Three experiments are described which investigated the ability of neonates to discriminate between the face of their mother and that of a strange adult female and to show face recognition. The first experiment indicated a reliable preference for the mother's face even where a control for olfactory information was used. No evidence for any effect of sex or breast vs. bottle feeding was found. A second experiment used the same procedure but substituted a visual mask for the olfactory one previously adopted. Under these conditions no evidence of preference was found. Finally, a third experiment considered the possibility that mothers were actively recruiting their own infant's attention and found that adult observers were unable reliably to distinguish mothers from strangers on the basis of any differential behaviour by mother and stranger. The conclusion is drawn that neonates can recognize their mother on the basis of visual clues alone and that these cues relate to memory for featural attributes of the mother's face rather than to attentionrecruiting behaviour on her part.The search for the limits of neonatal competence continues at a rapid pace with boundaries continually having to be redrawn in the light of fresh experimental evidence. The ontogeny of face discrimination and recognition is no exception to this general statement. It is not very many years since the weight of research indicated that, while young infants appeared to be particularly responsive to the human face, this was primarily the result of the face 'happening to embody' many of the appropriate stimulus characteristics to which infants' sensory systems are primarily attuned. Thus Schaffer (1971) amongst others argued that the face is not specialperse, in the sense that the human neonate is in any way genetically programmed to respond specifically to the human face, but rather that human sensory systems are strongly attuned to aspects such as movement (both absolute and relative), to contrast, to objects of a particular size and proximity that make relatively high-pitched noises and can operate contingently. All these attributes and more are appropriate to the human face in normal interaction and it is not therefore necessary to posit any conspecific processes (e.g. innate templates of the human face) to account for the special salience of the human face.While this argument makes a great deal of sense, there are some data which are not easily explained. Many studies have examined the ability of young infants to respond to the configuration of faces, rather than just the elements. Most of these early studies 'Requests for reprints.

Stratigraphy has been a descriptive science for most of its history. Recently, thanks to the development of the mechanistic view of Earth embodied in plate tectonics and to improvements in our understanding of sediment dynamics, the stratigraphic community has developed a first generation of quantitative models for the filling of basins and the formation of stratigraphic patterns. How do we test such models? The field is the ultimate repository of information, but exposure is limited, and it is often difficult to constrain key governing variables independently. We have developed a novel experimental basin-nicknamed Jurassic Tank-that allows us to produce experimental stratigraphy under precisely controlled and monitored conditions of sediment supply, subsidence, base-level variation, and transport mechanics. The unique feature of the basin is a fully programmable subsiding floor. In the first application of the system, we looked for evidence of decoupling (out-of-phase behavior) between shoreline and base level, as has been predicted by some recent stratigraphic models. We found little support for this idea, but the results demonstrate the potential that experiments have for complementing field and theoretical studies of the filling of sedimentary basins. Before you read this, try solving the problem posed in Figure 1.

Background and Purpose-The study aim was to assess the effects of magnesium sulfate (MgSO 4 ) administration on white matter damage in vivo in spontaneously hypertensive rats. Methods-The left internal capsule was lesioned by a local injection of endothelin-1 (ET-1; 200 pmol) in adult spontaneously hypertensive rats. MgSO 4 was administered (300 mg/kg SC) 30 minutes before injection of ET-1, plus 200 mg/kg every hour thereafter for 4 hours. Infarct size was measured by T2-weighted magnetic resonance imaging (day 2) and histology (day 11), and functional recovery was assessed on days 3 and 10 by the cylinder and walking-ladder tests. Results-ET-1 application induced a small, localized lesion within the internal capsule. Despite reducing blood pressure, MgSO 4 did not significantly influence infarct volume (by magnetic resonance imaging: median, 2.1 mm 3 ; interquartile range, 1.3 to 3.8, vs 1.6 mm 3 and 1.2 to 2.1, for the vehicle-treated group; by histology: 0.3 mm 3 and 0.2 to 0.9 vs 0.3 mm 3 and 0.2 to 0.5, respectively). Significant forelimb and hindlimb motor deficits were evident in the vehicle-treated group as late as day 10. These impairments were significantly ameliorated by MgSO 4 in both cylinder (left forelimb use, PϽ0.01 and both-forelimb use, PϽ0.03 vs vehicle) and walking-ladder (right hindlimb score, PϽ0.02 vs vehicle) tests. Conclusions-ET-1-induced

In this paper we investigate the development of interactive communication skills in 170 children aged seven to thirteen. Using a communication task that allows extended dialogues between pairs of young speakers, we are able to assess both the overall communicative success achieved by any pair; and from an analysis of the dialogues we can identify several interactive strategies that characterize older and more successful communicators. Successful communication involves the active involvement of both participants: asking and answering questions, volunteering information and responding sensitively to contributions from their partners. In contrast to the process of language acquisition, the development of these interactive skills takes place over an extended time period and subjects vary greatly in their ability to communicate effectively. For many analyses differences in the communicative success achieved by subjects differ more within than between age groups. For example, a substantial minority of our oldest subjects communicate no better than children six years younger