The information content of panoramic images II: view-based navigation in nonrectangular experimental arenas

Two recent studies testing navigation of rats in swimming pools have posed problems for any account of the use of purely geometric properties of space in navigation (M. Graham, M. A. Good, A. McGregor, & J. M. Pearce, 2006; J. M. Pearce, M. A. Good, P. M. Jones, & A. McGregor, 2004). The authors simulated 1 experiment from each study in a virtual reality environment to test whether experimental results could be explained by view-based navigation. The authors recorded a reference image at the target location and then determined global panoramic image differences between this image and images taken at regularly spaced locations throughout the arena. A formal model, in which an agent attempts to minimize image differences between the reference image and current views, generated trajectories that could be compared with the search performance of rats. For both experiments, this model mimics many aspects of rat behavior. View-based navigation provides a sufficient and parsimonious explanation for a range of navigational behaviors of rats under these experimental conditions.     

Modeling the Information Preferences of Parents of Children with Mental Health Problems: A Discrete Choice Conjoint Experiment

Although materials informing parents about children’s mental health (CMH) problems can improve outcomes, we know relatively little about the design factors that might influence their utilization of available resources. We used a discrete choice conjoint experiment to model the information preferences of parents seeking mental health services for 6 to 18 year olds. Parents completed 30 choice tasks presenting experimentally varied combinations of 20 four-level CMH information content, transfer process, and outcome attributes. Latent class analysis revealed three segments with different preferences. Parents in the Action segment (43%) chose materials providing step-by-step solutions to behavioral or emotional problems. They preferred weekly meetings with other parents and coaching calls from a therapist. The Information segment (41%) chose materials helping them understand rather than solve their child’s problems. These parents were more sensitive to logistical factors such as receiving information in groups, the location where information was available, the modality in which the information was presented, and the time required to obtain and use the information. The Overwhelmed segment (16%) reported more oppositional and conduct problems, felt their children’s difficulties exerted a greater adverse impact on family functioning, and reported higher personal depression scores than those in the Action or Information segments. Nonetheless, they did not choose information about, or solutions to, the problems their children presented. Simulations predicted that maximizing utilization and realizing the potential benefits of CMH information would require knowledge transfer strategies consistent with each segment’s preferences.

Face detection in normal and prosopagnosic individuals

Face detection, the process of finding a face in a visual scene, is a critical step in face processing, yet it has received relatively little attention compared with other face processes. The present study addresses this crucial first stage by investigating the effect of inversion on face detection and by examining how individuals with developmental prosopagnosia perform on face detection tasks. Fourteen control participants and fourteen individuals with developmental prosopagnosia (DPs) were tested with two face detection tasks: (1) Face versus Non‐Face, where arrays of small images were presented, one of which could contain a face and (2) Face versus Face Parts, where a two‐tone face could be embedded in a larger array of similar two‐tone face parts. On each trial, participants made a speeded response if a face was present in the visual display. On almost all measures both normal and prosopagnosic individuals showed strong inversion effects with significantly worse performance with inverted faces. This shows that the simple task of detection can show inversion effects comparable to those seen for other face tasks, including recognition. Finally, while there were prosopagnosics who were well within the normal range for detection, there were significant group differences, particularly for the case of the Face versus Face Parts, where prosopagnosics were worse than controls on upright but not on inverted face detection.     

Accurate forced-choice recognition without awareness of memory retrieval

Recognition confidence and the explicit awareness of memory retrieval commonly accompany accurate responding in recognition tests. Memory performance in recognition tests is widely assumed to measure explicit memory, but the generality of this assumption is questionable. Indeed, whether recognition in nonhumans is always supported by explicit memory is highly controversial. Here we identified circumstances wherein highly accurate recognition was unaccompanied by hallmark features of explicit memory. When memory for kaleidoscopes was tested using a two-alternative forced-choice recognition test with similar foils, recognition was enhanced by an attentional manipulation at encoding known to degrade explicit memory. Moreover, explicit recognition was most accurate when the awareness of retrieval was absent. These dissociations between accuracy and phenomenological features of explicit memory are consistent with the notion that correct responding resulted from experience-dependent enhancements of perceptual fluency with specific stimuli--the putative mechanism for perceptual priming effects in implicit memory tests. This mechanism may contribute to recognition performance in a variety of frequently-employed testing circumstances. Our results thus argue for a novel view of recognition, in that analyses of its neurocognitive foundations must take into account the potential for both (1) recognition mechanisms allied with implicit memory and (2) recognition mechanisms allied with explicit memory.     

Whither geometry? Troubles of the geometric module

In rectangular arenas, rats often confuse diagonally opposite corners, even when distinctive cues differentiate them. This led to the postulation that rats rely preferentially on the geometry of space, encoded in a dedicated geometric module. Recent research casts doubt on this idea. Distinctive featural cues such as entire walls of a distinct color can hinder or aid the learning of geometry. In one situation in which using geometry would help greatly, rats had trouble learning the task. An associative model has been developed to capture these different learning processes, and view-based matching has been proposed as an alternative to the explicit coding of geometric cues. Considerations about how cues interact in learning are crucial in a recent theory of human spatial cognition.     

Sensitization and habituation of motivated behavior in overweight and non-overweight children

The rate of habituation to food is inversely related to energy intake, and overweight children may habituate slower to food and consume more energy. This study compared patterns of sensitization, as defined by an initial increase in operant or motivated responding for food, and habituation, defined by gradual reduction in responding, for macaroni and cheese and pizza in overweight and non-overweight 8- to 12-year-old children. Non-overweight children habituated faster to both foods than overweight children (p = .03). All children recovered motivated responding for a new food (chocolate). Overweight children consumed more energy than non-overweight children (p = .0004). Children who showed a sensitization in responding consumed more food (p = .001), and sensitization moderated the effect of overweight on habituation, with slower habituation for overweight children who sensitized (p < .001). This study replicates previous data on overweight/non-overweight differences in habituation of food and energy intake, and provides new information that individual differences in sensitization and habituation of motivated responding to obtain food may be associated with a sustained motivation to eat, resulting in greater energy intake.