Spontaneous configuring in conditioned flavor aversion

A series of experiments investigated spontaneous configuring using the conditioned flavor aversion paradigm with rat subjects. In Experiment 1, extended training of a two-flavor compound stimulus did not produce spontaneous differentiation of conditioned responding to that compound and its elements. In Experiment 2 we found that extended nonreinforced exposure to a compound stimulus generated spontaneous element-compound differentiation when the elements were later conditioned. Rats that received extended preexposure to the compound showed less conditioned responding to the compound than to either of its elements. However, rats that had not received preexposure to the compound showed greater conditioned responding to the compound than to either of its elements (summation). In Experiment 3, nonreinforced preexposure to the compound stimulus prior to minimal reinforced compound training produced spontaneous compound-element differentiation, but extended reinforced compound training eliminated that differentiation. In Experiment 4, extended partial reinforcement training with a compound produced differentiation of the compound from its elements. Implications of these data for the mechanisms responsible for spontaneous configuring and for the summation assumptions common to most learning theories are discussed.     

Sociodemographic Factors Associated with Types of Projects Implemented by Volunteer Lay Health Educators in Their Congregations

This study focused on the association between type of community health interventions and lay health educator variables. Lay health educators are volunteers from local faith communities who complete a healthcare training program, taught by physicians in-training. Lay health educators are instructed to implement health-related initiatives in their respective communities after graduation. Of the 72 graduates since 2011, we surveyed 55 lay health educators to gain insight into their involvement with their congregation and the type of health projects they have implemented. We dichotomized the health projects into “raising awareness” and “teaching new health skills.” Using adjusted logistic regression models, variables associated with implementing health projects aimed at teaching health skills included length of time as a member of their congregation, current employment, and age. These results may help future programs prepare lay health community educators for the type of health interventions they intend to implement in their respective communities.     

Improving specific autobiographical memory in older adults: impacts on mood,social problem solving,and functional limitations

Older adults have difficulty recalling specific autobiographical events. This over-general memory style is a vulnerability factor for depression. Two groups receiving interventions that have previously been successful at reducing over-general memory in depressed populations were compared to a control group. Participants were healthy older adults aged ≥70 years: memory specificity training (MEST; n = 22), life review (n = 22), and control group (n = 22). There were significant improvements in autobiographical memory specificity in the MEST and life review groups at post-training, relative to the control group, suggesting that over-general memory can be reduced in older adults. Change in social problem solving ability and functional limitations were related to change in autobiographical memory specificity, supporting the suggested role of specific retrieval in generating solutions to social problems and maintaining independence. Qualitative analysis of participants’ feedback revealed that life review may be more appropriate for older adults, possibly because it involves integrating specific memories into a positive narrative.     

Nonword repetition stimuli for Vietnamese-speaking children

Nonword repetition (NWR) has been a widely used measure of language-learning ability in children with and without language disorders. Although NWR tasks have been created for a variety of languages, minimal attention has been given to Asian tonal languages. This study introduces a new set of NWR stimuli for Vietnamese. The stimuli include 20 items ranging in length from one to four syllables. The items consist of dialect-neutral phonemes in consonant–vowel (CV) and CVC sequences that follow the phonotactic constraints of the language. They were rated high on wordlikeness and have comparable position segments and biphone probabilities across stimulus lengths. We validated the stimuli with a sample of 59 typically developing Vietnamese–English bilingual children, ages 5 to 8. The stimuli exhibited the expected age and length effects commonly found in NWR tasks: Older children performed better on the task than younger children, and longer items were more difficult to repeat than shorter items. We also compared different scoring systems in order to examine the individual phoneme types (consonants, vowels, and tones) and composite scores (proportions of phonemes correct, with and without tone). The study demonstrates careful construction and validation of the stimuli, and future directions are discussed.     

