Asymmetric Reinstatement Effects in Recognition

Our experiment examined two questions: (1) Does reinstating a studied context affect recognition of an associated word, and (2) Does reinstating a studied word affect recognition of an associated context? After encoding 75 words, each of which was shown superimposed over a different 5-sec video of an environment (e.g., a playground, a traffic scene, or a grocery store), participants were asked to recognize 50 of the words and 50 of the video scenes. On the test, half of the studied words were shown superimposed over the same video contexts that had been present at encoding, and half were shown over new scenes. Similarly, videos were presented with either old or new words. Context reinstatement increased hits and reduced false alarms for words, but word reinstatement did not affect recognition of video contexts. The results suggest that the associations that bind word events with their contexts may not be bidirectional.     

Bartlett Revisited: Reconfiguration of Long-Term Memory in Young and Older Adults

This study was performed after the tradition of F. C. Bartlett (1932), who demonstrated that memory reconfigures over time. The authors investigated the memory of young and older adults to examine the degree to which the aging process influences reconfigurative tendencies. From an initial sample of 53 participants, 20 young and 19 older adults completed 6 tests of recall for Bartlett's original text materials over an 84-day period. Consistent with the broad conclusions of Bartlett's study, reconfiguration was observed: Both young and older adults introduced errors into memory. Older adult recall was lower overall than that of young adults, and recall performance diminished over time. However, there was no difference between the performances of young and older adults with respect to incorrectly recalled intrusive elements.     

Maternal Depressed Mood and Perceptions of Child Temperament

Research has suggested that women who experience postpartum depression are subsequently more likely to perceive their preschool-aged children as temperamentally difficult and maladjusted. However, previous studies have not controlled for the effects of concurrent depression levels on maternal ratings of child temperament or evaluated the accuracy of maternal reports. In the present study we assessed maternal and paternal ratings of child temperament 2 years after subjects had participated in a study of postpartum depression. The findings indicate that correlations between postpartum depression and subsequent child temperament ratings were accounted for statistically by concurrent levels of depression. Although fathers' ratings corroborated some aspects of maternal perceptions, levels of parental agreement were only moderately high. Moreover, discrepancies between the parents' reports were significantly associated with maternal depression, indicating that parental disagreement is more likely when the wife is dysphoric.     

Development of Postural Adjustment During Gait Initiation: Kinematic and EMG Analysis

The authors studied the development of postural adjustments associated with the initiation of gait in children by using kinematic and electromyographic (EMG) analysis. Participants (N = 28) included infants with 1-4 and 9-17 months of walking experience, children 4-5 years of age, and adults. Anticipatory postural adjustments (APA) were present in the youngest age groups, including a clear anticipatory lateral tilt of the pelvis and the stance leg, which enabled the child to unload the opposite leg shortly before its swing phase. An anticipatory activation of the hip abductor of the leg in stance phase prior to heel-off was found, suggesting pelvis stabilization. APA did not appear consistently until 4-5 years of age. A decrease in segmental oscillations occurred across the ages, indicating better control of intersegmental coordination in the frontal and sagittal planes during the postural phase of gait initiation. Young walkers presented APA involving movements of both the upper and the lower parts of the body, whereas, like adults, 4- to 5-year-olds were able to laterally shift only the pelvis and the stance leg. The oldest children and the adults also showed lower activation levels of hip and knee muscles but higher activation at the ankle level. Those kinematic and EMG results taken together suggest a clear developmental sequence from an en bloc operation of the body through an articulated operation with maturation, walking experience, or both.     

Sensitivity of Smoothness Measures to Movement Duration,Amplitude, and Arrests

ABSTRACT

Studies of sensory-motor performance, including those concerned with changes because of age, disease, or therapeutic intervention, often use measures based on jerk, the time derivative of acceleration, to quantify smoothness and coordination. However, results have been mixed: some researchers report sensitive discrimination of subtle differences, whereas others fail to find significant differences even when they are obviously present. One reason for this is that different measures have been used with different scaling factors. These measures are sensitive to movement amplitude or duration to different degrees. The authors show that jerk-based measures with dimensions vary counterintuitively with movement smoothness, whereas a dimensionless jerk-based measure properly quantifies common deviations from smooth, coordinated movement.     

