Birth month and suicide among major league baseball players

We examined the association between month of birth and completed suicides among major league baseball players (N = 76). More than twice as many players born in August committed suicide (N = 19) than any other birth month. This association was statistically significant when birth month was corrected for differences in days of the month. The differences were even larger when expressed in terms of birth month for those committing suicides divided by number of major league players born in each month. The association between birth month and suicide raises the possibility that prenatal factors may influence the inclination for suicide later in life.     

The "birthday blues" in a sample of major league baseball players' suicides

Among 74 major league baseball players known to have committed suicide, 17 occurred within 28 days of the players' birthdays as compared to an expected number of 11.4.     

A functional modulation for timing a movement: a coordinative structure in baseball hitting

In baseball hitting, a powerful bat-swing needs to be produced by utilizing ground reaction force (GRF) and it should also be temporally coordinated relative to the flight of the pitch. The temporal organization of hitting movements associated with these task requirements was investigated by analyzing GRF during hitting slow and fast pitches. The timing of stepping with a front foot and shifting weight forward was modulated relative to the pitch's speed. The temporal relation between successive motion phases was compensatory and timing variability progressively reduced up to ball-bat contact. These results demonstrated the coordinative structure of the hitting movement for timing the bat-swing relative to the pitch's flight.     

Perception-action coupling and anticipatory performance in baseball batting

The authors examined 10 expert and 10 novice baseball batters' ability to distinguish between a fastball and a change-up in a virtual environment. They used 2 different response modes: (a) an uncoupled response in which the batters verbally predicted the type of pitch and (b) a coupled response in which the batters swung a baseball bat to try and hit the virtual ball. The authors manipulated visual information from the pitcher and ball in 6 visual conditions. The batters were more accurate in predicting the type of pitch when the response was uncoupled. In coupled responses, experts were better able to use the first 100 ms of ball flight independently of the pitcher's kinematics. In addition, the skilled batters' stepping patterns were related to the pitcher's kinematics, whereas their swing time was related to ball speed. Those findings suggest that specific task requirements determine whether a highly coupled perception-action environment improves anticipatory performance. The authors also highlight the need for research on interceptive actions to be conducted in the performer's natural environment.     

Manual laterality in nonhuman primates: a distinction between handedness and manual specialization

This article examines individual and group manual lateralization in nonhuman primates as a function of task's demands. It is suggested to distinguish low- from high-level manual activities with respect to the novelty variable and to the spatiotemporal scale of the movements. This review shows that low-level tasks lead to (a) symmetrical distributions of hand biases for the group and (b) manual preferences that are not indicative of the specialization of the contralateral hemisphere. In contrast, behaviors expressed in high-level tasks (a) show asymmetrical distribution of hand biases for the group and (b) seem to be related to a specialization of the contralateral hemisphere. Two types of lateralization, handedness and manual specialization, correspond to the 2 levels of tasks that are distinguished.     

Laterality briefed: laterality modulates performance in a numerosity-congruity task

It is widely agreed that irrelevant numerical values are automatically activated. However, automatic and intentional activations may give rise to different numerical representations. We examined processing of symbolic and non-symbolic (i.e., numerosity) representations asking whether they differ in automatic and intentional processing. Participants were presented with two-dimensional displays containing repetitions of a digit and were asked to report, in different blocks, whether the digit or numerosity was smaller or larger than 5. Incongruent trials differed either in laterality between the relevant and irrelevant dimensions (i.e., the location of both dimensions in reference to the midpoint 5) or in numerical distance between dimensions. Congruency affected performance regardless of symbolic or non-symbolic presentation. For incongruent trials, laterality (not distance) affected performance, again regardless of presentation. This implies that automaticity does not mean similar processing of relevant and irrelevant dimensions. Specifically, the relevant dimension is processed elaborately whereas the irrelevant dimension is processed crudely.     