Stress modulation of cognitive and affective processes

This review summarizes the major discussion points of a symposium on stress modulation of cognitive and affective processes, which was held during the 2010 workshop on the neurobiology of stress (Boulder, CO, USA). The four discussants addressed a number of specific cognitive and affective factors that are modulated by exposure to acute or repeated stress. Dr David Morilak discussed the effects of various repeated stress situations on cognitive flexibility, as assessed with a rodent model of attentional set-shifting task, and how performance on slightly different aspects of this test is modulated by different prefrontal regions through monoaminergic neurotransmission. Dr Serge Campeau summarized the findings of several studies exploring a number of factors and brain regions that regulate habituation of various autonomic and neuroendocrine responses to repeated audiogenic stress exposures. Dr Kerry Ressler discussed a body of work exploring the modulation and extinction of fear memories in rodents and humans, especially focusing on the role of key neurotransmitter systems including excitatory amino acids and brain-derived neurotrophic factor. Dr Israel Liberzon presented recent results on human decision-making processes in response to exogenous glucocorticoid hormone administration. Overall, these discussions are casting a wider framework on the cognitive/affective processes that are distinctly regulated by the experience of stress and some of the brain regions and neurotransmitter systems associated with these effects.     

Multisensory information boosts numerical matching abilities in young children

This study presents the first evidence that preschool children perform more accurately in a numerical matching task when given multisensory rather than unisensory information about number. Three- to 5-year-old children learned to play a numerical matching game on a touchscreen computer, which asked them to match a sample numerosity with a numerically equivalent choice numerosity. Samples consisted of a series of visual squares on some trials, a series of auditory tones on other trials, and synchronized squares and tones on still other trials. Children performed at chance on this matching task when provided with either type of unisensory sample, but improved significantly when provided with multisensory samples. There was no speed–accuracy tradeoff between unisensory and multisensory trial types. Thus, these findings suggest that intersensory redundancy may improve young children’s abilities to match numerosities.     

Age and gender comparisons of driving while sleepy: Behaviours and risk perceptions

To assist road safety professionals in developing effective strategies to combat the risk associated with driving while fatigued, a survey was administered to 1000 Australian drivers. Participants reported their past behaviours in regards to driving while sleepy and their perceptions of risk associated with driving fatigued as compared to speeding and driving under the influence of alcohol. Although participants appeared to be aware of the substantial risk associated with driving while sleepy, many drivers reported that they frequently drive when sleepy. Age and gender comparisons, revealed that risk taking behaviour in regards to driving while sleepy is occurring across all age groups and in both male and female drivers. Overall young to middle age drivers and male drivers reported the highest frequency of driving while sleepy and reported the lowest perceived personal risk in regards to driving while sleepy.     

The influence of associability changes in negative patterning and other discriminations

Normal rats showed faster learning of a serial negative patterning (NP) discrimination (X+, A+, X-->A-) than of a comparable feature negative (FN) discrimination (A+, X-->A-). This advantage was absent in rats with lesions of the amygdala central nucleus. Earlier data indicated that this brain lesion interferes with surprise-induced increases in attention specified by the Pearce-Hall model (J. M. Pearce & G. Hall, 1980). In the NP task, but not the FN task, omission of the reinforcer after X on X-->A- trials was surprising. A variation of the NP task (NPX), in which X was reinforced on both X+ and X-->A- trials, was learned more rapidly than the NP task. Lesioned rats were unimpaired in learning the NPX task. Evaluation of the lesion effects and the results of posttraining transfer tests suggested that the NP advantage involved attentional processes, whereas the NPX advantage was based on the acquisition of inhibitory control by aspects of excitation conditioned to X.     

Weber's Law influences numerical representations in rhesus macaques (Macaca mulatta)

We present the results of two experiments that probe the ability of rhesus macaques to match visual arrays based on number. Three monkeys were first trained on a delayed match-to-sample paradigm (DMTS) to match stimuli on the basis of number and ignore continuous dimensions such as element size, cumulative surface area, and density. Monkeys were then tested in a numerical bisection experiment that required them to indicate whether a sample numerosity was closer to a small or large anchor value. Results indicated that, for two sets of anchor values with the same ratio, the probability of choosing the larger anchor value systematically increased with the sample number and the psychometric functions superimposed. A second experiment employed a numerical DMTS task in which the choice values contained an exact numerical match to the sample and a distracter that varied in number. Both accuracy and reaction time were modulated by the ratio between the correct numerical match and the distracter, as predicted by Weber's Law.