Primacy, Recency, and Suffix Effects in Auditory Short-Term Memory for Pure Tones: Evidence From a Probe Recognition Paradigm.

The present study was designed to explore serial position and suffix effects in the short-term retention of nonverbal sounds. In contrast with previous studies of these effects, a probe recognition paradigm was used to minimize the possibility that participants would use a verbal labelling strategy. On each trial, participants heard a memory set consisting of three pure tones, followed five seconds later by a probe tone. Participants were required to indicate whether or not the probe tone had been a member of the memory set. On most trials, a suffix sound was presented 1 second following the third sound in the memory set. Results revealed that tones presented in the first and last positions of the memory set were recognized more accurately than were tones presented in the middle position. Furthermore, recognition of sounds presented in the last position was compromised when the memory set was followed by a postlist suffix of similar pitch, spectral composition, and spatial location. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for proactive interference in the focus of attention of working memory.

Proactive interference (PI) occurs when an earlier item interferes with memory for a newer item. Whereas some researchers (e.g., Surprenant & Neath, 2009a) argue that PI can be observed in all memory systems, some multiple systems theorists (e.g., Cowan, 1999) propose that items in the focus of attention of working memory are immune to PI. Two experiments tested whether PI occurs when the to-be-remembered items are assumed, by multiple-systems theorists, to be held in the focus of attention. In each experiment, subjects saw four trials in a row with the same type of to-be-remembered items, followed by four trials in a row with a different type of material. On each trial, only 3 stimuli were shown, which is below the capacity limit of the focus of attention, and subjects were asked if a probe item was one of those 3 items seen. In both experiments, response time increased from Trial 1 to Trial 4, suggesting that items from the earlier trials interfered with memory on the later trials. In addition, release from PI was shown in that response times decreased with a change of materials. The results replicate those first reported by Hanley and Scheirer (1975), and pose a problem for theorists who argue that parts of short-term memory are immune to PI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of same-category and different-category extraneous memory sets on item recognition

In a study designed to distinguish between parallel and serial models of performance on Sternberg's item recognition task, Krueger (1975) presented subjects with a memory set (the "added" set) followed by a second ("core") set, a probe to the core set, and finally a probe to the added set. Response latency (RT) to both the core- and added-set probes initially increased with the size of the extraneous set. Over successive blocks of trials, the effect of the size of the extraneous set diminished. In Experiment 1 of the present study, Krueger's basic procedures were replicated with results similar to those he reported for early trials. Experiment 2 was a variation on the added-set procedure. Rather than the memory sets' being drawn from different categories (letters and digits), both sets consisted of digits. On half of the negative trials for both the core and the added tasks, the probe was drawn from the extraneous set, forcing the subjects to separate the two sets. Although RT on the core task did not increase with the size of the added set, there was an increase in RT to the added set with increases in core-set size, a finding inconsistent with the serial search model.     

Integration of auditory and kinesthetic information in motion: Alterations in Parkinson's disease.

The main aim in this work was to study the interaction between auditory and kinesthetic stimuli and its influence on motion control. The study was performed on healthy subjects and patients with Parkinson's disease (PD). Thirty-five right-handed volunteers (young, PD, and age-matched healthy participants, and PD-patients) were studied with three different motor tasks (slow cyclic movements, fast cyclic movements, and slow continuous movements) and under the action of kinesthetic stimuli and sounds at different beat rates. The action of kinesthesia was evaluated by comparing real movements with virtual movements (movements imaged but not executed). The fast cyclic task was accelerated by kinesthetic but not by auditory stimuli. The slow cyclic task changed with the beat rate of sounds but not with kinesthetic stimuli. The slow continuous task showed an integrated response to both sensorial modalities. These data show that the influence of the multisensory integration on motion changes with the motor task and that some motor patterns are modulated by the simultaneous action of auditory and kinesthetic information, a cross-modal integration that was different in PD-patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory response areas altered by intermodulation distortion products from background tones