Learning Under Conditions of Action Information Feedback

Methodological and empirical issues in research on action information feedback (AIF) are discussed, with particular reference to the procedures and results of Annett (1970). Positioning responses practiced under conditions of AIF training are learned, though generally less well than under terminal IF conditions. Effects obtained as a result of AIF training may be subject to variations in movement extent required, gain and other transformations, frequency, temporal locus, and mode of augmentation, many aspects of which remain to be systematically studied.     

Immediate and Latent Interlimb Transfer of Gait Stability Adaptation Following Repeated Exposure to Slips

The authors trained 21 participants by using blocked-and-mixed exposure to right-side slips and then caused them to slip unexpectedly on the untrained left side. Authors retested participants with a right slip and a left slip at 1 week, 2 weeks, 1 month, and 4 months. The authors found that preslip stability on the first untrained left slip improved and was significantly greater than that on the first right slip, which probably contributed to the reduction in incidence of falls from ~30% to ~10%. Postslip stability and base of support (BOS) slip velocity were similar to those on the first right slip and much lower than those on the last right slip. Increases in pre- and postslip stabilities and BOS slip velocity during the left slip led to reductions in backward balance loss (BLOB) from ~95% on initial left slip to ~60% and to ~25% on the 1st and 3rd retest sessions, respectively. In contrast, BLOB remained at a constant ~40% level on the right slip of the same retest sessions. The results indicate a partial immediate transfer and a possible latent transfer.     

Feedback in Response Recognition and Production

The role of feedback in the development of recognition memory was examined by testing pairs of subjects; one subject performed the movement while the other listened to the movement in an adjacent room. Both groups of subjects developed recognition memory during training with KR, and recognition performance was virtually identical for both groups. In addition, previous experience with the sensory consequences of the movement led to improved response production during initial trials. A possible mechanism to account for this finding is proposed. Appreciation is extended to Richard A. Schmidt and Anne Marie Bird for helpful comments in earlier drafts of this paper.     

Bimanual and Unimanual Convergent Goal-Directed Movement Times

Three experiments are reported, investigating the effects of using 1 or 2 hands when making convergent low index of difficulty (ID) and visually controlled movements (2 hands meeting together). The experiments involved movements in four different cases—a probe held in the right hand and moved to a target held in the stationary left hand, vice versa of this arrangement, both hands moving with the probe in the right hand and target in the left hand, and vice-versa of this arrangement. Experiments were the standard Fitts’ paradigm, moving a pin into a hole and a low-ID task. In Fitts’ task, 2-hand movements were faster than 1 hand only at higher IDs; this was also the case in the pin-to-hole transfer task and the movement times were lower when the pin was held in the preferred hand. Movements made with low ID showed a small effect of 1- or 2-handed movements, with the effective amplitude of the movement being reduced by about 20% when 2 hands were used.     

Perceptual Estimates of Motor Skill Proficiency Are Constrained by the Stability of Coordination Patterns

This study demonstrated that motor skill proficiency ratings are constrained by the same order parameter dynamics that constrain action production and action perception processes. Participants produced rhythmic actions simulated by an animated stick figure of the human arm. The primary finding was that participants’ proficiency ratings covaried most with relative phase (φ) variability compared to mean relative phase. In-phase (φ = 0°) was produced with the least variability and received the highest proficiency rating, whereas the patterns φ = ±150° were attempted with the most variability and received the lowest proficiency ratings. A temporal delay in attempting to produce the animated pattern had a large impact on produced relative phase, yet had little impact on the proficiency ratings. Proprioceptive processes provide individuals information on motor skill proficiency. The lead or lag motion of the hand to forearm segment of the animated arm was identified consistently through visual processes and revealed asymmetries in the mapping of visual input to motor output. The results are consistent with concepts from the dynamic pattern theory of coordination and are discussed with regard to relative phase as an informational variable that constraints the perception-action system across many levels.