Produce Interference Effects Research Articles

Interference Effects on Procedural Memory

Three experiments were conducted assessing interference effects acting on procedural task learning and performance using the Tower of Hanoi puzzle as the target procedural task. Experiment 1 found that participants in the no retroactive interference (RI) group completed the Tower of Hanoi task faster than the RI groups, with no differences between the type of the tactile interference. These results indicate that RI may hinder procedural task performance, but does not differentiate between consolidation and retrieval. Experiment 2 addressed RI placement by manipulating the delay prior to the interference task. Subsequent analyses suggested that interfering with only consolidation or recall does not produce interference effects, but qualitative feedback regarding emotion raised further questions about the effects of affect induction. Experiment 3 attempted to address the influence of a proactive and retroactive affect induction technique, but was unsuccessful in producing a dichotomous happy versus neutral effect. However, it was noted that alertness changed across the task acquisition stage, and the change in alertness may account for enhanced procedural memory acquisition. Overall, the series of experiments conducted provides conceptual replication of some previous research while contradicting other findings. This research not only extends our current understanding but also highlights the need to replicate research and continue to explore factors that may influence the practice or acquisition of novel procedural tasks.

ELF-EM fields in the multi-layer spherical ‘Earth-ionosphere’ model based on WKB

Abstract With a high signal-to-noise ratio and a great depth of exploration, the wireless electromagnetic method (WEM) has wide applications in the exploration of deep mineral resources and oil and gas reservoirs. Extremely low-frequency electromagnetic (ELF) waves emitted from a horizontal antenna are used to achieve synchronous acquisition for different receivers of multi-coverage information in a global region. However, previous research based on a planar model ignored the curvature of the Earth. This work focuses on the electromagnetic fields (EM fields) in the model of a spherical ‘Earth ionosphere’ to extend the coverage of WEM. By transferring the EM fields from a vertical electric dipole (VED) as well as a vertical magnetic dipole (VMD) in the multi-layered medium of the Earth, we obtain the formulae for the EM fields emitted by a horizontal electric dipole (HED) by using a reciprocity theorem. The correctness of the proposed method is verified by comparing it with the approximate analytical formula and previous work. Based on the above results, we have studied the propagation and frequency characteristics of electromagnetic fields in a spherical waveguide consisting of the ionosphere and earth. The results show that the electromagnetic fields under the spherical model produce interference effects that are different from those of the planar model. The electromagnetic response of the layered Earth was then discussed, and its potential as an electromagnetic technique for exploring the deep Earth was demonstrated.

Effects of eye and hand movement on cross-modal memory.

In this study, we determined whether information in eye-hand/hand-eye cross-modal memory is maintained by the input modality used for encoding, the output modality used for testing, or both. In experiments, two categories of effect were examined: facilitatory, produced by rehearsal work with eyes or hands corresponding to the movement of the stimulus to be memorized after its presentation, and interference, formed through the performance of a noncorresponding movement. The results indicated that both the eye and hand facilitated the eye-hand cross-modal memory tasks (Experiment 1A), confirming that both serve a rehearsal function. Subsequently, we conducted an interference effect experiment (Experiment 1B) using the same memory task as that used in Experiment 1A and found that neither modality produced interference effects. This result indicates that information was preserved via output-modality-specific representations when the eye-interference task interfered with the information retention of input-modality-specific representations and via input-modality-specific representations when the hand-interference task interfered with the information retention of output-modality-specific representations. We observed the same facilitation and disappearance of interference effects for the hand-eye cross-modal memory task (Experiments 2A and 2B). In the eye-hand/hand-eye cross-modal memory tasks, the effects of eye and hand rehearsals were found to be comparable, which indicated that the two types of representations functioned together during encoding and testing. From the disappearance of interference effects, the possibility that modality-specific representations have functional aspects arises.

The color-word Stroop effect driven by working memory maintenance.

Previous research has shown that holding a color word in working memory can produce interference effects in an intervening color-identification task, which mimics the classic color-word Stroop effect. Although this finding has previously been considered to suggest that the content of working memory can have behavioral consequences similar to those of externally perceived stimuli, it has remained unclear whether active internal maintenance of a color word indeed makes a critical contribution to the working memory Stroop effect. In the present study, we addressed this matter by asking participants to perform a color-identification task following display of eithera congruent or anincongruent color word. By controlling for encoding strategy and/or maintenance demand across Experiments 1-4, we consistently showed that the magnitude of the congruency effect in color-identification performance was markedly larger when the recently presented color word was actively retained in working memory, as compared to when the color word was perceptually identified without working memory processing, when the color word had once been remembered but was no longer being actively maintained in working memory, or when the color word was retro-cued to be irrelevant to the working memory task. The findings therefore demonstrate a critical role for active internal maintenance of a color word in producing the working memory Stroop effect. In addition, Experiment 5 further showed that the working memory Stroop effect was sustained over time during the retention interval. Moreover, we found that the intervening color-identification task conversely influenced working memory maintenance, leading to poorer memory performance on incongruent than on congruent trials. We discuss the implications of these findings for understanding the linkage between working memory and attention.