Response areas (RAs) of sensory neurones are dynamically modified by attention, denervation of specific afferent input, blocking inhibition, and by prolonged conditioning with extra-RA stimuli. Here we demonstrate in auditory neurones that the RA is also critically influenced by the background to stimuli. When RAs are measured in the presence of non-excitatory extra-RA tones, new RAs arise at frequencies otherwise not excitatory, as a consequence of non-linear receptor organ transduction. The new RAs can become more sensitive than the RA in quiet conditions such that neurones are then effectively tuned to a new frequency. Thus, even in a modestly complex environment, auditory neurones do not signal a fixed range of sounds but effectively code sounds to which they are otherwise unresponsive.     

Long-term proactive interference and novelty enhancement effects in monkey list memory.

Serial-probe-recognition (SPR) performance by 2 monkeys deteriorated over several months of training. Three hundred and twenty different items were presented without repetition within a session (trial unique) but were repeated between sessions. The cause of the deterioration was identified as proactive interference (PI) due to repetitive use of items from day to day. Introduction of novel stimuli across days improved performance from 63% to 82% correct (Experiment 1). Tests with only probe items and no list items (Experiment 2) revealed that the monkeys were using a familiar/novel response strategy in combination with a relational strategy (relating the probe item to the list items) to further improve their SPR performance. Intermixing familiar baseline trials and novel transfer trials within a session (Experiment 3) encouraged the subjects to use a relational strategy, and it improved performance on baseline trials as well as on transfer trials. Possible qualitative similarity between the relational strategy and the familiar/novel response strategy is discussed along with theoretical implications of these findings for experiments which have used small number of repeating stimuli within a session. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exploring auditory saltation using the "reduced-rabbit" paradigm.

Sensory saltation is a spatiotemporal illusion in which the judged positions of stimuli are shifted toward subsequent stimuli that follow closely in time. So far, studies on saltation in the auditory domain have usually employed subjective rating techniques, making it difficult to exactly quantify the extent of saltation. In this study, temporal and spatial properties of auditory saltation were investigated using the "reduced-rabbit" paradigm and a direct-location method. In 3 experiments, listeners judged the position of the 2nd sound within sequences of 3 short sounds by using a hand pointer. When the delay between the 2nd and 3rd sound was short, the target sound was shifted toward the subsequent sound. The magnitude of displacement increased when the temporal and spatial distance between the sounds was reduced. In a 4th experiment, a modified reduced-rabbit paradigm was used to test the hypothesis that auditory saltation is associated with an impairment of target sound localization. The findings are discussed with regard to a spatiotemporal integration approach in which the processing of auditory information is combined with information from subsequent stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal integration of sequential auditory events: silent period in sound pattern activates human planum temporale

Temporal integration is a fundamental process that the brain carries out to construct coherent percepts from serial sensory events. This process critically depends on the formation of memory traces reconciling past with present events and is particularly important in the auditory domain where sensory information is received both serially and in parallel. It has been suggested that buffers for transient auditory memory traces reside in the auditory cortex. However, previous studies investigating "echoic memory" did not distinguish between brain response to novel auditory stimulus characteristics on the level of basic sound processing and a higher level involving matching of present with stored information. Here we used functional magnetic resonance imaging in combination with a regular pattern of sounds repeated every 100 ms and deviant interspersed stimuli of 100-ms duration, which were either brief presentations of louder sounds or brief periods of silence, to probe the formation of auditory memory traces. To avoid interaction with scanner noise, the auditory stimulation sequence was implemented into the image acquisition scheme. Compared to increased loudness events, silent periods produced specific neural activation in the right planum temporale and temporoparietal junction. Our findings suggest that this area posterior to the auditory cortex plays a critical role in integrating sequential auditory events and is involved in the formation of short-term auditory memory traces. This function of the planum temporale appears to be fundamental in the segregation of simultaneous sound sources.     

Signals of threat do not capture, but prioritize, attention: A conditioning approach.

