ISSN 0439-755X
CN 11-1911/B


    30 June 2008, Volume 40 Issue 06 Previous Issue    Next Issue

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    Self-framing, Risk Perception and Risky Choice
    ZHANG Wen-Hui,WANG Xiao-Tian
    2008, 40 (06):  633-641. 
    Abstract ( 1778 )   PDF (1642KB) ( 2583 )  
    This study introduces and extends recent developments in the studies of framing effects in behavioral decision making, and examines the effects of self-framing on risky choice and its underlying mechanism. Until recently, framing studies had largely focused on how externally framed (phrased) choice problems affected risk preference. Little attention was given to how decision makers mentally frame decision problems themselves. Recent works by Wang and others found significant effects of self-framing of choice outcomes on risk preference of the decision maker. In the present study, we addressed several unanswered questions. Previous studies showed that a large proportion of the participants use both positive and negative frames to encode expected choice outcomes. Would the difference in the hedonic tone of self frames for different choice options (i.e., sure thing vs. a gamble of equal expected value) affect risk preference of the decision maker? We predicted that the positive hedonic tone of self-framing would increase the attractiveness of the framed option. Thus, the option that was more positively framed would be more likely to be chosen. Second, we examined the mechanism of self-faming effects with regard to how risk perception mediates the effects. We predicted that opportunity and threat perception would mediate the effects of self-framing on risky choice.
    One hundred and sixteen university students participated in the study. Adopting a within-subject design, each participant was provided with three risky choice problems presented in managerial, health, and investment contexts. After viewing a graphic display (pie chart or histogram) of a decision problem, participants discretionally described expected choice outcomes (self framing) in a sentence completion task. For each choice problem, the participants were asked to rate perceived opportunities and threats associated with each of the two options, either a sure thing or a gamble. The participants were then asked to make a choice between a sure-thing option and its gamble equivalent. Chi-square analysis was conducted to test self-framing effects; logistic regression analysis was used to examine the relationship between self-framing, risk (opportunity and threat) perception and risky choice.
    The study found that the hedonic tone of self-framing affected the final choice of the participant: the more positive the hedonic tone of self framing of a choice option (either a sure option or a gamble) was, the more likely the option would be chosen. This effect of self framing was partially mediated by the decision maker’s perception of opportunities and threats.
    This study enriched our understanding of framing effects. When decision makers are allowed to encode and frame the expected outcomes of a risky choice problem by themselves, the small difference in the hedonic tone of self-generated frames of alternative options may influence risk perception and risky choice. That is, the hedonic tone of self-framing as an encoding of decision information affects risk (opportunity and threat) perception, which in turn affects the risk preference and choice of the decision maker
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    Impulsivity in Heroin Abstainers: Reaction Pattern Based on the Delay-Discounting Task and the Iowa Gambling Task
    ZHANG Feng,ZHOU Yan-Yan,LI Peng, SHEN Mo-Wei
    2008, 40 (06):  642-653. 
    Abstract ( 705 )   PDF (2223KB) ( 1568 )  
    Impulsive drug-seeking has been one of typical characteristics of all drug-dependent individuals (Altman et al., 1996; Dawe et al., 2004; Dom, Hulstijn, et al., 2006), and questionnaire assessments based on self-reporting have been essentially taken as the conclusive metrical method of assessing impulsivity in the population. However, due to the varieties of meanings of “impulsivity” (Evenden, 1999; Dougherty et al., 2005), the correlation between the results of self-reporting and those of laboratory tasks has been marginal, or even rather weak (Dom, D’Haene, et al., 2006; Moeller et al., 2001; Reynolds et al., 2006; Dom et al., 2007). Moreover, researchers have pointed out that behavioral measures of impulsivity may be a better predictor of relapse risk than any measure utilizing self-reporting. In laboratory methods used to assess impulsivity, the Delay-Discounting Task (DDT) and Iowa Gambling Task (IGT) have been widely adopted to explore the high impulsivity characteristic of drug-dependent individuals. The DDT was propitious in assessing “myopic” behavior for future values in humans (Green et al., 1994; Rachlin & Siegel, 1994; Kirby & Herrnstein, 1995), but the function of IGT has remained unclear, as is its relationship with that of DDT (Bartzokis et al., 2000; Bechara, 2003; Monterosso et al., 2001; Dom et al., 2007). It is thus assumed in the present study that the high impulsivity characteristic of drug-dependent individuals is not only represented as a hyposensitivity to immediate rewards and an insensitivity to delayed value, but also as an immediate win-priority selection pattern and a tolerance to high risk. The present study explores the impulsive reaction patterns and the relationship in win-risk coincidence situations and delayed reinforcement situations in heroin abstainers in different abstinence phases.
