In this blogpost I will consider Quine’s relation to two of B.F. Skinner’s Verbal Operants: the Mand, and the Tact. I will argue that Quine’s Observation Sentence is analogous to Skinner’s Tact, but that Quine makes very little use of the notion of a Mand. A Mand is one of the most studied verbal operants, and it is the first verbal operants that is targeted by behavioural scientists if a child is experiencing language delays. Yet Quine gives the Mand a very small role in his overall theory of language acquisition. I will discuss Quine’s reasons for not considering things like Manding as important in sketching his naturalized epistemology and then discuss the degree to which these verbal operants are separable and how their separability will affect Quine’s choice of downplaying of the role of Mand’s in his story of how we go from stimulus-to science.

Quine’s Relation to Empirical Psychology

While Quine didn’t use the same vocabulary as Skinner some of his concepts map effortlessly onto Skinner’s concepts. Thus, Quine’s notion of an Observation Sentence is the same as Skinner’s notion of a Tact (both are shaped by discriminative stimulus and social feedback). Nonetheless despite arguing for this functional independence between different Verbal Operants Skinner noted that for ordinary speakers the two may be entwined. Thus, if a person has acquired a label as a Tact the chances are that they will be able to use it as a Mand. Skinner gives four reasons to support his argument for interdependence. (1) Tact emergence may be facilitated by the acquisition of a Mand in the presence of the Manded stimulus. (2) The similarity between the stimulus that evokes a Tact and that that evokes a Man may be similar enough to affect a transfer. (3) Transfer may occur if care givers reinforce one operant as if it were the other, (4) Children early in life may acquire generalized verbal skills which result in both the Mand, and the Tact being acquired (Petursdottir et all p.60). Skinner was speculating about these matters but in the 60 years since he wrote ‘Verbal Behaviour’ their partial interdependence has been confirmed.

Quine showed no interest in Mand’s and hence he had little interest in how Mand’s and Tacts related to each other and affected the process of acquiring a language.  He was clear that because of his interest in ontology and epistemology he was giving an idealized conception of how we acquire language. He was interested in observation sentences because they are our entering wedge into language and hence to our theory of the world. He is explicit that the story he gives of how we go from stimulus to science is meant to be an impressionistic one. He fully acknowledges that his story may deviate from the story told by a fully worked out science.

            Quine’s position on this matter is dubious. He was critical of Carnap for engaging in make belief in place of making use of current scientific psychology.

“But why all this creative reconstruction, all this make belief? The stimulation of his sensory receptors is all anybody has to go on, ultimately, in arriving at his picture of the world. Why not see how this reconstruction really proceeds? Why not settle for empirical psychology?” (Epistemology Naturalised p. 74)

 Yet Quine himself is in effect engaged in a made-up story about how we go from stimulus to science. He justifies this as follows:

“Much of what is earliest and most urgent in language learning, furthermore, is a matter of neither stating nor assenting nor acting upon statements, but of importuning…But statement learning is what is relevant to our study, which aims at understanding the acquisition of scientific theory.” (The Roots of Reference p. 46)

“Anyway, I am not bent even upon a factual account of the learning of English, welcome though it would be. My concern is with the essential psychogenesis of reference would be fulfilled in fair measure with a plausible account of how one might proceed from infancy step by step to a logically regimented language of science, even bypassing English” (Ibid p. 92)

 Because of Quine’s emphasis on cognitive language, he is ignoring the messier pragmatic aspects of learning a language that are described by people such as the later Wittgenstein, and Skinner. There is a sense in which we can justify this; it is after all standard practice in the sciences to engage in idealizations. Quine could be parsed as sketching a scientific story of how we go from stimulus to science; we can use this abstract sketch and fill in the details as we learn more about the acquisition process. Nonetheless, Quine does seem to be guilty of holding Carnap to higher standards than he holds himself to.

Because Quine is only interested in descriptive language and its role in us acquiring our theory of the world; he claims he doesn’t need to think about things such as importuning or as Skinner would it Manding.  Skinner had noted that Mands such as asking for water would be controlled by an establishment operation of a deprivation such as thirst and subsequent reinforcement of the thirst being relieved, while the Tact for Water could be controlled by a non-verbal discriminative stimulus, which the person was reinforced for saying the word in the presence of. Thus, you would have two different operants controlling the one sound for ‘Water’. As we saw above Skinner thought that these two operants would in practice end up entwined. If indeed Mands and Tacts are intertwined, then this would affect any proposed psychologically realistic story of how we go from stimulus to science.

Lamarre and Holand (1985) did a study on children tested the independence Tacts and Mands with preschool children. They trained children up on the relations “on the left” and “on the right” as both Mands and as Tacts. The study found that when the children learned them as Tacts, they couldn’t generalize them to Mands without training, while when they learned them as Mand’s they couldn’t generalize them to Tacts without training. This indicated that the two terms were for young children at first functionally independent and that transfer from one to the other wasn’t automatic.

Lamarre and Holland’s original study has been criticised by Wallace et al 2006. They noted that Lamarre and Holland’s establishing operations may not have been clear. There is no indication whether the items the child is manding for or the reinforcement they are receiving for Manding are items the child desires. When this was controlled for in other experiments the transfer from Tacts to Mands occurred for preferred items. Wallace et al claim their study demonstrates how responses taught as Tacts can facilitate the establishment of Mands for high preference items. And they noted that their experiments showed a difficulty with Tact-to-Mand transfer for low preference items (in line with Lamarre and Hollands study). Demonstrating that their lack of transfer was more than likely caused by not using sufficiently motivating reinforcers.

Gamba et al (2016) have done a meta-analysis on studies into whether functional independence in Mand-Tact independence has been demonstrate empirically. And they noted that there has been 28 empirical studies into the functional independence of the Mand and the Tact since Lamarre and Holland’s original study. They noted that there have been 13 studies which have demonstrated the functional independence of Mands and Tacts, but that in studies which the stimuli tacted and Manded were preferred items transfer of function occurred (Gamba et al p.27). Whether these studies are sufficient to cast doubt on the functional independence of the Mand and Tact is hard open to interpretation. Gamba et al note that in some of these experiments the Manded items were present which may have served to evoke previous Tacts and this may need to be controlled for in future experiments (ibid p. 31).

Thus far the experimental results are not sufficient to conclusively demonstrate the functional independence of Mand’s and Tacts. Quine appears to have been agnostic on this issue. However, one questions whether he has a right to this agnosticism. He was critical of Carnap for engaging in make belief in his epistemology, but his own Naturalized Epistemology engages in as much make belief. Quine’s focus on observation sentences at the expense of things like Mand’s serves to distort our picture of how we acquire our language and scientific heritage. In abstracting away from these details Quine is giving a hyper-intellectual fantasy of how we acquire language he is letting the metaphor of the scientist being a disinterested theorist keying observation sentences to stimuli, blind him to the more pragmatic aspects of language acquisition.

In this blogpost I discussed Quine’s relation to Skinner’s Verbal Operants of Mands and Tacts. In my next post I will focus on linking Quine’s concept of association of sentences to sentences with recent empirical work on Skinner’s Verbal Operant the Intraverbal.