Research suggests that threatening information captures attention more rapidly than neutral information. However, in most studies threat stimuli differ perceptually from neutral stimuli and are instrumental to perform the task, leaving the question unanswered whether threat is sufficient to capture attention. In experiment 1, we designed a visual search task with stimuli of equal salience (colored circles) that have the potential to lead to efficient search (10 ms/item). In experiment 2, one of the colors (conditioned stimulus, CS+) was made threatening by means of fear conditioning. Participants responded to a target presented in one of the circles. Overall, the search was faster on congruent trials (where the target was presented in the CS+) than on baseline trials (where the CS + was absent). Furthermore, the search was slower on incongruent trials (where the target was presented in another color than the CS+) than on baseline trials. The search on congruent trials was affected by set size (90 ms/item), but to a lesser extent than on baseline trials (105 ms/item). We conclude that threat prioritizes, but does not capture attention. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The extralist-feature effect: Evidence against item matching in short-term recognition memory.

The authors varied the similarity between negative probes and study items in a short-term item-recognition task. Current models treat similarity as a function of the number of occurrences of the probe's features in the study set, a factor that is often confounded with the number of the probe's features occurring in the study set. Unconfounded comparisons showed that performance reflected only the latter factor, with response time a linear function of the number of probe features in the study set. The effect was obtained for both stimuli with manipulated features (colored shapes) and words. Number of presented features is a global property of the study list, but existing global models calculate familiarity by averaging across item matches and cannot readily accommodate the data. The authors proposed that the probe's features are compared with a global representation of the study set's features. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lateralized auditory spatial perception and the contralaterality of cortical processing as studied with functional magnetic resonance imaging and magnetoencephalography

Functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) were used to study the relationships between lateralized auditory perception in humans and the contralaterality of processing in auditory cortex. Subjects listened to rapidly presented streams of short FM-sweep tone bursts to detect infrequent, slightly deviant tone bursts. The stimulus streams consisted of either monaural stimuli to one ear or the other or binaural stimuli with brief interaural onset delays. The onset delay gives the binaural sounds a lateralized auditory perception and is thought to be a key component of how our brains localize sounds in space. For the monaural stimuli, fMRI revealed a clear contralaterality in auditory cortex, with a contralaterality index (contralateral activity divided by the sum of contralateral and ipsilateral activity) of 67%. In contrast, the fMRI activations from the laterally perceived binaural stimuli indicated little or no contralaterality (index of 51%). The MEG recordings from the same subjects performing the same task converged qualitatively with the fMRI data, confirming a clear monaural contralaterality, with no contralaterality for the laterally perceived binaurals. However, the MEG monaural contralaterality (55%) was less than the fMRI and decreased across the several hundred millisecond poststimulus time period, going from 57% in the M50 latency range (20-70 ms) to 53% in the M200 range (170-250 ms). These data sets provide both quantification of the degree of contralaterality in the auditory pathways and insight into the locus and mechanism of the lateralized perception of spatially lateralized sounds.     

Analysis of perceptual confusions between nine sets of consonant-vowel sounds in normal and dyslexic adults

It is widely accepted that most developmental dyslexics perform poorly on tasks which assess phonological awareness. One reason for this association might be that the early or "input" phonological representations of speech sounds are distorted or noisy in some way. We have attempted to test this hypothesis directly. In Experiment 1, we measured the confusions that adult dyslexics and controls made when they listened to nine randomly presented consonant-vowel (CV) segments [sequence: see text] under four conditions of increasing white noise masking. Subjects could replay stimuli and were under no obligation to respond quickly. Responses were selected with a computer mouse from a set of nine letter-strings, corresponding to the auditory stimuli, presented on a VDU. While the overall pattern of confusions made by dyslexics and controls was very similar for this stimulus set, dyslexics confused [sequence: see text] significantly more than did controls. In Experiment 2, subjects heard each stimulus once only and were forced to respond as quickly as possible. Under these timed conditions, the pattern of confusions made by dyslexics and controls was the same as before, but dyslexics took longer to respond than controls. The slower responses of dyslexics in Experiment 2 could have arisen because: (a) they were slower at processing the auditory stimuli than controls, (b) they had worse visual pattern memory for letter strings than controls, (c) they were slower than controls at using the computer mouse. In Experiments 3, 4 and 5 subjects carried out control tasks which eliminated each of these possibilities and confirmed that the results from the auditory tasks genuinely reflected subjects' speech perception. We propose that the fine structure of dyslexics' input phonological representations should be further explored with this confusion paradigm by using other speech sounds containing VCs, CCVs and VCCs.     