    In the present study, 61 male heroin abstainers (19~38 years old, M=29.25, SD=4.17) in a variety of abstinence phases (1~26 months, M=11.34, SD=7.09) and 32 normal male controls (18~39 years old, M=26.78, SD=7.18) were selected to undertake Chinese computerized versions of the IGT and DDT. In the IGT, subjects had to choose between four decks of cards. Unknown to the subjects, two piles offered high rewards but had potentially high losses, and hence were disadvantageous in the long run. The other two piles offered lower rewards but had much lower losses, and hence offered a net gain in the long run. In the DDT, subjects had to choose between hypothetical monetary rewards available immediately or following a delay. Delayed rewards were ¥1,000 and ¥10,000 in value, and the immediate-reward amount was adjusted until the choices reflected indifference. This process was repeated at each of eight delays (six hours to 25 years).
    The results of the present study showed that (1) reaction patterns for pure win-cards were consistent between heroin abstainers and normal controls; however, the former still preferred to choose high win-cards in spite of potential high punishment, whereas the latter tended to transform the direction of card selection after getting corresponding feedback, to avoid potentially high risks; (2) whether the delayed rewards were ¥1,000 or ¥10,000, the delay-discounting rates (k) of heroin abstainers were much higher than those of normal controls; (3) the delay-discounting rates based on the DDT were not correlated with the decision-making performance (net score) based on the IGT, but the former was partially correlated with the transform ratio of selecting cards after a net loss based on the IGT; and (4) the net score and transform ratio of card selection after a net loss based on the IGT and delay-discounting rates based on the DDT in heroin abstainers did not improve in line with the abstinence time course.
    From the present study, we conclude that (1) the impairment of the decision-making function in win-risk coincidence situations in heroin abstainers was demonstrated in their immediate win-priority selection pattern and tolerance to high risk; (2) the impairment of the decision-making function in delayed reinforcement situations in heroin abstainers was manifested in their hyposensitivity to immediate rewards and their insensitivity to delayed value, which led to a quick decay of long-time value; (3) the IGT was more sensitive to heroin abstainers’ tolerance to risk, while the DDT was more efficient in evaluating their insensitivity to long-term value; both corresponded with two key variables of decision-making—namely, risk and delay; and (4) impulsivity in heroin abstainers did not improve in line with the abstinence time course
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    The Boundary Effect and Its Elimination in Chinese Text Reading: The Event Duration Effect
    HE Xian-You,LIN Chong-De
    2008, 40 (06):  654-661. 
    Abstract ( 511 )   PDF (1412KB) ( 1240 )  
    The boundary effect refers to the phenomenon of the reading time for the first sentence of a new discourse unit being longer than the reading time for any other sentence. This phenomenon was first discovered by Haberland and his colleagues (Haberland K F, Berian C & Sandson J, 1980). Other studies have also found evidences for this effect (Lorch R F, Lorch E P & Matthews, 1985; Bestgen Y & Vonk W, 2000). When reading, readers first try to integrate the new information with preceding information that has just been read and that still remains in the working memory. When a reader experiences difficulty in integrating new information with the preceding information, he/she will conclude that the topic has been changed and that a new mental representation needs to be constructed to lay an integral foundation for the incoming information. To maintain continuity, readers have to reinstate the preceding concept or make coherent inferences and each of these processes increases their cognitive load; at the same time, construction of a new mental representation also needs extra cognitive resources. Therefore, reading speed slows down, and reading time increases. Bestgen and his colleagues explored whether segmentation markers could eliminate this effect. Their results showed that a segmentation marker, for example, “around two o’clock,” could successfully eliminate the boundary effect. However, the segmentation marker in their study did not show the temporal relationship between the markers and the event preceding. In our opinion, when the markers are within the duration time of the event preceding them, boundary effect will be observed; however, when they are not within the duration time of the event preceding them, the boundary effect will be eliminated. This phenomenon is referred to as the event duration effect. In the present study, three experiments were conducted to examine whether the boundary and event duration effects are observed in Chinese text reading.
    A moving window technique was used in the study. Experiment 1 examined whether the boundary effect could be observed in Chinese text reading. A 2(topic continuous/topic shift) × 2(event duration long/short) design was used. Forty-four participants were asked to read 16 topic continuous or topic shift passages, and the reading times for the target sentences were recorded. Experiments 2 and 3 were designed to test whether segmentation markers could eliminate boundary effect. The segmentation marker “half an hour” was located before the target sentences. A 2(topic continuous/topic shift) × 2(event duration long/short) × 2(with/without segmentation marker) design was used. In Experiment 2, 48 subjects were asked to read the passages with or without the segmentation marker. The reading times for the target sentences in the topic continuous condition and topic shift condition were compared. In Experiment 3, the temporal relationship between the segmentation marker and the event preceding was controlled to further test the event duration effect.
    Experiment 1 showed that the reading time for the topic shift condition was significantly longer than that for the topic continuous condition irrespective of the duration of the event. Experiment 2 demonstrated that the reading time for the topic continuous condition did not differ reliably from that for the topic shift condition if there was a segmentation marker before the target sentence. However, the reading time for the topic shift condition was significantly longer than that for the topic continuous condition if there was no segmentation marker. Experiment 3 further replicated the results of Experiment 2 under strict control.
