Memory retrieval by 18--30-month-olds: age-related changes in representational flexibility

Deferred imitation was used to trace changes in memory retrieval by 18-30-month-olds. In all experiments, an adult demonstrated 2 sets of actions using 2 different sets of stimuli. In Experiments 1A and 1B, independent groups of infants were tested immediately or after a 24-hr delay. Each infant was tested with 1 set of stimuli from the original demonstration and 1 set of stimuli that was different. Recall of the target actions when tested with different stimuli increased as a function of age, particularly after a delay. In Experiment 2, infants were provided with a unique verbal label for the stimuli during the demonstration and the test. The verbal label facilitated performance by 24-month-olds tested with different stimuli but had no effect on performance by 18-month-olds. One hallmark of memory development appears to be an age-related increase in the range of effective retrieval cues for a particular memory.     

A seven-decimal table of the area (a) under the unit normal curve,for abscissae expressed in terms ofP.E.

A seven-decimal table is presented of the area under the unit normal curve, for abscissae expressed in terms of the “probable error” orPE. From the method of calculation, the partial verification by means of other tables, and the safeguards taken in the routine of computation, it is safe to consider the table reliable. Errors in previously published tables are pointed out.     

Sex and generational differences in desired characteristics in mate selection

This study compared the ranking of 18 personal characteristics or qualities which college students might use in selecting a future mate and builds on six other assessment periods from 1939-1996 which dealt with this issue. Among the most consistent findings for all seven assessment periods is the high value both sexes place on dependable character, emotional stability/maturity, pleasing disposition, and mutual attraction/love. Men across all assessment periods placed a higher value than women on good health, good cook/housekeeper, and good looks, while women placed a higher value on ambitious/industrious, similar educational background, and good financial prospect. These trends could go along with ethological theory. For both sexes chastity and similar religious background gained value; however, this may be an artifact of the current sample of 100 students.     

Context effects on lexical choice and lexical activation

Speakers are regularly confronted with the choice among lexical alternatives when referring to objects, including basic-level names (e.g., car) and subordinate-level names (e.g., Beetle). Which of these names is eventually selected often depends on contextual factors. The present article reports a series of picture-word interference experiments that explored how the designated target name (basic level vs. subordinate level) and contextual constraints rendering the name alternative either appropriate or inappropriate affect lexical activation and lexical choice. The experimental data demonstrate clear context effects on the eventual lexical choice. However, they also show that alternative nonselected object names are phonologically activated, even if a constraining context makes these alternative names currently inappropriate.     

Disseminating a smokeless tobacco cessation intervention model to dental hygienists: a randomized comparison of personalized instruction and self-study methods.

This study evaluated 2 methods of disseminating an empirically validated smokeless tobacco intervention delivered during routine dental care. Twenty cities within 12 states were stratified and then randomized to 1 of 3 groups: personalized instruction (PI), self-study (SS), or delayed training (DT) control. Dental hygienists in the SS condition were sent a manual and video. Those in the PI condition were recruited to attend a workshop. Thirty-seven percent of eligible hygienists agreed to participate. At 12 months postenrollment, hygienists in the SS and PI conditions significantly increased their "Assist" behaviors (discuss cessation techniques, help patient set a quit date, and provide cessation materials) and reported fewer perceived barriers to delivering the intervention as compared with hygienists in DT. An economic analysis suggests that SS is more cost-effective than PI.     

Kindling-induced changes in plasticity of the rat amygdala and hippocampus

Temporal lobe epilepsy (TLE) is often accompanied by interictal behavioral abnormalities, such as fear and memory impairment. To identify possible underlying substrates, we analyzed long-term synaptic plasticity in two relevant brain regions, the lateral amygdala (LA) and the CA1 region of the hippocampus, in the kindling model of epilepsy. Wistar rats were kindled through daily administration of brief electrical stimulations to the left basolateral nucleus of the amygdala. Field potential recordings were performed in slices obtained from kindled rats 48 h after the last induced seizure, and in slices from sham-implanted and nonimplanted controls. Kindling resulted in a significant impairment of long-term potentiation (LTP) in both the LA and the CA1, the magnitude of which was dependent on the number of prior stage V seizures. Saturation of CA1-LTP, assessed through repeated spaced delivery of high-frequency stimulation, occurred at lower levels in kindled compared to sham-implanted animals, consistent with the hypothesis of reduced capacity of further synaptic strengthening. Furthermore, theta pulse stimulation elicited long-term depression in the amygdala in nonimplanted and sham-implanted controls, whereas the same stimulation protocol stimulation caused LTP in kindled rats. In conclusion, kindling differentially affects the magnitude, saturation, and polarity of LTP in the CA1 and LA, respectively, most likely indicating an activity-dependent mechanism in the context of synaptic metaplasticity.     

Bayesian eggs and Bayesian omelettes: reply to Stern (2005)

In this response to Stern's (2005) discussion of Klugkist, Laudy, and Hoijtink (2005), model inference based on posterior probabilities on the parameter space is discussed. Furthermore, the authors respond to Stern's example in which all possible orderings are included via a short discussion of exploratory versus theory-based modeling. Finally, the authors show that the Bayesian approach is flexible and can deal with many types of constraints. This is illustrated using a model with constraints on the differences between means.     

Factor structure of the Beck Depression Inventory in a university sample

Factor analysis was performed on the Beck Depression Inventory with a university sample to examine its potential multidimensionality. A principal components analysis with an oblimin and varimax rotation produced a two-factor solution. These factors were labeled Cognitive-Affective and Physiological and accounted for approximately 39% of the common variance. This finding is consistent with multidimensionality of the inventory and with a similar study of college students. The commonalities of the two studies suggest the reliability (internal consistency) of the Cognitive-Affective and Physiological constructs among "minimally" depressed university samples.     

The cognitive and neural architecture of sequence representation

The authors theorize that 2 neurocognitive sequence-learning systems can be distinguished in serial reaction time experiments, one dorsal (parietal and supplementary motor cortex) and the other ventral (temporal and lateral prefrontal cortex). Dorsal system learning is implicit and associates noncategorized stimuli within dimensional modules. Ventral system learning can be implicit or explicit It also allows associating events across dimensions and therefore is the basis of cross-task integration or interference, depending on degree of cross-task correlation of signals. Accordingly, lack of correlation rather than limited capacity is responsible for dual-task effects on learning. The theory is relevant to issues of attentional effects on learning; the representational basis of complex, sequential skills; hippocampal-versus basal ganglia-based learning; procedural versus declarative memory; and implicit versus explicit memory.