The effects of encoding task on age-related differences in the functional neuroanatomy of face memory

Age-related differences in brain activity mediating face recognition were examined using positron emission tomography. Participants encoded faces using a pleasant-unpleasant judgment, a right-left orientation task, and intentional learning. Scans also were obtained during recognition. Both young and old groups showed signficant effects of encoding task on recognition accuracy, but older adults showed reduced accuracy overall. Increased brain activity in older adults was similar to that seen in young adults during conditions associated with deeper processing, but was reduced during the shallow encoding and recognition conditions. Left prefrontal activity was less in older adults during encoding, but greater during recognition. Differential correlations of brain activity and behavior were found that suggest older adults use unique neural systems to facilitate face memory.     

Semantic priming: on the role of awareness in visual word recognition in the absence of an expectancy

By hypothesis, awareness is involved in the modulation of feedback from semantics to the lexical level in the visual word recognition system. When subjects are aware of the fact that there are many related prime-target pairs in a semantic priming experiment, this knowledge is used to configure the system to feed activation back from semantics to the lexical level so as to facilitate processing. When subjects are unaware of this fact, the default set is maintained in which activation is not fed back from semantics to the lexical level so as to conserve limited resources. Qualitative differences in the pattern of data from two lexical decision experiments that employ masked priming are consistent with this hypothesis. Semantic context and stimulus quality interact when the prime is processed with awareness whereas these same two factors produce additive effects on RT when the prime is unlikely to have been processed with awareness. These experiments thus illustrate one way in which awareness (or lack thereof) affects the dynamics of visual word recognition.     

A basis for bias in geographical judgments

To determine why North Americans tend to locate European cities south of North American cities at similar latitudes (Tversky, 1981), we had observers provide bearing estimates between cities in the U.S. and Europe. Earlier research using latitude estimates of these cities has indicated that each continent has several subjective regions (Friedman & Brown, 2000a). Participants judged cities from two subjectively northern regions (Milwaukee-Munich), two subjectively southern regions (Memphis-Lisbon), and the two "crossed" regions (Albuquerque-Geneva; Minneapolis-Rome). Estimates were biased only when cities from the subjectively northern regions of North America were paired with cities from the subjectively southern region of Europe. In contrast to the view that biases are derived from distorted or aligned map-like representations, the data provide evidence that the subjective representation of global geography is principally categorical. Biases in numerical location estimates of individual cities and in bearing estimates between city pairs are derived from plausible reasoning processes operating on the same categorical representations.     

Primary care physicians attitude toward diagnosis and treatment of late-life depression

Underdiagnosis and undertreatment of late-life depression is common, especially in primary care settings. To help assess whether physicians attitude and confidence in diagnosing and managing depression serve as barriers to care, a total of 176 physicians employed in 18 primary care groups were administered surveys to assess attitudes towards diagnosis, treatment, and management of depression in elderly patients, (individuals over 65 years of age). Logistic regression was performed to assess the association of physician characteristics on attitudes. Nearly all of the physicians surveyed felt that depression in the elderly was a primary care problem, and 41% reported late-life depression as the most common problem seen in older patients. Physicians were confident in their ability to diagnose and manage depression, yet 45% had no medical education on depression in the previous three years. Physicians confidence in their ability to diagnose, treat, and manage depression, and their reported adequacy of training, do not appear to correspond to the amount of continuing medical education in depression, suggesting that physician overconfidence may potentially be serving as a barrier to care.     

Attitudes about antidepressants: influence of information about weight-related side effects

Antidepressant drugs are frequently prescribed for women and have various side effects, including potential effects on body weight. This experiment examined the effects of information about the weight-related side effects of antidepressants on women's attitudes toward the drugs. 60 college women were randomly assigned to read about one of two drugs, fluoxetine (Prozac) or imipramine (Tofranil). Participants were either told or not told about veridical weight-related side effects, namely, weight loss for Prozac and weight gain for Tofranil. As hypothesized, weight-gain information lowered the personal acceptability of Tofranil, and weight-loss information enhanced the acceptability of Prozac. Although research with clinical populations is required, undergraduate women's decisions about the use of antidepressant medications may be influenced by societal body-image ideals.     

