The right hemisphere maintains solution-related activation for yet-to-be-solved problems

In five experiments, we examined the time course of hemispheric differences in solution activation for insight-like problems. We propose that solving insight problems requires retrieval of unusual interpretations of problem elements, and that right-hemisphere (RH) coarse semantic coding is more likely than left-hemisphere (LH) fine semantic coding to maintain semantic activation of such interpretations. In four experiments, participants attempted word problems for 7 sec (Experiments 1A and 1B) or 2 sec (Experiments 2A and 2B), and 750 msec later responded to lateralized target words. After 7 sec of solving effort, Experiment 1A participants showed greater solution-related priming (i.e., they named solutions faster than unrelated words) for left visual field-RH (lvf-RH) targets than for right visual field-LH (rvf-LH) targets, and Experiment 1B participants made faster solution decisions on target words presented to the RH, as previously demonstrated following 15 sec of effort. After 2 sec of solving effort in Experiment 2A, women showed symmetric solution-related priming, although men showed a slight lvf-RH advantage in priming; and in Experiment 2B participants made equally quick solution decisions for targets presented to the LH and to the RH. In Experiment 3, participants viewed the problems for 1,250 msec then named lateralized target words; they showed symmetric solution-related priming. These experiments demonstrate solution activation initially in both hemispheres, but maintained solution activation only in the RH.     

Frontal-Lobe Involvement in Spatial Memory: Evidence from PET,fMRI, and Lesion Studies

Many studies have identified the prefrontal cortex as the brain area that is critical for spatial memory, both in humans and in other primates. Other studies, however, have failed to establish this relation. Therefore, the aim of this paper was to review the literature regarding the role of the human prefrontal lobe in spatial memory. This was done by examining the evidence obtained from neuropsychological patients and from studies using brain-imaging techniques (PET and fMRI). Evidence supporting the notion that the prefrontal cortex is extensively involved in spatial working memory was found. The majority of these studies, however, suggests that frontal-lobe involvement is not related to the type of material that is being processed (e.g., spatial vs. nonspatial), but to process-specific functions, such as encoding and retrieval. Theoretically, these functions could be linked to the central executive within Baddeley's working-memory model, or to recent theories that emphasize the various processes that play a role in working memory. Also, methodological issues were discussed. Further research is needed to enhance our understanding of the precise interaction of domain-specific and general processes.     

Toward specifying the attentional demands of recognition memory

Previous studies have concluded that recognition memory is immune to disruption from divided attention and therefore is a relatively automatic process (A. Baddeley, V. Lewis, M. Eldridge, & N. Thomson, 1984; F. I. M. Craik, R. Govoni, M. Naveh-Benjamin, & N. D. Anderson, 1996). Because costs have been found on the concurrent task used to divide attention, recognition may nevertheless require some attentional resources (M. Naveh-Benjamin, F. I. M. Craik, J. Guez, & H. Dori, 1998). The present authors used attention-demanding concurrent tasks to demonstrate significant costs on both the concurrent task and recognition memory performance. Decrements in recognition accuracy were found for classes of items that were studied deeply but not for more shallowly learned materials. The present findings suggest that recognition processes can require significant attentional resources when tested under the appropriate conditions. The results are discussed in terms of the requirements both at encoding and at test that are needed to observe dual-task decrements to recognition accuracy.     

The properties of retention intervals and their affect on retaining prospective memories

Five experiments were conducted to explore how the character of the retention interval affected event-based prospective memory. According to the canons of retrospective memory, prospective performance should have been worse with increasing delays between intention formation and the time it was appropriate to complete an action. That result did not occur. Rather, prospective memory was better with increasing retention intervals in Experiments 1A, 1B, and 3. In manipulating the nature of the retention interval, the authors found that there were independent contributions of retention interval length and the number of intervening activities, with more activities leading to better prospective memory (Experiments 2 and 3). The identical retention intervals did not improve retrospective memory in Experiment 4. Theoretical explanations for these dissociations between prospective and retrospective memory are considered.     

Moral conviction: another contributor to attitude strength or something more?

Attitudes held with strong moral conviction (moral mandates) were predicted to have different interpersonal consequences than strong but nonmoral attitudes. After controlling for indices of attitude strength, the authors explored the unique effect of moral conviction on the degree that people preferred greater social (Studies 1 and 2) and physical (Study 3) distance from attitudinally dissimilar others and the effects of moral conviction on group interaction and decision making in attitudinally homogeneous versus heterogeneous groups (Study 4). Results supported the moral mandate hypothesis: Stronger moral conviction led to (a) greater preferred social and physical distance from attitudinally dissimilar others, (b) intolerance of attitudinally dissimilar others in both intimate (e.g., friend) and distant relationships (e.g., owner of a store one frequents), (c) lower levels of good will and cooperativeness in attitudinally heterogeneous groups, and (d) a greater inability to generate procedural solutions to resolve disagreements.     

Straightness as a cue for luminance edge interpretation

In order to determine the reflectance of a surface, it is necessary to discount luminance changes produced by illumination variation, a process that requires the visual system to respond differently to luminance changes that are due to illumination and reflectance. It is known that various cues can be used in this process. By measuring the strength of lightness illusions, we find evidence that straightness is, used as a cue: When a boundary is straight rather than curved, it has a greater tendency to be discounted, as if it were an illumination edge. The strongest illusions occur when a boundary has high contrast and has multiple X-junctions that preserve a consistent contrast ratio.