When knowing more means less: the effect of fan on metamemory judgments

The authors used a "fan" paradigm (J. R. Anderson, 1974) to test the accessibility and competition models of metamemory using judgments of learning (JOLs). JOLs in this study reflect one's confidence level in subsequently recognizing newly learned material. The number of facts, or "fan," associated with JOL-queried concepts varied from 1 to 3 associates. Results of 3 experiments indicated that as the level of fan increased, the magnitude of JOLs decreased. This finding was observed even when the fan effect (i.e., slower recognition as number of facts increase) was attenuated on a verification task in 2 of the experiments by manipulating the organization of the multiple concepts. The results supported the competition hypothesis (T. A. Schreiber, 1998; T. A. Schreiber & D. L. Nelson, 1998) as an important determinant of JOLs.     

Left-side dominance for song discrimination in Bengalese finches (Lonchura striata var. domestica)

Male Bengalese finches are left-side dominant for the motor control of song in the sensorimotor nucleus (the high vocal center, or HVc) of the telencephalon. We examined whether perceptual discrimination of songs might also be lateralized in this species. Twelve male Bengalese finches were trained by operant conditioning to discriminate between a Bengalese finch song and a zebra finch song. Before training, the left HVc was lesioned in four birds and the right HVc was lesioned in four other birds. The remaining four birds were used as controls without surgery. Birds with a left HVc lesion required significantly more time to learn to discriminate between the two songs than did birds with a right HVc lesion or intact control birds. These results suggest that the left HVc is not only dominant for the motor control of song, but also for the perceptual discrimination of song. Accepted after revision: 11 September 2001 Electronic Publication     

Acquisition of auditory–visual intermodal matching-to-sample by a chimpanzee (Pan troglodytes): comparison with visual–visual intramodal matching

A chimpanzee acquired an auditory–visual intermodal matching-to-sample (AVMTS) task, in which, following the presentation of a sample sound, the subject had to select from two alternatives a photograph that corresponded to the sample. The acquired AVMTS performance might shed light on chimpanzee intermodal cognition, which is one of the least understood aspects in chimpanzee cognition. The first aim of this paper was to describe the training process of the task. The second aim was to describe through a series of experiments the features of the chimpanzee AVMTS performance in comparison with results obtained in a visual intramodal matching task, in which a visual stimulus alone served as the sample. The results show that the acquisition of AVMTS was facilitated by the alternation of auditory presentation and audio-visual presentation (i.e., the sample sound together with a visual presentation of the object producing the particular sample sound). Once AVMTS performance was established for the limited number of stimulus sets, the subject showed rapid transfer of the performance to novel sets. However, the subject showed a steep decay of matching performance as a function of the delay interval between the sample and the choice alternative presentations when the sound alone, but not the visual stimulus alone, served as the sample. This might suggest a cognitive limitation for the chimpanzee in auditory-related tasks. Accepted after revision: 11 September 2001 Electronic Publication     

Contextual learning induces an increase in the number of hippocampal CA1 neurons expressing high levels of BDNF

We examined behaviorally induced expression of brain-derived neurotrophic factor (BDNF) in area CA1 of the hippocampus. Sprague-Dawley rats were trained in a contextual fear conditioning (CFC) task, sacrificed 4h later, and their brains were processed for immunohistochemistry. We found distinctively high levels of BDNF immunoreactivity in a small number ( approximately 1%) of CA1 neurons in untrained animals. The number of these exceptional neurons, which are identified as BDNF(++) in this study, was increased by up to approximately 3% after CFC. This increase was blocked in the presence of a memory-impairing dose of a NMDA receptor antagonist (MK801 0.3 mg/kg, i.p.) given 30 min prior to training. The BDNF signal intensity in BDNF(++) neurons correlated with that of surrounding glutamic acid decarboxylase (GAD) 65. This correlation between GAD65 and BDNF signal intensities suggests that BDNF upregulation was associated with increased signaling via inhibitory GABAergic synapses that would lessen further intervening neuronal activity. Our observation that neurons which upregulate BDNF expression following a learning experience are rich in GAD65-enriched afferent synapses suggests that these neurons may have distinct roles in memory consolidation.     

