Effects of binding in the identification of objects

The binding problem requires a solution at the level of individual neurons, but no definite mechanism has yet be given. Therefore, the neuronal level is as yet inadequate for modeling cognitive processes in which binding plays a crucial role. Moreover, the neuronal level involves too many details that are unlikely to be essential for understanding cognition. A general model of cognitive brain functioning is described in which cognitive tasks are represented in a network of cell assemblies. In the network, binding is functionally defined in a way that is compatible with the neuronal level. A computer simulation of the model clarifies how the binding of location and identity of a set of simultaneously presented letters takes place and how questions about the location and identity of the letters are answered. From the simulation of the task three predictions on the logistics of neural processes are derived: 1. When the cell assembly representing a letter participates in more than one temporary excitation loop, it will reach its critical threshold faster. At the behavioral level this means that as the number of identical letters in the display increases, responses will be faster. 2. In order to answer questions about the location and identity of presented letters cell assemblies representing the target location and the target identity have to become bound to their appropriate values. As a consequence the facilitatory effect of identical letters will be stronger if they involve the target location or the target identity than when identical non-targets are involved. 3. Negative identifications are more dependent on the presentation time of the letters than positive identifications because the excitation loops involved take more time to reach the critical threshold. Therefore, the facilitatory effect of identical letters is stronger when the external activation is relatively strong, i.e., when presentation time of the letters is sufficiently long. The reaction times obtained in three behavioral experiments support these hypotheses. Effects of binding can therefore be predicted on the basis of the general logistics of neural processes, without assumptions about a specific binding mechanism at the neuronal level.     

Spatial learning in rats is impaired by microinfusions of protein kinase C-gamma antisense oligodeoxynucleotide within the nucleus accumbens

The nucleus accumbens (NAcc) has been shown to play a role in motor and spatial learning. Protein kinase C (PKC) has been implicated in the mechanisms of initiation and maintenance of long-term potentiation that is thought to be involved in the storage of long-term memory. In the present study, the importance of de novo synthesis of PKC-gamma within the NAcc in the acquisition and retention of spatial discrimination learning was assessed using an antisense knockdown approach. Separate groups of Long-Evans rats were exposed to acute microinfusions (6microg/microl) of PKC-gamma antisense oligodeoxynucleotide (AS-ODN), control oligodeoxynucleotide (C-ODN) or vehicle into the NAcc at 24 and 3h before each training session. Behavioral findings showed that the blockade of NAcc-PKC-gamma translation caused impairments in the early phase of learning and retention of spatial information. Biochemical experiments showed that PKC-gamma expression was reduced and Ca(2+)/phospholipid-dependent protein kinase C (PKC) activity was blocked significantly in the AS-ODN-treated rats in comparison with control rats. The present findings suggest that NAcc-PKC-gamma plays a role during the early acquisition of spatial learning. Also, retention test results suggest that NAcc-PKC-gamma may be working as an intermediate factor involved in the onset of molecular mechanisms necessary for spatial memory consolidation within the NAcc.     

The effect of context on the processing of type-shifting verbs

Recent research in lexical semantics has suggested that verbs such as begin and enjoy semantically select for a complement that denotes an activity or an event. When no such activity or event is specified in the form of a progressive or infinitival complement, as in John began (to read/reading) the book, the verb is said to "coerce" the NP direct object to shift its role to encompass the activity that begin requires as complement (e.g., writing, reading). Empirical support for this view has been provided by McElree, Traxler, Pickering, Seely, & Jackendoff (2001). In the present study, however, in two self-paced reading experiments, type-shifting effects (taken to be longer reading times engendered by the computation of the coercion process) were not obtained with sentences in isolation (Experiment 1) or with sentences embedded in contexts that specified the nature of the activity performed over the complement NP (Experiment 2). It is argued that type-shifting verbs are similar to non-preferred verbs for given contexts and that type-shifting operations are pragmatic inferences computed over underspecified semantic representations.     

