Pigeons see correspondence between objects and their pictures

The extent to which nonhumans recognize the correspondence between static pictures and the objects they represent remains an interesting and controversial issue. Pictures displayed on computers are used extensively for research on behavioral and neural mechanisms of cognition in birds, yet attempts to show that birds recognize the objects seen in pictures have produced mixed and inconclusive results. We trained pigeons to discriminate between two identically colored but differently shaped three-dimensional objects seen directly or as pictures, and we found clear bidirectional transfer of the learned object discrimination. Transfer from objects to pictures occurred even when pigeons were trained with 12 views and only novel views of the objects were presented in transfer. This study provides the strongest evidence yet that pigeons can recognize the correspondence between objects and pictures.     

Importing perceived features into false memories

False memories sometimes contain specific details, such as location or colour, about events that never occurred. Based on the source-monitoring framework, we investigated one process by which false memories acquire details: the reactivation and misattribution of feature information from memories of similar perceived events. In Experiments 1A and 1B, when imagined objects were falsely remembered as seen, participants often reported that the objects had appeared in locations where visually or conceptually similar objects, respectively, had actually appeared. Experiment 2 indicated that colour and shape features of seen objects were misattributed to false memories of imagined objects. Experiment 3 showed that perceived details were misattributed to false memories of objects that had not been explicitly imagined. False memories that imported perceived features, compared to those that presumably did not, were subjectively more like memories for perceived events. Thus, perception may be even more pernicious than imagination in contributing to false memories.     

Intramuscular electrical stimulation of facial muscles in humans and chimpanzees: Duchenne revisited and extended

The pioneering work of Duchenne (1862/1990) was replicated in humans using intramuscular electrical stimulation and extended to another species (Pan troglodytes: chimpanzees) to facilitate comparative facial expression research. Intramuscular electrical stimulation, in contrast to the original surface stimulation, offers the opportunity to activate individual muscles as opposed to groups of muscles. In humans, stimulation resulted in appearance changes in line with Facial Action Coding System (FACS) action units (AUs), and chimpanzee facial musculature displayed functional similarity to human facial musculature. The present results provide objective identification of the muscle substrate of human and chimpanzee facial expressions- data that will be useful in providing a common language to compare the units of human and chimpanzee facial expression.     

An age-related deficit in prefrontal cortical function associated with refreshing information

Older adults are slower than young adults to think of an item they just saw, that is, to engage or execute (or both) the simple reflective operation of refreshing just-activated information. In addition, they derive less long-term memory benefit from refreshing information. Using functional magnetic resonance imaging (fMRI), we found that relative to young adults, older adults showed reduced refresh-related activity in an area of dorsolateral prefrontal cortex (left middle frontal gyrus, Brodmann's Area 9), but not in other refresh-related areas. This provides strong evidence that a frontal component of the circuit that subserves this basic cognitive process is especially vulnerable to aging. Such a refresh deficit could contribute to poorer performance of older than young adults on a wide range of cognitive tasks.     

Preserved spatial memory over brief intervals in older adults

Two studies compared young and older adults' memory for location information after brief intervals. Experiment 1 found that accuracy of intentional spatial memory for individual locations was similar in young and older participants for set sizes of 3 and 6. Both groups also encoded individual locations in relation to the larger configuration of locations. Experiment 2 showed that like young adults, older adults' latency to respond to a test probe in a letter working memory task was negatively influenced by spatial information that was irrelevant to the task. This interference effect indicated preserved incidental memory for spatial information in older adults. Together, these data suggest that initial encoding of spatial information for relatively small numbers of items is largely preserved in healthy older adults and that representations of spatial information persist over short intervals.     

Recognizing rotated views of objects: Interpolation versus generalization by humans and pigeons

Pigeons and humans were trained to discriminate between pictures of three-dimensional objects that differed in global shape. Each pair of objects was shown at two orientations that differed by a depth rotation of 90° during training. Pictures of the objects at novel depth rotations were then tested for recognition. The novel test rotations were 30°, 45°, and 90° from the nearest trained orientation and were either interpolated between the trained orientations or extrapolated outside of the training range. For both pigeons and humans, recognition accuracy and/or speed decreased as a function of distance from the nearest trained orientation. However, humans, but not pigeons, were more accurate in recognizing novel interpolated views than novel extrapolated views. The results suggest that pigeons’ recognition was based on independent generalization from each training view, whereas humans showed view-combination processes that resulted in a benefit for novel views interpolated between the training views.     

Attention during adaptation weakens negative afterimages

The effect of attention during adaptation on subsequent negative afterimages was examined. One of 2 overlapped outline figures was attended during a 7-10-s adaptation period. When the figures were readily perceptually segregated (on the basis of color or motion), the subsequent afterimages were initially weaker for the previously attended figure. This effect was confirmed by demonstrations that the onset of a single afterimage was delayed when an afterimage inducer was attended during adaptation compared with when a central digit stream or an overlapped (brightness-balanced) figure that did not generate an afterimage was attended. The attention effect was further confirmed using a criterion-independent (dot-integration) paradigm. The fact that selective attention during adaptation weakened or delayed afterimages suggests that attention primarily facilitates the adaptation of polarity-independent processes that modulate the visibility of afterimages rather than facilitating the adaptation of polarity-selective processes that mediate the formation of afterimages.     

Introduction to the special section on Resources for Enhancing Alzheimer's Caregiver Health (REACH)

This article provides background information and an overview on Resources for Enhancing Alzheimer's Caregiver Health (REACH) a multisite intervention trial for caregivers of persons with Alzheimer's disease designed to reduce caregiver burden and depression. REACH is the largest randomized controlled clinical trial to date, involving 1,222 caregiver and care recipient dyads recruited from 6 different sites in the United States. The authors describe the design of the study, summarize the interventions implemented at each site, and provide an overview of the 4 articles in this special section.     

The Resources for Enhancing Alzheimer's Caregiver Health (REACH): project design and baseline characteristics

The Resources for Enhancing Alzheimer's Cargiver Health (REACH) project was designed to test promising interventions for enhancing family caregiving for persons with dementia. The purpose of this article is to describe the research design, interventions, and outcome measures used in REACH and to characterize the sample recruited for the study. Nine interventions and 2 control conditions were implemented at 6 sites; 1,222 dyads were randomly assigned to an intervention or a control condition. The caregiver sample was 18.6% male with an average age of 62.3 years (56% Caucasian, 24% Black, and 19% Hispanic). Caregivers reported high levels of depressive symptoms and moderate burden. Care recipients were older, with a mean age of 79, and were moderately to severely impaired with mean Mini-Mental State Exam scores of 13/30.