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.     

Detection of heteroquality taste mixtures

Detection thresholds were measured for sweet (sucrose), salty (sodium chloride), sour (citric acid), and bitter (quinine hydrochloride) and for the 11 possible mixtures of these four substances. These 11 mixtures (6 binary, 4 ternary, and 1 quaternary) all turned out to be stimulus additive, in the sense that a person could reliably detect mixtures whose individual components are weaker than their unmixed thresholds. Tastants too weak to be perceived alone can thus make impact when in mixtures. The threshold concentration for a given compound was reduced in approximate proportion to the number of compounds added to it. This liberal heteroquality additivity contests the widespread belief that heteroquality mixtures (different chemicals evoking different qualities) are nonadditive and homoquality mixtures (different chemicals evoking the same quality) are additive. Heteroquality additivity emerges on appropriate definition of the subject’s task by forced choice (unavailable to earlier investigators), in order to skirt methodological pitfalls. Operating together, homoand heteroquality additivity may concomitantly enable a person to sense natural mixtures of hosts of weak constituents, such as drinking water. In this regard, gustatory mixtures may function much as do mixtures of frequencies in audition and mixtures of gaseous compounds in olfaction.     

Dielectric and thermodynamic behaviour of binary mixtures of anisole with o-chlorophenol and with o-cresol

The molecular interactions in binary mixtures of anisole with o-chlorophenol and o-cresol have been studied at three different temperatures using dielectric measurements. The static permittivity and the permittivity at optical frequency have also been determined and used to obtain the Kirkwood correlation factors, the Bruggeman parameter, the excess permittivity and the excess free energy for different concentrations of two binary mixtures, namely (1) anisole + o-chlorophenol and (2) anisole + o-cresol. Using the effective Kirkwood correlation factor, parallel and anti-parallel alignments among the dipoles are identified. The corrective Kirkwood correlation factor, the excess permittivity and the Bruggeman parameter are used to explain the interaction between unlike molecules. The temperature dependences of the above parameters are also reported. The investigation shows systematic changes in the dielectric behaviour with variations in concentration and temperature.     

Mothers' affect dysregulation,depressive symptoms,and emotional availability during mother–infant interaction

Maternal affect dysregulation and maternal depressive symptoms were examined as predictors of maternal emotional availability (EA) during mother–infant interaction in a nonclinical sample. In particular, we investigated if affect dysregulation predicts EA and is more important than are depressive symptoms in predicting EA. Questionnaire measures and 30 min of free play were obtained from 46 mothers of 4‐ to 5‐month‐old infants. Mothers' self‐reported affect dysregulation was inversely related to EA, but mothers' depressive symptoms were not related to EA. More specifically, mothers' tendency to use unhealthy externalizing behaviors to reduce tension and distress predicted less EA. These results suggested that even in relatively low‐risk samples, mothers' self‐reported affect dysregulation, particularly the tendency to act out inappropriately in response to tension and distress, may be a more proximal predictor of EA than are depressive symptoms.     

The effect of similarity between elemental stimuli and compounds in olfactory patterning discriminations

We studied the ability of honeybees to discriminate between single odorants and binary olfactory mixtures. We analyzed the effect of the number of common elements between these two stimulus classes on olfactory discrimination. We used olfactory conditioning of the honeybees' proboscis extension reflex (PER), a paradigm in which odors can be associated with a reinforcement of sucrose solution. Bees were asked to discriminate reinforced from nonreinforced olfactory stimuli. They were trained with two elemental odors (A and B) versus a binary olfactory mixture. The mixture was either AB (group 2CE, two common elements), AC (group 1CE, one common element A), or CD (group 0CE, no common element). Three groups followed a positive patterning schedule (mixture reinforced and elements nonreinforced: groups 2CE+, 1CE+, and 0CE+) and three other groups a negative patterning schedule (mixture nonreinforced and elements reinforced: groups 2CE-, 1CE-, and 0CE-). We showed that a reduction of similarity (number of common elements) between elemental odors and compounds enhanced the ability to discriminate elements from compounds and that the kind of compound processing used by the bees supports theories that assume nonelemental compound processing (i.e., that exclude the mere summation of the elemental associative strengths upon compound presentation).     

