Auditory and visual spatial working memory

A series of experiments compared short-term memory for object locations in the auditory and visual modalities. The stimulus materials consisted of sounds and pictures presented at different locations in space. Items were presented in pure- or mixed-modality lists of increasing length. At test, participants responded to renewed presentation of the objects by indicating their original position. If two independent modality-specific and resource-limited short-term memories support the remembering of locations, memory performance should be higher in the mixed-modality than in the pure-modality condition. Yet, memory performance was the same for items in both types of list. In addition, responses to the memory load manipulation in both modalities showed very similar declines in performance. The results are interpreted in terms of object files binding object and location information in episodic working memory, independently of the input modality.     

Auditory spatial concepts in blind football experts

ObjectivesWe compared the spatial concepts given to sounds' directions by blind football players with both blind non-athletes and sighted individuals.MethodParticipants verbally described the directions of sounds around them by using predefined spatial concept labels, under two blocked conditions: 1) facing front, 2) pointing with the hand towards the stimulus.ResultsBlind football players categorized the directions more precisely (i.e., they used simple labels for describing the cardinal directions and combined labels for the intermediate ones) than the other groups, and their categorization was less sensitive to the response conditions than blind non-athletes. Sighted participants' categorization was similar to previous studies, in which the front and back regions were generally more precisely described than the sides, where simple labels were often used for describing directions around the absolute left and right.ConclusionsThe differences in conceptual categorization of sound directions are a) in sighted individuals, influenced by the representation of the visual space b) in blind individuals, influenced by the level of expertise in action and locomotion based on non-visual information, which can be increased by auditive stimulation provided by blind football training.     

Auditory spatial attention using interaural time differences

Previous probe-signal studies of auditory spatial attention have shown faster responses to sounds at an expected versus an unexpected location, making no distinction between the use of interaural time difference (ITD) cues and interaural-level difference cues. In 5 experiments, performance on a same-different spatial discrimination task was used in place of the reaction time metric, and sounds, presented over headphones, were lateralized only by an ITD. In all experiments, performance was better for signals lateralized on the expected side of the head, supporting the conclusion that ITDs can be used as a basis for covert orienting. The performance advantage generalized to all sounds within the spatial focus and was not dissipated by a trial-by-trial rove in frequency or by a rove in spectral profile. Successful use by the listeners of a cross-modal, centrally positioned visual cue provided evidence for top-down attentional control.     

Auditory and audiovisual inhibition of return

Two experiments examined any inhibition-of-return (IOR) effects from auditory cues and from preceding auditory targets upon reaction times (RTs) for detecting subsequent auditory targets. Auditory RT was delayed if the preceding auditory cue was on the same side as the target, but was unaffected by the location of the auditorytarget from the preceding trial, suggesting that response inhibition for the cue may have produced its effects. By contrast, visual detection RT was inhibited by the ipsilateral presentation of a visual target on the preceding trial. In a third experiment, targets could be unpredictably auditory or visual, and no peripheral cues intervened. Both auditory and visual detection RTs were now delayed following an ipsilateral versus contralateral target in either modality on the preceding trial, even when eye position was monitored to ensure central fixation throughout. These data suggest that auditory target—target IOR arises only when target modality is unpredictable. They also provide the first unequivocal evidence for cross-modal IOR, since, unlike other recent studies (e.g., Reuter-Lorenz, Jha, & Rosenquist, 1996; Tassinari & Berlucchi, 1995; Tassinari & Campara, 1996), the present cross-modal effects cannot be explained in terms of response inhibition for the cue. The results are discussed in relation to neurophysiological studies and audiovisual links in saccade programming.     

Auditory spatial pattern perception aided by visual choices

Summary Thirty-six human subjects, facing a panel of 100 loud-speakers, were requested to match sounds outlining geometrical and alphabetical patterns with visual pattern choices, which were given to them on a folder. The listeners' correct responses were found to be above chance. Geometrical patterns were better perceived when transmitted at the sound frequency of 800 cps as compared to 6400 cps. The number of visual pattern choices given with the sound pattern presentations affected the number of correct responses. The results indicate that the perception of acoustic spatial patterns depends on mechanisms different from those defining the spatial localization of single acoustic signals.This work was supported by the Swiss National Science Foundation, Grants 3.74.68, 4.0120.70 and 4.0860.73 to E. Perret.     