Effects of aerodynamic modification mechanisms on interference from neighboring buildings

This paper investigates the effect of the single and multiple aerodynamic modification mechanisms on the dynamic behavior of the principal building that is interfered by a very closely located building. For the study, aeroelastic vibration tests and high-frequency force balance tests are conducted to compare responses and wind forces in a well-simulated turbulent boundary layer flow. The principal building is manufactured with three different building configurations to represent the single and multiple aerodynamic modification treatments; the neighboring building which produces interference effects is made into a square prism model. Results show that the multiple modification treatment is efficient in reducing wind forces in all interference location series. However, it is also found that in certain critical conditions, such treatment is sensitive to reduced velocity, and may amplify the interference effect and result in larger displacements.

Distracted by pleasure: Effects of positive versus negative valence on emotional capture under load.

We report 3 experiments examining the effects of positive versus negative valence and perceptual load in determining attention capture by irrelevant emotional distractors. Participants performed a letter search task searching for 1 of 2 target letters (X or N) in conditions of either low perceptual load (circular nontarget letters) or high perceptual load (angular nontarget letters that are similar to the target letters). On 25% of the trials an irrelevant emotional distractor was presented at the display center and participants were instructed to ignore it. The distractor stimulus was either positive or negative and was selected from 3 different classes: IAPS pictures of erotica or mutilated bodies (Experiment 1), happy or angry faces (Experiment 2), and faces associated with gain or loss in a prior value-learning phase involving a betting game (Experiment 3). The results showed a consistent pattern of interaction of load and valence across the 3 experiments. Irrelevant emotional distractors produced interference effects on search reaction time (RT) in conditions of low load, with no difference between negative and positive valence. High perceptual load, however, consistently reduced interference from the negative-valence distractors, but had no effect on the positive-valence distractors. As these results were consistently found across 3 different categories of emotional distractors, they suggest the general conclusion that attentional capture by irrelevant emotional distractors depends on both their valence and the level of perceptual load in the task and highlight the special status of distractors associated with pleasure.

The role of meaning and form similarity in translation recognition in highly proficient balanced bilinguals: A behavioral and ERP study

Abstract Previous behavioral findings showed that pairs of words that are highly related in meaning across two languages and pairs in which the second word is related in lexical form to the correct translation of the first one produce interference effects when highly proficient balanced bilinguals perform a translation recognition task (Ferre, Sanchez-Casas, & Guasch, 2006; Moldovan, Sanchez-Casas, Demestre, & Ferre, 2012). In contrast, interference effects were not observed when the two words were less related in meaning. The lack of interference with less related words could be explained by the fact that the level of activation of the corresponding semantic representations is too low so as to produce interference at the time the translation decision has to be made. Moreover, behavioral measures might be not sensitive enough to capture the activation of such representations. In the present study, highly proficient balanced Catalan–Spanish bilinguals performed a translation recognition task in which a short stimulus onset asynchrony (SOA, i.e., 250 ms) was used and event related potentials (ERPs) were recorded. There were three critical conditions: pairs of words highly related in meaning, pairs of words less related in meaning, and pairs in which the second word was similar in lexical form to the correct translation of the first word. Behavioral results showed interference effects in all conditions. ERPs revealed modulations of the N400 for the two semantic conditions, and modulations of the LPC for the form condition. These results reveal that when short SOAs and sensitive measures are used, interference effects with words less related in meaning are obtained as well. In addition, these findings suggest that meaning is accessed before the translation equivalent becomes available, that is, highly proficient balanced bilinguals can directly access the conceptual system from both of their languages.

Study of Optical Coherence Theory in Measurement

Light is a transverse electromagnetic wave, which has the volatility and particles. When light waves are added up in the spatial uniform medium, different conditions will produce interference effects in the meeting area. Optical path difference affects the distribution of the interference pattern directly, and the light interference pattern gives information of phase and amplitude in turn. Due to the measurement precision and extremely high sensitivity of response, the principle of optical coherence has been studied based on measuring the related physical quantity indirectly.

