Iconic memory, location information, and partial report.

In 3 experiments, each using 14 adult Ss (primarily undergraduates), a 7-item array was presented to the S on every trial. Seven consonants were selected randomly, without replacement, from an ensemble of 20 consonants. A question mark was used as the partial report probe. Tested were suggestions that (1) the systematic decline of partial report as the delay of the partial-report cue increases is due to a time-related loss of location information and (2) the backward masking effect is precipitated by the disruption of location information before and after identification. Results from these experiments do not support the claims when new indices of location information and of item information were used. Instead, it was found that (a) the systematic decline in partial report was due to a time-related loss of item information and (b) location information was affected neither by the delay of the partial-report cue nor by the delay of backward masking. Ss adopted the select-then-identify mode of processing. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rabbit eyelid conditioning as a function of unconditioned stimulus duration.

Reports eyelid conditioning data for 85 male New Zealand white rabbits, employing UCS durations of 50, 100, and 200 msec. Ss with a 50-sec UCS were slower to start conditioning than the 100- or 200-msec groups. The 200-msec group reached a lower terminal performance level than the other 2 groups. Results are related to drive-reduction theory and to possible technical difficulties in the presentation of the cheek-shock UCS. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cue search and comparison processes in visual search for letters.

In 2 experiments, each with 16 college students and laboratory staff members, Ss searched 4- and 8-letter arrays for the presence of a T or an F. The position of the target was indicated by a bar marker presented at 1 of 7 stimulus onset asynchronies (SOAs): –200, –25, 50, 125, 200, 275, or 350 msec. In Exp I, SOA conditions were blocked; in Exp II, SOA conditions varied randomly from trial to trial. In both experiments array size and SOA interacted. With 8-letter arrays, reaction time (RT) increased linearly with SOA with a slope less than 1. With 4-letter arrays, RT increased with SOA but reached asymptote at the level of no-cue control RTs at the 125-msec SOA. Results support the notion that cue search and comparison processes may function concurrently. (French summary) (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Information transfer in iconic memory experiments.

To report letters from briefly exposed letter arrays, Ss must transfer information from a rapidly decaying trace (iconic memory) to more durable storage. In a partial-report paradigm, the proportion (P) of trials with a long cue delay relative to a short cue delay was systematically varied. Practiced Ss used the same transfer strategy independent of P. Data from a partial-report-plus-masking experiment were used to construct a computational model that accurately predicted partial- and whole-report performance with and without masks. Assumptions: Prior to a cue, Ss attend primarily to the middle row of a 3-row display, resulting in nonselective transfer. After the cue, they attend only to the cued row. Transfer rate is the product of iconic legibility (which depends on the time and retinal location) and attention allocation (which shifts after a cue). Cumulative transfer is limited by the capacity of durable storage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in memory-driven selective attention.

Investigated the ability of young and elderly adults to use memory-driven selective attention in 2 visual-search experiments. In Exp I, 16 18–22 yr olds and 16 60–74 yr olds were Ss in a yes–no search paradigm. Stimulus-onset-asynchrony (SOA) was varied from 200 to 1,000 msec. In Exp II, 18 18–24 yr olds and 18 60–73 yr olds were presented 1 of 2 target letters as a cue, using the same SOA ranges. Results in both experiments show that both age groups exhibited faster RTs to a visual display on trials when advance information (a cue) correctly predicted the particular target letter that would most likely be present in the display. Variations in the SOA between the cue and the display demonstrated that both age groups were capable of developing this selective preparation for a particular target letter within 200 msec. Results indicate that age differences in performance were determined primarily by quantitative changes in the speed of information processing rather than by qualitative changes in attention. In both experiments, the 2 age groups differed in the type of relationship between speed and accuracy that they adopted, suggesting a possible age difference in performance strategy. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time-windowing of click-evoked otoacoustic emissions to increase signal-to-noise ratio

