Comparison of video- and EMG-based evaluations of the magnitude of children’s emotion-modulated startle response

We investigated the reliability and validity of a video-based method of measuring the magnitude of children’s emotion-modulated startle response when electromyographic (EMG) measurement is not feasible. Thirty-one children between the ages of 4 and 7 years were videotaped while watching short video clips designed to elicit happiness or fear. Embedded in the audio track of the video clips were acoustic startle probes. A coding system was developed to quantify from the video record the strength of the eye-blink startle response to the probes. EMG measurement of the eye blink was obtained simultaneously. Intercoder reliability for the video coding was high (Cohen’sκ = .90). The average within-subjects probe-by-probe correlation between the EMG- and video-based methods was .84. Group-level correlations between the methods were also strong, and there was some evidence of emotion modulation of the startle response with both the EMG- and the video-derived data. Although the video method cannot be used to assess the latency, probability, or duration of startle blinks, the findings indicate that it can serve as a valid proxy of EMG in the assessment of the magnitude of emotion-modulated startle in studies of children conducted outside of a laboratory setting, where traditional psychophysiological methods are not feasible.     

Pre-event stereotypes and misinformation effects in young children

This study examined the effects of pre-event stereotypes on 5-year-old children's memories for the visit of an adult male to their school. Children were read three stories in which this man was described in positive, negative, or neutral terms. Following the visit, children were read post-event narratives which contained positive and negative misinformation that was consistent and inconsistent with the pre-event stereotype. Children were then given a recognition test under inclusion and exclusion instructions. Negative misinformation was correctly rejected more often than positive misinformation. Children given a positive pre-event stereotype were more likely to accept positive misinformation than those in the other stereotype conditions. Process dissociation analyses revealed that recollection for negative misinformation was larger than for positive misinformation; the opposite was the case for familiarity.     

Inhibition of acoustic startle using different mechanoreceptive channels

In this experiment, we investigated the impact of vibrotactile prepulse frequency and intensity on the acoustically elicited startle response in humans. Mechanoreceptive channels differing in their sensitivity to transient stimulation have been identified in the skin. The Pacinian channel is optimally sensitive to vibrations at approximately 300 Hz and is specialized for the detection of stimulus transients, whereas the non-Pacinian I and III channels are optimally sensitive to vibrations at approximately 30 Hz. Vibrotactile prepulses with frequencies of 30 and 300 Hz and intensities of 95 and 130 mV were presented for 50 msec to the dominant hand of college students (N = 31), followed on some trials by a 95-dB broadband acoustic startle stimulus. The 300-Hz prepulses resulted in significantly more pronounced inhibition of startle magnitude, amplitude, and probability, whereas only the 30-Hz prepulses significantly facilitated blink latency. These results support the idea that the inhibition of acoustic startle is determined more by transient than by sustained aspects of vibrotactile prepulse stimuli. This study also demonstrates that different aspects of the startle response differentially reflect stimulus characteristics of the prepulse.     

"Economic man" in cross-cultural perspective: behavioral experiments in 15 small-scale societies

Researchers from across the social sciences have found consistent deviations from the predictions of the canonical model of self-interest in hundreds of experiments from around the world. This research, however, cannot determine whether the uniformity results from universal patterns of human behavior or from the limited cultural variation available among the university students used in virtually all prior experimental work. To address this, we undertook a cross-cultural study of behavior in ultimatum, public goods, and dictator games in a range of small-scale societies exhibiting a wide variety of economic and cultural conditions. We found, first, that the canonical model - based on self-interest - fails in all of the societies studied. Second, our data reveal substantially more behavioral variability across social groups than has been found in previous research. Third, group-level differences in economic organization and the structure of social interactions explain a substantial portion of the behavioral variation across societies: the higher the degree of market integration and the higher the payoffs to cooperation in everyday life, the greater the level of prosociality expressed in experimental games. Fourth, the available individual-level economic and demographic variables do not consistently explain game behavior, either within or across groups. Fifth, in many cases experimental play appears to reflect the common interactional patterns of everyday life.     

Analyzing a complex visuomotor tracking task with brain-electrical event related potentials

Non-invasive techniques such as neuroimaging and event-related potential (ERP) methods have dramatically enhanced our understanding of the human brain. According to the requirements of the applied method, it is useful to simplify tasks for methodological reasons. In the present study we tested whether ERP measures are also suitable for analyzing complex tasks. In order to do this, we developed an analysis strategy based on the post hoc analysis of the behavioural data. We applied this method to a pursuit-tracking task of 25 s trial duration, consisting of repeated and non-repeated waveforms, where subjects had to track a target cross with a mouse-controlled cursor cross. An EEG was recorded from 62 channels. Response-locked ERPs were computed for two types of error correction: the correction of errors induced externally by the change of target direction and of internal errors generated by the subject itself. We found several ERP components that could be assigned to different feedback and feedforward controlled processing steps in the frontoparietal circuitry underlying visuomotor control, such as movement planning, movement execution (motor potential), reafferent activity, visuospatial analysis, and attentional (P300) processes. Our results support newer models that propose a role for the posterior parietal cortex in integrating multimodal sensory information. In addition, fast (about 180 ms and probably facilitated by anticipation) and slow (about 230-260 ms) error corrections could be differentiated by the time course of ERP activity. Our results show that complex (motor) tasks can be investigated with ERPs. This opens fruitful perspectives for future research on motor control in an ecological setting.     