When semantics means less than morphology: The processing of German prefixed verbs

This study investigated whether form and meaning relatedness modulate the processing of morphologically related German verbs. In two overt visual priming experiments, we compared responses for verb targets (kommen, come) that were preceded by a purely semantically related verb (nahen, approach), by a morphologically and semantically related verb (mitkommen, come along), by a purely morphologically related verb (umkommen, perish), or by an unrelated verb (schaden, harm). In Experiment 1, morphological relatedness produced robust facilitation, which was not influenced by semantic relatedness. Moreover, this morphological facilitation was far stronger than the priming by purely semantically related verbs. In Experiment 2, orthographically similar primes (kämmen, comb) produced interference effects and thus indicated that the morphological facilitation effects were not the result of sheer form overlap between primes and targets. These findings argue for a single system that processes morphological relations independently of form and meaning relatedness.

The role of working memory in spatial text processing: What benefit of imagery strategy and visuospatial abilities?

This study investigated the construction of a spatial model in relation to working memory (WM) and visuospatial abilities. Participants were trained to use either imagery or verbal strategies to process route spatial texts. Results obtained on a free recall task, a verification test and a graphic representation task showed the beneficial effect of using a strategy based on mental images. When imagery strategies were used, a concurrent articulatory task produced interference effects on recall performance, and a spatial tapping task also impaired performance as compared to the control condition. These interference effects suggest that both visuospatial and verbal WM were involved in construction of the spatial model. When repetition strategies were used, however, only the articulatory task produced interference effects, highlighting the role of the verbal WM. To elucidate how the involvement of the visuospatial component may differ in relation to visuospatial abilities, participants with good or poor ability in generation of visual images and spatial manipulation of objects were compared. The benefit of the imagery strategy was found in both groups, but whereas low-visuospatial imagery participants were sensitive to spatial interference, their high ability counterparts were not. These results question the role of imagery processes in the construction of spatial models and their relation to the visuospatial WM.

Structure of Sodium Glycodeoxycholate Micellar Aggregates from Small-Angle X-ray Scattering and Light-Scattering Techniques

Small-angle X-ray scattering (SAXS) and dynamic light scattering (DLS) measurements were accomplished on sodium glycodeoxycholate (NaGDC) aqueous electrolyte solutions as a function of NaGDC and NaCl concentrations with the aim to determine with satisfactory approximation the NaGDC micellar aggregate structure at a gross molecular level, assuming monodispersity. Different conditions of interparticle interactions by varying ionic strength (NaCl concentration from 0 to 0.70 M) and NaGDC concentration (from 0.02 to 0.10 M) were studied. Smeared scattering intensities and electron pair distance distribution functions, radii of gyration, and aggregate heights are in satisfactory agreement with the corresponding functions calculated using a 2(1) helix as model. It is formed by trimers, each one composed by three NaGDC and nine H2O molecules related by a 3-fold rotation axis, and can be described by a hollow cylinder, probably filled by water molecules, characterized by a conventional radius of 23.7 A and a trimer repeat along the helical axis of 3.6 A. The helix is considerably inhomogeneous since the volume of the cylinder occupied by NaGDC molecules is less than one-third of the total. On the other hand, calculations performed with the average radial electronic density of the helix without water molecules or totally filled by water molecules (a NaGDC/H2O molecular ratio of about 1/50) or by using a three-shell average radial electronic density, independently evaluated on absolute scale, do not show significant differences, thus supporting the helical model. The aggregate size increases for all the samples by increasing either the NaCl or NaGDC concentration. The NaGDC low concentration (0.02 M) samples with NaCl within the range 0.30-0.70 M are characterized by short cylindrical aggregates that do not give rise to sensible interference effects. This assertion is supported by the satisfactory fit between the observed apparent mean hydrodynamic radii and the calculated ones by means of the method of Ortega and Garcia de la Torre (J. Chem. Phys. 2003, 119, 9914), valid for rods with a length-to-diameter ratio > or = 0.1 in dilute solution (noninteracting rods). The NaGDC moderate concentration (0.10 M) samples with NaCl within the range 0.20-0.60 M are characterized by cylindrical aggregates that, in the presence of repulsive Coulombic interactions progressively more and more screened, produce interference effects, due to the hard-body repulsion and attractive forces, but the agreement between observed and calculated SAXS data is satisfactory. The results of the low and moderate NaGDC concentration samples seem to indicate that the aggregation number increase, produced by adding 0.10 M NaCl, is constant within an ionic strength range and occurs by the addition of oligomers formed by trimers. The samples with a variable NaGDC concentration (0.02-0.10 M) at a fixed and high NaCl concentration (0.6 M) contain cylindrical aggregates that give rise to an attractive term effect prevailing on the hard-body repulsive one. The same situation seems to occur in the NaGDC moderate concentration samples.

