evolution in Four Dimensions (2005) we identify four types of inheritance (genetic, epigenetic, behavioral, and symbol-based), each of which can provide variations on which natural selection will act. Some of these variations arise in response to developmental conditions, so there are Lamarckian aspects to evolution. We argue that a better insight into evolutionary processes will result from recognizing that transmitted variations that are not based on DNA differences have played a role. This is particularly true for understanding the evolution of human behavior, where all four dimensions of heredity have been important. (shrink)

This paper examines how innovative skills and knowledge are transmitted and acquired among adolescents in two hunter-gatherer communities, the Aka of southern Central African Republic and the Chabu of southwestern Ethiopia. Modes of transmission and processes of social learning are addressed. Innovation as well as social learning have been hypothesized to be key features of human cumulative culture, enhancing the fitness and survival of individuals in diverse environments. The innovation literature indicates adult males are more innovative than children and female (...) adults and therefore predicts that adolescents will seek out adult males. Further, the mode of transmission should be oblique. Thus, learning of innovations should be oblique or horizontal rather than vertical, with adolescents paying particular attention to “successful” innovative individuals. The social learning literature indicates that complex skills or knowledge is likely to be learned through teaching, and therefore that teaching will be an important process in the transmission of innovations. In-depth and semi-structured interviews, informal observations, and systematic free-listing were used to evaluate these hypotheses. The study found that cultural context patterned whether or not adolescents sought out adult male or female innovators; oblique modes of transmission were mentioned with greater frequency than horizontal or vertical modes; knowledge and skill bias was notable and explicitly linked by the adolescents to reproductive effort; and teaching was biased toward same-sex individuals and was an important but not an exclusive means of transmitting complex skills and social knowledge. (shrink)

Our concern is with Ramsey et al.'s method for identifying innovation. We show that either it yields false positives or the authors offer insufficient guidance for its application. To avoid these results, the authors need to modify the key or offer better guidelines for delineating input. Either choice requires addressing the processes that generate a behavior.

Innovation is a key component of most definitions of culture and intelligence. Additionally, innovations may affect a species' ecology and evolution. Nonetheless, conceptual and empirical work on innovation has only recently begun. In particular, largely because the existing operational definition (first occurrence in a population) requires long-term studies of populations, there has been no systematic study of innovation in wild animals. To facilitate such study, we have produced a new definition of innovation: Innovation is the process that generates in an (...) individual a novel learned behavior that is not simply a consequence of social learning or environmental induction. Using this definition, we propose a new operational approach for distinguishing innovations in the field. The operational criteria employ information from the following sources: (1) the behavior's geographic and local prevalence and individual frequency; (2) properties of the behavior, such as the social role of the behavior, the context in which the behavior is exhibited, and its similarity to other behaviors; (3) changes in the occurrence of the behavior over time; and (4) knowledge of spontaneous or experimentally induced behavior in captivity. These criteria do not require long-term studies at a single site, but information from multiple populations of a species will generally be needed. These criteria are systematized into a dichotomous key that can be used to assess whether a behavior observed in the field is likely to be an innovation. (shrink)

Building off the recent work on the semantics of problem, we suggest a more general account that encompasses problems of all agents, human or nonhuman, individual or communal. Situation X is a problem for agent A, iff situation X is at odds with the agent’s goal G and removing the discrepancy between X and G presents some difficulty for agent A. In addition, for agent A to actually have a problem, they must also be in such situation X. In contrast, (...) agent A recognizes that situation X is a problem for them iff agent A represents, correctly or incorrectly, that situation X is at odds with their goal G, agent A represents, correctly or incorrectly, that removing the discrepancy between X and G presents some difficulty, and agent A represents, correctly or incorrectly, that they are in situation X. Several conclusions follow from these definitions. (1) Not every problem involves questions. (2) Not all problems involve undesirable states. (3) For an agent to consider a situation problematic, they should be aware of the situation; yet awareness of the situation is not necessary for an agent to have a problem or for a situation to be a problem for an agent. (4) Contexts need not be part of the problem: the context of a specific problem need not also be part of a more general problem. (5) The complete elimination of the discrepancy between a situation and a goal eliminates the problem, while the problem continues to exist when it receives a partial solution. (6) For something to be a problem, it does not have to be solvable, and the agent does not have to accept that something needs to be done about it, nor should they use the language of ameliorable/solvable. (shrink)

The commentaries have both drawn out the implications of, and challenged, our definition and operationalization of innovation. In this response, we reply to these concerns, discuss the differences between our operationalization and the preexisting operationalization if innovation, and make suggestions for the advancement of the challenging and exciting field of animal innovation.

Great promise for the evolutionary analysis of animal behavior lies in the distinction between generative novelties and the evolutionary innovations to which they can give rise. Ramsey et al. succeed in emphasizing the contribution of individual learning and intelligence to behavioral innovations, but do not correct the tendency to confound individual invention with socio-ecological or group-level innovation.

We agree with Ramsey et al. regarding the need for new methods and concepts in the study of innovation, and welcome their initiative, but are concerned that their operationalization is over-reliant on subjective judgements.

Although the authors' ingenuity in identifying criteria for innovation for field studies is appealing, most field studies will lack adequate data. Additionally, their definition does not clearly distinguish innovation from individual learning and is vague about cognitive mechanisms involved. We suggest that developmental data are essential to identifying the causes and consequences of learning new behaviors.