**5. Grounding Slips**

Recall the phenomenon of slips. The cognitive processes underlying knowledge how and knowledge that, and how they come apart, can be elucidated by this phenomenon:

The 'slips of action' that punctuate daily life illustrate that our behaviour is not always goal-directed in nature. Folk wisdom suggests that such slips of action occur when well-practised responses intrude to compromise our goal-directed behaviour. For example, it is a common-place experience to find oneself arriving at the door of the old o ffice although one's original intention was to ge<sup>t</sup> to the new one. Adams [58] was the first to show that in rats extensive training of the instrumental response of lever pressing rendered it impervious to devaluation of the food outcome, a finding that has now been replicated in a number of rodent studies. [59] (p. 471).

Goal-directed control of actions is important to ensure that one's behavior has the desired result. However, experiments by de Wit et al. [60] show that such control competes with habitual responses. In dual process terminology; reflective Type 2 processes can be "hijacked" by reflexive Type 1 processes, which results in slips of action. Importantly, de Wit et al. point out that a reason for such slips can be that although Type 2 processes allow for greater flexibility, Type 1 processes demand less cognitive effort. Loosely speaking, the system (agent) might thus automatically fall back into default mode in order to save energy. If this is done incorrectly the agen<sup>t</sup> slips. Empirical studies<sup>7</sup> sugges<sup>t</sup> that dopamine plays a central role in regulating the interplay between the cognitive processes regarding this matter, and how slips occur (see, e.g., [60,61]).<sup>8</sup>

Rasmussen [62] (see also [48], p. 43) o ffers a three-level model that classifies human behavior as being either skill-based, rule-based, or knowledge-based. Skill-based behavior consists in non-conscious automatic actions demanding extensive training. Rule-based behavior, on an intermediate level, consists in actions guided by information acquired empirically or through communicated instructions. Knowledge-based behavior consists in goal-controlled actions that do not rely on know how or rules but rather are based on reflective cognitive processes.

Focusing on knowledge how, Rasmussen's account can be interpreted as presenting an olive branch towards Stanley's [3] and Stanley and Williamson's [5] accounts in that knowledge how might plausibly be seen as consisting in both a procedural element (procedural memory) and a rule-based element (semantic memory):

In general, the skill-based performance rolls along without the person's conscious attention, and he will be unable to describe how he controls and on what information he bases the performance. The higher level rule-based coordination is generally based on explicit know how, and rules used can be reported by the person. [62] (p. 259)

Where Stanley and Williamson go wrong is that they ignore the procedural element and only focus on the rule-based element. Moreover, they ascribe features more suitably linked to knowledge-based

<sup>7</sup> Studies have primarily been done on animals, but those that focus on humans indicate that generalizability is plausible.

<sup>8</sup> This said, for example, serotonin is also thought to play an important role.

behavior to knowledge how, and finally claim that it is possible to reduce knowledge how to knowledge that which is completely unsubstantiated.

Representing actions with schemas, Norman (1981)<sup>9</sup> develops a similar account:

A major assumption of the ATS [activation-trigger-schema] theory for slips is that skilled actions—actions whose components are themselves all highly skilled—need only be specified at the highest levels of their memory representations. Once the highest-level schema is activated, the lower-level parent components of that action sequence complete the action, to a large extent autonomously, without further need for intervention except at critical choice points. [36] (p. 4)

Mismatches from episodic memory (false beliefs) can, arguably, be seen as involving knowledge that. This is so since formations of intentions involve reflective features that we have argued above is linked to episodic long-term memory and working memory. These types of mismatches can usually be fixed by focused attention and additional cognitive energy expenditure. Slips due to mismatches from procedural memory are more readily seen to involve knowledge how, where a particular action schema is executed–but not the intended one. In these cases, we are thus in possession of relevant knowledge how, but we accidentally carry out some other knowledge how (schema) that we also possess.

## **6. The Neuro-Psychological Implausibility of Intellectualism**

Humans are but one animal among others. It is therefore essential to take animal cognition research into account when investigating knowledge how and knowledge that. As we have argued above, knowledge can be seen to be grounded in the memory systems. An important point regarding this topic is that procedural memory (linked to knowledge how) is evolutionarily prior to semantic and episodic memory (linked to knowledge that).