Dissociating emotion-induced blindness and hypervision.

Previous findings suggest that emotional stimuli sometimes improve (emotion-induced hypervision) and sometimes impair (emotion-induced blindness) the visual perception of subsequent neutral stimuli. We hypothesized that these differential carryover effects might be due to 2 distinct emotional influences in visual processing. On the one hand, emotional stimuli trigger a general enhancement in the efficiency of visual processing that can carry over onto other stimuli. On the other hand, emotional stimuli benefit from a stimulus-specific enhancement in later attentional processing at the expense of competing visual stimuli. We investigated whether detrimental (blindness) and beneficial (hypervision) carryover effects of emotion in perception can be dissociated within a single experimental paradigm. In 2 experiments, we manipulated the temporal competition for attention between an emotional cue word and a subsequent neutral target word by varying cue–target interstimulus interval (ISI) and cue visibility. Interestingly, emotional cues impaired target identification at short ISIs but improved target identification when competition was diminished by either increasing ISI or reducing cue visibility, suggesting that emotional significance of stimuli can improve and impair visual performance through distinct perceptual mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Standardized stimuli and procedures for investigating the retrieval of lexical and conceptual knowledge for actions

We have developed a set of naming and recognition tests for evaluating the retrieval of lexical and conceptual knowledge for actions. As a first step, normative information about 280 items was collected for the following variables: (1) the naming responses elicited by each item, (2) the degree to which the image of each item agreed with a target name, (3) the familiarity to each depicted action, and (4) the visual complexity of each item. This information was used to develop administration and scoring procedures for a standardized test of action naming. The effectiveness and reliability of these procedures were evaluated in a second experiment. In a third experiment, five tests were developed to probe the retrieval of conceptual knowledge: (1) independently of the production of a naming response, (2) in response to pictorial and nonpictorial stimuli, (3) in terms of the attributes associated with specific actions, and (4) in terms of similarities and differences between various actions.     

Optimal integration of auditory and vibrotactile information for judgments of temporal order.

Recent research that assessed spatial judgments about multisensory stimuli suggests that humans integrate multisensory inputs in a statistically optimal manner by weighting each input by its normalized reciprocal variance. Is integration similarly optimal when humans judge the temporal properties of bimodal stimuli? Twenty-four participants performed temporal order judgments (TOJs) about 2 spatially separated stimuli. Stimuli were auditory, vibrotactile, or both. The temporal profiles of vibrotactile stimuli were manipulated to produce 3 levels of precision for TOJs. In bimodal conditions, the asynchrony between the 2 unimodal stimuli that comprised a bimodal stimulus was manipulated to determine the weight given to touch. Bimodal performance on 2 measures—judgment uncertainty and tactile weight—was predicted with unimodal data. A model relying exclusively on audition was rejected on the basis of both measures. A second model that selected the best input on each trial did not predict the reduced judgment uncertainty observed in bimodal trials. Only the optimal maximum-likelihood-estimation model predicted both judgment uncertainties and weights; the model’s validity is extended to TOJs. Alternatives for modeling the process of event sequencing based on integrated multisensory inputs are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the nature of the decision axis in signal-detection-based models of recognition memory.

