Age-related differences in reaction time task performance in young children

Performance of reaction time (RT) tasks was investigated in young children and adults to test the hypothesis that age-related differences in processing speed supersede a “global” mechanism and are a function of specific differences in task demands and processing requirements. The sample consisted of 54 4-year-olds, 53 5-year-olds, 59 6-year-olds, and 35 adults from Russia. Using the regression approach pioneered by Brinley and the transformation method proposed by Madden and colleagues and Ridderinkhoff and van der Molen, age-related differences in processing speed differed among RT tasks with varying demands. In particular, RTs differed between children and adults on tasks that required response suppression, discrimination of color or spatial orientation, reversal of contingencies of previously learned stimulus-response rules, and greater stimulus-response complexity. Relative costs of these RT task differences were larger than predicted by the global difference hypothesis except for response suppression. Among young children, age-related differences larger than predicted by the global difference hypothesis were evident when tasks required color or spatial orientation discrimination and stimulus-response rule complexity, but not for response suppression or reversal of stimulus-response contingencies. Process-specific, age-related differences in processing speed that support heterochronicity of brain development during childhood were revealed.     

How Many Casualties Are Too Many? Proportional Reasoning in the Valuation of Military and Civilian Lives1

People frequently judge saved lives as less valuable and deaths more acceptable when they are characterized as small fractions of larger “at‐risk” groups. Two studies with U.S. college students demonstrated this effect in judgments concerning acceptable numbers of U.S. military and Middle Eastern civilian casualties. At the beginning of the current U.S.–Iraq conflict ( Study 1 ), priming cost–benefit reasoning produced greater proportional devaluation for Iraqi civilian than for U.S. military lives. In a hypothetical armed intervention in Iran to halt weapons development ( Study 2 ), women but not men showed greater proportional devaluation for U.S. military than for Iranian civilian lives. In both studies, proportional reasoners were willing to accept more casualties. Implications for public perceptions and attitudes are discussed.     

Juries,Gender, and Assault Weapons1

Firearms appearance can have psychological import in legal proceedings by keying aggressive ideations, impacting sentencing and gender‐based attributions. We presented mock jurors with a homeowner's defensive gun use. Reasonable arguments were for shooting or not in the scenario by the defendant. The firearm varied in type. Assault rifle use led to harsher legal outcomes than did other firearms. A female defendant was at more risk than a male. In the last experiment, a police shooting scenario was tested. In that case, the male officer was at more risk than the female officer when wielding the assault rifle. Weapons and gender interactions were, for the most part, congruent with social cognitive theories of attribution and weapons priming of aggressive ideation.     

In the Eye of the Beholder: Do Behavior and Character Affect Victim and Perpetrator Responsibility for Acquaintance Rape?1

Acquaintance rape attributions of responsibility were investigated. In Study 1, participants viewed videotapes that varied the female victim's resistance (verbal, physical, verbal/physical) and the reaction of the perpetrator (anger, no reaction) or a control videotape. The victim was held less responsible and the perpetrator was held more responsible when the victim resisted. In Study 2, participants viewed videotapes that manipulated victim and perpetrator reputation. Victims were held more responsible when they had a bad reputation; perpetrators were held more responsible when the victim had a good reputation or the perpetrator had a bad reputation. Hostile sexism predicted victim responsibility in both studies; rape myth predicted victim and perpetrator responsibility in Study 2. Implications for the legal system are discussed.     

Reward value effects on timing in the peak procedure

Three experiments examined the effect of motivational variables on timing in the peak procedure. In Experiment 1, rats received a 60-s peak procedure that was coupled with long-term, between-phase changes in reinforcer magnitude. Increases in reinforcer magnitude produced a leftward shift in the peak that persisted for 20 sessions of training. In a final phase, the rats received lithium chloride-induced aversion prior to testing and a rightward shift in the peak was observed. Experiment 2 confirmed the rightward shift in the peak under lithium chloride devaluation and induced a comparable shift with satiety devaluation. The degree of rightward shift was neither additive nor multiplicative, suggesting that two processes may have contributed. Experiment 3 examined the effect of extinction on peak responding, revealing a decrease in response rate, but no evidence of any change in the timing of responding. The implications of the results for contemporary timing theories are discussed.     

