Detection of a deficit in visual discrimination of pattern following lesions of anterior cortex: role of type of motivation.

6 albino rats were trained under appetitive motivation to perform diametrically opposed visual discriminations of pattern via opposite eyes. Small lesions were subsequently placed unilaterally in anterior neocortex. Following a period of post-surgical recovery, subjects were re-trained on the diammetrically opposed discriminations in alternating 10-trial blocks. Every subject made more post-surgical errors on the discrimination mediated by the eye contralateral to the lesion. Since albino rats have virtually complete decussation of the visual system, this indicates selective impairment in mediation of performance of pattern discrimination in the part of the lesioned hemispheres. Thus, findings previously obtained in studies involving aversive motivation are general to appetitively motivated tasks.     

Is future self-relevance necessary to increase saving for retirement? A replication study

Insufficient saving for retirement is one consequence of excessive discounting of the future but attempts to mitigate it often involve costly or time-intensive personalized interventions. Marques, Mariano, Lima, and Abrams, by contrast, found that using a generic Future Time Perspective questionnaire to increase future “self-relevance” was an effective method to increase money allocation to retirement when the salience of future aging was also higher. Originally conducted in Portugal, the present study aimed to replicate Marques et al’s findings in the UK context. In the present study (n = 219), participants were shown a website advertising a financial product. The results support Marques and colleagues’ assertion that, alone, a website priming future aging was insufficient to increase retirement savings in a money allocation task. However, in contrast to Marques et al’s original findings, we find no evidence that future self-relevance moderates the effect such that priming future aging becomes effective when individuals have higher future self-relevance. Instead, we find that aging primes are ineffective at increasing retirement saving regardless of whether individuals are high or low in future self-relevance. Possible explanations for this discrepancy in findings, including methodological and cultural differences, are explored as well as directions for future research.     

Additive factors analysis of reaction time with alphanumericals and line orientations as stimuli

Most additive factors method (AFM) analyses of choice reaction time (CRT) have used alphanumerics whereas tests of single process models have often used line length or line orientation. The suggestion is raised that commonly observed additive effects of variables on CRT might not apply to stimuli of the latter category. This would mean a severe limitation of the AFM in that the stage structure of choice reactions would be stimulus specific. The issue is addressed in two experiments. The first showed additive effects of stimulus quality and stimulus-response compatiblility for both alphanumerics and line orientations as stimuli. The second showed that for both stimulus categories the effect of stimulus quality was fully reflected in visual fixation time. Together the results argue against a single central process and favour a stage model of CRT.     

Age differences in overlapping-task performance: evidence for efficient parallel processing in older adults

Two psychological refractory period (PRP) experiments were conducted to examine overlapping processing in younger and older adults. A shape discrimination task (triangle or rectangle) for Task 1 (T1) and a lexical-decision task (word or nonword) for Task 2 (T2) were used. PRP effects, response time for T2 increasing as stimulus onset synchrony (SOA) decreased, were obtained for both age groups. The effect of word frequency on T2 was smaller at the short SOA than at the long SOA, reflecting slack effects, which were larger for older than younger adults in both experiments. These results suggest that older adults can perform lexical access of T2 in parallel with the processing of T1 at least as efficiently as younger adults.     

Angry adolescents who worry about becoming violent

In the present study, 31 of 89 adolescents responded affirmatively to the following statement: "Sometimes I get so angry that I worry I will become violent." These adolescents (the anger group) were compared with the nonanger group, and several differences were found. The anger group (1) reported less intimacy with parents, received less support from them, and was less close to siblings; (2) had more opposite-sex friends, dated more frequently, and more frequently had a boyfriend or girlfriend; (3) had a lower grade point average; (4) were more depressed; and (5) used marijuana more frequently. Results of a regression analysis revealed that depression and dating were the only significant predictors of anger, explaining 17% of the variance.     

Object onset and parvocellular guidance of attentional allocation

The parvocellular visual pathway in the primate brain is known to be involved with the processing of color. However, a subject of debate is whether an abrupt change in color, conveyed via this pathway, is capable of automatically attracting attention. It has been shown that the appearance of new objects defined solely by color is indeed capable of modulating attention. However, given evidence suggesting that the visual system is particularly sensitive to new onsets, it is unclear to what extent such results reflect effects of color change per se, rather than effects of object onset. We assessed attentional capture by color change that occurred as a result of either new objects appearing or already-present "old" objects changing color. Results showed that although new object onsets accrued attention, changing the color of old objects did not. We conclude that abrupt color change per se is not sufficient to capture attention.     

Deletion of the mu opioid receptor results in impaired acquisition of Pavlovian context fear

The mu opioid receptor may constitute a critical component of a negative feedback system that regulates Pavlovian fear conditioning. We investigated context fear conditioning acquisition and expression in mu opioid receptor knockout mice (on an inbred, C57 genetic background). We discovered that the mu receptor knockout results in an unexpected and significant deficit in context fear acquisition. Mice lacking the mu receptor showed normal fear acquisition when subjected to a 1-day fear conditioning protocol but evinced deficient fear learning when acquisition was conducted across 5 days. The knockout mice showed normal reactivity to footshock in both fear conditioning protocols. Finally, we confirmed the effectiveness of the receptor deletion in the C57 strain by subjecting the mice to a test of morphine analgesia in the hot-plate assay. As has been seen with mixed genetic background, the receptor deletion resulted in a complete lack of analgesic response to 10 mg/kg morphine. Surprisingly, mice with a single copy of the mu receptor gene (heterozygous knockouts) showed intact sensitivity to morphine but a significant deficit in Pavlovian fear conditioning. The results indicate that deletion of the mu receptor gene impairs fear conditioning and that the conditioning and analgesia effects of heterozygous deletion are dissociable. The conditioning deficit seen in this line of mice may be related to impairment in hippocampus function.