OBJECTIVE: To investigate the effects of decreasing the response-window duration on the signal-to-noise ratio (S/N) of click-evoked otoacoustic emissions (CEOAEs). DESIGN: The ILO88 (Otodynamics, Ltd.) was used to measure CEOAEs from 149 normal adult ears, and 75 adult ears with high-frequency sensorineural hearing loss. Data were collected using the default response window of 2.5 to 20.5 msec post-click. Each response was rewindowed, post-hoc, from 2.5 to 7.5 msec, 2.5 to 9 msec, 7.75 to 14.25 msec, and 13 to 19.5 msec post-click. For each window, spectra of the CEOAE and of the background noise were determined. The S/N was estimated by subtracting the noise level from the CEOAE amplitude. RESULTS: The 13- to 19.5-msec window contained little CEOAE energy relative to earlier windows. Relative to the 2.5- to 20.5-msec window, the 2.5- to 7.5- and 2.5- to 9-msec windows reduced noise levels more than CEOAE amplitudes, yielding increased S/N, and greater "reproducibility" values. The increased S/N of the 2.5- to 7.5- and 2.5- to 9-msec windows allowed measurement of greater CEOAE-amplitude reductions in the impaired ears relative to the normal ears. With short-duration windows, click-presentation rate could be increased, allowing more responses to be averaged in a given time, thus further decreasing noise levels. Although click rate was not varied in the present study, the decrease of noise levels is predictable. Accounting for this factor, it is expected that a specified S/N would be obtained about five times faster using the 2.5- to 7.5-msec window with a 7.5-msec interstimulus interval, than when using the default window. CONCLUSIONS: Decreasing the response-window duration substantially increases the measurement efficiency of CEOAEs in adults, and thus may enhance clinical-test performance.     

Adult age differences in shifting focused attention.

Young and older adults performed a choice response task in which 1 of 2 target letters was presented visually at 1 of 4 display locations. In 2 experiments, the validity of a target location cue and the presence of nontarget characters (distractors) were varied. With target-only displays and 40% cue validity (Experiment 1), the estimated time to shift attention between display locations was essentially 0 msec for both age groups. With 70% cue validity, Experiment 2 demonstrated significant increases in the attention shift time as a function of both increased age and the presence of distractors (asterisks). The results suggest that age-related changes in the shifting of focused attention are minimal except when the processing of nontarget information is required. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceived numerosity: An information processing analysis.

Presented 3 university students with matrices of from 1 to 16 dots and asked them to count the dots they could see. In Condition 1 a visual noise pattern followed the display of dots by one of several intervals in order to control the time available to process them. In Condition 2 no mask was used, but the exposure duration was varied. In the processing time condition, dots were counted at a rate of 4 msec/dot when less than 6 dots were presented, and at a rate of 60 msec/dot for all dots in excess of 6. If enough time was given to process all the dots presented, virtually all were reported, whereas, if enough time was given to count only some of the dots, virtually none of the excess were counted. In the duration condition, in which processing time was not restricted, counting appeared to be a function of the visibility of the dots, as shown by a family of more linear functions between number of dots presented and number counted, with the slope determined by the duration of exposure. Data are consistent with a serial processing interpretation of dot counting occurring at a very early stage of information extraction, in which there is a serial scanning mechanism which extracts information from an initial brief store and transfers it to a 2nd store for actual counting. (French summary) (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The extension of the interference effect to multiplication.

Investigated the interference effect in the number matching task using multiplication facts. 40 Ss verified the presence of a target number (e.g., 8) in a previously presented cue (e.g., 5 x 8) that was masked after 60 msec. The stimulus onset asynchrony (SOA) between cue and target was 100, 120, 220, and 350 msec. Ss were slower to reject targets that were the product of the cue (e.g., 40) than unrelated targets (e.g., 42) at the 100- and 120-msec SOAs. Findings indicate interference effects at these SOAs and support the hypothesis that the cues activated associated numbers resulting in slower latencies for product than unrelated trials. This pattern is consistent with the interference effect found by J. LeFevre et al (see records 76-00346, 79-04985, and 81-43827) using addition facts. The authors conclude that the interference effect previously found with addition facts was due to obligatory activation and not to automatic counting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tests of a model of informational persistence.