Dielectric and spectrometric investigations of binary mixtures of tetrahydrofuran with propionic acid

The static permittivity (ε_m ) and the permittivity at the high-frequency limit (ε_∞m ) of a binary mixture of propionic acid with tetrahydrofuran (THF) have been determined for different concentrations at temperatures of 303, 308, 313, and 318 K. The data have been used to compute the Kirkwood correlation factor, the excess permittivity, and the excess free-energy of the mixtures. The Kirkwood correlation factor is found to increase with increasing THF concentration. The mixture exhibited positive values of the excess permittivity and negative values of the excess free-energy of mixing, respectively. UV-Vis and FT-IR spectral measurements have also been carried out. The observed bathochromism and hypochromism in the UV-Vis spectra have been explained in terms of complex formation and ordering of dipoles of the complex. The FT-IR spectrum of the mixture shows considerable shifts in the positions of some of the absorption bands, indicating extensive hydrogen bonding between solute and solvent molecules.     

The equiratio taste mixture model successfully predicts the sensory response to the sweetness intensity of complex mixtures of sugars and sugar alcohols

The equiratio taste mixture model was originally developed for the prediction of psychophysical power functions of equiratio mixtures of substances that have a similar taste and that also exhibit mutual cross adaptation. Earlier studies have shown that the model is valid for mixtures of sugars and/or sugar alcohols. Two experiments are reported in which it is questioned whether the psychophysical functions of mixtures of higher physical complexity can be predicted by the model. In the first experiment the psychophysical power functions of binary and quaternary equiratio mixture types were determined experimentally and compared to those predicted by the generalized model. In the second, similar, experiment quaternary and eight-component mixture types were examined. The method of magnitude estimation, in combination with the sip and spit procedure, was used. The functions predicted by the model were almost identical to the functions established on the basis of the experimental data. These results reconfirm that the gustatory modality operates like an 'averaging' system when processing this kind of mixture. It is argued that for other kind of mixtures the model will predict incorrectly. The status of the equiratio mixture model is discussed.     

Dielectric relaxation study of mixtures of alkyl methacrylates and 1-alcohols using time-domain reflectometry

Dielectric relaxation measurements on alkyl methacrylates (methyl methacrylate, ethyl methacrylate and butyl methacrylate) with 1-alcohols (1-propanol, 1-pentanol, 1-heptanol, 1-octanol and 1-decanol) have been carried out using time-domain reflectometry (TDR) over the frequency range 10?MHz to 20?GHz at 303?K for different concentrations of alcohols. The dielectric parameters, namely the static dielectric constant (ε ₀), the dielectric constant at microwave frequencies (ε _∞) and the relaxation time (τ) were determined. The Kirkwood correlation factor, which contains information regarding solute–solvent interaction and corresponding structural information, the excess permittivity and the excess inverse relaxation time were also determined. The values of the static dielectric constant and the relaxation time increase with the percentage of alkyl methacrylates in the alcohol, whereas the static dielectric constant decreases and the relaxation time increases with an increase in the alkyl chain length of both the methacrylates and the alcohols.     

Taste-taste,odor-odor,and taste-odor mixtures: Greater suppression within than between modalities

Subjects judged the intensities of the component qualities of two taste stimuli [sucrose (S) and NaCl (N)], two odor stimuli [citral (C) and anethole (A)], and the mixtures of these stimuli [taste-taste (SN), odor-odor (CA), and taste-odor (SC, NC, SA, and NA)]. The within-modality mixtures, taste-taste and odor-odor, produced greater suppression of perceived intensity than did the between-modality mixtures, taste-odor. However, taste-odor mixtures also produced a significant amount of suppression of perceived intensity when compared with the individual taste and odor stimuli. The data are discussed with respect to peripheral and central mechanisms in mixture suppression.     

Differential associative conditioning and olfactory discrimination in the spiny lobster Panulirus argus

A differential aversive associative conditioning paradigm was used to assess the ability of the spiny lobster Panulirus argus both to associatively learn not to respond to the odorant stimulus to which it was conditioned and to discriminate between odorants. The paradigm consisted of pairing an aversive stimulus (pseudopredator) with a conditioned chemical stimulus (shrimp mixture). Four artificial mixtures (crab, mullet, oyster, and shrimp), each at 0.05 and 0.5 mM, were presented to the animals prior to, during, and following conditioning to both concentrations of the shrimp mixture. Pre- vs postconditioning changes in three types of behavioral responses (and an index based on a composite of these three behaviors) were used as indicators of learned aversions. Olfactory discrimination abilities were determined by comparing the aversion to the conditioned mixture with the aversions to the three nonconditioned mixtures. A high degree of associative learning was attained after 10 pairings of the pseudopredator with the shrimp mixture over a period of 5 test days. According to the aversion index, animals conditioned to shrimp mixture perceived crab mixture as being more similar to shrimp mixture than were mullet and oyster mixtures, but all three nonconditioned mixtures were perceived as being significantly different from the shrimp mixture. These results are in concordance with results of a cluster analysis based on the mixture compositions, which indicates that shrimp and crab mixtures are compositionally similar, while mullet and oyster mixtures are compositionally distinct from the shrimp mixture.     