Paranormal belief and susceptibility to the conjunction fallacy

Numerous studies have shown paranormal believers misperceive randomness and are poor at judging probability. Despite the obvious relevance to many types of alleged paranormal phenomena, no one has examined whether believers are more susceptible to the ‘conjunction fallacy’; that is to misperceiving co‐occurring (conjunct) events as being more likely than singular (constituent) events alone. The present study examines believer vs. non‐believer differences in conjunction errors for both paranormal and non‐paranormal events presented as either a probability or a frequency estimation task. As expected, believers made more conjunction errors than non‐believers. This was true for both event types, with both groups making fewer errors for paranormal than for non‐paranormal events. Surprisingly, the response format (probability vs. frequency) had little impact. Results are discussed in relation to paranormal believers' susceptibility to the conjunction fallacy and more generally, to their propensity for probabilistic reasoning biases. Copyright © 2008 John Wiley & Sons, Ltd.     

Working mother-infant interactions across the second year of life

Play interactions between 36 college-educated, middle-income, working mothers and their infants, who had attended nursery school since 1 month of age, were videotaped when the infants were 12, 18, and 24 months of age. The videotapes were coded for mother and infant looking at each other, vocalizing, affectionate play, and constructive play. Changes noted in the infants' play behaviors across this period included an increase in infant vocalizations and constructive play and a decrease in affectionate play. These results, together with corresponding decreases in the mothers' constructive and affectionate play behavior, suggest growing autonomy of the infants' play and encouragement of autonomy by the mothers. Stability of behaviors across this period and stability of relations between infant and mother behaviors were only moderate. Comparison of these data with data from a study by Clarke-Stewart and Hevey (1981) suggested greater frequency of interactive behavior among working mothers and their infants than among nonworking mothers and their infants.     

Infants' responses to mothers' imitative behaviors

Several investigators have suggested that young infants' smiles and vocalizations following their mothers' imitative behaviors might reflect infant recognition that the mother's behavior is imitative or at least contingent. This study investigated whether infants smile and vocalize more frequently subsequent to maternal imitative than non-imitative behavior during both spontaneous and imitative face-to-face interactions. Fourteen 3 1/2-month-old infants and their mothers were videotaped in these two face-to-face interaction situations. The infants vocalized more frequently during the imitative situation and infant vocalizations plus simultaneous smiling, and vocalizations occurred more often following maternal imitative than non-imitative behavior. Although these data suggest that infant vocalizations and simultaneous smiles and vocalizations may reflect the infants' recognition of maternal imitative behavior, they do not establish definitively that it is the imitation per se vs. the contingency aspect that is recognized by the infant.     

Developmental effects of an intervention for preterm infants of teenage mothers

Since preterm infants and infants born to teenage mothers are noted to be at risk for developmental delays, a group of infants who were both preterm and born to teenage mothers was provided a sensorimotor exercise intervention program for the first year of infancy. The development of these infants was compared to the development of preterm infants without intervention and term infants of teenage mothers as well as term and preterm infants of adult mothers to determine the degree to which developmental delays were prevented. The intervention infants showed more optimal growth, cognitive development, temperament and play behaviors during interactions with their mothers across the first year of development.     

Play behaviors of handicapped preschool children in the presence and absence of nonhandicapped peers

Sixteen minimally handicapped children and 18 nonhandicapped children were observed playing as separate classes and as a combined group on their preschool playground. Play behaviors directed toward self, toys, teachers, and peers were recorded using a time sampling procedure. Repeated measures analyses revealed that: (1) handicapped children engaged in less peer-directed and more teacher-directed behaviors than the similar chronological age but developmentally more advanced normal children; (2) a comparison between a subsample of normal and handicapped children who were approximately equivalent on developmental age suggested that the normal children only vocalized more often; (3) when integrated with the normal children, handicapped children engaged in more peer-directed and less teacher-directed behaviors than when playing in the non-integrated situation; (4) during the combined group play situation, normal children directed more behaviors to their own classmates while handicapped children directed approximately equal amounts of behavior to their own classmates and to their normal peers. These results suggest that the normal children were not negatively affected and the handicapped children were positively affected by the integrated play situation.