I've Got My Eyes on You: Implicit Social‐Pressure Cues and Prosocial Behavior

Explicit social pressure has been shown to be a powerful motivator of prosocial behavior‐like voting in elections. In this study, I report the findings of a randomized field experiment designed to study the impact of more subtle, implicit social‐pressure treatments. The results of the experiment, conducted in the October 2011 municipal elections in Key West, Florida, demonstrate that even subtle, implicit observability cues can effectively mobilize citizens to vote, perhaps as much as explicit surveillance cues. The findings speak more broadly to our understanding of human decision making, and even evolution, and provide fodder for the claim that humans are evolutionarily programmed to respond to certain stimuli. I interpret the evidence to support the notion that evolutionarily charged impulses, like exposure to images that implicitly signal the potential for surveillance and observability, are sufficient to overcome powerful collective action incentives to free ride.     

Maternally administered interventions for preterm infants in the NICU: Effects on maternal psychological distress and mother–infant relationship

Although studies have examined the effects of interventions focused on preterm infants, few studies have examined the effects on maternal distress (anxiety, depressive symptoms, post-traumatic stress symptoms, parenting stress) or parenting. This study examined the effects of the auditory–tactile–visual–vestibular (ATVV) intervention and kangaroo care (KC) on maternal distress and the mother–infant relationship compared to an attention control group.240 mothers from four hospitals were randomly assigned to the three groups. Maternal characteristics in the three groups were similar: 64.1% of ATVV mothers, 64.2% of KC mothers, and 76.5% of control mothers were African American; maternal age averaged 26.3 years for ATVV mothers, 28.1 for KC mothers, and 26.6 for control mothers; and years of education averaged 13.6 for ATVV and KC mothers, and 13.1 for control mothers. Mothers only differed on parity: 68.4% of ATVV and 54.7% of KC mothers were first-time mothers as compared to 43.6% of control mothers. Their infants had a similar mean gestational ages (27.0 weeks for ATVV, 27.2 for KC, and 27.4 for control) and mean birthweights (993 g for ATVV, 1022 for KC, and 1023 for control).Mothers completed questionnaires during hospitalization, and at 2, 6 and 12 months corrected age on demographic characteristics, depressive symptoms, state anxiety, post-traumatic stress symptoms, parenting stress, worry about child health, and child vulnerability (only at 12 months). At 2 and 6 months, 45-min videotapes of mother–infant interactions were made, and the HOME Inventory was scored. Behaviors coded from the videotapes and a HOME subscale were combined into five interactive dimensions: maternal positive involvement and developmental stimulation and child social behaviors, developmental maturity, and irritability.Intervention effects were examined using general linear mixed models controlling for parity and recruitment site. The groups did not differ on any maternal distress variable. Kangaroo care mothers showed a more rapid decline in worry than the other mothers. The only interactive dimensions that differed between the groups were child social behaviors and developmental maturity, which were both higher for kangaroo care infants. Change over time in several individual infant behaviors was affected by the interventions. When mothers reported on the interventions they performed, regardless of group assignment, massage (any form including ATVV) was associated with a more rapid decline in depressive symptoms and higher HOME scores. Performing either intervention was associated with lower parenting stress. These findings suggest that as short-term interventions, KC and ATVV have important effects on mothers and their preterm infants, especially in the first half of the first year.     

Female face preference in 4-month-olds: The importance of hairline

At 3–4 months of age, infants respond to gender information in human faces. Specifically, young infants display a visual preference toward female over male faces. In three experiments, using a visual preference task, we investigated the role of hairline information in this bias. In Experiment 1, we presented male and female composite faces with similar hairstyles to 4-month-olds and observed a preference for female faces. In Experiment 2, the faces were presented, but in this instance, without hairline cues, and the preference was eliminated. In Experiment 3, using the same cropping to eliminate hairline cues, but with feminized female faces and masculinized male faces, infants’ preference toward female faces was still not in evidence. The findings show that hairline information is important in young infants’ preferential orientation toward female faces.     

Hand preference status and reach kinematics in infants

Infants show age-related improvements in reach straightness and smoothness over the first years of life as well as a decrease in average movement speed. This period of changing kinematics overlaps the emergence of handedness. We examined whether infant hand preference status is related to the development of motor control in 53 infants ranging from 11 to 14 months old. Hand preference status was assessed from reaching to a set of 5 objects presented individually at the infant's midline; infants were classified into ‘right preference’ or ‘no preference’ groups. Three-dimensional (3-D) recordings were made of each arm for reaches under two distinct conditions: pick up a ball and fit it into the opening of a toy (grasp-to-place task) or pick up a Cheerio^® and consume it (grasp-to-eat task). Contrary to expectations, there was no effect of hand preference status on reach smoothness or straightness for either task. On the grasp-to-eat task only, average speed of the left hand differed as a function of hand preference status. Infants in the no preference group exhibited higher left hand average speeds than infants in the right preference group. Our results suggest that while behavioral differences in the use of the two hands may be present in some infants, these differences do not appear to be systematically linked to biases in motor control of the arms early in development.     

Object representations are biased toward each other through statistical learning

The visual system is remarkably efficient at extracting regularities from the environment through statistical learning. While such extraction has extensive consequences on cognition, it is unclear how statistical learning shapes the representations of the individual objects that comprise the regularities. Here we examine how statistical learning alters object representations. In three experiments, participants were exposed to either random arrays containing objects in a random order, or structured arrays containing object pairs where two objects appeared next to each other in fixed spatial or temporal configurations. After exposure, one object in each pair was briefly presented and participants judged the location or the orientation of the object without seeing the other object in the pair. We found that when an object reliably appeared next to another object in space, it was judged as being closer to the other object in space even though the other object was never presented (Experiments 1 and 2). Likewise, when an object reliably preceded another object in time, its orientation was biased toward the orientation of the other object even though the other object was never presented (Experiment 3). These results demonstrated that statistical learning fundamentally shapes how individual objects are represented in visual memory, by biasing the representation of one object toward its co-occurring partner. Importantly, participants in all experiments were not explicitly aware of the regularities. Thus, the bias in object representations was implicit. The current study reveals a novel impact of statistical learning on object representation: spatially co-occurring objects are represented as being closer in space, and temporally co-occurring objects are represented as having more similar features.     

Preferences for suicide prevention strategies among university students in Japan: a cross-sectional study using full-profile conjoint analysis

In Japan, implementation of suicide prevention policies is mainly supported by public funds. However, it is unclear what kinds of suicide prevention strategies people prefer. We conducted a survey to clarify people’s preferences regarding suicide prevention strategies adopted in Japan. This was a cross-sectional self-administered questionnaire survey. Participants were recruited through a lecture held by the first author at their university. We distributed questionnaires to 324 people present at the lecture; 249 completed questionnaires were included in the final analysis. We estimated suicide prevention strategy preferences using full profile conjoint analysis. For all six prevention strategies, the inclusion of each strategy in the policy profile was statistically significantly related to the positive evaluation of the overall policy profile. Marginal Willingness to Pay (MWTP) for restriction of access to means showed the highest value of the six suicide prevention strategies. MWTP was the lowest for public awareness activities. Preferred suicide prevention strategies in Japan are restriction of access to means and enhancement of psychiatric services. The results of this study indicate the strategies that are preferred have a high level of evidence of suicide prevention and do not directly intervene in a person’s free will to die by suicide.