    The results implied that the impact of temporal segmentation markers on the boundary effect depended on the temporal relationship between the markers and the event preceding, a phenomenon referred to as the event duration effect. In other words, when the markers are within the duration time of the event preceding, the boundary effect can still be observed, however, when they are not within the duration time of the event preceding them, the boundary effect is not observed. This shows that segmentation markers reduce the amount of processing required for the part of the sentence that is topic discontinuous
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    Effects of Character Frequency and Preexisting Representation on the Subsequent Memory Effect
    LIU Cong-Hui, GUO Chun-Yan,DING Jin-Hong,YU Guo-Liang
    2008, 40 (06):  662-670. 
    Abstract ( 886 )   PDF (1548KB) ( 1308 )  
    The late positive component (LPC) difference based on later memory performance is called the Dm effect. Many studies have shown that the LPC for items recognized in a subsequent memory test was more positive than for those that were not recognized. This effect was moderated by many factors, such as material type, encoding or orientating tasks, testing format, and study-test relationship. Most of the existing studies found that the low-frequency words showed a greater Dm effect than did the high-frequency words. However, some researchers did not find a significant Dm effect for high-frequency words. In addition, there is no consistency in whether or not access to preexisting representation is a prerequisite for the emergence of the Dm effect. In order to test the hypothesis that the Dm effect depends on accessing preexisting representation and to further explore the role of word frequency in the Dm effect, the present ERP study was designed to investigate the temporal and spatial distributions of the Dm effects for high/low-frequency characters, pseudocharacters, and noncharacters.
    Eighteen healthy undergraduates participated in this study. There were seven blocks in the experiment including three real character blocks and four pseudo and noncharacter blocks. In each real character block, 118 characters (8 filler characters, 12 targets, and 98 study characters) were selected and presented on the screen during the study phase, after which the participants had to perform a test with 98 other additional characters. In each pseudo/noncharacter block, 78 stimuli (7 filler characters, 9 targets, and 62 study pseudo/noncharacter) were presented on the screen during the study phase, which was followed by a test phase with 62 additional pseudo/noncharacters. In each block, the stimuli were randomly presented on the screen for 200 ms. The duration between the onset of a stimulus and the very beginning of the next adjacent trial was randomized between 1400 ms to 1800 ms. The task was to determine whether or not each stimulus presented on the screen was a real character. An electroencephalography (EEG) was recorded continuously using an electro-cap with 119 locations (the extension of the International 10–20 System).
    The results were analyzed using a five-way repeated-measures ANOVA for five time windows: 140~240 ms, 440~500 ms, 500~650 ms, 650~720 ms, and 720~800 ms. The five factors were hemisphere (left, right), location (frontal, temporal, central, parietal, and occipital), electrode, stimuli type (high- and low-frequency character, pseudocharacter, and noncharacter), and recognition (remember and forget). In addition, a three-way repeated-measures ANOVA was used for the central and occipital areas. The three factors were electrode, stimuli type (high- and low-frequency character, pseudocharacter, and noncharacter), and recognition (remember and forget). The ANOVA results indicated that the temporal and spatial distributions of the Dm effects for low-frequency characters were longer and wider than those for high-frequency characters. Moreover, the Dm effect was generally greater for noncharacters than it was for high/low-frequency characters. However, the Dm effect was not observed for pseudocharacters in any interval.
    First, a significant character frequency effect was found in the Dm effect, suggesting that less commonly used characters are processed in a manner that facilitates their subsequent recognition. There might be different neural mechanisms between subsequent memory effects of high- and low-frequency characters. Second, the emergence of a subsequent memory effect may not depend on accessing preexisting representation
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    Neural Distinction between Chinese Nouns and Verbs in the Grammatical Context: An ERP Study
    LIU Tao,YANG Yi-Ming,ZHANG Hui,ZHANG Shan-Shan,LIANG Dan-Dan,GU Jie-Xin', HU Wei
    2008, 40 (06):  671-680. 
    Abstract ( 1472 )   PDF (1859KB) ( 1252 )  
    Many current researches in neurolinguistics focus on the different possible neural representations of nouns and verbs. Evidence from neuropsychological and neuroimaging studies suggests different neural representations of nouns and verbs in Indo-European languages. Specifically, verbs are represented in the frontal region, while nouns are represented in more posterior brain areas. This is consistent with the results of electrophysiological studies. In contrast to other Indo-European languages, Chinese is characterized by the lack of inflectional morphology. Some investigators argued that nouns and verbs in Chinese are not dissociable with regard to grammatical classes but rather are differentiated by their semantic properties. The current study aims to investigate whether noninflectional nouns and verbs in Chinese could be dissociated at the neural level and whether the dissociation reflects their grammatical roles.
