Animal Thinking: Contemporary Issues in Comparative Cognition

8 Status of Nonhuman Memory Monitoring and Possible Roles in Planning and Decision Making

8 Status of Nonhuman Memory Monitoring and Possible Roles in Planning and Decision Making Robert R. Hampton Abstract In this chapter, the concept of monitored and unmonitored memory and cognition is introduced, and behavioral as well as neurobiological findings are used to link the application of these concepts in humans and other animals. Techniques are described that assess cognitive monitoring in nonverbal species, which indicate some of the putative differences in function associated with monitored and unmonitored cognition. Difficulties in characterizing the mechanisms which support the monitoring of cognition are highlighted, and thoughts on how this work might best proceed are provided. Introduction Monitoring of cognitive processes may improve decision making by conditionalizing behavioral choices on the availability of needed knowledge. The dichotomy between memory that is accessible to monitoring (explicit) and that which is not (implicit) is at the theoretical core of human cognitive neuroscience . The explicit-implicit distinction has not, however, been systematically applied in nonhumans, creating a significant gap in our understanding of the relations between human and nonhuman cognition, and cognitive evolution in general. The failure to apply these concepts in nonhumans likely results from the fact that humans usually demonstrate access to cognitive processes by providing verbal commentaries on their experience of cognition that are not available from nonverbal animals. In the absence of parallel data from nonverbal animals, some have concluded that nonhuman species do not possess accessible memory (e.g., Tulving and Markowitsch 1994), or that it is impossible to 106 R. R. Hampton determine whether or not they do (Shettleworth 2010b). However, new techniques using memory monitoring paradigms (Washburn et al. 2006; Hampton 2001; Smith et al. 2003; Hampton et al. 2004b; Kornell et al. 2007; Inman and Shettleworth 1999) may permit us to apply the explicit-implicit distinction in nonhuman species. Accessible explicit memory and cognition may be used more flexibly in decision making than inaccessible knowledge and may be especially critical for planning. While some forms of metacognition depend on accessible explicit representations, many others do not, so all metacognition should not be equated with access to explicit cognition or memory. The connection between metacognition or memory monitoring and consciousness remains unclear and is probably beyond the scope of studies using nonhuman subjects. In future work, we should endeavor to move beyond functional demonstrations of metacognition and aim to identify the diversity of stimuli, cognitive processes, and neural substrates that explain it. This shift in focus will help develop an understanding of cognitive monitoring in both nonhumans and humans that is mechanistic and avoids invoking nonexplanatory homunculi. Monitored and Unmonitored Memory and Cognition Vertebrate brains are widely recognized to contain multiple individual memory systems, each specialized for different cognitive demands (Sherry and Schacter 1987; Cohen and Eichenbaum 1994). In popular taxonomies of human memory systems, a major distinction is made between memory systems that are consciously accessible to monitoring (explicit or declarative) and those that are unconscious (Cohen and Eichenbaum 1994). Human memory monitoring is associated with consciousness and is most often identified on the basis of verbal reports of private experience (e.g., “I knew” versus “I guessed”). Because nonhuman species cannot verbally report their experience of memory as do humans, it has been difficult to establish behavioral criteria that unambiguously capture the phenomenon of accessibility in nonhumans. Discriminating between accessible and inaccessible memory in nonhumans is further complicated by the fact that much learning and cognition in humans occurs without conscious awareness (e.g., some forms of classical conditioning, skill learning, and priming). It is not obvious a priori which kinds of learning and memory might require, or be associated with, cognitive access. Understanding this dimension of nonhuman memory, and the evolution of memory generally, therefore requires disciplined interpretation of studies designed to discriminate between accessible and inaccessible memory and cognition. Extensive progress has been made in identifying the functional properties and the neural substrates of nonhuman memory, and this progress has been made without techniques for characterizing findings with respect to the accessibility of memories. Most of this work has been done under the (probably correct) assumption that phenomenal consciousness is not a helpful construct Nonhuman Memory Monitoring, Planning and Decision Making 107 in studies of nonhumans because it is not clear what evidence would indicate the presence of such consciousness in nonhumans. Even as they focus on functional and mechanistic properties of memory, investigators often claim, directly or indirectly, that...