Frequency-dependent performance and handedness in professional baseball players (Homo sapiens)

I used data on handedness and pitching and hitting performance in annual cohorts of professional baseball players (1957-2005) to test the hypothesis that handedness among pitchers was subject to negative frequency-dependent selection. As predicted by this hypothesis, right-handed pitchers were more successful (i.e., opposing batters hit more poorly against them) when they were relatively rare in the population. Contrary to the predictions of this hypothesis, however, left-handed pitchers were more successful when they were relatively common. Both right- and left-handed batters performed better in years dominated by right-handed pitchers, despite the fact that right-handed batters perform relatively poorly against right-handed pitchers. I suggest that batters form cognitive representations based on pitcher handedness, and that these representations are strengthened by repeated exposure or priming. When the pitcher handedness polymorphism is more balanced (e.g., 67% right-handed, 33% left-handed), these cognitive representations are less effective, which leads to decreased batting averages and improved performance by all pitchers. Furthermore, these cognitive representations are likely to be more critical to the success of right-handed hitters, who have reduced visuomotor skills relative to left-handed hitters.     

Catching moods and hitting runs: mood linkage and subjective performance in professional sport teams

Are the moods and subjective performances of professional sports players associated with the ongoing collective moods of their teammates? Players from 2 professional cricket teams used pocket computers to provide ratings of their moods and performances 3 times a day for 4 days during a competitive match between the teams. Pooled time-series analysis showed significant associations between the average of teammates' happy moods and the players' own moods and subjective performances; the associations were independent of hassles and favorable standing in the match. Mood linkage was greater when players were happier and engaged in collective activity. An intraperson analysis of data from these teams and 2 other teams showed that mood linkage was also greater for players who were older, more committed to the team, and more susceptible to emotional contagion. The results support and extend previous findings concerning mood linkage.     

Manual performance in the cold with gloves and bare hands

Previous research aimed at quantifying and reducing the decrements encountered in performing manual tasks in cold weather has not described the relationships between task characteristics and cold-induced impairments. The amount of decrement and, often times, the optimal means for reducing the decrement, appear to be task-specific. The research reported here is one in a series of studies formulated to explore those relationships. The strategy is to use tasks from the battery developed by Fleishman (1967) to measure the factorially 'pure' abilities needed to perform all manual tasks. 24 U.S. Marines performed this battery of nine tasks across a range of cold temperatures. To determine if the decrement due to wearing gloves might be less than the decrement due to cold hands as the air temperature decreased, performance on the battery of tasks was measured with and without gloves. Only three of the tasks (abilities) were affected by cold temperatures, and the amount of decrement increased as the air temperature decreased. Three tasks deteriorated due to wearing of gloves, two of those affected by cold and one other. Temperature affected performance independently of the glove effect. Half of the subjects did not complete bare-handed testing at -18 degrees C (approximately 20 min.), indicating this is the lower end of the temperature range in which bare-handed performance for more than a few minutes is practical.     

Field independence and laterality in the perception of faces.

For a sample of 28 college males the degree of left visual-field bias in the perception of faces correlated .45 (p less than .01) with extent of field-independent performance, as assessed by a composite score based on the Embedded-Figures Test, the Rod-and-Frame Test, and ratings on the Articulation-of-Body-Concept Scale. In a second study with 16 female and 10 male college subjects using the Group Embedded-Figures Test, field-independent subjects again showed greater left visual-field lateralization of face perception (r = .43, p less than .05). Based on Witkin's view of field independence as a manifestation of psychological differentiation, possible links between extent of differentiation at the psychological and neurophysiological levels are suggested.     

Dichotic perception and laterality in neonates

Groups of 4-day-old neonates were tested for dichotic discrimination and ear differences with the High-Amplitude-Sucking procedure. In the first experiment, dichotic speech discrimination was attested by comparison with a control group. Furthermore, among those subjects who showed a substantial recovery of sucking response at least after one of the two syllable changes, it was observed that significantly more subjects manifested a stronger reaction to a right-ear change than to a left-ear change. In the second experiment, 4-day-old neonates were tested on syllable and music timbre discrimination. The significant Stimulus Type x Ear interaction observed suggests perceptual asymmetries indicative of very precocious brain specialization.     

Bilateral tachistoscopic perception, handedness, and laterality.