    All the nouns and verbs used in the experiments were all words that were not characterized by inflectional morphology. There were three sets of stimuli used in the experiments: (1) disyllabic unambiguous nouns, (2) unambiguous verbs, and (3) noun-verb ambiguous words. These stimuli were combined with a priming word to construct two contrastive phrase contexts, namely, noun-predicting (e.g., “yi Q + _”) and verb-predicting (e.g., “bu M + _”). The subjects were asked to decide whether the presented phrase represented a legal or illegal phrase. ERPs in response to the three sets of stimuli in different contexts were recorded. The ERPs were then analyzed using a repeated-measures ANOVA.
    We observed significant ERP differences between nouns and verbs in intervals of 145~225 ms, 250~400 ms, and 450~650 ms. Unambiguous nouns elicited a larger P200 than did unambiguous verbs. When the context completely matched their role, unambiguous verbs elicited a larger N400 and a smaller P600 than unambiguous nouns. Similarly, ambiguous words used as nouns elicited a larger P600 than did ambiguous words used as verbs.
    Our results do not support the claim that nouns and verbs in Chinese are not dissociable in terms of grammatical classes. On the contrary, the results demonstrated clear ERP responses that reflect a grammatical process. We argue that although the Chinese language lacks inflectional morphology, grammatical features are embedded in nouns and verbs and function regardless of whether there are explicit grammatical signs in these words. Grammatical features play an important role in the neural processing of Chinese nouns and verbs
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    The Mental Scale in Anchoring Effects: Evidence from Event-Related Potentials
    QU Chen,ZHOU Li-Ming,LUO Yue-Jia
    2008, 40 (06):  681-692. 
    Abstract ( 1125 )   PDF (2305KB) ( 1450 )  
    There are two main models accounting for anchoring effects: the anchoring and adjustment heuristic and selective accessibility model. Further, anchors can be externally provided or self-generated. Considering prior studies researchers of the prior studies found that the adjustment heuristic model accounted more for anchoring effects in the case of responding to self-generated anchors, while the SA model accounted more for responses to externally provided anchors. In the present study, a mental scale was first introduced to distinguish the effortful adjustment process from effortless accessibility, using an event-related brain potential (ERP) technique. We hypothesized that the coarseness of the scale would influence the process related to the response to self-generated anchors but not that related to experimenter provided anchors.
    Two ERP experiments on young normal subjects examined the impact of a mental scale on responses to self-generated anchors and externally provided anchors, respectively. We also designed a new paradigm for ERP recording. In Experiment 1, higher or lower numbers as externally provided anchors were presented as cues on the screen; the participants’ task was to estimate the quantity of dots in a target circle, analogous to the two-stage standard anchoring paradigm. In Experiment 2, the cues serving as self-generated anchors were the circles for which the participants had already estimated the number of the dots, analogous to the one-stage anchoring paradigm. Behavioral results and ERP results were collected for statistical analysis.
    Behavioral results validated the effectiveness of the mental scale in diminishing the anchoring bias in the case of responding to self-generated anchors. Adjustment on a coarser scale with fewer categories resulted in a greater skewness from the anchors. Further, ERP results showed a scale effect in the anchoring process even in the case of responding to self-generated anchors too. A positive deflection appeared at 250–800 ms after target onset, and the amplitude of this deflection was more positive in the finer scale condition. Source localization found two free dipoles: one was at the lingual gyrus; the other at the parietal lobe. In the anchoring process, an N300 component was the only component that responded to externally provided anchors and whose amplitude was not influenced by the mental scales. The results of dipole analysis showed that N300 was localized at the cingulate gyrus.
    In conclusion, the two experiments in the present research showed that the manipulation of the mental scale was proficient in anchoring effects only in the case of responding to self-generated anchors, when the true adjustment process was invoked. ERP results provided more evidence of the neural correlate of anchoring effects. An N300 component was related to the accessibility process responding to externally provided anchors, and the positive deflection at 250–800 ms poststimulus, which was modulated by the mental scale, was related to the adjustment process responding to self-generated anchors. In all, our findings provided electrophysiological evidence for the dual nature of anchoring effects. Whether anchoring serves the purpose of adjustment or accessibility is subject to the relevant context, which is consistent with the two-system review. Although anchoring leads to judgment bias, anchoring effects reflect the flexible intelligence of human beings
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    Feedback-related Negativity in Outcome Evaluation with a Deception Task
    SUN Shi-Yue,LUO Yue-Jia
    2008, 40 (06):  693-700. 
    Abstract ( 1882 )   PDF (1398KB) ( 1417 )  
    Outcome evaluation is one of the important functions of the cognitive system. It can provide rapid and efficient information about the outcomes of one’s behavior in order to facilitate the performance of the behavior. Recently, researchers have shown great interest in the neural mechanisms of outcome evaluation. Many studies have confirmed that a significant ERP component—feedback-related negativity (FN)—could be elicited by negative performance feedback compared to positive outcomes. The purpose of this study was to investigate the mechanisms of the outcome evaluation reflected by FN and to explore whether FN is affected by the magnitude information carrying different intensity levels of the expectation.
