Treadmill Gait Analysis Characterizes Gait Alterations in Parkinson's Disease and Amyotrophic Lateral Sclerosis Mouse Models

The effect of anxiety on learning and performance of a complex motor task was determined. In addition the effects of two stressors—competition and failure—and the interactions between these stressors and anxiety were investigated. 40 high and 40 low anxiety Ss (selected by the Taylor Manifest Anxiety Scale) learned and performed a coincident timing task. Competition was presented by offering the Ss a monetary reward for the best performance, while failure was manipulated by giving false knowledge of results and indicating that the performance level was inferior. Results showed that Ss low in anxiety performed significantly better than Ss high in anxiety during the initial learning of a complex motor task. No difference was found between Ss extreme in anxiety once the task was well-learned. Competition and failure did not affect performance or interact with the anxiety level of Ss.     

Age differences in integration of components of a motor task.

To study effects of practice on the ability of 6-, 11-, and 18-yr.-old Ss to integrate the components of the Rho task 3 groups of 50 boys performed 30 consecutive trials. (a) With practice all age groups improved in total movement time; (b) 11-yr.-old Ss attained the 18-yr.-olds' level of performance in both components, initial differences existing only the linear component; (c) relative to the 18-yr.-old Ss, the 6-yr.-olds achieved proportionally less improvement in the linear component; (d) unlike 11- and 18-yr.-old Ss, the 6-yr.-olds evidenced increasing specificity of task components across trials. Unlike the two older age groups, the 6-yr.-old Ss were unable to achieve a high degree of integration of task components. The findings were discussed in light of Pascual-Leone's neo-Piagetian model of learning and development.     

Oral and visual presentation and production of original responses.

Verbal originality scores were obtained from Onomatopoeia and Images, Form 1B, given to 106 Ss aged 10 to 12 yr. and 94 Ss aged 16 to 19 yr. The older Ss scored significantly higher than the younger Ss with significant main effects for age, but not for method of word presentation. A significant interaction was found between word presentation method and age. Older Ss were more original with the oral presentation while the younger Ss performed approximately the same with both methods.     

Efficiency of Learning as a Function of Practice Schedule and Initial Ability

2 groups of 50 Ss practiced a pursuit rotor skill under different schedules of practice. A massed practice (MP) group (40 sec. work, 20 sec. rest) performed just as well as a distributed practice (DP) group (20 sec. work, 20 sec. rest) on the first day of practice. However, after 24 hr. of interpolated rest MP Ss demonstrated significantly greater amounts of learning. A further analysis of the 15 high initial ability and 15 low initial ability Ss from each of the two main groups resulted in no statistical differences among these subgroups in Day 1 performance that could be attributed to the practice schedules; however, a significant Ability Level × Practice Schedule interaction was obtained for Day 2 performance. It was caused by the low ability Ss under MP learning relatively more than the high ability Ss under MP when compared to the two DP groups. Thus learning was seen as being a function not only of schedule of practice but also of initial ability level.     

Processing of ambiguous and unambiguous feedback by depressed and nondepressed college students: schematic biases and their implications for depressive realism

Explored schematic processing as a mechanism for predicting (a) when depressed Ss would be negative relative to nondepressed Ss and (b) when depressed and nondepressed Ss would show biased or unbiased (i.e., "realistic") processing. Depressed and nondepressed Ss performed multiple trials of a task under conditions in which the two groups held either equivalent or different schemas regarding this task. Ss received either an unambiguous or objectively normed ambiguous feedback cue on each trial. In full support of schematic processing, depressed Ss showed negative encoding relative to nondepressed Ss only when their schemas were more negative, and both depressed and nondepressed Ss showed positively biased, negatively biased, and unbiased encoding depending on the relative feedback cue-to-schema match. Depressed and nondepressed Ss' response latencies to unambiguous feedback also supported the occurrence of schematic processing. We discuss the methodological, treatment, and "realism" implications of these findings and suggest a more precise formulation of Beck's schema theory of depression.     

An objective test of goodness of fit of the continuous strength model in STM

The continuous strength model of recognition memory was evaluated in a task where Ss were tested for recognition of 10-number lists using a rating procedure. Maximum likelihood estimates of the parameters of the model were obtained by an iterative method on a high-speed computer, and a chi-square goodness-of-fit test was performed for individual Ss. For 15 of 20 Ss, the chi-square values were nonsignificant, p < .05, indicating that the model provided a good fit to the data. Although the model gave a good fit to the data, the Δm measure of sensitivity was highly correlated with a true recognition score computed by subtracting false alarmsfrom correct recognitions.     