Agonistic sensory effects of airborne chemicals in mixtures: Odor, nasal pungency, and eye irritation

Threshold responses of odor, nasal pungency (irritation), and eye irritation were measured for single chemicals (1-propanol, 1-hexanol, ethyl acetate, heptyl acetate, 2-pentanone, 2-heptanone, toluene, ethyl benzene, and propyl benzene) and mixtures of them (two three-component mixtures, two sixcomponent mixtures, and one nine-component mixture). Nasal pungency was measured in subjects lacking a functional sense of smell (i.e., anosmics) to avoid interference from olfaction. Various degrees of stimulus agonism (additive effects) were observed for each of the three sensory channels when testing mixtures. As the number of components and the lipophilicity of such components in the mixtures increased, so did the degree of agonism. Synergistic stimulus agonism characterized the eyeirritation response for the most complex (the nine-component) and the most lipophilic (one of the sixcomponent) mixtures. Physicochemical properties play a large role in the determination of sensitivity to airborne chemicals, particularly to their ability to evoke irritation. While this has revealed itself previously with respect to single chemicals, it seems to have relevance to mixtures as well.     

任务转换和目标变化下的自我加工优势

本研究旨在通过联结学习任务和线索转换任务探讨自我关联刺激在任务转换和目标变化下的加工优势。结果发现：（1）相比于朋友和陌生人,自我更容易学习联结;（2）在线索转换任务中,所有关联刺激均未出现任务转换成本;（3）在目标变化条件下,自我关联刺激的目标结转效率最佳。结果表明自我关联刺激能够调节任务转换成本,并且在目标变化条件下能快速聚焦注意,表现出基于感知的特异性加工优势。     

An interaction model for odor quality and intensity

The perceived intensity and quality of binary odor mixtures are studied in relation to bow their components are perceived when presented separately. Subjects judged the perceived intensity and quality of 6 concentrations of pyridine, 6 concentrations ofn-butanol, and their 36 possible combinations. The results show that the perceived intensity of the mixture can be predicted from the perceived intensity of its components presented separately (R _A andR _B) by the Euclidian arithmetic model. The maximum probability of identifying a mixture as a “mixture” is reached whenR _A andR _B are equally strong. An interaction model for mixtures that relates perceived intensity and quality is presented and tested. The test reveals that both the perceived intensity of a mixture and the probability that it will be identified as the one or the other component can, by a simple interaction model, be successfully predicted fromR _A andR _B.     

Odor intensity of mixed and unmixed stimuli under environmentally realistic conditions

Subjects judged the odor intensity of single odorants and binary mixtures of fixed or varying proportions presented in the atmosphere of an environmental chamber. The subjects were exposed to the vapors either continuously (15 min) or periodically (once a minute for 15 min). As found previously, the mixtures smelled less intense than predicted from the simple sum of their unmixed components. The degree of hypoadditivity proved about the same for the four pairs of odorants studied, but varied from periodic to continuous exposure. Periodic exposure led to a greater departure from simple additivity and confirmed the presence of the phenomenon of compromise whereby the mixture can smell less intense than its stronger component alone. Continuous exposure led to a closer approximation to simple additivity and exhibited no compromise. Nevertheless, the behavior seen under continuous exposure apparently derived from a tendency for mixtures to exhibit less adaptation than their components. Whereas mixtures may seem to lack potency relative to their unmixed components, they may in fact compensate for any deficiency in momentary intensity through an increase in durability.     

The Temporal Placement of Interpolated Movements in Short-Term Motor Memory,

Directional response biasing as a function of the recency of an interpolated act was examined on a lever device in a within-S design. The temporal occurrence of an interpolated act was systematically varied (5, 30, or 55 sec. after the criterion act) for three retention intervals (15, 40, and 65 sec.), and the location of the interpolated movement was held constant ± 40 deg. from the criterion position. Analysis of constant errors showed significant positive directional biasing for interpolated acts greater than criterion positions. Further analyses at the 40-and 65-sec. retention intervals supported a recency interpretation. As the retention interval increased, the positive constant error was maintained for interpolated acts with the same post-biasing interval, whereas constant error became increasingly negative as the post-biasing interval increased. Examination of variable error revealed a slight increase over time and no significant differences between directional conditions. The recency findings were discussed in terms of the view that reproduction of a criterion act is dependent on the relative decay states between the interpolated and criterion traces.     