Evaluated a model of informational persistence, the memory underlying performance in partial-report experiments, proposed by the 1st author and J. M. Yeomans (see record 1986-26361-001). This model consisted of 2 components: (1) a visual analog representation that briefly maintains form and location information about the contents of a visual display and (2) a durable, abstract identity representation that codes location information poorly. Results of pattern mask and row vs category partial-report performance experiments involving the authors and 11 undergraduates were consistent with the model, but indicate that the abstract identity representation may actually code location information quite well. An expanded version of the model is proposed in which the abstract identity representation is viewed as a location-specific, limited capacity memory. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Saccadic eye movements of children and adults to double-step stimuli.

Investigated the programming and reprogramming of oculomotor responses to double-step and single-step targets in Exp I with 5 college students, 5 5–6 yr olds, and 7 8–10 yr olds. Independent variables were intertarget interval (50, 100, 150, and 200 msec) and target location. The number of trials on which a saccade was made to both 1st and 2nd targets increased with age and intertarget interval, but the 2 factors did not interact. On trials where responses were made only to the 2nd target, children responded slower than adults but showed generally similar patterns of response latencies. In Exp II, a warning signal was presented 0, 100, or 300 msec prior to the 1st target. For 18 college students, the 100- and 300-msec warning intervals reduced the latency of single-step responses and the 1st saccade of double-step responses, whereas only the 300-msec warning interval was similarly effective with 15 children. All Ss exhibited amplitude transition functions, indicating that the modifiability of saccadic programming is basically similar for adults and children. A comparison of simultaneous programming characteristics suggested possible age differences. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional components of partial report.

In 8 bar-probe, partial-report experiments, performance declined as the duration of the cue increased. This effect obtained with peripheral but not central cues occurred even when cues are uninformative and was not found when the cue required some interpretation. Results suggest that the effect of cue duration is related to the exogenous attentional system and is not found when the endogenous attentional system is used exclusively. Results also suggest that long-duration cues do not interfere with shifts of attention and that local contour proximity is neither necessary nor sufficient to produce the effect. It is hypothesized that long-duration cues generate interference because they direct attention to a period of time when the decaying visual representation of the array is unreliable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing time and memory for pictures.

Postexposure processing of an iconic memory following the presentation of pictures of complex, colored, naturalistic scenes was assessed in 3 experiments which examined the effects of exposure duration and mask delay upon recognition memory. Ss were 50 undergraduates. Exposure durations ranged from 50 to 550 msec and mask delays from 0 to 500 msec. For exposure durations of 300 msec and longer, recognition accuracy was primarily determined by exposure duration, and mask delay had no significant effect. For exposure durations of less than 300 msec, postexposure processing continued for up to 250 msec following the offset of a target picture, and recognition accuracy was a function of total processing time (i.e., the total time separating target and mask onsets.) This reciprocity between exposure duration and mask delay was similar to that previously demonstrated for verbal materials. The processing-time/recognition memory relationship was also shown to be due to differences in initial encoding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Randomized, double-blind clinical trial of amphotericin B colloidal dispersion vs. amphotericin B in the empirical treatment of fever and neutropenia

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.     

Memory for position and identity across eye movements.

Used a "transsaccadic" partial report procedure to measure memory for position and identity information across saccades. Delaying the partial-report cue after the eye movement had little effect on report accuracy. Mask presentation hindered recall only at the shortest delay. Accuracy was much higher when the letter array contained 6 letters than when it contained 10 letters. Intra-array errors were much more frequent than extra-array errors. These results suggest that memory across eye movements decays slowly, has a limited capacity, is maskable for a brief time, and retains identity information better than position information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A behavioral study of temporal processing and visual persistence in young and aged rats.