Attention bias to faces in Asperger Syndrome: a pictorial emotion Stroop study

Emotional Stroop tasks have shown attention biases of clinical populations towards stimuli related to their condition. Asperger Syndrome (AS) is a neuropsychiatric condition with social and communication deficits, repetitive behaviours and narrow interests. Social deficits are particularly striking, including difficulties in understanding others. We investigated colour-naming latencies of adults with and without AS to name colours of pictures containing angry facial expressions, neutral expressions or non-social objects. We tested three hypotheses: whether (1) controls show longer colour-naming latencies for angry versus neutral facial expressions with male actors, (2) people with AS show differential latencies across picture types, and (3) differential response latencies persist when photographs contain females. Controls had longer latencies to pictures of male faces with angry compared to neutral expressions. The AS group did not show longer latencies to angry versus neutral expressions in male faces, instead showing slower latencies to pictures containing any facial expression compared to objects. When pictures contained females, controls no longer showed longer latencies for angry versus neutral expressions. However, the AS group still showed longer latencies to all facial picture types, compared to objects, providing further evidence that faces produce interference effects for this clinical group. The pictorial emotional Stroop paradigm reveals normal attention biases towards threatening emotional faces. The AS group showed Stroop interference effects to all facial stimuli regardless of expression or sex, suggesting that faces cause disproportionate interference in AS.

It's not that bad: Error introduced by oral stimulants in salivary cortisol research

Evidence that oral stimulants can produce interference effects in salivary cortisol assays has led to advice to avoid their use. However, in studies with young children, the use of these saliva-producing substances increases compliance with collection procedures. Four experiments are described to examine the effects of two commonly used stimulants, SweetTarts and Koolaid. Across these experiments, interference effects produced by different quantities of these stimulants (0.025, 0.1, and 0.2 g) and those produced in two commonly used assays, DELFIA and EIA, were explored. The impact of using cotton rolls soaked with an oral stimulant prior to saliva collection was also examined. In general, oral stimulants did not affect the rank ordering of cortisol values, as the results for stimulant-treated samples were highly correlated with those of untreated samples (approximately .90 for serially collected samples and .95 for aliquots of the same saliva pool). Depending on which assay was used, however, oral stimulants increased or decreased the cortisol levels reported, with effects sizes in the small to medium range. Thus, oral stimulants should not be used with only a portion of the subjects in a study, nor should researchers assay stimulant-treated samples from the same study using different assays. When used sparingly, oral stimulants can be employed without compromising the quality of salivary cortisol data.

Horizontal information flow in spoken sentence production.

In 4 experiments the authors used a variant of the picture-word interference paradigm to investigate whether there is a temporal overlap in the activation of words during sentence production and whether there is a flow of semantic and phonological information between them. Experiments 1 and 2 demonstrate that 2 semantically related nouns produce interference effects either when they are in the same or different phrases of a sentence. Experiments 3 and 4 demonstrate that 2 phonologically related nouns produce facilitation effects but only when they are within the same phrase of a sentence. The results argue against strictly serial models of multiple-word access and provide evidence of a flow of semantic and phonological information between words during sentence production.

NAIM and site-specific functional group modification analysis of RNase P RNA: magnesium dependent structure within the conserved P1-P4 multihelix junction contributes to catalysis.

