Building on the ideas of others: An examination of the idea combination process

Two experiments were conducted to explore the process of building on ideas in brainstorming. Although this is presumed to be an important role of brainstorming, this has never been explored experimentally. In one experiment individual and group brainstormers generated ideas which were subsequently presented to these same individuals and groups to combine and build on for additional ideas, either as groups or individuals. The combination process was influenced by whether the participants had previously brainstormed alone or in groups and the phase of the combination period (early vs. late). In a second study participants were presented lists of rare or common ideas to combine and build on either as individuals or groups. Although groups generated fewer combinations than nominal groups, they generated more novel and feasible combinations when combining rare ideas. These findings indicate that groups are able to benefit from the exchange process in building on each other's ideas and are interpreted in the context of past research on idea generation and evaluation in groups.     

Fractal 1/ƒ dynamics suggest entanglement of measurement and human performance

Variability of repeated measurements in human performances exhibits fractal 1/? noise. Yet the relative strength of this fractal pattern varies widely across conditions, tasks, and individuals. Four experiments illustrate how subtle details of the conditions of measurement change the fractal patterns observed across task conditions. The results call into question whether measurement noise and measured signal can be distinguished in human performance, suggesting that human performance is inextricably entangled with measurement context. Perhaps, though, a hypothesis of soft assembly of human performance can circumvent the conundrum (e.g., Turvey, 2007).     

EMG and kinematics analysis of the trunk and lower extremity during the sit-to-stand task while wearing shoes with different heel heights in healthy young women

This study investigated the EMG characteristics and the kinematics of the trunk and lower extremity during the sit-to-stand (STS) task while wearing 1-, 4-, and 8-cm high-heeled shoes. We examined differences in the EMG data of the internal oblique, erector spinae, medial hamstring, and rectus femoris muscles during the STS task. The motion of the hip joint during an STS task was measured with a NorAngle Electrogoniometer System. Twelve young healthy women were recruited to this study. EMG characteristics and the hip joint angle were recorded during the performance of an STS task by subjects wearing high-heeled shoes of three different heel heights. The muscle onset time and EMG activity during this task were analyzed. In 8-cm high-heeled shoes, the onset time for the erector spinae muscle was significantly delayed, and the onset latency for the medial hamstring and the rectus femoris was significantly decreased. There was increased activity in the erector spinae and rectus femoris muscle during this task when wearing 8-cm high-heeled shoes. The initial hip flexion angle at the start point of the STS task did not differ among the 1-, 4-, and 8-cm heel-height conditions, but the trunk flexion angle, corresponding to the displacement between the peak hip flexion and initial hip flexion, was significantly larger in the 8-cm heel-height condition than in the 1- and 4-cm heel-height conditions. The findings suggest that excessive heel height has the potential to induce muscle imbalance during the STS task.     

Too powerless to speak up: Effects of social rejection on sense of power and employee voice

Enabling and amplifying the voice of employees creates opportunities for organizational improvement. Prior research has shown that employees' sense of power has impact on their voice behavior. As such, when would employees feel too powerless to speak up in the workplace? The current study investigates the indirect effect of social rejection (via sense of power) on employee voice. We use conservation of resources theory to explain this relationship. Experimental data from two studies demonstrate that participants reminded of social rejection (vs. acceptance) exhibit a lower sense of power. Specifically, we observe that social rejection diminishes a person's sense of power, and that social acceptance does not enhance this sense. That is, social rejection has an indirect effect on employee voice through sense of power. We discuss the theoretical and practical implications of our findings with regard to social rejection, sense of power, and workplace voice behavior.     

The relationship between testosterone and route-learning strategies in humans

The relationships between route-learning strategies and circulating testosterone and estradiol levels were investigated in men and women. Testosterone and estradiol concentrations were measured by salivary assays and route-learning strategies were assessed using a direction-giving paradigm based on a novel map. Testosterone was positively correlated with the use of male-biased route-learning strategies in men, but not in women. These findings suggest sex-specific patterns of relationships between circulating testosterone and spatial processing, which apply to everyday spatial behavior.     

Scaling affordances for human reach actions

A methodology developed by Cesari and Newell [Cesari, P., & Newell, K. M. (1999). The scaling of human grip configuration. Journal of Experimental Psychology: Human Perception and Performance 25, 927-935; Cesari, P., & Newell, K. M. (2000). The body-scaling of grip configurations in children aged 6-12 years. Developmental Psychobiology 36, 301-310] was used to delineate the roles of an object's weight (W) and distance (D) as well as the actor's strength (S) in determining the macroscopic action used to reach for the object. Participants reached for objects of five different weights placed at 10 distances. The findings of a single discriminant analysis revealed that when object weight is scaled in terms of each individual's strength and reach distance is scaled in terms of each individual's maximum-seated reach distance, a single discriminant analysis was able to predict 90% of the reach modes used by both men and women. The result of the discriminant analysis was used to construct a body-scaled equation, K=lnD+ln(W/S)/36, similar in form to the one derived by Cesari and Newell, accurately predicted the reach action used. Our findings indicate that Cesari and Newell's method can identify a complex relationship between geometric and dynamic constraints that determine the affordances for different reach actions.     