Comparison of selected perceptual variables for backpacks with internal and external frames

Differences in perceptions of comfort, exertion, balance, and heart rate were investigated with two types of backpack. Subjects were 20 male volunteers (M age = 24.3 yr., SD: 3.6, M height = 180.02 cm, SD: 8.0, and M weight = 86.46 kg, SD: 14.84). Following oral briefing and practice trials, each subject was fitted at random with either an internal- or external-frame backpack containing 18.2 kg. By random, cross-over design, subjects completed a 30-m simulated hiking trial consisting of 16 separate obstacles designed to resemble actual off-trail hiking. Trials were conducted in a controlled environment with the walking intensity regulated by a metronome. Upon completion of each trial, the subjects rated the experience on perceived comfort, balance and stability, and rating of perceived exertion. Heart rate was recorded immediately prior to and following each trial. Analysis yielded a significant difference only on rating of perceived exertion in favor of the internal-frame backpack. Under limited circumstances, these data suggest that both types of backpacks provide similar comfort and balance and stability; however, internal frames in backpacks may reduce perceived exertion during short, demanding hikes.     

Oscillator-based memory for serial order

A computational model of human memory for serial order is described (OSCillator-based Associative Recall [OSCAR]). In the model, successive list items become associated to successive states of a dynamic learning-context signal. Retrieval involves reinstatement of the learning context, successive states of which cue successive recalls. The model provides an integrated account of both item memory and order memory and allows the hierarchical representation of temporal order information. The model accounts for a wide range of serial order memory data, including differential item and order memory, transposition gradients, item similarity effects, the effects of item lag and separation in judgments of relative and absolute recency, probed serial recall data, distinctiveness effects, grouping effects at various temporal resolutions, longer term memory for serial order, list length effects, and the effects of vocabulary size on serial recall.     

Diagnosing written language disabilities using the Woodcock-Johnson Tests of Educational Achievement-Revised and the Wechsler Individual Achievement Test

The writing portions of the Woodcock-Johnson Tests of Educational Achievement-Revised and the Wechsler Individual Achievement Test are often administered when establishing eligibility for special education services due to learning disabilities. The scores on these measures are typically regarded as equivalent although little is known about how scores on the two measures differ for the same students. Differences of only a few points, however, may affect eligibility for special education services. These tests were administered to 25 sixth grade students previously diagnosed with learning disabilities in written expression only. Students' Wechsler scores were consistently higher on the overall writing composite, while there was no difference in the mean scores on the language mechanics subtests. The WIAT Written Expression subtest mean, however, was significantly higher than the Woodcock-Johnson Writing Samples subtest mean. Use of the Wechsler test would be less likely to identify children for special education services in written expression when point discrepancy criteria are utilized for eligibility. Clinicians should be cognizant of the effect of the specific test chosen on eligibility outcome.     

Contrast effects do not underlie effects of preceding liquids on stop-consonant identification by humans

These experiments explored the claim by A. Lotto and K. Kluender (1998) that frequency contrast explains listeners' compensations for coarticulation in the case of liquid consonants coarticulating with following stops. Evidence of frequency contrast in experiments that tested for it directly was not found, but Lotto and Kluender's finding that high- and low-frequency precursor tones can produce contrastive effects on stop-consonant judgments were replicated. The effect depends on the amplitude relation of the tones to the third formant (F3) of the stops. This implies that the tones mask F3 information in the stop consonants. It is unknown whether liquids and following stops in natural speech are in an appropriate intensity relation for masking of the stop. A final experiment, exploiting the McGurk effect, showed compensation for coarticulation by listeners when neither frequency contrast nor masking can be the source of the compensations.