Current Issue : July - September Volume : 2013 Issue Number : 3 Articles : 4 Articles
Background: The literature on social dilemmas and punishment focuses on the behaviour of the punisher.\r\nHowever, to fully explain the effect of punishment on cooperation, it is important to understand the psychological\r\nmechanisms influencing the behaviour of those who expect to be punished. This paper examines whether the\r\nexpectation of punishment, rather than the implementation of punishment is sufficient to prevent individuals from\r\nfree riding. Individual differences in the punishment sensitivity have been linked to both threat responses (flight,\r\nfight, fear system, or the FFFS) and to the response to the uncertainty of punishment (BIS-anxiety).The paper,\r\ntherefore, examines if individual differences in BIS-anxiety and FFFS can explain some of the variability in free riding\r\nin the face of implemented and non-implemented punishment.\r\nMethods: Participants took part in a series of one-shot Public Goods Games (PGGs) facing two punishment\r\nconditions (implemented and non-implemented) and two standard non-punishment PGGs. The punishment was\r\nimplemented as a centralized authority punishment (i.e., if one participant contributed less than their group\r\nmembers, they were automatically fined). Individual contribution levels and presence/absence of zero contributions\r\nindexed free riding. Individual differences in behavioural inhibition were assessed.\r\nResults: Individuals contributed more under the threat of punishment (both implemented and non-implemented).\r\nHowever, individuals contributed less when the punishment was not implemented compared to when it was.\r\nThose scoring high in BIS-anxiety contributed more when the punishment expectations were not implemented.\r\nThis effect was not observed for FFFS.\r\nConclusion: Supporting previous research, punishment had a powerful effect in increasing contribution levels in\r\nthe PGGs. However, when expected punishment was not implemented, individual differences in punishment\r\nsensitivity, specifically in BIS-anxiety, were related to fewer contributions (increased free riding) as compared to the\r\nsituation when punishment was not implemented. This has implications for our understanding of why some\r\npeople cannot resist the temptation to free ride, even when facing possible punishment for their actions. Our\r\nfindings suggest that the diminished functioning of mechanisms, associated with trait behavioural inhibition, can\r\npartly explain such behaviours....
Background: Tryptophan hydroxylase-2 (TPH2) is a potential candidate gene for screening tic disorder (TD).\r\nMethods: A caseââ?¬â??control study was performed to examine the association between the TPH2 gene and TD. The\r\nSequenomW Mass ARRAY iPLEX GOLD System was used to genotype two single nucleotide polymorphisms (SNPs) of\r\nthe TPH2 gene in 149 TD children and in 125 normal controls.\r\nResults: For rs4565946, individuals with the TT genotype showed a significantly higher risk of TD than those with TC plus\r\nCC genotypes [odds ratio (OR) =3.077, 95% confidence interval (CI): 1.273ââ?¬â??7.437; P = 0.009], as did male TD children with\r\nthe TT genotype (OR = 3.228, 95% CI: 1.153ââ?¬â??9.040; P = 0.020). The G allele of rs4570625 was significantly more frequent in\r\nTD children with higher levels of tic symptoms (Yale Global Tic Severity Scale, YGTSS) than those in controls among the\r\nmale children (OR = 1.684, 95%: 1.097ââ?¬â??2.583; P = 0.017]. TD children with severe tic symptoms had significantly higher\r\nfrequencies of rs4546946 TT genotype than did normal controls in boys (OR = 3.292, 95% CI: 1.139ââ?¬â??9.513; P = 0.022). We\r\nalso found that genotype distributions of both SNPs were different between the Asian and European populations.\r\nConclusions: Our results indicated that the TT genotype of rs4565946 is a potential genetic risk factor for TD, and the\r\nallele G of rs4570625 might be associated with the severity of tic symptoms in boys. These polymorphisms might be\r\nsusceptibility loci for TD in the Chinese Han population. Because of the confounding of co-existing attention deficit\r\nhyperactivity disorder (ADHD),these findings need to be confirmed by studies in much larger samples....
Recent evidence suggests that neglect patients seem to have particular problems representing relatively smaller\r\nnumbers corresponding to the left part of the mental number line. However, while this indicates space-based\r\nneglect for representational number space little is known about whether and - if so - how object-based neglect\r\ninfluences number processing.\r\nTo evaluate influences of object-based neglect in numerical cognition, a group of neglect patients and two control\r\ngroups had to compare two-digit numbers to an internally represented standard. Conceptualizing two-digit\r\nnumbers as objects of which the left part (i.e., the tens digit should be specifically neglected) we were able to\r\nevaluate object-based neglect for number magnitude processing.\r\nObject-based neglect was indicated by a larger unit-decade compatibility effect actually reflecting impaired\r\nprocessing of the leftward tens digits. Additionally, faster processing of within- as compared to between-decade\r\nitems provided further evidence suggesting particular difficulties in integrating tens and units into the place-value\r\nstructure of the Arabic number system.\r\nIn summary, the present study indicates that, in addition to the spatial representation of number magnitude, also\r\nthe processing of place-value information of multi-digit numbers seems specifically impaired in neglect patients...
Background: Fatigue has a multi-factorial nature. We examined the effects of two types of mental fatigue on\r\nspontaneous oscillatory brain activity using magnetoencephalography (MEG).\r\nMethods: Participants were randomly assigned to two groups in a single-blinded, crossover fashion to perform two\r\ntypes of mental fatigue-inducing experiments. Each experiment consisted of a 30-min fatigue-inducing 0- or 2-back\r\ntest session and two evaluation sessions performed just before and after the fatigue-inducing mental task session.\r\nResults: After the 0-back test, decreased alpha power was indicated in the right angular gyrus and increased levels\r\nin the left middle and superior temporal gyrus, left postcentral gyrus, right superior frontal gyrus, left inferior frontal\r\ngyrus, and right medial frontal gyrus. After the 2-back test, decreased alpha power was indicated in the right\r\nmiddle and superior frontal gyrus and increased levels in the left inferior parietal and superior parietal lobules, right\r\nparahippocampal gyrus, right uncus, left postcentral gyrus, left middle frontal gyrus, and right inferior frontal gyrus.\r\nFor beta power, increased power following the 0-back test was indicated in the left middle temporal gyrus, left\r\nsuperior frontal gyrus, left cingulate gyrus, and left precentral gyrus. After the 2-back test, decreased power was\r\nsuggested in the left superior frontal gyrus and increased levels in the left middle temporal gyrus and left inferior\r\nparietal lobule. Some of these brain regions might be associated with task performance during the fatigue-inducing\r\ntrials.\r\nConclusions: Two types of mental fatigue may produce different alterations of the spontaneous oscillatory MEG\r\nactivities. Our findings would provide new perspectives on the neural mechanisms underlying mental fatigue....
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