Facilitating children's understanding of misinterpretation: explanatory efforts and improvements in perspective taking

The authors investigated children's understanding of how mistaken beliefs can arise through misinterpretation of ambiguous information. Children (N = 91), aged 4 to 5 years, were given pre- and posttests on their ability to infer a puppet's interpretation of a restricted-view drawing after the puppet had been led to an erroneous expectation about the drawing's identity. Before the posttest, the children received either self-explanation training or other-explanation training in which they explained the source of their own or a puppet's misinterpretations of drawings; a control group received no training. The children who received training improved from pre- to posttest, and those who had practiced explaining misinterpretations by referring to previously viewed pictures or to features of a target picture showed the greatest improvement. These results indicate that learning to explain misinterpretations can help children recognize situations in which misinterpretations are likely to occur.     

A comparison of the effects of differences in temporal gating and ear of presentation on profile discrimination

The aim of the study was to examine the effects of differences in temporal gating and ear of presentation (both separately and in combination) on listeners' ability to detect an increment in the level of a 1 kHz component (the target) relative to that of four spectrally flanking components. The flanking components were always presented to the listeners' right ear, while the target component was either presented to the same ear (monaural presentation) or to the left ear (dichotic presentation). Similarly, the target and flanking components were either gated on and off at the same time (synchronous presentation), or else the target component began 100 ms before and terminated 100 ms after the four flanking components (asynchronous presentation). On average, thresholds were lowest in the synchronous, monaural condition, and highest in the two asynchronous conditions. Ear differences alone did result in elevated thresholds for most listeners. However, combining differences in gating and ear of presentation produced thresholds that were indistinguishable from those obtained when gating differences alone were employed. These results are consistent with the suggestion that differences in temporal gating lead to more complete segregation of concurrent frequency components than differences in spatial location.     

Activist purpose orientation: Definition and predictors

Activism is responsible for many of the positive social changes we have seen across time, and is central to pushing for continued social change. However, these positive outcomes do not come without a cost, as activism can also be draining and can lead to physical and emotional harm for those involved. Social policies and intervention programs have addressed how to help people maintain their engagement with activism aims, though few have considered the motivational role of purpose in life. As purpose in life involves a sustained commitment to one's goals, having a purpose in life centered around activism may help an individual remain committed to activism and to the creation of change in the face of these obstacles. If activist purpose can help us understand and predict who is likely to remain engaged in activism, then it is valuable to consider what factors influence the development of activist purpose, in order to continue necessary social change. Thus, in this work we define activist purpose, and theorize as to what factors may be relevant to the development of an activist purpose by situating predictors of activism and collective action within the literature on pathways to purpose in life. This work may thus provide a greater understanding of how to encourage activism or reduce the harmful effects associated with activism.     

Understanding inference as a source of knowledge: children's ability to evaluate the certainty of deduction, perception, and guessing

Three experiments investigated children's understanding of inference as a source of knowledge. Children observed a puppet make a statement about the color of one of two hidden toys after the puppet (a) looked directly at the toy (looking), (b) looked at the other toy (inference), or (c) looked at neither toy (guessing). Most 4-, 5-, and 6-year-olds did not rate the puppet as being more certain of the toy's color after the puppet looked directly at it or inferred its color than they did after the puppet guessed its color. Most 8 and 9-year-olds distinguished inference and looking from guessing. The tendency to explain the puppet's knowledge by referring to inference increased with age. Children who referred to inference in their explanations were more likely to judge deductive inference as more certain than guessing.     

Emotional Reactions to COVID-19 Projections and Consequences for Protective Policies and Personal Behavior

How does the public react to information about the likely progression of COVID-19 cases in the United States? How do these reactions vary over the course of the pandemic and by partisanship, and with what consequences for policy attitudes and personal behavior? We argue that reading projections about the peak of COVID-19 cases in the United States is likely to lead to increased levels of anxiety and sadness. We expect that these effects will be more pronounced and less polarized along partisan lines earlier in the pandemic. Finally, we expect that elevated anxiety and sadness should in turn lead to greater support for protective policies to combat the pandemic and a greater inclination to engage in protective behaviors. To test these arguments, we fielded online survey experiments at three points in time (April, June, and August 2020), in which respondents were randomly assigned to a control group or one of two projections about the likely progression of COVID-19 cases in the United States. Across all three waves, we find that exposure to information about case peaks increases anxiety and sadness, though the effects get weaker over time, particularly among Republicans. We also find evidence that these elevated emotional responses increase support for protective policies and behavior.