Facilitated pointing to remembered objects in front: Evidence for egocentric retrieval or for spatial priming?

Recent spatial memory theories propose that long-term spatial memories are retrieved egocentrically. One source of evidence comes from imagined perspective taking, in which participants learn an object layout, later imagine standing at one object and facing a second (orienting) object, and then point to a third (target) object from the imagined perspective. Pointing is faster for target objects in the anterior than in the posterior half of imaginal space. This “front facilitation” is consistent with asymmetric sensory and biomechanical body properties (favoring the anterior half of body space), supporting claims of egocentric retrieval. However, front facilitation might actually result from spatial priming: Proximity differences might cause orienting objects to prime target objects more in the anterior than in the posterior half of imagined space. Using a modified perspectivetaking task that unconfounded front facilitation and spatial priming, two experiments identified separate influences of front facilitation and spatial priming when participants imagined perspectives within the surrounding environment or a remote environment.     

iSTART 2: Improvements for efficiency and effectiveness

iSTART (interactive strategy training for active reading and thinking) is a Web-based reading strategy trainer that develops students’ ability to self-explain difficult text as a means to improving reading comprehension. Its curriculum consists of modules presented interactively by pedagogical agents: an introduction to the basics of using reading strategies in the context of self-explanation, a demonstration of self-explanation, and a practice module in which the trainee generates self-explanations with feedback on the quality of reading strategies contained in the self-explanations. We discuss the objectives that guided the development of the second version of iSTART toward the goals of increased efficiency for the experimenters and effectiveness in the training. The more pedagogically challenging high school audience is accommodated by (1) a new introduction that increases interactivity, (2) a new demonstration with more and better focused scaffolding, and (3) a new practice module that provides improved feedback and includes a less intense but more extended regimen. Version 2 also benefits experimenters, who can set up and evaluate experiments with less time and effort, because pre- and posttesting has been fully computerized and the process of preparing a text for the practice module has been reduced from more than 1 person-week to about an hour’s time.     

Subjective hierarchies in spatial memory

Two experiments investigated the structure of spatial memories. Subjects learned locations of objects in spatial layouts (Experiment 1) or locations of object names on maps (Experiment 2). Physical and perceptual boundaries were absent in these spatial arrays. Subjects then participated in three tasks: item recognition, in which the variable of interest was spatial priming; free and cued recall; and Euclidean distance estimation. Ordered-tree analysis of individual subjects' recall protocols produced hierarchical trees consistent with regularities in output order. Spatial priming and distance estimations depended on whether pairs of objects appeared in the same subtree or in different subtrees. These findings indicate that spatial memories have a hierarchical component, even when physical and perceptual boundaries are nonexistent. Priming also increased with depth of clustering in ordered trees. This result supports spreading-activation theories of retrieval but provides evidence against several "non-spreading-activation" theories.     

Prompt comprehension in UNIX command production

We hypothesize that a cognitive analysis based on the construction-integration theory of comprehension (Kintsch, 1988) can predict what is difficult about generating complex composite commands in the UNIX operating system. We provide empirical support for assumptions of the Doane, Kintsch, and Polson (1989, 1990) construction-integration model for generating complex commands in UNIX. We asked users whose UNIX experience varied to produce complex UNIX commands, and then provided help prompts whenever the commands that they produced were erroneous. The help prompts were designed to assist subjects with respect to both the knowledge and the memory processes that our UNIX modeling efforts have suggested are lacking in less expert users. It appears that experts respond to different prompts than do novices. Expert performance is helped by the presentation of abstract information, whereas novice and intermediate performance is modified by presentation of concrete information. Second, while presentation of specific prompts helps less expert subjects, they do not provide sufficient information to obtain correct performance. Our analyses suggest that information about the ordering of commands is required to help the less expert with both knowledge and memory load problems in a manner consistent with skill acquisition theories.     

The role of life events,family support,and competence in adolescent substance use: A test of vulnerability and protective factors

Tested propositions from a model of vulnerability and protective factors with a multiethnic sample of 1,289 urban adolescents, aged 11-13 years. The criterion variable was a composite score for cigarette, alcohol, and marijuana use. Multiple regression analyses indicated that vulnerability factors (negative life events, negative affect) were related to a higher level of substance use, and protective factors (parent emotional and instrumental support, academic and adult competence, positive affect) were related to a lower level of substance use; peer competence was positively related to substance use in a multivariate model. There was a significant overall interaction of Vulnerability x Protective Factors, consistent with a stress-buffering effect. Individual interactions for Life Events x Family Support, Life Events x Competence, and Negative x Positive Affect also were consistent with buffering effects. Implications for theories of substance use and primary prevention are discussed.