Comment on "personality organization as an aspect of back pain in a medical setting".

The methodology and results of a recent investigation by Louks, Freeman, and Calsyn (1978) are reviewed. It is demonstrated that the results may have been confounded by inappropriate experimental procedures. Regardless of the methodological deficiencies associated with the experimental procedures, the results do not provide adequate support for the continued differentiation of individual low back pain patients with respect to the etiology of their pain. It is suggested that psychologists may best contribute to the assessment and treatment of individual pain patients by developing actuarial rules regarding the pain-related behavioral characteristics shared by members of various patient subgroups and the specific treatments to which subgroup members best respond.     

Comment on Hofsten and Spelke, object perception and object-directed reaching in infancy

Hofsten and Spelke (1985) reported a series of studies that quite clearly demonstrated infant sensitivity to depth and relative motion cues. They suggest a salience hierarchy for those cues in which relative motion takes precedence over depth when both cues are present. Based on reports that infants reach for and grasp boundaries in the visual display, the authors make the further claim that these data argue for object perception infants by the time they are 5 months old. The present article argues against this claim on two grounds: First, the authors do not report that infants specifically reached and grasped at boundaries in the display. Second, although patterns of reach are clearly affected by changes in boundary cues, there is no evidence that the boundaries the infants perceive are necessarily object boundaries.     

Contingent auditory feedback of arm movement facilitates reaching behavior in infancy

The purpose of this study was to investigate the influence of contingent auditory feedback on the development of infant reaching. Eleven full-term infants were observed biweekly from the age of 10 weeks to 16 weeks, and their arm kinematics were recorded. Auditory feedback that was contingent on arm kinematics was provided in the form of: (a) the mother's voice; and (b) musical tones. Results showed that providing auditory feedback (mother's voice or musical tones): (i) increased the amplitude of exploratory arm movements before the onset of reaching; and (ii) increased the number of reaches at the onset of reaching. These results show that infants are able to use contingent auditory feedback to explore the relevant possibilities for action that are subsequently shaped into goal-directed movements.     

Average uncertainty as a determinant of observing behavior

After discrimination training on a multiple variable-interval extinction schedule of food reinforcement, pigeons were placed on the uncued or mixed version of the same schedule and allowed to make an optional “observing response” that converted the uncued schedule to the corresponding cued schedule by providing a 20-sec exposure to the appropriate discriminative stimulus. The schedule consisted of one hundred 40-sec components, and the probability that any one of them would be a variable-interval component was systematically varied between 0.00 and 1.00. The results showed that the amount of observing behavior was an inverted “U” function of the probability of the variable-interval component. Few observing responses occurred at probabilities of 0.00 or 1.00, and maximum responding occurred at a value less than 0.50.     

Symbols presentation modality as a determinant of gambling behavior

In this study, the authors investigated the effects that modality of symbol presentation on video lottery terminals (sequential vs. simultaneous) has on gambling behavior. They predicted that sequential presentation would incite players to prolong their gambling session. Results confirmed this prediction and showed that modality of presentation is a determinant of gambling persistency. The authors discuss the relationship between modality of presentation, hopes of an imminent win, losses, and practical and theoretical issues about other cognitive and emotional elements that may influence gamblers' behaviors.     

Hand preference as related to development and behavior in infancy

55 healthy infants were assessed for their developmental and behavioral patterns at the age of 9 mo. Hand preference was assessed at 20 mo. of age. The distribution of hand preference showed 12 were right-handed, 11 left-handed and 23 ambidextrous. This distribution appears shifted more to the left than that reported for older children. Although their data were based on different tests not appropriate for 9-mo.-old infants, ambidexterity appeared to reflect part of the hand-preference continuum. No significant relationship between hand preference and developmental attainments was noted. Perhaps a larger sample would provide a clear developmental behavioral pattern and hand preference in infancy.     

Perceiving children's behavior and reaching limits in a risk environment

The purpose of this study was to investigate the accuracy of parents' perception of children's reaching limits in a risk scenario. A sample of 68 parents of 1- to 4-year-olds were asked to make a prior estimate of their children's behavior and action limits in a task that involved retrieving a toy out of the water. The action modes used for reaching, accuracy of estimates, and error tendency were investigated. Several morphological variables, walking experience, and swimming program experience were analyzed as predictors of maximum and estimated maximum reachability. Most children sat to retrieve the toy out of the water and fell in while attempting to grasp beyond their reaching limit. Nearly 80% of the parents correctly predicted their children's behavior when the toy was unreachable. Parents were cautious in predicting their children's maximum reachability (>50% underestimates). Mothers were more accurate than fathers in estimating their children's reaching limit. The prediction of children's capabilities was based partially on body dimensions and proportions.     

Evidence of motor planning in infant reaching behavior

When adults reach for an object, kinematic measures of their approach movement are affected by what they intend to do after grasping it. We examined whether such future intended actions would be reflected in the approach-to-grasp phase of infant reaching. Twenty-one 10-month-old infants were encouraged to either throw a ball into a tub or fit it down a tube. Kinematic measures of the approach phase of the reach toward the ball were obtained using a motion analysis system. Infants, like adults, reached for the ball faster if they were going to subsequently throw it as opposed to using it in the precision action. The perceptual aspects of the ball were the same and cannot account for these kinematic differences. Infants appear to be planning both segments of their actions in advance. Our findings provide evidence for a level of sophistication in infant motor planning not reported before.     

Cohesion as a constraint on object persistence in infancy

A critical challenge for visual perception is to represent objects as the same persisting individuals over time and motion. Across several areas of cognitive science, researchers have identified cohesion as among the most important theoretical principles of object persistence: An object must maintain a single bounded contour over time. Drawing inspiration from recent work in adult visual cognition, the present study tested the power of cohesion as a constraint as it operates early in development. In particular, we tested whether the most minimal cohesion violation - a single object splitting into two - would destroy infants' ability to represent a quantity of objects over occlusion. In a forced-choice crawling paradigm, 10- and 12-month-old infants witnessed crackers being sequentially placed into containers, and typically crawled toward the container with the greater cracker quantity. When one of the crackers was visibly split in half, however, infants failed to represent the relative quantities, despite controls for the overall quantities and the motions involved. This result helps to characterize the fidelity and specificity of cohesion as a fundamental principle of object persistence, suggesting that even the simplest possible cohesion violation can dramatically impair infants' object representations and influence their overt behavior.     

The "drinking-buddy" scale as a measure of para-social behavior

Para-social behavior is a form of quasi-interpersonal behavior that results when audience members develop bonds with media personalities that can resemble interpersonal social interaction, but is not usually applied to political communication. This study tested whether the "Drinking-Buddy" Scale, a simple question frequently used in political communication, could be interpreted as a single-item measure of para-social behavior with respect to political candidates in terms of image judgments related to interpersonal attraction and perceived similarity to self. The participants were college students who had voted in the 2008 election. They rated the candidates, Obama or McCain, as drinking buddies and then rated the candidates' perceived similarity to themselves in attitude and background, and also the social and task attraction to the candidate. If the drinking-buddy rating serves as a proxy measure for para-social behavior, then it was expected that participants' ratings for all four kinds of similarity to and attraction toward a candidate would be higher for the candidate they chose as a drinking buddy. The directional hypotheses were supported for interpersonal attraction, but not for perceived similarity. These results indicate that the drinking-buddy scale predicts ratings of interpersonal attraction, while voters may view perceived similarity as an important but not essential factor in their candidate preference.