We agree with Kline that a greater dialogue between the different approaches to the study of teaching is needed to understand this aspect of behavior in an integrative manner. We further agree that the disparate views held by different research communities regarding what constitutes “teaching” have been a major stumbling block in this endeavor. However, the approach suggested here requires further development for it to be adequate for the task.
The critical component requiring development is the definition of teaching. According to Kline, “teaching is a behavior that evolved to facilitate learning in others” (sect. 1, paragraph 5). This is of course a conceptual definition, and, as such, might not be expected to be readily operationalized. But a clear operational definition is required for this framework to be useful for empirical study. The given definition does not meet this goal. Framing teaching in terms of its evolutionary sources does not help the empirical researcher to recognize it. In any case, evolutionary origins (i.e., selective histories) for a specific feature are notoriously hard to determine.
Without a clear operational definition, we have to understand the scope of what the author sees as “teaching” through the different mechanisms she details. From looking at those mechanisms, we get a definition so inclusive as to be almost meaningless. Two of the mechanisms, “teaching by social tolerance” and “teaching by stimulus or local enhancement” are especially hard to distinguish from behaviors not evolved for the purpose of facilitating learning in others. Kline proposes that “teaching by social tolerance” could be distinguished from other forms of social tolerance by looking at the degree of tolerance by one individual towards a “pupil” in a given setting, which should be greater than the tolerance shown by that individual towards other conspecifics, or, we add, that same “pupil” in other situations. But if this pattern were observed – say, an adult chimpanzee allows a juvenile to stand very close to it as it is fishing for termites and to touch its arm, but does not allow this behavior at other times (Humle et al. Reference Humle, Snowdon and Matsuzawa2009) – would we be justified in calling this teaching? While theoretically it is of course possible that some forms of social tolerance evolved specifically to facilitate learning, there are alternative explanations for situationally variable tolerance that do not hinge on its value to juveniles for learning which must be considered. For example, it may be that heightened tolerance by the adult in a feeding setting is associated with the adult's assessment of the social risk to itself (via agonism) from provoking a noisy protest by the juvenile if it rejects the juveniles' advances. Would we call this “teaching through coercion”? As for “teaching by stimulus or local enhancement,” when the activity of an adult directs the attention of a young individual to an object, does it matter for definitional purposes if this was done with the purpose of teaching, or if it was an incidental consequence of the adult's ongoing activity? For example, if nut-cracking is performed by an individual in the same way with or without an audience, but when a juvenile is nearby, this activity increases the likelihood that the juvenile will explore nuts, anvils, and hammer stones (activities that aid learning to crack nuts) (Fragaszy et al. Reference Fragaszy, Biro, Eshchar, Humle, Izar, Resende and Visalberghi2013), should the proficient individual's nut-cracking be identified as “teaching” when the juvenile is nearby? We cannot know if there was intention on the part of the proficient individual to influence the juvenile. It seems in this case that we can identify the learner, but we cannot identify a “teacher.”
The question of when an activity is “teaching by tolerance” or “teaching by enhancement” can be answered in cases involving humans – but only by means not possible in studies with nonhuman animals. Indeed, when we look at the examples given by the author of “teaching by social tolerance” in humans, we see that the interpretation of this behavior as teaching is based on the teachers' mental state – the children are not simply tolerated, they are tolerated “with the expectation that they will learn” (sect. 4.2, para. 2). Of course, it is impossible to know what nonhuman animals expect. In the case of nonhuman animals, it seems that the author is satisfied with including all instances of tolerance towards young individuals as potential teaching, suspending the standard adopted for humans that an expectation of learning accompanies the tolerance. Returning to the example of nut-cracking, classifying a monkey that is proficient at cracking as “teaching” whenever it cracks when there are juveniles around it, makes the term meaningless.
This problem is not unique to this one mechanism: In the presentation of most of the mechanisms, the examples described for humans and other animals are not only different, but based on interpretation derived from different approaches. For example, one case of “teaching by opportunity providing” describes the behavior of a music teacher who plays music for his students and “expects that the students will learn as a result” (sect. 4.2, para. 3). Several cases involved verbal instructions – not just in cases of “direct active teaching,” but also of “teaching by opportunity providing,” “teaching by enhancement,” and “evaluative feedback.” This is of course a behavior that cannot be seen in nonhuman animals. As the goal of this new approach is to incorporate the mechanisms of teaching in humans and nonhuman animals into a cohesive framework, these inconsistencies present a major hurdle.
In short, the author has provided a conceptual framework, but has not yet achieved the definitional clarity needed to meet her objectives. She has identified a laudable goal and provided a stimulating set of ideas and examples; we hope that the research community can work from these to flesh out operational definitions adequate to realize the goal of an integrative understanding of teaching.