    To observe the outcome evaluation following complex cognitive processes, a deception task was conducted in a simulated experimental situation involving the identification of currency. The participants were required to identify pictures of genuine Renminbi (RMB) from a set of pictures of fake ones. The participants were asked to press the left key to indicate genuine RMB pictures and the right key to indicate fake ones. However, we told them that for each genuine RMB picture, they could decide whether to “declare” (tell the truth) or “smuggle” (lie) and that telling the truth would result in them receiving a small but certain monetary reward, whereas lying may lead to a potential gain if they escaped being caught or a risk of double penalty if their lie was detected by the software.
    Seventeen healthy undergraduates who had never participated in any electroencephalography (EEG) experiment before volunteered for this study. The EEG was recorded from 64 scalp channels using electrodes mounted in an elastic cap. Feedback-related ERPs were calculated for an 800 ms epoch including a 100 ms pre-feedback baseline. The outcome valences (gain when deception was successful and loss when deception was unsuccessful) by the magnitudes (pictures of the RMB worth 1, 5, and 10) resulted in six waveforms. The brain electrical source analysis (BESA) technique was also adopted in order to estimate the dipole sourcing of FN.
    The ERPs of the truthful condition were obviously distinct from those of the two deceptive conditions. With regard to the deceptive conditions, compared with the “gain” feedback, the “loss” outcomes elicited a more negative deflection at the frontocentral sites in the time windows of 230–450 ms. A repeated-measures ANOVA on the mean amplitudes of this time window revealed significant main effects of the outcome valences and the magnitudes; however, the interaction between these two factors did not reach significance. Further tests indicated that the “loss” outcomes elicited larger FN than did the gain outcomes and the magnitudes did not affect the FN. Finally, sourcing analysis showed that FN may be generated from brain regions near the anterior cingulated cortex (ACC).
    These results suggested that the FN was sensitive to the valance rather than the magnitude of the outcome information. This finding is in agreement with the contemporary theories of outcome evaluation as well as the developed concept of the “adaptive critic” in the reinforcement learning error-related negativity (ERN) hypothesis, which suggested that FN reflected a binary evaluation of good versus bad outcomes based on whether the outcomes were consistent with the expectation

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    The Development of Behavioral Inhibition in Chinese Children From 2 to 7 Years of Age
    HOU Jing, CHEN Hui-Chang,CHEN Xinyin
    2008, 40 (06):  701-708. 
    Abstract ( 2045 )   PDF (1533KB) ( 1885 )  

    Behavioral inhibition is one of the most important dimensions of temperament that has a pervasive and long-term impact on individual personality and social functioning. The present study examined the stability of behavioral inhibition, based on laboratory observations, in a sample of children in China from two to seven years of age.
    The participants in the initial study included 124 children at two years. Among them, 103 participated in a follow up study at four years, and 100 at seven years. There were 113 children who took part in the laboratory observation at least once at 2, 4 and 7 years, and the complete longitudinal sample consisted of 89 children.
    The results indicated that the stability of behavioral inhibition of Chinese children from 2 to 7 years was generally weak. From 2 to 7 years, 31.5% (28) of the children were classified as the stable group and 68.5% (61) as the unstable group. With the increase of age from 2 to 7 years, there was a tendency for children in the extremely inhibited and uninhibited groups to change toward the middle group. However, from 2 to 4 years, behavioral inhibition in the extreme groups was more stable than that in the middle group. There was no sex difference in the behavioral inhibition from 2 to 7 years. The results might be related to the influence of the macro-level social and cultural changes in the society

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    The Effects of Enriched Environment on Structural Modification of Synaptic Interface and PSD-95 mRNA of Rats after Transient Focal Cerebral Ischemia
    YE Ling-Jing,XU Xiao-Hong,WANG Ya-Min,ZHANG Jing,
    FU Ji-Qiang,ZHONG Pu-Feng,ZHU Ting
    2008, 40 (06):  709-716. 
    Abstract ( 1794 )   PDF (1340KB) ( 882 )  
    Reports have shown that damage to the adult brain can result in adaptive changes in regions adjacent to or surrounding the site of the principal injury, and that these changes may be modulated by rehabilitation training. An enriched environment has been shown to improve the cognitive, behavioral, and histopathological outcomes following focal cerebral ischemia and head trauma. Morphological changes in areas adjacent to the injury site have been reported following damage to the adult brain. In transient global cerebral ischemia, changes are observed in neuronal and non-neuronal cells in the regions that surround the primary injury site, including dendritic restructuring, reactive changes in glia, reactive synaptogenesis, and enhanced neurogenesis. The purpose of this study was to investigate the effects of an enriched environment on the structural modification of synaptic interface and PSD-95 mRNA of rats following transient focal cerebral ischemia, and elucidate the underlying mechanism.
