The K-factor: Individual differences in life history strategy

Until recently, variations in life history strategy were studied exclusively at the species level. Although this domain of study has been extended to examine systematic differences in life history strategy among various human ethnic groupings, more recent evolutionary theories of human development and related behavioral genetic work imply substantial within-group individual variation in life history strategy. We constructed a latent variable model identifying a single common factor, denoted as K, which underlies a variety of otherwise disparate life history parameters. This “K-Factor” loaded 0.36 on childhood attachment to the biological father, −0.36 on childhood attachment to any non-biological father figure, 0.38 on adult romantic partner attachment, −0.51 on mating effort, −0.58 on Machiavellianism, and −0.41 on risk propensity. The bivariate correlations of the K-factor with higher-order personality factors were statistically significant, −0.24 with “Big Neuroticism” and −0.67 with “Big Psychoticism”, and approached significance, correlating 0.12, with “Big Extraversion”. The K-factor appears to be an underappreciated individual difference variable of major importance to human development.     

Short-term visual memory for location in depth: A U-shaped function of time

Short-term visual memory was studied by displaying arrays of four or five numerals, each numeral in its own depth plane, followed after various delays by an arrow cue shown in one of the depth planes. Subjects reported the numeral at the depth cued by the arrow. Accuracy fell with increasing cue delay for the first 500 ms or so, and then recovered almost fully. This dipping pattern contrasts with the usual iconic decay observed for memory traces. The dip occurred with or without a verbal or color–shape retention load on working memory. In contrast, accuracy did not change with delay when a tonal cue replaced the arrow cue. We hypothesized that information concerning the depths of the numerals decays over time in sensory memory, but that cued recall is aided later on by transfer to a visual memory specialized for depth. This transfer is sufficiently rapid with a tonal cue to compensate for the sensory decay, but it is slowed by the need to tag the arrow cue’s depth relative to the depths of the numerals, exposing a dip when sensation has decayed and transfer is not yet complete. A model with a fixed rate of sensory decay and varied transfer rates across individuals captures the dip as well as the cue modality effect.     

Confident failures: Lapses of working memory reveal a metacognitive blind spot

Attention, Perception, & Psychophysics - Working memory performance fluctuates dramatically from trial to trial. On many trials, performance is no better than chance. Here, we assessed...     

Persistent bias in expert judgments about free will and moral responsibility: a test of the expertise defense

Many philosophers appeal to intuitions to support some philosophical views. However, there is reason to be concerned about this practice as scientific evidence has documented systematic bias in philosophically relevant intuitions as a function of seemingly irrelevant features (e.g., personality). One popular defense used to insulate philosophers from these concerns holds that philosophical expertise eliminates the influence of these extraneous factors. Here, we test this assumption. We present data suggesting that verifiable philosophical expertise in the free will debate—as measured by a reliable and validated test of expert knowledge—does not eliminate the influence of one important extraneous feature (i.e., the heritable personality trait extraversion) on judgments concerning freedom and moral responsibility. These results suggest that, in at least some important cases, the expertise defense fails. Implications for the practice of philosophy, experimental philosophy, and applied ethics are discussed.     

Effectiveness of a brief intervention using mental simulations in reducing alcohol consumption in corporate employees

A theory-based intervention aimed at reducing corporate employees' alcohol consumption in excess of guideline limits is presented. The intervention adopted an outcome mental simulation technique and was administered to a sample of corporate employees from three companies. A single-arm randomized-controlled design was adopted. All participants completed baseline psychological measures and self-reported number of alcohol units consumed and binge-drinking occasions. Participants allocated to the intervention condition were presented with a mental simulation exercise. One month later, participants completed follow-up measures of the psychological variables and alcohol consumption. Results revealed a significant effect of the mental simulation intervention on number of units of alcohol consumed at follow-up. There was no effect of the intervention on frequency of binge-drinking occasions. There was no evidence for the mediation of the effect of mental simulations on alcohol consumption by the perceived behavioural control and motivation variables. Results support the efficacy of the mental simulation intervention in reducing alcohol consumption but not in reducing binge drinking or alcohol consumption in excess of guideline limits, among corporate employees. Results are discussed with respect to the importance of the mental simulation intervention to inform practice and the proposed processes by which mental simulations affect alcohol consumption.     