We agree with Kline that a greater dialogue between the different approaches to the study of teaching is needed to understand this aspect of behavior in an integrative manner. We further agree that the disparate views held by different research communities regarding what constitutes “teaching” have been a major stumbling block in this endeavor. However, the approach suggested here requires further development for it to be adequate for the task.
The critical component requiring development is the definition of teaching. According to Kline, “teaching is a behavior that evolved to facilitate learning in others” (sect. 1, paragraph 5). This is of course a conceptual definition, and, as such, might not be expected to be readily operationalized. But a clear operational definition is required for this framework to be useful for empirical study. The given definition does not meet this goal. Framing teaching in terms of its evolutionary sources does not help the empirical researcher to recognize it. In any case, evolutionary origins (i.e., selective histories) for a specific feature are notoriously hard to determine.
Without a clear operational definition, we have to understand the scope of what the author sees as “teaching” through the different mechanisms she details. From looking at those mechanisms, we get a definition so inclusive as to be almost meaningless. Two of the mechanisms, “teaching by social tolerance” and “teaching by stimulus or local enhancement” are especially hard to distinguish from behaviors not evolved for the purpose of facilitating learning in others. Kline proposes that “teaching by social tolerance” could be distinguished from other forms of social tolerance by looking at the degree of tolerance by one individual towards a “pupil” in a given setting, which should be greater than the tolerance shown by that individual towards other conspecifics, or, we add, that same “pupil” in other situations. But if this pattern were observed – say, an adult chimpanzee allows a juvenile to stand very close to it as it is fishing for termites and to touch its arm, but does not allow this behavior at other times (Humle et al. Reference Humle, Snowdon and Matsuzawa2009) – would we be justified in calling this teaching? While theoretically it is of course possible that some forms of social tolerance evolved specifically to facilitate learning, there are alternative explanations for situationally variable tolerance that do not hinge on its value to juveniles for learning which must be considered. For example, it may be that heightened tolerance by the adult in a feeding setting is associated with the adult's assessment of the social risk to itself (via agonism) from provoking a noisy protest by the juvenile if it rejects the juveniles' advances. Would we call this “teaching through coercion”? As for “teaching by stimulus or local enhancement,” when the activity of an adult directs the attention of a young individual to an object, does it matter for definitional purposes if this was done with the purpose of teaching, or if it was an incidental consequence of the adult's ongoing activity? For example, if nut-cracking is performed by an individual in the same way with or without an audience, but when a juvenile is nearby, this activity increases the likelihood that the juvenile will explore nuts, anvils, and hammer stones (activities that aid learning to crack nuts) (Fragaszy et al. Reference Fragaszy, Biro, Eshchar, Humle, Izar, Resende and Visalberghi2013), should the proficient individual's nut-cracking be identified as “teaching” when the juvenile is nearby? We cannot know if there was intention on the part of the proficient individual to influence the juvenile. It seems in this case that we can identify the learner, but we cannot identify a “teacher.”
The question of when an activity is “teaching by tolerance” or “teaching by enhancement” can be answered in cases involving humans – but only by means not possible in studies with nonhuman animals. Indeed, when we look at the examples given by the author of “teaching by social tolerance” in humans, we see that the interpretation of this behavior as teaching is based on the teachers' mental state – the children are not simply tolerated, they are tolerated “with the expectation that they will learn” (sect. 4.2, para. 2). Of course, it is impossible to know what nonhuman animals expect. In the case of nonhuman animals, it seems that the author is satisfied with including all instances of tolerance towards young individuals as potential teaching, suspending the standard adopted for humans that an expectation of learning accompanies the tolerance. Returning to the example of nut-cracking, classifying a monkey that is proficient at cracking as “teaching” whenever it cracks when there are juveniles around it, makes the term meaningless.
This problem is not unique to this one mechanism: In the presentation of most of the mechanisms, the examples described for humans and other animals are not only different, but based on interpretation derived from different approaches. For example, one case of “teaching by opportunity providing” describes the behavior of a music teacher who plays music for his students and “expects that the students will learn as a result” (sect. 4.2, para. 3). Several cases involved verbal instructions – not just in cases of “direct active teaching,” but also of “teaching by opportunity providing,” “teaching by enhancement,” and “evaluative feedback.” This is of course a behavior that cannot be seen in nonhuman animals. As the goal of this new approach is to incorporate the mechanisms of teaching in humans and nonhuman animals into a cohesive framework, these inconsistencies present a major hurdle.
In short, the author has provided a conceptual framework, but has not yet achieved the definitional clarity needed to meet her objectives. She has identified a laudable goal and provided a stimulating set of ideas and examples; we hope that the research community can work from these to flesh out operational definitions adequate to realize the goal of an integrative understanding of teaching.