Right-handed, familial left-handed, and nonfamilial left-handed males and females reported high- or low-imagery words which were located to the left and right of fixation in bilateral tachistoscopic displays. On each trial, an arrowhead appeared in the center of the display. The arrowhead pointed to either the left or the right half-field, indicating the order of report. Right-handers reported more accurately from the right half-field, and familial left-handers reported more accurately from the left half-field. The order of report results showed that right-handers were similar to nonfamilial left-handers; for left half-field presentation, both groups were more accurate when the arrowhead pointed to the left than when it pointed to the right (i.e., first report was more accurate than second report). There was a main effect of word imagery, but this factor did not interact with visual half-field. Thus, there was no evidence that representations of high-imagery words are lateralized differently than representations of low-imagery words. The results are discussed with respect to lateralization of memory for verbal material.     

An analysis of an optimal selection process for characteristics and technical performance of baseball pitchers

Selection of a qualified pitcher has relied previously on qualitative indices; here, both quantitative and qualitative indices including pitching statistics, defense, mental skills, experience, and managers' recognition were collected, and an analytic hierarchy process was used to rank baseball pitchers. The participants were 8 experts who ranked characteristics and statistics of 15 baseball pitchers who comprised the first round of potential representatives for the Chinese Taipei National Baseball team. The results indicated a selection rate that was 91% consistent with the official national team roster, as 11 pitchers with the highest scores who were recommended as optimal choices to be official members of the Chinese Tai-pei National Baseball team actually participated in the 2009 Baseball World Cup. An analytic hierarchy can aid in selection of qualified pitchers, depending on situational and practical needs; the method could be extended to other sports and team-selection situations.     

Manual performance asymmetries and motor control processes: Subject-generated changes in response parameters

Performance asymmetries between the hands have recently been explained in terms of differences in the nature of motor control processes between the hands. If performance asymmetries between the hands on a serial tapping task are due to differences in motor control processes, the degree of asymmetry should be sensitive to changes in the manipulated response parameter, speed of tapping. The results strongly supported this prediction. The differences in control processes observed here seem to be explained by the feedback model proposed by Flowers. Alternate models to that of Flowers (1975) are, however, presented.     

Verbal and affective laterality effects in P-dyslexic, L-dyslexic and normal children.

Lateralization of verbal and affective processes was investigated in P-dyslexic, L-dyslexic and normal children with the aid of a dichotic listening task. The children were asked to detect either the presence of a specific target word or of words spoken in a specific emotional tone of voice. The number of correct responses and reaction time were recorded. For monitoring words, an overall right ear advantage was obtained. However, further tests showed no significant ear advantage for P-types, and a right ear advantage for L-types and controls. For emotions, an overall left ear advantage was obtained that was less robust than the word-effect. The results of the word task are in support of previous findings concerning differences between P- and L-dyslexics in verbal processing according to the balance model of dyslexia. However, dyslexic children do not differ from controls on processing of emotional prosody although certain task variables may have affected this result.     

Transposed-letter and laterality effects in lexical decision

Two divided visual field lexical decision experiments were conducted to examine the role of the cerebral hemispheres in transposed-letter similarity effects. In Experiment 1, we created two types of nonwords: nonadjacent transposed-letter nonwords (TRADEGIA; the base word was TRAGEDIA, the Spanish for TRAGEDY) and two-letter different nonwords (orthographic controls: TRATEPIA). In Experiment 2, the controls were one-letter different nonwords (TRAGEPIA) instead of two-letter different nonwords (TRATEPIA). The effect of transposed-letter similarity was substantially greater in the right visual field (left hemisphere) than in the left visual field. Furthermore, nonwords created by transposing two letters were more competitive than the nonwords created by substituting one or two letters of a target word. We examine the implications of these findings for the models of visual word recognition.     

Cerebral laterality and verbal-performance discrepancies in intelligence

The cerebral laterality of children with various configurations of verbal-performance discrepancies was inferred with an objective measure of lateral preference. Specifically, Verbal and Performance IQ scores of the WISC-R were used to divide 90 learning-disabled children into three equal groups: (a) Verbal significantly higher than Performance, (b) Performance significantly higher than Verbal, and (c) Verbal not significantly different from Performance. Analysis of the scores on the Laterality Preference Schedule showed children in the Verbal > Performance group were significantly more bilateral in their preference patterns than either of the other groups. Data on familial laterality showed this Verbal > Performance group to also have parents who were significantly more mixed in their preference patterns than either the VSIQ < PSIQ or VSIQ = PSIQ groups. The results were interpreted as lending support to the notion of competition antagonism between cortical hemispheres and a possible genetic relationship.