Neural coding of formant-exaggerated speech in the infant brain

Speech scientists have long proposed that formant exaggeration in infant-directed speech plays an important role in language acquisition. This event-related potential (ERP) study investigated neural coding of formant-exaggerated speech in 6-12-month-old infants. Two synthetic /i/ vowels were presented in alternating blocks to test the effects of formant exaggeration. ERP waveform analysis showed significantly enhanced N250 for formant exaggeration, which was more prominent in the right hemisphere than the left. Time-frequency analysis indicated increased neural synchronization for processing formant-exaggerated speech in the delta band at frontal-central-parietal electrode sites as well as in the theta band at frontal-central sites. Minimum norm estimates further revealed a bilateral temporal-parietal-frontal neural network in the infant brain sensitive to formant exaggeration. Collectively, these results provide the first evidence that formant expansion in infant-directed speech enhances neural activities for phonetic encoding and language learning.     

Europeans Work to Live and Americans Live to Work (Who is Happy to Work More: Americans or Europeans?)

This paper compares the working hours and life satisfaction of Americans and Europeans using the World Values Survey, Eurobarometer and General Social Survey. The purpose is to explore the relationship between working hours and happiness in Europe and America. Previous research on the topic does not test the premise that working more makes Americans happier than Europeans. The findings suggest that Americans may be happier working more because they believe more than Europeans do that hard work is associated with success.     

Media multitasking behavior: concurrent television and computer usage

Changes in the media landscape have made simultaneous usage of the computer and television increasingly commonplace, but little research has explored how individuals navigate this media multitasking environment. Prior work suggests that self-insight may be limited in media consumption and multitasking environments, reinforcing a rising need for direct observational research. A laboratory experiment recorded both younger and older individuals as they used a computer and television concurrently, multitasking across television and Internet content. Results show that individuals are attending primarily to the computer during media multitasking. Although gazes last longer on the computer when compared to the television, the overall distribution of gazes is strongly skewed toward very short gazes only a few seconds in duration. People switched between media at an extreme rate, averaging more than 4 switches per min and 120 switches over the 27.5-minute study exposure. Participants had little insight into their switching activity and recalled their switching behavior at an average of only 12 percent of their actual switching rate revealed in the objective data. Younger individuals switched more often than older individuals, but other individual differences such as stated multitasking preference and polychronicity had little effect on switching patterns or gaze duration. This overall pattern of results highlights the importance of exploring new media environments, such as the current drive toward media multitasking, and reinforces that self-monitoring, post hoc surveying, and lay theory may offer only limited insight into how individuals interact with media.     

Implicit coordination: Sharing goals with similar others intensifies goal pursuit

The current research explored whether sharing intentionality leads to implicit coordination, a situation in which isolated individuals independently adopt a similar standard of behavior. We propose that knowing that a given goal is experienced in common with other in-group members or similar others intensifies goal pursuit. Two experiments examined whether simply being aware that one's own individual goal was also being separately pursued by similar others results in more goal-congruent behavior. When a promotion goal was shared with similar others, participants produced greater promotion behaviors than when the same goal was shared with different others. Similarly, sharing a prevention goal with similar others led to greater prevention behavior than conditions where a) similar others had a different goal and b) different others shared the same goal. Overall, shared goals served as an intensifier of individual goal pursuit. We discuss shared goals as a foundation for the emergence of social synchrony in groups.     

Positive reactions to tobacco predict relapse after cessation

Among chronic smokers, individual differences in subjective reactions to smoking may characterize important facets of nicotine dependence that relate to abstinence-induced craving, withdrawal symptom profiles, and risk for relapse. Although the negative reinforcing properties of smoking have achieved prominent positions in models of relapse (Baker, Brandon, & Chassin, 2004), vulnerability to relapse risk may also arise from seeking positive reinforcement from smoking (Shiffman & Kirchner, 2009). In this study, 183 cessation-motivated smokers provided subjective craving, positive and negative reactions to standardized cigarettes following overnight abstinence. Level of craving, negative mood, and positive mood after overnight abstinence were significantly predictive of withdrawal on quit-day. Increased positive reactions to smoking were uniquely predictive of relapse after quitting (Hazard Ratio = 1.22, p < .001). Individual differences in positive reactions to smoking may be important markers of neurobiological systems that promote dependence and interfere with cessation efforts.