Culture and alexithymia: mean levels,correlates, and the role of parental socialization of emotions

Two studies examined the relationship between culture and alexithymia. In Study 1, mean levels and correlates of alexithymia were examined in 3 cultures: European American (EA), Asian American (AA), and Malaysian college students. Both Asian groups had higher alexithymia levels than the EA group. Somatization was more strongly associated with alexithymia in the Asian groups than in the EA group. Mood and life satisfaction were associated with alexithymia in similar ways across groups. In Study 2, the relations among culture, gender, retrospective reports of parental socialization of emotions, and alexithymia were examined among EA and AA college students. Cultural and gender differences were found in alexithymia and emotion socialization levels. Most important, parental emotion socialization mediated the relations among culture, gender, and alexithymia.     

Cultural models of education in American Indian,Asian American and European American contexts

Three studies examined models of education among American Indian (AI), Asian American (AA), and European American (EA) students. Cultural models of education are patterns of ideas and practices relevant to schools, teachers, and self that mediate and regulate behavior in the academic domain. In study 1, mainstream university students (N = 148) and AI University students (N = 187) viewed education as a tool for success. AI, however, generated more mentions of education as a tool for community success and more negative associations to education. Study 2 (N = 166) showed that AI, in contrast to EA and AA, placed family and community concerns ahead of academic concerns. In Study 3 (N = 118), AI and AA endorsed independent and interdependent representations of self, while EA endorsed only independent representations. For AI and AA, but not for EA, interdependent representations were positively related to trust for teacher.     

A modified version of the unique cue theory accounts for olfactory compound processing in honeybees

We investigated the capability of honeybees to discriminate between single odorants, binary olfactory mixtures, and ternary olfactory mixtures in olfactory conditioning of the proboscis extension reflex. In Experiment 1, three single odorants (A+, B+, and C+) and three binary mixtures of these odors (AB+, AC+, and BC+) were reinforced while the ternary compound, consisting of all three odors (ABC-), was nonreinforced. In Experiment 2, only one single odorant (A+) and one binary olfactory compound (BC+) were reinforced while the ternary compound (ABC-) consisting of the single odor and the binary compound was nonreinforced. We studied whether bees can solve these problems and whether the course of differentiation can be predicted by the unique cue theory, a modified unique cue theory, or Pearce's configural theory. Honeybees were not able to differentiate reinforced from nonreinforced stimuli in Experiment 1. However, summation to ABC observed at the beginning of training contradicts the predictions of Pearce's configural theory. In Experiment 2, differentiation between the single odorant A and the ternary compound developed more easily than between the binary compound BC and ABC. This pattern of differentiation is in line with a modified unique cue theory and Pearce's configural theory. Summation to ABC at the beginning of training, however, again was at odds with Pearce's configural theory. Thus, olfactory compound processing in honeybees can best be explained by a modified unique cue theory.     

A complete minimal logic of the propositional contents of thought

Our purpose is to formulate a complete logic of propositions that takes into account the fact that propositions are both senses provided with truth values and contents of conceptual thoughts. In our formalization, propositions are more complex entities than simple functions from possible worlds into truth values. They have a structure of constituents (a content) in addition to truth conditions. The formalization is adequate for the purposes of the logic of speech acts. It imposes a stronger criterion of propositional identity than strict equivalence. Two propositions P and Q are identical if and only if, for any illocutionary force F, it is not possible to perform with success a speech act of the form F(P) without also performing with success a speech act of the form F(Q). Unlike hyperintensional logic, our logic of propositions is compatible with the classical Boolean laws of propositional identity such as the symmetry and the associativity of conjunction and the reduction of double negation.Presented byJan Zygmunt     

Optical characterization of spin-coated cobalt porphyrazine thin films: effect of annealing temperature

Cobalt porphyrazine thin films were prepared by the spin-coating technique. The coated substrates were annealed at different temperatures (373, 423 and 523 K). The optical properties of the films were investigated by measuring the transmittance and reflectance spectra. The refractive index, extinction coefficient, optical band gap, dielectric constant values and thickness of the films were determined. Results showed that the refractive index, the extinction coefficient and the dielectric constants increased on annealing the films at 373 K in comparison with films annealed at other temperatures. On the other hand, the values of the band gap energy and thickness of the annealed film at 373 K were found to be the lowest in comparison with films annealed at different temperatures.