Consistent inter-individual differences in susceptibility to bodily illusions

Illusory senses of ownership and agency (that the hand or effector that we see belongs to us and moves at our will, respectively) support the embodiment of prosthetic limbs, tele-operated surgical devices, and human-machine interfaces. We exposed forty-eight individuals to four different procedures known to elicit illusory ownership or agency over a fake visible rubber hand or finger. The illusory ownership or agency arising from the hand correlated with that of the finger. For both body parts, sensory stimulation across different modalities (visual with tactile or visual with kinesthetic) produced illusions of similar strength. However, the strengths of the illusions of ownership and agency were unrelated within individuals, supporting the proposal that distinct neuropsychological processes underlie these two senses. Developing training programs to enhance susceptibility to illusions of agency or ownership for people with lower natural susceptibility could broaden the usefulness of the above technologies.     

Individual differences in need for cognition and decision-making competence among leaders

When making decisions, people sometimes deviate from normative standards. While such deviations may appear to be alarmingly common, examining individual differences may reveal a more nuanced picture. Specifically, the personality factor of need for cognition (i.e., the extent to which people engage in and enjoy effortful cognitive activities; Cacioppo & Petty, 1982) may moderate decision makers’ susceptibility to bias, as could personality factors associated with being a leader. As part of a large-scale assessment of high-level leaders, participants completed a battery of decision-making competence and personality scales. Leaders who scored higher on need for cognition performed better on two of four components of a decision-making competence measure: framing and honoring sunk costs. In addition, the leader sample performed better than published controls. Thus, both individual differences in need for cognition and leadership experience moderate susceptibility to decision biases. Implications for broader theories of individual differences and bias are discussed.     

Individual differences in need for cognition and decision making in the Iowa Gambling Task

Differences in decision making between individuals differing in Need for Cognition (NFC) are examined using the Iowa Gambling Task (IGT). Previous work using normative one time decisions suggests that individual low in NFC process gains and losses differently than those high in NFC and are more susceptible to decision biases. The IGT is a popular laboratory task that involves making risky decisions from experience involving both gains and losses. In the first experiment, low NFC participants performed significantly worse than the high NFC participants. A second experiment designed to examine the nature of these differences provides evidence that low NFC participants place more importance on gains as opposed to losses when performing the IGT. Results are discussed in light of previous work suggesting that low NFC participants place more importance on losses in mixed outcome decisions.     

Individual differences in nostalgia proneness: The integrating role of the need to belong

Who is the nostalgia-prone person? The ‘sociality view’ sees an individual who frequently recalls meaningful memories rich in social content. The ‘maladaptation view’ sees an emotionally unstable, neurotic individual. In four studies, we integrated these contrasting views. We hypothesized that the link between neuroticism and nostalgia proneness arises because (a) neuroticism is associated with the need to belong and (b) the need to belong triggers nostalgia, with its abundant social content. Consistent with this hypothesis, Studies 1–2 found that the correlation between neuroticism and nostalgia proneness was eliminated when controlling for the need to belong. The need to belong predicted increased nostalgia proneness, above and beyond neuroticism. Specifically, Study 2 revealed that a deficit-reduction (rather than growth) belongingness orientation predicted increased nostalgia proneness. When the role of this deficit-reduction belongingness orientation was controlled, the positive correlation between neuroticism and nostalgia disappeared. Studies 3–4 showed that experimental inductions of a belongingness deficit augmented nostalgia, providing support for its compensatory role.     

Individual differences in susceptibility to infection and illness following respiratory virus challenge

Abstract

The aim of the present research was to investigate whether susceptibility to experimentally-induced respiratory virus infections and illness is related to measures of personality, physiological state, performance efficiency, and subjective ratings of alertness and motivation obtained prior to virus challenge. Two studies, using different viruses, showed that volunteers who subsequently developed colds had higher temperatures prior to virus challenge than those who remained free from illness. Similarly, those who later had colds were worse than other volunteers on certain performance tests given in the pre-challenge period. The results also showed that task-related motivation was related to subsequent infection. Personality scores were poor predictors of infection and illness, the only exception being introversion, which, in one study, was related to the likelihood of developing a sub-clinical infection.     

Individual differences in the ability to focus and divide attention

This research deals with individual differences in the ability to focus and divide attention. Eighty-five subjects performed visual search and auditory detection tasks in three conditions: single channel, focused attention, and divided attention. Reaction time (RT) was fastest in the single channel condition, intermediate in the focused attention condition, and longest in the divided attention condition, and these effects were much stronger in the auditory than the visual task. Correlations among RTs in the three conditions were very high within modality (>.88), and lower between modalities (.5 to .6). The correlational data was well fit by a model that included separate factors for the visual and auditory tasks. Measures from the three attentional conditions within each modality loaded equally on these factors. The data provided no evidence for distinct abilities to divide or focus attention.     

Individual differences in aggressive responses to attack: Internal-external locus of control and field dependence-independence

Two experiments assessed the effect of individual differences on aggression. In both studies subjects were exposed to opponents in the competitive reaction time task who decreased the intensity of their attack from high to low, remained constantly moderate in their attack, or increased the intensity of their attack from low to high. In the first experiment Internal Locus of Control subjects consistently set high intensity shocks in response to high intensity attack and low shocks in response to mild attack. External subjects showed relatively minor variations in their aggressive responses to varying intensities of attack. In the second experiment field-independent subjects set more intense shocks than field-dependent subjects only in the Decreasing attack condition.