Cardiovascular reactivity in hypertensives: differential effect of expressing and inhibiting emotions during moments of interpersonal stress

This study investigated cardiovascular reactivity of hypertensive adults during periods of emotional stress. Two types of instructions were given at different moments, to the same subject, either to express or to suppress feelings during role-play. Expressing, but not inhibiting, emotions elicited significantly higher reactivity during responding to negative scenes, followed by responding during the positive interactions. Blood pressure increases in both expressing and inhibiting conditions, were also found during the instruction periods. Results indicated that socially demanding situations represent a stressor whose effects may vary depending on whether or not respondents regulate expression of emotions. It is suggested that the difficulty in expressing emotions found in some hypertensive individuals may have the function of controlling or reducing blood pressure reactivity.     

Religious identity development of adolescents in religious affiliated schools. A theoretical foundation for empirical research

The question, how religious affiliated schools for secondary education shape religious education and what effects this education has on the religious identity development of pupils, is relevant in a time when the position of religious affiliated schools is highly disputable. In earlier empirical research on religious identity development of adolescence, hardly any attention was paid to the theoretical framework of this question. Therefore, connections are sought with the identity theory of Erikson and with operationalizations of his theory by Marcia and others. The key concepts are ‘exploration’ and ‘commitment’. Religious identity development is seen from a pragmatic perspective in which the transactional relation of individuals and environment is stressed.     

Explicit but not implicit sexist beliefs predict benevolent and hostile sexist behavior

Much work has been carried out on sexist attitudes, but only little on sexist behaviors. The goal of the present research was to close this gap by testing how a variety of benevolent and hostile sexist behaviors correlate with implicit and explicit sexist attitudes. In Study 1 (N = 126), we developed implicit association tests for benevolent sexism and hostile sexism and illustrated that implicit and explicit benevolent sexist beliefs, as well as implicit and explicit hostile sexist beliefs, were positively correlated. In Study 2 (N = 83 of Study 1), we tested whether implicit and explicit benevolent and hostile sexist attitudes correlate with benevolent and hostile sexist behaviors. As expected, explicit benevolent (but not hostile) sexist attitudes predicted benevolent sexist behavior, whereas explicit hostile (but not benevolent) sexist attitudes predicted hostile sexist behavior. Implicit sexist attitudes did not predict sexist behavior. The implications of these findings are discussed.     

大脑两半球功能不对称性与儿童学业成绩

本研究调查了 3 1 8名小学一至三年级学生大脑两半球优势情况 ,然后对不同优势半球学生的语文和数学成绩进行了比较。结果发现优势半球为右半球的学生人数较少 ,只有 3 .8% ,明显少于优势半球为左半球的学生 (χ2 =2 3 9.83 0 ,p<0 .0 0 1 )。对不同优势半球学生的语文和数学成绩的比较 ,未发现两者有显著差异 (语文 :F=1 .1 3 0 ,p>0 .0 5 ;数学 :F=0 .5 75 ,p>0 .0 5 )。     

学习困难儿童的问题解决特点研究

本研究选取学习困难儿童和正常儿童各 3 2名 ,设置河内塔问题解决的情境 ,采用临床观察法 ,对学习困难儿童在问题解决中的特点作了初步的探究。研究发现 :1与正常儿童相比 ,学习困难儿童在发现和有效运用策略方面明显不足 ,但当学习困难儿童对问题情境比较熟悉后 ,有明显的进步 ;2一定的提示并不能帮助学习困难儿童最有效地应用策略。     

Recognizing people seen in events via dynamic "mug shots"

This study examined effects of an event and dynamic mug shots on facial recognition. Witnesses saw either a film of a liquor store holdup staged by six perpetrators, slides of the same targets, or freeze-framed views from the filmed event. Slides of different facial views of targets among 12 foils, or dynamic 180 degrees mug shots of the same men, or multiple static views were administered 24 hr later in yes-no recognition tests. Recognition (d') was poorer for the same men seen in the event than in slides, but better for dynamic than for static mug shots. Nondynamic event characteristics were responsible for poor recognition of people seen in events, whereas dynamic aspects of facial transformations, not multiple views, seemed responsible for the superiority of dynamic mug shots. The implications of these results for issues of ecological validity of traditional face recognition methodology and for static feature models vs. dynamic transformation models of face recognition are discussed.