Inhibitory processes in auditory selective attention: Evidence of location-based and frequency-based inhibition of return

The possibility that there is an inhibitory component to auditory covert orienting was addressed. Each trial consisted of a cue followed by a target, and listeners were required to detect, localize, or identify the frequency of the target. At 150-msec stimulus onset asynchrony (SOA), performance was best when stimuli sounded from the same location or were of the same frequency. However, at 750-msec SOA, performance was best when stimuli differed in location or were of different frequencies. These results document the existence of both location-based and frequency-based auditory inhibition of return.     

Tactile spatial acuity differs between fingers: a study comparing two testing paradigms

Tactile spatial acuity (TSA) is a reliable and reproducible measure of somatosensory system function that has been used to study abroad range of subject populations. Although TSA is most often assessed at the fingertip, published studies employing identical stimuli disagree on whether TSA differs between the fingers of neurologically normal subjects. Using a validated grating orientation discrimination task, we determined TSA bilaterally at the index and ring fingers of 16 healthy young adults. Motivated by earlier work, we utilized two stimulus presentation paradigms, the method of constant stimuli (MCS) and a staircase (SC) method. We found that TSA was significantly higher (the discrimination threshold was lower) at the index than at the ring finger, which was consistent with a prior study. Although mean thresholds at both fingers were higher when measured with the SC than with the MCS paradigm, this difference did not reach statistical significance (p = .14). These findings should facilitate both design and interpretation of future studies investigating TSA.     

Collaborative inhibition in spatial memory retrieval

Collaborative inhibition refers to the finding that pairs of people working together to retrieve information from memory—a collaborative group—often retrieve fewer unique items than do nominal pairs, who retrieve individually but whose performance is pooled. Two experiments were designed to explore whether collaborative inhibition, which has heretofore been studied using traditional memory stimuli such as word lists, also characterizes spatial memory retrieval. In the present study, participants learned a layout of objects and then reconstructed the layout from memory, either individually or in pairs. The layouts created by collaborative pairs were more accurate than those created by individuals, but less accurate than those of nominal pairs, providing evidence for collaborative inhibition in spatial memory retrieval. Collaborative inhibition occurred when participants were allowed to dictate the order of object placement during reconstruction (Exp. 1), and also when object order was imposed by the experimenter (Exp. 2), which was intended to disrupt the retrieval processes of pairs as well as of individuals. Individual tests of perspective taking indicated that the underlying representations of pair members were no different than those of individuals; in all cases, spatial memories were organized around a reference frame aligned with the studied perspective. These results suggest that inhibition is caused by the product of group recall (i.e., seeing a partner’s object placement), not by the process of group recall (i.e., taking turns choosing an object to place). The present study has implications for how group performance on a collaborative spatial memory task may be optimized.     

Selection and inhibition in infancy: evidence from the spatial negative priming paradigm

We used a spatial negative priming (SNP) paradigm to examine visual selective attention in infants and adults using eye movements as the motor selection measure. In SNP, when a previously ignored location becomes the target to be selected, responses to it are impaired, providing a measure of inhibitory selection. Each trial consisted of a prime and a probe, separated by 67, 200, or 550 ms interstimulus intervals (ISIs). In the prime, a target was accompanied by a distractor. In the probe, the target appeared either in the location formerly occupied by the distractor (ignored repetition) or in another location (control). Adults exhibited the SNP effect in all three ISI conditions, producing slower saccade latencies on ignored repetition versus control trials. The SNP effect obtained for infants only under 550 and 200 ms ISI conditions. These results suggest that important developments in visual selection are rooted in emerging inhibitory mechanisms.     