    Seventy adult male Sprague-Dawley rats (weight: 250~300 g) were included in this study. A transient ischemic model of rats was established by occluding the right middle cerebral artery (MCAO) with a nylon filament (diameter 0.234 mm). Three days following ischemia or sham surgery, the rats were randomly assigned to the following environmental conditions for 14 days: enriched environment housing (ischemia enriched environment (IE) and sham enriched environment (SE)) or standard environment housing (ischemia standard environment (IS) and sham standard environment (SS)). In order to observe (a) the changes in learning and memory and (b) the ultrastructure of the frontal cortex and hippocampus of the rats following focal cerebral ischemia, the Morris water maze test and transmission electron microscopy, and morphological measurements, respectively, were used in the present study. Simultaneously, the expression of PSD-95 mRNA was measured by RT-PCR.
    The results of the water maze revealed that although cerebral ischemia significantly damaged the ability of spatial learning and memory, environmental enrichment significantly improved the memory damage induced by cerebral ischemia. Meanwhile, environmental enrichment restrained the reduction of the synaptic density caused by cerebral ischemia, particularly in the frontal cortex. Further, environmental enrichment also reversed the changes in synaptic interface parameters caused by cerebral ischemia at different levels, particularly increasing the thickness of postsynaptic density and decreasing the synaptic cleft width. Furthermore, environmental enrichment significantly up-regulated the expression of PSD-95 mRNA in the ipsilateral cortex and hippocampus of MCAO rats.
    These results suggest that the enriched environment significantly promoted spatial learning and memory in MCAO rats. The amelioration of structural modification of the synaptic interface and up-regulation of the expression of PSD-95 mRNA were also involved
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    Effects of Psychological Stress on the Hsp70 Expression and Apoptosis of the Peripheral Blood Lymphocytes in Rats
    YAN Jun,CHEN Ai-Guo,HU Mao-Zi
    2008, 40 (06):  717-722. 
    Abstract ( 1779 )   PDF (1024KB) ( 964 )  
    Heat shock proteins (HSP) represent a very conservative family of cytoprotective proteins that are specifically induced in response to several environmental stresses at the cellular level (heat shock, cellular energy depletion, oxidative stress, or inflammation). Among these proteins, the inducible form of the 70 kDa family, i.e., Hsp72, plays an important role in cytoprotection by preventing the abnormal folding of newly synthesized polypeptides, or by assisting in the repair of damaged proteins or in the degradation of irreversibly damaged proteins. An adapted stress response in terms of transcription and translation of Hsp70 is necessary to ensure cell survival under stressful conditions. Lymphocytes apoptosis plays an important role in the immune function. It is now well documented that acute psychological stress, particularly when it reaches high intensity, leads to high Hsp70 expression and lymphocytes apoptosis. Relatively fewer studies have been conducted on the effects induced by chronic psychological stress on Hsp70 expression in lymphocytes, and the relation between Hsp70 expression and lymphocytes apoptosis. The aim of this study is to investigate the effect of psychological stress on Hsp70 expression, lymphocytes apoptosis, and the relationship between them.
    Twenty-four SD rats were randomly divided into three groups of eight as follows: control group (C), high intensity psychological stress group (H), and moderate intensity psychological stress group (M). A flow cytometer detected the extent of apoptosis and hsp70 expression in the peripheral blood lymphocytes of rats under psychological stress of varying intensity. One-way ANOVA and correlation analysis were used for the statistical analysis.
    In comparison with group C, the Hsp70 expression in lymphocytes groups H and M was significantly higher. The extent of apoptosis in group H increased significantly, while the extent of apoptosis in group M did increase, but not significantly. The positive correlation between the changes of Hsp70 expression and the lymphocytes apoptosis in group M was significant, while the correlation for group H was positive, but not significantly.
    This study suggested that chronic psychological stress, especially that of high intensity, increased the Hsp70 expression and the lymphocytes apoptosis in peripheral blood lymphocytes. Furthermore, as the intensity of psychological stress increases, the Hsp70 expression in lymphocytes increased slowly while the extent of apoptosis increased rapidly. As a result, the immune function kept deteriorating
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    Effects of Chronic Immobilization Stress on the Expression of Fas/FasL in the Brain of Rats
    ZHU Wan-Er,ZHANG Rong,HU Chang-Chun,DONG Feng-Quan,WU Li-Xia,CHEN Zhi-Yun2
    2008, 40 (06):  723-728. 