Stimulus information and stimulus interference in bisensory short-term memory

An attempt was made to determine if Ss’ strategy of retaining stimulus material changed under conditions of bisensory simultaneous stimulation when one of the two inputs was relevant information as opposed to interference. Thus in Group 1 Ss were stimulated bisensorily, attended to both inputs (information), but recalled only one input. Ss in Group 2 were stimulated bisensorily, attended to only one input, and recalled only that input (interference). It was found that S’s efficiency of recall was decreased in the information condition (Group 1) but strategy was not altered. In both groups, Ss performed similarly; performance was in turn similar to that observed in the typical bisensory situation, i.e., where both channels are recalled.     

Perceptual dependence: Evidence for an internal threshold

Ss were asked to make two forced-choice discriminations on each trial: in Experiment I, they had to tell on which side of the display a latter pair appeared and whether or not its members were identical; in Experiment II, to say where the pair appeared and whether it consisted of Xs or Os; in Experiment III, to say where a letter appeared and whether it rhymed with E; and in Experiment IV, to say whether a letter pair was presented and whether it was a word. In Experiment III, and for some Ss in Experiment I, the second discrimination was dependent on the first; that is, when the S was wrong on the first, he performed at chance level on the second. In Experiment IV, when Ss indicated that nothing was presented (with confidence), they performed at chance level on the recognition task; thus, recognition was dependent upon some information about the detection task. It is argued that perceptual dependence implies that a threshold state, a state in which the S has no information, exists for the dependent discrimination. One explanation of dependence assumes mediation of the dependent discrimination by a processing stage which succeeds stages mediating the other task.     

Asymmetry of doubt in medical self-diagnosis: the ambiguity of "uncertain wellness".

In 2 studies Ss received a clear or an unclear diagnosis, indicating either disease or no disease. In Experiment 1, Ss responded to a hypothetical bacteria test. In Experiment 2, Ss performed 2 saliva tests purportedly measuring risk for pancreatic disorders. Responses to the unclear well diagnosis were unique in several ways. Ss thought the test more invalid, inferred a greater likelihood of illness from a 2nd identical result, saw the disorder as more pernicious, and held no self-protective beliefs about the test or the disease. Moreover, desire for treatment among these Ss was as great as among those receiving a clear diagnosis of illness. Possible mechanisms are discussed, as are potential applications to clinical issues and to the development and maintenance of hypochondriacal health concerns.     

A comparison of auditory monitoring performance in blind subjects with that of sighted subjects in light and dark

Two experiments were performed in which blind Ss, sighted Ss working in the dark, and sighted Ss working in the light were compared as to their efficiency on an auditory watchkeeping task. Absolute and differential auditory thresholds were measured in both experiments, and in the second experiment the groups also underwent a signal detection session under alerted conditions. There was some inconsistency as to relative performance of the sighted groups, but in both experiments the blind Ss were superior on the auditory watchkeeping task as to signals detected and effective sensitivity (d’). 1 This difference was not attributable to a difference in auditory sensitivity or to a criterion adopted for     

Individual differences in power functions for a 1-week intersession interval

Two experiments examined correlations of the power function exponents of individual Ss obtained in each of two sessions. Half the Ss for any task performed second sessions immediately after the first, the other half after a week’s delay. In Experiment I, groups of 16 Ss gave magnitude estimations of apparent area, or else of area and loudness. In Experiment II, groups of 16 Ss made cross-modality matches of apparent time duration to area. Significant correlations in all cases indicated consistent and persisting S differences in exponents. The results are related to the findings of other studies of such individual differences.     

Categorization of disoriented faces in the cerebral hemispheres of normal and commissurotomized subjects

We examined the capacity of the cerebral hemispheres to process faces that deviate from canonical perspective. In Experiment 1, normal Ss performed a gender categorization of faces presented at varying angular orientations in the left visual field (LVF) or right visual field (RVF). Orientation affected processing speed, more so in the RVF than in the LVF. The function relating reaction times to disorientation of the faces was approximately monotonic and reflected the increased difficulty in extracting relevant configurational information as the faces were rotated from canonical perspective. In Experiment 2, 3 commissurotomized Ss performed the same task. They responded above chance in the 2 visual fields, and the pattern of their results was similar to that obtained with the normal Ss, but the effect of disorientation was considerably more pronounced. It is suggested that the right hemisphere contribution becomes more critical the further the visual pattern departs from conventional view. Issues regarding the specification of processes correcting for disorientation and comparison of normal and commissurotomized Ss are discussed.     

Verbal and visuospatial recall by younger and older subjects: use of matched tasks

In this study, 18 older (over age 65, M = 75.61 years) and 18 younger (below age 40 and over age 17, M = 26.44 years) healthy volunteers were tested on verbal and visuospatial recall. Tasks were matched on discriminating power. Older Ss performed worse than younger Ss on both tasks. The older Ss also showed a larger deficit in visuospatial than in verbal recall, relative to the younger Ss. These results are consistent with the theory of aging according to which verbal tasks are more resistant to deterioration than are nonverbal tasks. A psychological explanation based on lifetime experience with verbal material is preferred over the physiological explanation advocating faster aging of the right hemisphere.     

