The ontogeny of relational memory and pattern separation

Episodic memory relies on memory for the relations among multiple elements of an event and the ability to discriminate among similar elements of episodes. The latter phenomenon, termed pattern separation, has been studied mainly in young and older adults with relatively little research on children. Building on prior work with young children, we created an engaging computer‐administered relational memory task assessing what‐where relations. We also modified the Mnemonic Similarity Task used to assess pattern discrimination in young and older adults for use with preschool children. Results showed that 4‐year‐olds performed significantly worse than 6‐year‐olds and adults on both tasks, whereas 6‐year‐olds and adults performed comparably, even though there were no ceiling effects. However, performance on the two tasks did not correlate, suggesting that two distinct mnemonic processes with different developmental trajectories may contribute to age‐related changes in episodic memory.     

Relative salience of syllable structure and syllable order in zebra finch song

There is a rich history of behavioral and neurobiological research focused on the ‘syntax’ of birdsong as a model for human language and complex auditory perception. Zebra finches are one of the most widely studied songbird species in this area of investigation. As they produce song syllables in a fixed sequence, it is reasonable to assume that adult zebra finches are also sensitive to the order of syllables within their song; however, results from electrophysiological and behavioral studies provide somewhat mixed evidence on exactly how sensitive zebra finches are to syllable order as compared, say, to syllable structure. Here, we investigate how well adult zebra finches can discriminate changes in syllable order relative to changes in syllable structure in their natural song motifs. In addition, we identify a possible role for experience in enhancing sensitivity to syllable order. We found that both male and female adult zebra finches are surprisingly poor at discriminating changes to the order of syllables within their species-specific song motifs, but are extraordinarily good at discriminating changes to syllable structure (i.e., reversals) in specific syllables. Direct experience or familiarity with a song, either using the bird’s own song (BOS) or the song of a flock mate as the test stimulus, improved both male and female zebra finches’ sensitivity to syllable order. However, even with experience, birds remained much more sensitive to structural changes in syllables. These results help to clarify some of the ambiguities from the literature on the discriminability of changes in syllable order in zebra finches, provide potential insight on the ethological significance of zebra finch song features, and suggest new avenues of investigation in using zebra finches as animal models for sequential sound processing.     

Measuring motor speed through typing: a surrogate for the finger tapping test

Motor speed is an important indicator and predictor of both cognitive and physical function. One common assessment of motor speed is the finger-tapping test (FTT), which is typically administered as part of a neurological or neuropsychological assessment. However, the FTT suffers from several limitations, including infrequent in-person administration, the need for a trained assessor and dedicated equipment, and potential short-term sensory–motor fatigue. In this article, we propose an alternative method of measuring motor speed, with face validity to the FTT, that addresses these limitations by measuring the interkeystroke intervals (IKI) of familiar and repeated login data collected in the home during a subject’s regular computer use. We show significant correlations between the mean tapping speeds from the FTT and the median IKIs of the nondominant (r = .77) and dominant (r = .70) hands, respectively, in an elderly cohort of subjects living independently. Finally, we discuss how the proposed method for measuring motor speed fits well into the framework of unobtrusive and continuous in-home assessment.     

Perceived past, present, and future control and adjustment to stressful life events

Perceived control is a central construct in psychology and is key to understanding individual differences in poststress outcomes (Frazier, Berman, & Steward, 2001). The goals of the current studies (using 4 samples of undergraduate students, total N = 1,421) were to examine the relations between different aspects of perceived control and poststress outcomes and to differentiate perceived control over specific events from related constructs (i.e., general control beliefs, coping strategies). To accomplish these goals, we first developed a new measure of perceived past, present, and future control over stressful life events. The data supported the content validity, factor structure, internal consistency and test-retest reliability, and convergent and discriminant validity of the new measure. Consistent with the temporal model of control (Frazier et al., 2001), these 3 forms of control had very different relations with adjustment. Present control was consistently related to lower distress levels in cross-sectional, longitudinal, and prospective analyses. Present control also predicted outcomes beyond the effects of general control beliefs and coping strategies. Past and future control had nonsignificant or positive relations with distress, although future control was associated with better outcomes (i.e., course grades) when the stressor was controllable. Thus, our measure can be used to assess the relations between perceived past, present, and future control and outcomes across a range of stressors. Because the relations between these 3 forms of control and outcomes differ markedly, measures that combine these aspects of control hinder the understanding of the important role of perceived control in adjustment to stress.     

Two rooms,two representations? Episodic‐like memory in toddlers and preschoolers

Episodic memory involves binding together what‐where‐when associations. In three experiments, we tested the development of memory for such contextual associations in a naturalistic setting. Children searched for toys in two rooms with two different experimenters; each room contained two identical sets of four containers, but arranged differently. A distinct toy was hidden in a distinct container in each room. In Experiment 1, which involved children between 15 and 26 months who were prompted with a very explicit cue (a part of the hidden toy), we found a marked shift in performance with age: while 15‐ to 20‐month‐olds concentrated their searches on the two containers that sometimes contained toys, they did not distinguish between them according to context, but 21–26‐month‐olds did. However, surprisingly, without toy cues, even the youngest children showed a fragile ability to disambiguate the two containers by room context. In Experiment 2, we tested 34‐ to 40‐month‐olds and 64‐ to 72‐month‐olds without toy cues. The 5‐year‐olds were nearly perfect, and the 3‐year‐olds showed a significant preference for the correct container given only the context. In Experiment 3, we filled in the age range, and also investigated the effects of the use of labels (i.e. names of experimenters and rooms) and of familiarization time, in groups of 34‐ to 40‐month‐olds, 42‐ to 48‐month‐olds, and 50‐ to 56‐month‐olds. Neither labels nor familiarization time had an effect. Across experiments, there was regular age‐related improvement in context‐based memory. Overall, the results suggest that children's episodic memory may undergo an early qualitative change, yet to be precisely characterized, and that continuing increments in the use of contextual cues occur throughout the preschool period. A video abstract of this article can be viewed at https://www.youtube.com/watch?v=DkwEFw0UEz4&list=PLwxXcOKHPC0llAPVcJyW4EtzlA934A2Rz&index=1