    Abstract ( 1934 )   PDF (903KB) ( 1132 )  
    Currently, there exists a substantial body of evidence suggesting that chronic stress can increase susceptibility to diseases such as depression and posttraumatic stress disorder. Chronic stress induces neuronal atrophy and death in the cortex as well as in the hippocampus. Proto-oncogene protein kinase B (PKB), also known as Akt, plays a central role in a signaling pathway whose various components have been linked to cellular survival. In recent years, Akt as well as one of its downstream targets Forkhead transcription factors (forkhead homologue in rhabdomyosarcoma, (FKHR)) and the Fas/FasL system have emerged as cardinal pathways underlying cellular survival and opposing apoptosis in neurons. In our previous experiments, we observed that repeated immobilization stress exposure can change the levels of phosphorylation of Akt and FKHRL1 in the rat hippocampus. However, the activation of the Fas/FasL system following chronic stress in the brain remains poorly defined. We hypothesized that repeated immobilization stress exposure may change the levels of the Fas/FasL system in the brains of rats. The purpose of the present study was to detect the effects of chronic immobilization stress on the expression of Fas/FasL in the prefrontal cortex, entorhinal cortex, and hippocampus in rats.
    Twenty four male Sprague-Dawley rats (280 ± 20 g) were purchased from Shanghai Laboratory Animal Center, Chinese Academy Sciences, and they were used for all experiments. These rats were randomly divided into three groups—the immobilization stressed group, apparatus control group, and control group. Each group comprised eight rats. The rats were housed in groups of four, under standard laboratory conditions in temperature-controlled rooms (24℃), and maintained under a 12-h light/dark cycle (lights on at 0800 hours) with food pellets and water available ad libitum. Rats from the immobilization stressed group were immobilized by fixing a board on their backs for an hour each day for 14 consecutive days. The apparatus controls were placed in a novel environment for an hour per day for 14 consecutive days. The controls were free of stress. At the end of the experimental period, the rats were decapitated and their prefrontal cortex, entorhinal cortex, and hippocampi were rapidly removed and maintained at &#8722;80℃ until analysis. The protein levels of Fas and FasL were determined by Western blotting. The intensities of the bands corresponding to the protein of interest were quantified using scanning densitometry and compared using one-way ANOVA. The adrenal gland and thymus gland indices were also calculated on the day following the 14-day-stress modeling. Organ index = wet weight/weight of rat × 100. The statistical significance was determined at p < 0.05.
    A total of 24 rats were considered in the analysis of the results. The body weight gain of the stressed group was significantly lower than that of the control group and the apparatus control group. A significant change was observed in the organ indices of the stressed groups as compared to the control group. The Fas and FasL levels of the hippocampus revealed a significant difference among three groups (F = 26.9, p < 0.001; F = 40.29, p < 0.01, respectively). The Fas and FasL levels were significantly increased in the immobilization stressed group than in the control group (p < 0.01). The Fas levels of the prefrontal cortex and entorhinal cortex in the immobilization stressed group were significantly increased than those in the control group (p < 0.01). In contrast, the FasL levels of the prefrontal cortex and entorhinal cortex did not reveal a significant deference between the immobilization stressed group and control group.
    The results suggested that chronic immobilization stress can induce a more significant increase in both the Fas and FasL levels in the hippocampus. Changing the expression of Fas/FasL may be an effective biological predictor for the change of structure or function of hippocampus induced by chronic stress in rats
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    Appropriate Standardized Estimates for Moderating Effects in Structural Equation Models
    WEN Zhong-Lin, HAU Kit-Tai ,Herbert W. MARSH
    2008, 40 (06):  729-736. 
    Abstract ( 2355 )   PDF (1162KB) ( 2728 )  
    The analyses of interactions or moderating effects are very important in psychological, behavioral and management researches. The exogenous (predictors) and endogenous (outcomes) constructs in these studies can be simple manifest variables or latent factors (made up of several observed indicators). The present paper discusses the standardized estimates of the models with moderating effects.
    Standardized estimates are routinely used to summarize the results of multiple regression models of manifest variables and structural equation models (SEM) of latent variables because they facilitate interpretation and comparison. Although the typical standardized estimates of moderating effects are not appropriate for multiple regression models with moderating terms, straightforward alternatives are well known. Whereas the analogous problem exists for the estimation of latent moderating effects in SEM, the situation is more complicated and apparently the difficulty has not been resolved. Here we propose appropriate standardized parameter estimates which can be easily formulated from the raw and completely standardized estimates routinely available from existing SEM software packages.
    It can be derived that for a structural equation with an moderating term , the appropriate standardized parameters , , should be , , , where , and are the usual completely standardized estimates of , and , while and are the raw estimates of the variances of , and . Both , , and , are available from commercial SEM softwares.
    Some scale invariant properties of the appropriate standardized estimates are described, including that the main and moderating effects are scale invariant. That is, irrespective of the metric (e.g., meter, centimeter) we use for the measurement, the appropriate standardized parameter estimates are identical. These desirable properties of the appropriate standardized estimates are illustrated with a simulation data set using the unconstrained approach to estimate the latent moderating effects. The results support the use of the appropriate standardized estimates in interpreting and comparing SEM estimates in latent moderating effect models.