The spatial distribution of inhibition of return

Inhibition of return (IOR) refers to the finding that response times (RTs) are typically slower for targets at previously attended (cued) locations than for targets at novel (uncued) locations. Although previous research has indicated that IOR may spread beyond a cued location, the present study is the first to examine the spatial distribution of IOR with high spatial resolution over a large portion of the central visual field. This was done by using a typical IOR procedure (cue, delay, target) with 4 cue locations and 441 target locations (each separated by 1° of visual angle). The results indicate that IOR spreads beyond the cued location to affect the cued hemifield. However, the cues also produced a gradient of RTs throughout the visual field, with inhibition in the cued hemifield gradually giving way to facilitation in the hemifield opposite the cue.     

Auditory food cue conditioning: Effects of spatial contiguity and taste quality

The effects of spatial location of an auditory stimulus and quality of a potentiating taste on the aversive conditioning of an auditory food cue were investigated. In Experiment 1 rats ate salty food activating a tone from a speaker either in (spatially contiguous with) or displaced from the food and were then made ill. It was found that spatial contiguity during conditioning resulted in avoidance of food with a contiguous or a displaced tone in testing, and spatial displacement during conditioning resulted in avoidance of food only if the tone was also displaced in testing. Experiment 2 was identical, except rats ate salty, bitter, or sweet food with a displaced tone during conditioning and testing. The salty and bitter food groups demonstrated an avoidance of noisy food relative to the sweet food group. These results indicate that spatial contiguity interacts with taste quality in the conditioning of nongustatory food cues.     

Auditory spatial attention capture,disengagement, and response selection in normal aging

Attention control is a core element of cognitive aging, but the specific mechanisms that differ with age are unclear. Here we used a novel auditory spatial attention task to evaluate stimulus processing at the level of early attention capture, later response selection, and the lingering effects of attention capture across trials in young and older adults. We found that the shapes of spatial attention capture gradients were remarkably similar in young and older adults, but only the older group had lingering effects of attention capture on the next trial. Response selection for stimulus-response incompatibilities took longer in older subjects, but primarily when attending to the midline location. The results suggest that the likelihood and spatial tuning of attention capture is comparable among groups, but once attention is captured, older subjects take longer to disengage. Age differences in response selection were supported, but may not be a general feature of cognitive aging.     

Focal spatial attention can eliminate inhibition of return

Inhibition of return (IOR) is an orienting phenomenon characterized by slower responses to spatially cued than to uncued targets. In Experiment 1, a physically small digit that required identification was presented immediately following a peripheral cue. The digit could appear in the cued peripheral box or in the central box, thus guaranteeing a saccadic response to the cue in one condition and maintenance of fixation in the other. An IOR effect was observed when a saccadic response to the cue was required, but IOR was not generated by the peripheral cue when fixation was maintained in order to process the central digit. In Experiment 2, IOR effects were observed when participants were instructed to ignore the digits, whether those digits were presented in the periphery or at fixation. These findings suggest that behaviorally manifested, cue-induced IOR effects can be eliminated by focal spatial attentional control settings.     

The representational locus of spatial influence on backward inhibition

When one is sequentially switching among three tasks, performance is impaired when tasks alternate (ABA) relative to when one is switching between all three tasks (CBA), an effect known as backward inhibition (BI). BI is not observed when component tasks are uniquely located in space, however (Arbuthnott, 2005). In this study, the locations of task precues and target stimuli were manipulated independently to determine whether this elimination of BI is related to distinct cue location or to distinct target location. Results clearly indicated that BI is eliminated with distinct cue localization independent of the location of target stimuli. This indicates that BI, which reflects suppression of task-set representations, can be influenced by cue characteristics that are associated with task representations.     