Accordingly, many animals are capable of knowledge how without having a language, and thus arguably not having knowledge that. Once again, if there is a reduction to be made, it should therefore reduce knowledge that to knowledge how rather than the other way around (see, e.g., [52,53]).

Now, Stanley and Krakauer [7] try to wedge knowledge how apart by focusing on skilled actions, where they argue that motor skill demands propositional knowledge that of facts whereas motor acuity ("precision of selected actions") does not. Contrary to canonical cognitive scientific interpretations keeping propositional knowledge and skill apart, Stanley and Krakauer [7] (p. 1) argue that " ... learning to become skilled at a motor task, for example tennis, depends also on knowledge-based selection of the right actions[,]" and then go on to argue that " ... skilled activity requires both acuity and knowledge, with both increasing with practice." We concede that Stanley and Krakauer have a point in that knowledge that indeed might increase acuity, but that it only can do so to a comparatively very limited—indeed infinitesimally small—amount. It is therefore, in our view, misleading to push this detail in the manner Stanley and Krakauer do. Stanley and Krakauer even go further and promote an idiosyncratic view, that appears contrary to well-established interpretations in cognitive psychology and cognitive neuroscience, in claiming that "the identification of procedural knowledge, itself a misnomer, with the colloquial understanding of motor skill ... [and] the identification of declarative knowledge with knowledge in the traditional sense [are incorrect]" [7] (p. 2):

Does the fact that manifesting skill requires knowledge preclude non-human animals from possessing skills? We are agnostic as to whether animals can be skilled. It is possible that as a task is weighted increasingly toward rules, alternative actions, and on-the-fly problem

<sup>9</sup> According to Norman [36], slips in the form of intentional formational errors involve cases where a specific action schema is intended but vagueness and contextual factors intervene. Slips, in the form of faulty activations, involves actions that result from unintended schemas that might be similar to or associated with the intended schema, or are due to the loss of activation. Slips, in the form of faulty triggerings, can result both from failures to trigger schemas or by triggering at inappropriate circumstances.

solving, then simple operant conditioning may not su ffice to accomplish the task. In this sense non-human animals may be limited in a way similar to the amnestic patients in the Roy and Park experiment. Although non-human animals may exhibit the same behavior as humans, this does not entail that the explanation for the behavior is the same. It could be that the explanation skilled action in humans involves intellectual capacities lacking in non-human animals. ... Alternatively, it could be that animals can both possess concepts and bear the knowledge relation to propositions (if so, one would need to explain why animals cannot acquire certain skills that humans can; perhaps because there complex skills require complex concepts, which cannot be grasped by animals). [7] (p. 9)

As Noë highlights, abilities are embodied and situated in ways that are deeply problematic for intellectualism [15] (p. 284), and contrary to the intellectualist position, we have shown that procedural knowledge how is a distinct form of knowledge from propositional knowledge that, involving separate brain areas, cognitive processes, and cell-types (see, e.g., [56]), and these findings are generalizable across species:

Rodent studies have implicated prelimbic cortex and its striatal e fferents on dorsomedial striatum as a key circuit responsible for goal-directed learning. In a series of fMRI studies, vmPFC has been found to be involved in encoding reward predictions based on goal-directed action–outcome associations in humans, suggesting that this region of cortex in the primate prefrontal cortex is a likely functional homolog of prelimbic cortex in the rat. Furthermore, the area of anterior caudate nucleus found in humans to be modulated by contingency would seem to be a candidate homolog for the region of dorsomedial striatum implicated in goal-directed control in the rat. Finally, the evidence reviewed here supports the suggestion that a region of dorsolateral striatum in rodents and of the putamen in humans is involved in the habitual control of behavior, which when taken together with the findings on goal-directed learning reviewed previously, provides converging evidence that the neural substrates of these two systems for behavioral control are relatively conserved across mammalian species. [56] (p. 54).