    Although the difficult mathematical derivation is a bit beyond most applied SEM users, the ultimate procedures to obtain the appropriate standardized estimates are quite simple and straightforward, easily accomplished in a hand-held calculator or Excel spreadsheets. We demonstrate how applied users can obtain the appropriate standardized parameter estimates for models involving latent moderating terms
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    Research on Computerized Adaptive Testing that Allows Reviewing and Changing Answers

    CHEN Ping,DING Shu-Liang

    2008, 40 (06):  737-747. 
    Abstract ( 953 )   PDF (1798KB) ( 1043 )  
    In the past decade, some paper-and-pencil (P&P) tests have been replaced by computerized adaptive testing (CAT) within many large-scale standardized testing programs. However, many researches and applications on CAT had limitations because most of the CAT did not allow examinees to review and change their answers. Among the operative CAT applications, there was only one that incorporated item review. Not allowing examinees to review and change their answers would result in test pressure and affect their performances. Moreover, a majority of examinees manifested a clear preference for item review because they believed that the inclusion of item review made the test fairer and considered it to be a disadvantage if review was disallowed. The CAT test organizers did not allow examinees to review and change answers mainly because they were apprehensive that examinees would use the deceptive Wainer strategy in the review stage to obtain positively biased ability estimates, consequently affecting the fairness and precision of the test. If we could provide a solution that not only allowed examinees to review and change answers but that was also able to deal with the Wainer strategy, the meaning would be great for the development of CAT. Until now, there have been few relevant studies on this topic worldwide. Moreover, the previous studies had a nonnegligible disadvantage, in that the researchers only recorded the answers of the review stage and used them as a basis for scoring, without considering the answers of the adaptive stage. We assumed that comprehensively considering the answers before and after review could produce a more accurate ability estimation. Therefore, this paper employed a new scoring method and attempted to deal with the Wainer strategy:

    This study involved two experiments. Experiment 1 used the Monte Carlo method to simulate the entire process of CAT that allows the reviewing and changing of answers, with the aim of investigating the influence of different beta values on ability estimation. Experiment 2 used simulation data generated by the Monte Carlo method to evaluate the effectiveness of the Wainer strategy and attempted to deal with the strategy by using a new scoring method.
    The simulation results of Experiment 1 indicated the following. First, comprehensively considering the answers before and after review did produce a more accurate ability estimation, and the most accurate estimates occurred when beta = 0.50. Second, the share of examinees who changed their answers was 66.80%; further, 6.40% of the answers were changed, and 75% of the modified answers represented changes from incorrect to correct answers. Experiment 2 indicated the following: When using the new scoring method, the ability estimates generated by the CAT involving the use of the Wainer strategy obviously diverged from the true ability values. Moreover, the bias increased as the true ability value increased.
    The new scoring method employed in this study was not able to effectively deal with the Wainer strategy because of the abnormal ability estimates and abnormal estimated standard error. However, through a simulation experiment, we found the following: When beta = 0, comprehensively considering the expected a posteriori (EAP) and maximum likelihood estimation (MLE) ability estimates of CAT involving the use of the Wainer strategy succeeded in roughly dealing with the Wainer strategy. Our future task involves developing a more accurate method to deal with the Wainer Strategy
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    “Mind” and “Psychology” in the Chinese Context
    ZHONG Nian
    2008, 40 (06):  748-756. 
    Abstract ( 2033 )   PDF (1622KB) ( 1848 )  
    The Chinese viewed psychology as an alien concept. However, words such as “xin” and “xinli” have been used for long in the history of the Chinese language, and the Chinese people’s understanding of these words has reflected their level of knowledge on aspects of the “mind.” After Western psychology was introduced to China, the term psychology in the Chinese language experienced a process of choice, reflecting the modern Chinese scholars’ consideration of mind and psychology. The Chinese perspectives on mind and psychology represent the dialectical relation that the mind is a function of the brain. However, psychology should not be reduced to physiology, as it is not a discipline of brain science.
    Hence, according to the Chinese view, psychology is a discipline that has the characteristics of natural science and social science. In a parallel evolution, the implication of the Chinese word “xin” changed from signifying an internal organ (the heart) to representing thoughts, ideas, affections, dispositions, and morals of people. In this sense, the term “xinlixue” (psychology) in Chinese was more encompassing and conformed to the current definition of psychology as endorsed in international academic circles.
    A discipline cannot be immune to the influence of the society and culture from which it originates, and Chinese psychology is no exception in this regard. It has for long been subject to the impact of ideology, scientism, common sense, and folk psychology. In recent years, Chinese scholars have reflected on the problems surrounding the discipline of psychology, which has evoked a global response from an emerging of “second psychology,” such as cultural psychology. The Chinese people’s understanding of mind and psychology might facilitate the integration of various disciplines of psychology, which in turn might develop a common body of psychology
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    On Pan Shu
    Ye Haosheng,Song Xiaodong
    2008, 40 (06):  757-758. 
    Abstract ( 1147 )   PDF (307KB) ( 1105 )  
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