The tRNA processing endonuclease ribonuclease P contains an essential and highly conserved RNA molecule (RNase P RNA) that is the catalytic subunit of the enzyme. To identify and characterize functional groups involved in RNase P RNA catalysis, we applied self-cleaving ribozyme-substrate conjugates, on the basis of the RNase P RNA from Escherichia coli, in nucleotide analogue interference mapping (NAIM) and site-specific modification experiments. At high monovalent ion concentrations (3 M) that facilitate protein-independent substrate binding, we find that the ribozyme is largely insensitive to analogue substitution and that concentrations of Mg2+ (1.25 mM) well below that necessary for optimal catalytic rate (>100 mM) are required to produce interference effects because of modification of nucleotide bases. An examination of the pH dependence of the reaction rate at 1.25 mM Mg2+ indicates that the increased sensitivity to analogue interference is not due to a change in the rate-limiting step. The nucleotide positions detected by NAIM under these conditions are located exclusively in the catalytic domain, consistent with the proposed global structure of the ribozyme, and predominantly occur within the highly conserved P1-P4 multihelix junction. Several sensitive positions in J3/4 and J2/4 are proximal to a previously identified site of divalent metal ion binding in the P1-P4 element. Kinetic analysis of ribozymes with site-specific N7-deazaadenosine and deazaguanosine modifications in J3/4 was, in general, consistent with the interference results and also permitted the analysis of sites not accessible by NAIM. These results show that, in this region only, modification of the N7 positions of A62, A65, and A66 resulted in measurable effects on reaction rate and modification at each position displayed distinct sensitivities to Mg2+ concentration. These results reveal a restricted subset of individual functional groups within the catalytic domain that are particularly important for substrate cleavage and demonstrate a close association between catalytic function and metal ion-dependent structure in the highly conserved P1-P4 multihelix junction.

Size effects in multiple quantum NMR of finite spin chains

Exact calculations of multiple quantum NMR spectral intensities in finite one-dimensional quantum spin chains with nearest-neighbor couplings and evolving under a two-quantum/two-spin propagator reveal a transition between regular and erratic behavior in the spin dynamics. The onset for this transition, which depends on the number of spins in the chain, arises from spin wave packet propagation and reflection which produce interference effects in finite chains. Implications for excitation of high-order coherences in solids are discussed. The perturbations of one and two spins on the multiple quantum NMR response of an N-spin chain are also examined.

Phase-coherent multilevel two-photon transitions in cold Rb atoms: Ultrahigh-resolution spectroscopy via frequency-stabilized femtosecond laser

A two-photon transition in cold Rb atoms will be probed with a phase-coherent wide bandwidth femtosecond laser comb. Frequency domain analysis yields a high-resolution picture where phase coherence among various transition pathways through different intermediate states produces interference effects on the resonantly enhanced transition probability. This result is supported by the time domain Ramsey interference effect. The two-photon transition spectrum is analyzed in terms of the pulse repetition rate and carrier frequency offset, leading to a cold-atom-based frequency stabilization scheme for both degrees of freedom of the femtosecond laser.

Neutrino oscillations in structured matter

A layered material structure in a monochromatic neutrino beam produces interference effects that could be used for the measurement of features of the neutrino mass matrix. The phenomenon would be most useful at high energies.

The Effects of Visual Discomfort and Pattern Structure on Visual Search

Unpleasant somatic and perceptual side effects can be induced when viewing striped repetitive patterns, such as a square wave or a page of text. This sensitivity is greater in participants with higher scores on a scale of visual discomfort. In three experiments the effect that this sensitivity has on performance efficiency in a reading-like visual search task was investigated. In experiments 1 and 2, the 'global' structure of the patterns was manipulated to produce a square-wave, a checkerboard, and a plaid pattern. It was found that the group that suffered severe visual discomfort took significantly longer than other groups to perform the task, with interference greatest with presentation of the square-wave-like pattern. This supports the prediction of greatest distraction of visual attention from the local target elements with presentation of the pattern structure inducing greatest visual discomfort. In experiment 3, the internal pattern components were manipulated and task difficulty reduced. A no-interference and two interference patterns, one with a global characteristic only and the second made up of distracting line elements, containing global and local components were used. The global pattern structure produced interference effects on the visual-search task. All groups performed with the same speed and accuracy on the task involving the no-interference pattern, a finding attributed to reduced task difficulty. McConkie and Zola's model of visual attention was used to explain these results.

Semiconductor laser confocal and interference microscopy

We describe a semiconductor laser confocal microscope which has the capability to produce both confocal and interference images. This versatility is achieved by using different lasing regimes of the laser, which are controlled by its injection current. When operated just above threshold the coherence length of the laser is too short to allow interferometry so a pure confocal image is obtained. At higher injection currents the coherence length is sufficient to produce interference effects. We present an almost common path interference confocal microscope in which a single mode optical fibre is used both to launch and to detect the confocal signal as well as to provide the reference beam. To obtain surface profilometry we introduce a high frequency modulation to the semiconductor laser injection current which results in a corresponding modulation of the laser wavelength. We then use lock-in demodulation together with a simple feedback system to obtain the phase image and hence the surface profile. We also discuss the issue of resolution in phase imaging systems.