The limited capacity of humans to identify the components of taste mixtures and taste-odour mixtures

The capacity of humans to identify the components of taste mixtures and odour-taste mixtures was investigated in two experiments. Subjects were trained to identify the components presented alone and to use a 'yes/no' procedure to identify them in mixtures. All stimuli were presented with a retronasal (by mouth) technique. A maximum of three tastants were identified in both types of mixtures, only one tastant was identified in five-component taste mixtures, and no component was identified in four-component odour-taste mixtures. Importantly, in no instance was the olfactory stimulus identified in any mixture with tastes, including binary mixtures. Loss of identity of the odorant in binary and ternary mixtures may have been due to suppression as a consequence of temporal processing, or to the absence of an association between the odorant and tastants that had established an identifiable percept. In contrast, poor identification of the components of the quaternary odour-taste mixture and quinternary taste mixture is attributed to the limited capacity of working memory. Overall, the poorer ability to identify components in odour-taste mixtures than in taste mixtures indicates that interactions occurred between the two senses, challenging the proposal that odours and tastes are processed independently when present in complex chemosensory stimuli.     

The congruency sequence effect emerges when the distracter precedes the target

The congruency effect in distracter interference tasks is typically smaller when the previous trial was incongruent as compared to congruent, suggesting the operation of a control process that minimizes the influence of irrelevant stimuli on behavior. However, both the conditions under which this congruency sequence effect (CSE) can be most easily observed without the typical learning and memory confounds, and the control process underlying it, remain controversial. We therefore tested a recent hypothesis that the CSE is most easily observed without the typical confounds when the distracter is processed before the target. In line with this “distracter head start” hypothesis, in Experiments 1 and 2 the CSE was larger when the distracter appeared before, relative to with, the target. Further, in Experiment 3, we observed a negative congruency effect after incongruent trials when a long interval separated the distracter from the target, consistent with a modulation of the response engendered by the distracter but not with a shift of attention toward the target. These findings reveal an important determinant of CSE magnitude when the typical learning and memory confounds are absent and new insights into the nature of control processes that contribute to this phenomenon.     

Appraisals of Fear, Helplessness, and Perceived Life-Threat During Emergent Cardiac Surgery: Relationship to Pre-surgical Depression, Trauma History, and Posttraumatic Stress

Depression and posttraumatic stress (PTS) have been linked to medical/psychological outcomes following coronary artery bypass graft (CABG) surgery. This study assessed pre-surgical trauma history, PTS, and depression; and peri-surgical appraisals of fear, helplessness, and perceived life-threat among 110 patients. All CABGs were emergent, rather than elective, surgeries. In hierarchical multiple regressions, total severity score for pre-surgical PTS predicted fear regarding the cardiac event and the CABG, and perceived life-threat regarding the cardiac event and the CABG. Pre-surgical depression predicted perceived helplessness regarding the cardiac event and the CABG, and contributed to prediction of perceived life-threat. Trauma history contributed to prediction of fear and perceived helplessness regarding surgery (but not regarding the cardiac event necessitating surgery). When posttraumatic stress disorder diagnosis (PTSD) was entered, rather than total severity of PTS, PTSD did not predict any appraisals, and depression showed stronger prediction of fear, helplessness, and perceived life-threat than did PTSD.     

Temporal constraints on binding? Evidence from quantal state transitions in perception

Do behavioural observations on the transitions between alternative perceptual interpretations of stimuli carry information about temporal characteristics of brain activity involved in binding? Promising methods for capturing critical attributes of this activity are the psychophysical methods of parameter adjustment. Of particular value are situations that include an adjustment of periodically repeating components, since the interaction of these with periodic “carrier processes” in the brain may produce informative patterns of interference. Previous evidence reveals that in different paradigms the spectral time signatures of transition tune in to a superordinate structure of quantal time values. In agreement with predictions of the taxonomic “time quantum model” (TQM), quantal time values are organized in groups called ranges which cover intervals of discretely varying sizes. These findings suggest properties characteristic of oscillatory mechanisms which are active in temporal binding. Of critical importance is the extreme precision of timing, agreement of critical periods across individuals, as well as across tasks of varying complexity, and indications of single-shot timing.     

Do specific types of networking predict specific mobility outcomes? A two-year prospective study

Previous research has established a general relation between networking and career outcomes, as postulated by theories on protean careers and career self management. We suggest that specific facets of networking behavior differentially affect specific career mobility outcomes over time. In a 2-year prospective study, we examined the impact of six facets of networking on the likelihood receiving a promotion, changing employer, or remaining in the current position. Results show that internal networking is related to promotions and change of employer, whereas external networking is only related to change of employer. Moreover, internal networking shows a differential relation with the temporal proximity of promotions where using internal contacts predicts promotions in the first year and building and maintaining internal contacts predict promotions in the second year. However, this temporal pattern did not hold for external networking, where only maintaining external contacts predicted change of employer in the second year.     

Individual payments as a longer-term incentive in online panels

Does it pay to pay online panel members? A three-wave longitudinal experiment was conducted with an online panel to examine whether per person payments, paid through an online intermediary, influence response and retention rates. In the payment condition, participants were promised payment for participation at each wave, whereas control participants were not offered any payment. The promise of a payment had a negative effect on response in Wave 1, but a positive effect on response in Wave 2. Payment had no significant effect on retention. Completing a given wave was an indicator for responding to a subsequent invitation.     

Commentary on high-performance computing and psychological models: Theory-building and model-fitting processes

For a psychological theorist, a merging of the interactive capability of a desktop computer and the speed/ memory capability of a supercomputer is needed. Ready-to-use modeling software is especially useful in the behavioral sciences so that researchers do not need to reinvent each other’s wheels. Dynamical models of psychological processes require different analyses from routine statistical treatments.