Subject differences in cross-modality matching

Forty-eight Ss performed four tasks each: (1) magnitude estimation of area, (2) magnitude estimation of numerousness, (3) cross-modality matching of force of handgrip to area, and (4) cross-modality matching of force of handgrip to numerousness. An additional 48 Ss performed Tasks 2 and 4. Psychophysical power functions were fitted to the data of each S for each condition. Higher correlations between individual exponents were found for conditions employing a common response (i.e., estimating or squeezing) than were found for conditions with the same set of stimuli. Individual differences among exponents stem more from the idiosyncratic use of the dependent variable than from different sensory characteristics.     

Switching attention between the ears to monitor tones Nigel Harvey

Alternating dichotic presentation of tones was compared with monaural presentation in two different perceptual tasks. When Ss were asked to detect higher frequency target tones in fists of six background tones, they missed less than 5%. However, when the presentation was fast (10/sec) and the tones alternated dichotically, Ss reported “hearing” only three or four tones. In two further experiments, Ss were asked to judge the number of tones or to report their spatial and temporal positions; these tasks were much less accurately performed, for the dichotic lists, than the target detection task. The differing effects of switching rate on these tasks are discussed in relation to the types of processing they require.     

Affect and stereotyping: the effect of induced mood on distinctiveness-based illusory correlations.

In 2 studies, the effects of mood on the formation of distinctiveness-based illusory correlations were examined. After exposure to stimuli inducing positive, neutral, or negative mood, Ss read information about behaviors performed by members of 2 groups in an illusory correlation paradigm. In both experiments, only Ss in a neutral mood formed illusory correlations. In addition, Experiment 2 assessed Ss' processing latencies as a means of investigating differential attention to distinctive behaviors. Only Ss in a neutral mood differentially attended to the minority group's infrequent behaviors. Induced mood apparently interfered with the processing necessary to differentially encode distinctive stimuli, undermining the illusory correlation effect.     

Depressive deficits in memory: focusing attention improves subsequent recall.

Ss diagnosed as depressed, recovered from depression, or without a history of depression performed an unintentional learning task, followed by tests of free and forced recall. In the learning task, Ss decided whether a series of nouns sensibly completed corresponding sentence frames that varied in decision difficulty. For half of the Ss, the focus of attention was unconstrained by the demands of this task. The others, however, were required to repeat the targeted noun at the end of the trial as a means of focusing their attention on the task. Depressed Ss in the unfocused condition subsequently recalled fewer words than did both control groups, but this deficit disappeared in the focused condition. These results suggest that depression might not fundamentally impair the resources required for good performance on such tasks. The results' relevance to resource-allocation, initiative, and inhibition accounts of depressive deficits in memory is discussed.     

Observations with self-embedded sentences using written aids

Self-embedded sentences of any degree beyond one are permitted by the syntactic rules of English, yet previous studies report that Ss typically reject these sentences as being ungrammatical and, in addition, often cannot recover the meaning of these sentences. The present paper investigated the possibility of introducing specially structured self-embedded sentences as “aids” to the discovery of the structure of more complex self-embedded sentences. The group of Ss who received these aids performed significantly better in discovering the subject-verb and subject-object assignments in the complex sentences (many achieved perfect scores) in contrast to Ss who did not initially receive these aids (these latter Ss obtained close to the minimum possible scores).     

Self-perception and characteristics of premanipulation attitudes: A test of Bem’s theory

In a study to provide evidence for the assumption of self-perception theory that premanipulation attitudes are not salient to postmanipulation phenomenology, Bem and McConnell (1970) performed two forced-compliance experiments. One experiment was a typical forced-compliance experiment in which Ss indicated their postmanipulation attitudes. In the other experiment, the Ss were asked to recall their premanipulation attitude after the essay writing task. It was found that the recall ratings were essentially the same as the postmanipulation attitude ratings. The present study was a partial replication of the Bern and McConnell experiment. The results of this study indicate that premanipulation attitudes are salient to the postmanipulation phenomenology of Ss for whom these attitudes are highly relevant.     

Age-related changes in cardiovascular response as a function of a chronic stressor and social support.

The effects of aging, chronic stress, and social support on cardiovascular functioning were examined using a cross-sectional design. Thirty-six family caregivers of Alzheimer's disease victims and 34 control Ss performed 2 active coping tasks while continuous noninvasive measures of cardiovascular activity were monitored. Results revealed that caregivers high in social support displayed typical age-related decreases in heart-rate reactivity, whereas caregivers low in social support displayed age-related increases in heart-rate reactivity. Analyses further indicated that only Ss with low social support were characterized by age-related increases in systolic blood pressure. These results suggest that social support can moderate age-related changes in cardiovascular functioning, particularly in Ss exposed to a chronic stressor.