Judgments of associative memory

Judgments of associative memory (JAM) were indexed by ratings given to pairs of cue and response words. The normed probabilities, p(response|cue), were obtained from free association norms. The ratings were linearly related to the probabilities. The JAM functions were characterized by high intercepts ( approximately 50 on a 100 point scale) and shallow slopes (<0.5). The JAM function generalized across materials and method of rating. The function was not affected by expectancies or semantic similarity. Attempts to alter the function by making alternative responses more available were unsuccessful. A computer simulation model (MINERVA 2) exhibited the linear JAM function and successfully accounted for more complex phenomena (like the joint influence of forward and backward associative strengths on ratings). The shallow JAM slope appears to result from a fundamental lack of discrimination among associative strengths. The high intercept appears to result partly from an independent post-mnemonic source of bias producing over-estimation of association.     

Intervening with Multiplication Fact Difficulties: Examining the Utility of the Instructional Hierarchy to Target Interventions

Examining the use of conceptual frameworks such as the instructional hierarchy (IH) to drive academic interventions represents an important area of inquiry in order to understand why an intervention was effective. However, to date, the IH has only been examined retroactively to explain the effectiveness of math interventions and has not been used to drive intervention implementation based on students’ needs. Therefore, the current study used a multiple baseline single-case design to examine the utility of the IH to determine an appropriately targeted acquisition (incremental rehearsal) or proficiency (timed drill) intervention for difficulties with multiplication facts. Students first received the contraindicated intervention (i.e., non-targeted) and then their correctly targeted intervention. Results showed that all students demonstrated greater fluency growth during their targeted intervention and that students in need of an acquisition intervention also demonstrated greater multiplication fact retention and growth rate during their targeted intervention. The utility of the IH as a heuristic to correctly target interventions based on students’ baseline skill levels is discussed.

     

A Study of the Conceptual Structure of Growth Mindsets and Their Impact on Self-Improvement Motivation

This study examined the conceptual structure and motivational effects of growth mindsets based on the perspective of character strengths. An internet survey was conducted with 1,000 workers (500 males and 500 females; age range 20–59 years, M = 40.1 years, SD = 10.7 years). Participants were presented with 25 strengths (i.e., intelligence and 24 character strengths) and were asked to rate their perceived competence, growth mindset, and improvement intention for each strength. The exploratory factor analyses on perceived competence, growth mindset, and improvement intention identified five common factors: wisdom, willpower, temperance, transcendence, and groupness. Moreover, regression analyses indicated that a growth mindset was more strongly related to improvement intention than perceived competence. Furthermore, regression analyses found domain-specific effects of growth mindsets on improvement intention. Thus, the intention to improve a particular strength was more closely related to that particular growth mindset than to other growth mindsets. The theoretical and educational implications are aired in the discussion section.     

The phenomenology and temporal distributions of autobiographical memories elicited with emotional and neutral cue words

In this study we examined whether the temporal distribution of autobiographical memory changes when different types of cue words are used to elicit the memories, and how the type of cue word affects the phenomenal characteristics of the memories. A total of 76 participants, ranging in age from 21 to 69 years, were presented with 22 cue words (emotional, emotion-provoking, and neutral). They were asked to recall a personal event and to complete the Autobiographical Memory Questionnaire (Rubin, Schrauf, & Greenberg, 2003, 2004) for each cue word. Results showed that the phenomenological properties of autobiographical memories which were cued with emotional and emotion-provoking words were rated higher than those of memories which were cued with neutral words, and that the peak in the temporal distributions of the autobiographical memories that were cued with emotional or emotion-provoking words were located later than the peak of the distribution of the memories that were cued with neutral words.     

Anxiety and heart rate variability before sleep indicate chronic stress in students

The purpose of the present study was to investigate the effect of chronic stress on the first-night effect in terms of autonomic nervous system activity and anxiety. Participants (N = 11; M age = 20.3 yr., SD = 0.47) included six with high stress (High stress group) and five with low stress (Low stress group), for whom all EEG data were available from three consecutive nights. Heart rate variability was calculated using the MemCalc method. The ratio of low to high frequency of heart rate variability before sleep onset in the High stress group on the first night indicated significantly higher activities than the ratio before sleep onset in the Low stress group. No significant difference in sleep latency was found between the two groups. However, the High stress group was more aware of anxiety than was the Low stress group, and the former estimated more subjective difficulty in falling asleep. These results suggest that measuring LF/HF before sleep may constitute a new way to assess chronic stress.