The import of the cortisol rise in child care differs as a function of behavioral inhibition

Children of ages 3 to 4.5 years (N = 107; 45 boys, 62 girls) were studied twice, 6 months apart, to examine whether the cortisol rise in child care at Time 1 (T1) was associated with (a) changes in anxious, vigilant behavior from T1 to Time 2 (T2) and (b) higher internalizing symptoms at T2. Controlling for measures of home environment and child care quality at T1, as well as for cortisol activity at T2, we obtained results indicating that behavioral inhibition moderated the associations between the rise in cortisol at T1 and child outcomes at T2 (i.e., anxious, vigilant behavior and internalizing symptoms). For both outcomes, the rise in cortisol at T1 became more positively predictive at increasing levels of behavioral inhibition. Specifically, at higher levels of behavioral inhibition, children with larger T1 cortisol increases expressed more internalizing symptoms than did children at lower levels of behavioral inhibition; in contrast, for those with low cortisol activity at T1, children with higher levels of inhibition expressed fewer internalizing symptoms than did children at lower levels of inhibition. In addition, children with higher levels of behavioral inhibition and lower cortisol activity at T1 exhibited reductions in anxious, vigilant behavior from T1 to T2, whereas at lower levels of behavioral inhibition, variations in the T1 cortisol rise bore no relation to changes in this behavior. These results suggest that the rise in cortisol at child care may have differential predictive value as a function of behaviorally inhibited temperament.     

Apparent displacement with a monocular prism differs from optical displacement

This experiment showed that phoria-induced displacement adds to or subtracts from prism-induced displacement. A near stimulus (25 cm) was apparently displaced more than the optical displacement when the base of a prism was out and less when the base was in. In contrast, a far stimulus (200 cm) was displaced less when the base was out and more when the base was in. Moreover, the between-subjects variability of the apparent displacement was greater with monocular than with binocular viewing. Some implications for studies on monocular prism adaptation are discussed.     

The role of spatial working memory in inhibition of return: evidence from divided attention tasks

Inhibition of return (IOR) refers to a bias against returning attention to a location that has been recently attended. In the present experiments, we examined the role of working memory in IOR by introducing secondary tasks (in the temporal interval between the cue and the target) that involved a working memory component. When the secondary task was nonspatial in nature (monitoring odd digits or adding digits), IOR was present, although overall reaction times were greater in the presence of the secondary task. When the task involved a spatial working memory load (remembering the directionality of arrows or the orientation of objects), IOR was eliminated. However, when the participants had incentive to process the directionality of an arrow but did not have to use any memory system, IOR persisted at peripheral locations. Overall, the results suggest that IOR is partially mediated by a spatial working memory system.     

Face detection differs from categorization: Evidence from visual search in natural scenes

In this study, we examined whether the detection of frontal, ¾, and profile face views differs from their categorization as faces. In Experiment 1, we compared three tasks that required observers to determine the presence or absence of a face, but varied in the extents to which participants had to search for the faces in simple displays and in small or large scenes to make this decision. Performance was equivalent for all of the face views in simple displays and small scenes, but it was notably slower for profile views when this required the search for faces in extended scene displays. This search effect was confirmed in Experiment 2, in which we compared observers’ eye movements with their response times to faces in visual scenes. These results demonstrate that the categorization of faces at fixation is dissociable from the detection of faces in space. Consequently, we suggest that face detection should be studied with extended visual displays, such as natural scenes.     

Event-related potentials indicate that reality monitoring differs from external source monitoring

This experiment investigated differences in event-related potentials (ERPs) observed in 2 types of source monitoring decisions. Participants discriminated between self-generated, heard, and new words (reality monitoring) in one condition; in another they discriminated between words heard in a male or female voice and new items (external source monitoring). The data support the source monitoring framework, which argues that reality monitoring discriminations differ from external source monitoring discriminations. Analysis revealed better overall source accuracy during reality monitoring than during external source monitoring. In the external source monitoring task, an early old-new ERP difference was observed at parietal electrodes followed by frontal old-new effect that persisted longer, replicating previous ERP results. However, early ERP amplitude differences between sources were observed at parietal electrode sites during reality monitoring, suggesting that self-generated items activate more differentiated information during remembering. Furthermore, there were no frontal old-new ERP differences during reality monitoring, suggesting that different decision processes are used in these types of source monitoring decisions.