Cognition is a general term describing the mental capacities of an animal, and often includes the ability to categorize, remember, and communicate about objects in the environment. Numerous regions of the telencephalon (cerebral cortex and limbic system) are responsible for these cognitive functions. Although many researchers have used traditional laboratory animals such as rodents and pigeons in the study of animal cognition, an increasing number of studies focus on species such as non-human primates, dolphins, and domestic dogs (Canis familiaris). Such studies can provide insight into the evolution of cognitive processes in humans (Miklssi et al., 2004; Gomez, 2005). Here we describe a laboratory exercise we have used with great success with college students, although the exercise would be equally effective at the middle- or high-school levels. The primary objective of this exercise is to use an animal familiar to all students, the domestic dog, to examine the phenomena of object permanence and social cueing. More specifically, the approach described here will teach students about the importance of careful experimental design and the interpretation of data. In this regard, the activity is consistent with the National Science Education Standards (National Research Council, 1996) in that it encourages the skills of scientific inquiry (Standards B and E), allows students to engage in extended investigations (Standard D), and nurtures collaboration among students (Standard E). In addition, this exercise aligns with the National Standard that secondary science teachers should be able to demonstrate "Measurement as a way of knowing and organizing observations of constancy and change."
A relatively simple form of cognition is illustrated by the phenomenon known as object permanence, the awareness that objects exist even when they are not visible. Object permanence is a universal characteristic among primates (Gomez, 2005). Most studies of object permanence utilize the scheme originally conceived by the Swiss developmental psychologist Jean Piaget from his studies of human infants and toddlers (e.g., Piaget & Inhelder, 1969; Table 1). In the 1980s and 1990s, comparative psychologists began applying this same scheme to dogs (Triana & Pasnak, 1981; Gagnon & Dori, 1992, 1993). Some studies found that dogs perform at a level consistent with a one- to two-year-old human toddler, meaning that they usually score better than 50% on Visible and Invisible Displacement Tests (see below). Other studies have suggested that dogs may simply associate the location of the hidden object with some fixture of the environment (Collier-Baker et al., 2004). Thus, the degree of object permanence in domestic dogs is still very much a question of scientific debate.
A separate but equally interesting area of research focuses on the ability of animals to follow social cues from humans. The most frequently investigated cue is pointing toward a hidden object, which has been studied in a diverse array of mammals including non-human primates, dogs, wolves, goats, and cetaceans (Miklssi & Soproni, 2006). Interestingly, dogs perform much better at this task than do either wolves (Canis lupus) or chimpanzees (Pan troglodytes), which originally led some researchers (Hare et al., 2002) to speculate that domestication selects for a particular set of cognitive abilities that allow for human-dog communication. More recent work (Hare et al., 2005) suggests that social cueing may simply be a byproduct of the domestication process itself. At a minimum, dogs' ability to follow social cues means that they quickly learn to associate human pointing with rewards such as food or toys. A more intriguing possibility, however, is that dogs might possess what cognitive psychologists call a "theory of mind," the ability to recognize another individual--in this case a human--as a separate, sentient being in possession of information different from what the dog possesses. …