Cognitive adaptations for gathering-related navigation in humans.

Current research increasingly suggests that spatial cognition in humans is accomplished by many specialized mechanisms, each designed to solve a particular adaptive problem. A major adaptive problem for our hominin ancestors, particularly females, was the need to efficiently gather immobile foods which could vary greatly in quality, quantity, spatial location and temporal availability. We propose a cognitive model of a navigational gathering adaptation in humans and test its predictions in samples from the US and Japan. Our results are uniformly supportive: the human mind appears equipped with a navigational gathering adaptation that encodes the location of gatherable foods into spatial memory. This mechanism appears to be chronically active in women and activated under explicit motivation in men.

Spatial adaptations for plant foraging: women excel and calories count.

We present evidence for an evolved sexually dimorphic adaptation that activates spatial memory and navigation skills in response to fruits, vegetables and other traditionally gatherable sessile food resources. In spite of extensive evidence for a male advantage on a wide variety of navigational tasks, we demonstrate that a simple but ecologically important shift in content can reverse this sex difference. This effect is predicted by and consistent with the theory that a sexual division in ancestral foraging labour selected for gathering-specific spatial mechanisms, some of which are sexually differentiated. The hypothesis that gathering-specific spatial adaptations exist in the human mind is further supported by our finding that spatial memory is preferentially engaged for resources with higher nutritional quality (e.g. caloric density). This result strongly suggests that the underlying mechanisms evolved in part as adaptations for efficient foraging. Together, these results demonstrate that human spatial cognition is content sensitive, domain specific and designed by natural selection to mesh with important regularities of the ancestral world.

The role of information about "convention," "design," and "goal" in representing artificial kinds.

In this chapter, we have considered the nature and development of our capacities for the representation of artificial kinds. We have presented a range of evidence collected using varying methods and from our own laboratories and those of others that speaks to the question of the kinds of information that might be central to knowledge of artifacts and their functions in human semantic memory. One key argument here has been that despite the fact that information about shared convention has been argued to play an important role in understanding of the "proper" uses of artifacts, just as it does in the case of the use of linguistic symbols within language communities, there are important differences between the two cases, and indeed across development, decisions about categories and functions dissociate. We have argued here that the nonarbitrary relationship between the material kind and mechanical structure of artifacts and the functions that can be supported undercuts the force of information about convention as important to determining proper artifact function. Shared convention appears less important for determining this facet of our semantic memory for artifacts than it does in supporting the proper relationship between linguistic symbols and the categories of artifact to which they refer.

Conditions under which function information attenuates name extension via shape.

Children often extend names to novel artifacts on the basis of overall shape rather than core properties (e.g., function). This bias is claimed to reflect the fact that nonrandom structure is a reliable cue to an object having a specific designed function. In this article, we show that information about an object's design (i.e., about its creator's intentions) is neither necessary nor sufficient for children to override the shape bias. Children extend names on the basis of any information specifying the artifact's function (e.g., information about design, current use, or possible use), especially when this information is made salient when candidate objects for extension are introduced. Possible mechanisms via which children come to rely less on easily observable cues (e.g., shape) and more on core properties (e.g., function) are discussed.