Most models of recognition memory involve a signal-detection component in which a criterion is placed along a decision axis. Older models generally assume a familiarity-decision axis, but newer models often assume a likelihood ratio axis instead because it allows for a more natural account of the ubiquitous mirror effect. In 3 experiments reported here, item strength was differentially manipulated to see whether a mirror effect would occur. Within a list, the items from 1 category were strengthened by repetition, but the items from another category were not. On the subsequent recognition test, the hit rate was higher for the strong category, but the false-alarm rates for the weak and strong categories were the same (i.e., no mirror effect was observed). This result suggests that the decision axis represents a familiarity scale and that participants adopt a single decision criterion that they maintain throughout the recognition test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Within- and between-modality associations in probed recall: A test of the separate-streams hypothesis.

Tested the separate-streams hypothesis that short-term processing of verbal information is functionally separated according to presentation modality. Lists of 10 digits were presented to 32 university students such that presentation modality (auditory or visual) changed after every 2nd digit. One digit was repeated at the end of each list as a recall probe. In 1 condition (next-item), Ss were instructed to recall the item that had immediately followed the probe in the original list regardless of presentation modality. In the 2nd condition (next item in the same modality), Ss were instructed to recall the item after the probe and in the same modality. The combination of instructions and positions of the probe and target within the list created 3 main conditions: (1) The probe immediately preceded the target item and was in the same presentation modality (same-mode probe). (2) The probe immediately preceded the target but was in a different presentation modality (different-mode probe). (3) The probe was in the same modality as the target but was separated from it by 2 items in the other modality (temporally distant probe). For both auditory and visual targets, highest recall was obtained with same-mode probes, next highest with temporally distant probes, and lowest with different-mode probes. The results support the hypothesis that auditory and visual information is processed separately in short-term verbal memory. (French abstract) (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mesograde amnesia during the sleep onset transition: replication and electrophysiological correlates

The present study was designed to explore mechanisms of amnesia for meaningful auditory material presented during the sleep onset transition. Thirty undergraduate subjects (17 female, 13 male) were presented with auditory stimuli in an oddball paradigm until sleep onset. Subjects were allowed to accumulate either 30 seconds or 10 minutes of sleep, then awakened and tested on free recall and recognition memory for the meaningful stimuli. After 10 minutes of sleep, but not after 30 seconds of sleep, subjects had profound amnesia on free recall for stimuli presented in the 4-minute window prior to sleep onset. Increased beta electroencephalograph (EEG) power during the sleep period correlated positively with recall of stimuli in the 4-minute presleep window. Event-related potential recordings provided suggestive evidence that subjects continued to process the auditory stimuli to some extent during the sleep onset transition. When allowed to sleep for 10 minutes, subjects evidenced a mixed anterograde and retrograde amnesia for auditory stimuli presented in the 4-minute window prior to sleep onset. The results are discussed in terms of stimulus encoding, consolidation, and retrieval.     

Bisensory stimulation: inferring decision-related processes from P300 component

Three experiments were conducted to evaluate the P300 component of the human evoked response as an index of bisensory information processing. On different blocks of trials, subjects were presented with auditory stimuli alone, visual stimuli alone, or with audiovisual compounds. In each series there were two possible stimuli, one of which was presented less frequently than the other; the subjects' task was to count the infrequent stimuli. In the first two experiments the information in the two modalities was redundant, whereas in the third the modalities provided nonredundant information. With redundant information, the P300 latency indicated bisensory facilitation when the unimodal P300 latencies were similar; when the unimodal latencies were dissimilar, the bisensory P300 occurred at the latency of the earlier unimodal P300. Reaction times paralleled P300 latency. When the information in the two modalities was nonredundant, both P300 amplitude and reaction-time data indicated interference between the two modalities, regardless of which modality was task relevant. P300 latency and reaction time did not covary in this situation. These data suggest that P300 latency and amplitude do reflect bisensory interactions and that the P300 promises to be a valuable tool for assessing brain processes during complex decision making.