Extinction-induced neuroplasticity attenuates stress-induced cocaine seeking: a state-dependent learning hypothesis

Chronic drug use weakens excitatory neocortical input to the nucleus accumbens (NAc). We previously reported that extinction training, a form of inhibitory learning that progressively reduces cocaine-seeking behaviour when reward is withheld, reverses this deficit by up-regulating GluR1 and GluR2/3 subunits of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) glutamate receptors in the NAc. The level of GluR1 up-regulation is positively associated with a reduction in cocaine seeking, suggesting that extinction-induced up-regulation in AMPA receptors in the NAc opposes motivational influences that maintain cocaine seeking. This hypothesis is supported by the finding that over-expression of GluR1 and GluR2 in the NAc facilitates extinction of cocaine self-administration. Furthermore, a single extinction training session conducted during GluR1 and GluR2 over-expression strongly and selectively attenuates the ability of an environmental stressor to trigger relapse to cocaine seeking long after GluR1 and GluR2 over-expression declines. These results could suggest that excitatory input to the NAc promotes extinction learning, but only when memory is recalled under stressful situations. Recent studies indicate that both environmental stress and the frustrative stress of withholding reward during extinction of drug self-administration induce similar neurochemical events in the NAc. These neurochemical events could impose a "state-dependency" on extinction learning such that subsequent exposure to stress acts as a cue to enhance retrieval of extinction memory. Our results suggest that extinction-induced up-regulation in NAc AMPA receptors acts reciprocally to facilitate state-dependent extinction learning, as stressful situations evoke extinction memories that exert powerful inhibitory control over drug-seeking behaviour. These results may have important therapeutic implications for behaviour-based approaches aimed at treating drug addiction.     

Extinction training regulates neuroadaptive responses to withdrawal from chronic cocaine self-administration

Cocaine produces multiple neuroadaptations with chronic repeated use. Many of these neuroadaptations can be reversed or normalized by extinction training during withdrawal from chronic cocaine self-administration in rats. This article reviews our past and present studies on extinction-induced modulation of the neuroadaptive response to chronic cocaine in the mesolimbic dopamine system, and the role of this modulation in addictive behavior in rats. Extinction training normalizes tyrosine hydroxylase levels in the nucleus accumbens (NAc) shell, an effect that could help ameliorate dysphoria and depression associated with withdrawal from chronic cocaine use. Extinction training also increases levels of GluR1 and GluR2/3 AMPA receptor subunits, while normalizing deficits in NR1 NMDA receptor subunits, in a manner consistent with long-term potentiation of excitatory synapses in the NAc shell. Our results suggest that extinction-induced increases in AMPA and NMDA receptors may restore deficits in cortico-accumbal neurotransmission in the NAc shell and facilitate inhibitory control over cocaine-seeking behavior. Other changes identified by gene expression profiling, including up-regulation in the AMPA receptor aggregating protein Narp, suggest that extinction training induces extensive synaptic reorganization. These studies highlight potential benefits for extinction training procedures in the treatment of drug addiction.     

Dynamic changes in acetylcholine output in the medial striatum during place reversal learning

The present studies explored the role of the medial striatum in learning when taskcontingencies change. Experiment 1 examined whether the medial striatum is involved in place reversal learning. Testing occurred in a modified cross-maze across two consecutive sessions. Injections of the local anesthetic, bupivacaine, into the medial striatum, did not impair place acquisition, but impaired place reversal learning. The reversal-learning deficit was due to an inability to maintain the new choice pattern following the initial shift. Experiment 2 determined whether changes in acetylcholine (ACh) output occur during the acquisition or reversal learning of a place discrimination. Extracellular ACh output from the medial striatum was assessed in samples collected at 6-min intervals using in vivo microdialysis during behavioral testing. ACh output did not change from basal levels during place acquisition. During reversal learning, ACh output significantly increased as rats began to learn the new choice pattern, and returned to near basal levels as a rat reliably executed the new place strategy. The present results suggest that the medial striatum may be critical for flexible adaptations involving spatial information, and that ACh actions in this area enable the shifting of choice patterns when environmental conditions change.     

Conversing across cultures: East-West communication styles in work and nonwork contexts

Four experiments provided evidence that East-West differences in attention to indirect meaning are more pronounced in work settings compared with nonwork settings as suggested by prior research on Protestant relational ideology. Study 1 compared errors in interpreting indirect messages in work and nonwork contexts across three cultures. Studies 2 and 3 examined differences in self-reported indirectness with coworkers versus nonwork acquaintances across three cultures controlling for variation in individualism--collectivism. Study 4 examined self-reported indirectness in bicultural managers and experimentally manipulated the salience of Western versus Eastern culture. The results showed that Americans, but not East Asians, were less attentive to indirect cues in work than nonwork settings and that East-West differences in indirectness were greater in work than nonwork settings.