Consensus effects in categorization decisions

A previous study (Gilat et al., J. Exp. Psychol. Appl. 3 (1997) 83) has shown that the incentive to reach consensus can raise the tendency to rely on base rates in signal detection decisions and can reduce the probability that less likely events will be accurately classified. This phenomenon was named the “consensus effect”. The current study assesses the conditions under which this effect develops and in particular the effects of information about the game and of the incentive structure on the learning process. The results of three experiments show that the learning process slows when participants have information about the actual state of nature. This finding is captured by a reinforcement learning model with the assumption that information narrows the distribution of the initial propensities for choosing among cutoffs. The results are further evidence for the utility of the combination of learning models and analyses of cognitive processes for the prediction of decision making in situations involving multiple players.     

Evidence for the substantia nigra pars compacta as an essential component of a memory system independent of the hippocampal memory system

The aim of the present study was to test if the nigrostriatal pathway is an essential component for a water maze cued task learning and if it works independently of the hippocampal memory system. This hypothesis was tested using an animal model of Parkinson's disease in which male Wistar rats were lesioned in the substantia nigra pars compacta (SNc) by the intranigral infusion of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), thus causing a partial depletion of striatal dopamine. SNc-lesioned and sham-operated animals were implanted bilaterally with guide cannulae above the dorsal hippocampus in order to be tested after the administration of 0.4 microl 2% lidocaine or saline into this structure. The animals were tested in a spatial or in a cued version of the water maze, memory tasks previously reported to model hippocampal-dependent spatial/relational and striatal-dependent S-R learning, respectively. Hippocampal inactivation, but not SNc lesion, impaired learning and memory in the spatial version of the water maze. An opposite situation was observed with the cued version. No significant interaction was observed between the SNc lesion and hippocampal inactivation conditions affecting scores in the spatial or in the cued version of the water maze. These results suggest that the nigrostriatal pathway is an essential part of the memory system that processes S-R learning and that it works independently of the hippocampal memory system that processes spatial/relational memories.     

Is perseveration caused by inhibition failure? Evidence from preschool children's inferences about word meanings

Four studies examined the relation between children's cognitive inhibition and flexibility in a lexical inference task. Children's linguistic flexibility was assessed by the Flexible Induction of Meaning (FIM) test (Deák, 2000a), which requires that children shift inferences about the meanings of several words for novel objects. In Study 1, 54 3-year-olds either were trained between blocks of problems, for a delay of 3 min, or received no training or delay. Training delays did not influence perseveration. In Study 2 (N=72 3- and 4-year-olds') novel word problems were grouped either to increase the frequency of cue switches (i.e., reduce response "set") or minimize the interval between problems about the same objects. Again, no effect was found. In Study 3, 48 3- and 4-year-olds completed 6 preliminary trials; in a high interference group these trials generated a response set to be inhibited upon the first switch to a new cue context. This group did not perseverate more than a control group. There was no association between FIM perseveration and a Stroop-like test of verbal inhibition though both were marginally related to receptive vocabulary. In study 4 (48 3- and 4-year-olds), FIM was again unrelated to Stroop performance, but was related to the ability to tell whether a situation or problem is indeterminate. Thus, flexibility across semantic inferences is not influenced by timing, order, and number of pre-switch problems and is not predicted by individual differences in a test of verbal inhibition. However previously reported age and individual differences in flexible induction of word meanings are robust and related to vocabulary and logical ability.     

“What Button Do I Press?” the Consequences of Conducting a Service Learning Project with Senior Citizens

In an effort to build interest in the two-year old service learning center and to fulfill its mission to integrate academic life with service in thoughtful and relevant ways, a competition was held to award developmental grants to faculty to create innovative courses incorporating service learning. The winning proposal from the business school used a business ethics course as the vehicle for formally introducing service into the business curriculum. This paper will tell the story of the intended and unintended consequences of building collaboration on several levels: between generations, between college and community, between faculty and college resources, between student teams, and between theory and practice.     

学习困难学生认知加工机制的研究

采用两因素混合实验设计,在严格控制条件下,比较了学困生和学优生在工作记忆容量上的差异,并在此基础上引入提示程序进一步探讨,学困生ＷＭ容量低主要是由存贮能力造成的还是由加工效率造成的或是两者时起作用的问题。     

A Review Of Geraldine Jonçich's The Sane Positivist: A Biography Of Edward L. Thorndike

This book review, unfinished at the author's death, examines in historical context Thorndike's law of effect, his Animal Intelligence monograph of 1898, and related works on learning and behavior.     

Thorndike's Puzzle Boxes And The Origins Of The Experimental Analysis Of Behavior

The year of Thorndike's dissertation on animal intelligence, 1898, may mark the beginning of the field that eventually became known as the experimental analysis of behavior. The dissertation began a major shift in thinking about animal and human learning, provided important methodological innovations, and carried the seeds of later research and theory, particularly by B. F. Skinner. Although Thorndike was an associationist in 1898, the dissertation began the systematic search for fundamental behavioral processes, and laid the foundation for an empirical science of behavior.     

Personalized System Of Instruction In Cyberspace

Four different undergraduate psychology courses with no allotted classroom time slots were taught in the same term by means of a computer-based version of Keller's personalized system of instruction (PSI), called computer-aided personalized system of instruction (CAPSI). Students' performance and ratings indicate that CAPSI is a viable on-line educational method.     

Facilitation of Sodium Aversion Learning in Sodium-Deprived Rats

Two experiments with rats explored the effects of sodium deprivation induced by furosemide injections upon acquisition of taste aversion to sodium chloride (NaCl). In Experiment 1, rats under either sodium deprivation or a balanced nutrition condition were given access to a limited amount of NaCl solution prior to poisoning. When all rats were tested under sodium repletion, the previously sodium-deprived rats consumed less NaCl than did the nondeprived rats. This finding was replicated in Experiment 2A in which ingestion of a compound solution of NaCl and hydrochloric acid (HCl) was followed by poisoning. Consumption of HCl, however, showed the opposite pattern: the sodium-deprived rats drank more HCl than did the nondeprived rats, a result that was replicated in Experiment 2B. These results suggest that sodium deprivation strengthens the salience of NaCl, thereby facilitating acquisition of aversion to this taste and strongly overshadowing that to a simultaneously presented taste.     

The Neural Basis of Motor-Skill Learning

Recent work indicates that motor-skill learning is supported by four processes: a strategic process that selects new goals of what to change in the environment, a perceptual-motor integration process that adjusts to new relationships between environmental stimuli and the appropriate motor response, a sequencing process that learns sequences of motor acts, and a dynamic process that learns new patterns of muscle activations. These four processes can operate in one of two modes: an unconscious mode, in which one is aware only of the goal of the movement, or a conscious mode, in which one consciously controls detailed aspects of the movement. This article provides an overview of these four processes and two modes, and describes their neural bases.