Effects of normal aging and Alzheimer's disease on emotional memory

Recall is typically better for emotional than for neutral stimuli. This enhancement is believed to rely on limbic regions. Memory is also better for neutral stimuli embedded in an emotional context. The neural substrate supporting this effect has not been thoroughly investigated but may include frontal lobe, as well as limbic circuits. Alzheimer's disease (AD) results in atrophy of limbic structures, whereas normal aging relatively spares limbic regions but affects prefrontal areas. The authors hypothesized that AD would reduce all enhancement effects, whereas aging would disproportionately affect enhancement based on emotional context. The results confirmed the authors' hypotheses: Young and older adults, but not AD patients, showed better memory for emotional versus neutral pictures and words. Older adults and AD patients showed no benefit from emotional context, whereas young adults remembered more items embedded in an emotional versus neutral context.     

What does the implicit association test measure? A test of the convergent and discriminant validity of prejudice-related IATs

Drawing on recent criticism of the Implicit Association Test (IAT), the present study tested the convergent and discriminant validity of two prejudice-related IATs to corresponding explicit prejudice measures in a German student sample (N = 61). Confirming convergent validity, (a) an IAT designed to assess negative associations related to Turkish people was significantly related to the explicit endorsement of prejudiced beliefs about Turkish people, and (b) an IAT designed to assess negative associations related to East Asians was significantly related to explicit prejudice against East Asians. Moreover, confirming discriminant validity, (c) the Asian IAT was unrelated to the explicit endorsement of prejudiced beliefs about Turkish people, and (d) the Turkish IAT was unrelated to explicit prejudice against Asian people. These results further corroborate the assumption that the IAT is a valid method to assess the strength of evaluative associations in the domain of prejudice and stereotypes.     

Framing interethnic ideology: effects of multicultural and color-blind perspectives on judgments of groups and individuals

In 3 experiments, White American college students received a message advocating either a color-blind or a multicultural ideological approach to improving interethnic relations and then made judgments about various ethnic groups and individuals. Relative to a color-blind perspective, the multicultural perspective led to stronger stereotypes, greater accuracy in these stereotypes, and greater use of category information in judgments of individuals. This increase in between-category differentiation occurred both for attributes that favored the in-group and for attributes that favored the out-group and was also paired in some cases with greater overall positivity toward the out-group. The findings lead us to question the implicit assumption driving the majority of social psychological efforts at prejudice reduction: that the categorization process leads to prejudice, and that the relevance of social categories must therefore be de-emphasized.     

Additional study of the Youth-Depression Adjective Check List

Replicated and extended aspects of determinations of reliability and validity for the State version of the Youth-Depression Adjective Check List. Students from Grades 9 through 12 (64 girls and 41 boys) completed the State version and the Adolescent Activities Checklist on each of 12 consecutive days and completed the Trait version, the Reynolds Adolescent Depression Scale, the Multiple Affect Adjective Check List--Revised Grade 6, and the Adolescent Activities Checklist at the beginning and the end of the study. Good reliability and validity of the State version were confirmed and extended, and preliminary information on characteristics of the Trait version of the Youth-Depression Adjective Check List also was presented. The State version seems suitable for use in research with adolescents and preadolescents. More study of the Trait version is recommended.     

Color discrimination under chronic hypoxic conditions (simulated climb "Everest-Comex 97")

Hypoxia is known to alter visual functions. In the present study, the effects of chronic hypobaric hypoxia upon visual color discrimination were studied in 8 subjects participating in a simulated climb from sea level (PO2 = 210 hPa) to 8,848 m (PO2 = 70 hPa) over a 31-day period of confinement in a decompression chamber ('Everst-Comex 97'). During these investigations, the subjects were required to discriminate between colors of different hue in the red, blue, and green ranges. Alterations in color discrimination increased slightly but significantly as altitude increased. Impairments occurred mainly in the red and blue ranges. In addition, our results further indicate that color discrimination would be affected only when a minimum threshold of difference between color stimuli is not present. Methodological and physiological implications are discussed.     

Infants' and adults' use of duration and intensity cues in the segmentation of tone patterns

Adults and 8-month-olds were presented with sequences in which every third complex tone was either longer or more intense. Segmentation was measured by comparing the detection of silent gaps inserted into three possible locations in each pattern: Silent gaps inserted at perceived segmentation boundaries are harder to detect than gaps within perceived phrases or groups. A go/no-go conditioned head-turn (hand-raising for adults) procedure was used. In Experiment 1, detection was worse for the gaps following the longer complex tones than for the gaps at the other locations, suggesting that the longer tones marked the ends of perceived groups for both infants and adults. Experiment 2 showed that an increase in intensity did not result in any systematic grouping at either age.     

Effects of differences in timbre on sequential grouping

Differences in the timbre of sounds in a sequence can affect their perceptual organization. Using a performance measure, Hartmann and Johnson (1991) concluded that streaming could be predicted primarily by the extent to which sounds were passed by different peripheral channels. However, results from a rating task by Dannenbring and Bregman (1976) suggested that sounds in the same spectral region (passed by the same peripheral channels) can be allocated to different streams. In Experiment 1, it was found, using an interleaved melody task, that target sounds could be selected from distractors in the same spectral region more easily when they differed in timbre. This finding might result from primitive stream segregation or schema-driven selection, but not from peripheral channeling. In Experiment 2, a rhythm discrimination task was used, requiring the sounds to be integrated for good performance. Differences in timbre impaired performance, indicating the occurrence of primitive stream segregation.     

Attending, ignoring, and repetition: on the relation between negative priming and inhibition of return

A series of spatial localization experiments is reported that addresses the relation between negative priming and inhibition of return. The results of Experiment 1 demonstrate that slowed responses to repeated location stimuli can be obscured by repetition priming effects involving stimulus dimensions other than spatial location. The results of Experiments 2, 3A, and 3B demonstrate that these repetition priming effects may occur only when participants are required to respond to the prime display. Together, these results suggest that differences between attended and ignored repetition effects in selective attention studies of spatial localization do not provide a basis for distinguishing between spatial negative priming and inhibition of return.     

On belief bias in syllogistic reasoning

A multinomial model is used to disentangle the respective contributions of reasoning processes and response bias in conclusion-acceptance data that exhibit belief bias. A model-based meta-analysis of 22 studies reveals that such data are structurally too sparse to allow discrimination of different accounts of belief bias. Four experiments are conducted to obtain richer data, allowing deeper tests through the use of the multinomial model. None of the current accounts of belief bias is consistent with the complex pattern of results. A new theory of belief bias is proposed that assumes that most reasoners construct only one mental model representing the premises as well as the conclusion or, in the case of an unbelievable conclusion, its logical negation. New predictions derived from the theory are confirmed in 4 additional studies.