Young rats were presented with light flash prepulses varying in duration from 1 to 128 msec, with light offset or light onset fixed at 70 msec prior to an acoustic startle stimulus (Experiment 1A), and, with single or paired 1-msec flashes, the 2nd (or only) flash given 100 to 500 msec before the startle, and 1 msec to 400 msec interflash intervals (Experiment 1B). Older rats (10 and 20 mo old) received the same single and double flashes but with the maximum interflash interval extended to 1,500 msec (Experiment 2). Reflex inhibition increased with increased duration from 1 to 8 msec and decreased as light onset progressively exceeded 100 msec. Inhibition for both single and double flashes also declined for onset lead times beyond 100 msec, then increased for a double flash once the interflash interval exceeded 100 msec in young and middle-aged rats and 1,500 msec in the oldest rats. Peak inhibition was much reduced in the oldest rats at short lead times but was greater than that of younger rats at long lead times. These data suggest that aged rats process visual stimuli more slowly than younger rats and show poorer temporal acuity coupled with greater visual persistence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral and computational models of spatial attention.

Pigeons pecked for food in a spatially cued choice reaction time (RT) task. A brief (50-msec) white light appeared on a left or right key and probabilistically predicted the location (on either the left or right key) of a subsequent target stimulus. The time between cue and target onset (stimulus onset asynchrony), the base rate of left cues, and the probability that the cue correctly predicted the target (cue validity) were experimentally varied. The mean RT to respond to the target key was faster on correctly cued trials (defining a validity effect), decreased for both valid and invalid trials as stimulus onset asynchrony increased (defining an alerting effect), showed a variety of base-rate effects, and did not depend on cue validity. It is shown with a computational-processing model that dynamic interactions of short-term and associative memory processes are sufficient to produce these attention-like empirical phenomena. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reflex modification in the rat: The inhibitory effects of intensity and frequency changes in steady tones.

Four experiments with 50 male albino Charles River rats investigated the relation between the inhibitory effects of tonal frequency change and the length of the silent period (gap) preceding it. It is noted that, in both laboratory rats and in humans, a low-intensity tone that precedes a high-intensity burst of noise by approximately 100 msec can reduce the amplitude of the startle reaction elicited by the burst of noise. Overall results show that a gap in an otherwise continuous pure tone inhibited startle when the gap occurred approximately 100 msec prior to the noise burst. Although an increase in gap duration increased the inhibition afforded by the gap, the maximum inhibition was yielded by gaps of 100 msec and greater; this maximum was equivalent to the inhibition yielded by the presentation of a postgap tone alone. A shift in tonal frequency across a 10-msec gap yielded more inhibition than did the same gap with no frequency shift; again, the shift yielded equivalent inhibition to the presentation of the postgap tone alone. An increase in the frequency shift increased inhibition when the shift occurred across a 10-msec gap but not across a 100-msec gap. It is concluded that the amount of inhibition afforded by a complex acoustic event is more than a mere additive function of the inhibitory effects of the different elements that make up the event. For example, a tonal onset is just as inhibitory as a frequency shift across a gap, which includes a tonal onset, tonal offset, and frequency shift. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual perception of sequential numerosity by normals and retardates.

Presented sequences of 2-10 50-msec light flashes at interstimulus intervals (ISIs) of 100, 200, 300, 400, 500, and 600 msec. for multiple- and single-locus conditions to 20 educable retardates and 20 equal MA normals. Numerosity discrimination of the younger, normal children was more accurate at all ISIs (p     

Changes in visuospatial attention over the adult lifespan

Shifts of visual attention elicited by spatial cues were examined for detection and letter-discrimination tasks in 90 normal adults ranging in age over each decade from the 20s to the 70s. Spatial cues were valid, invalid, or neutral in indicating probable target location and were presented either centrally at fixation or peripherally 6.7 degrees to the left or right of fixation. Stimulus-onset asynchrony (SOA) between cue and target was varied between 200, 500 and 2000 msec. Reaction time (RT) costs and benefits associated with spatial cueing did not vary with age for: (1) the detection task; (2) the letter-discrimination task with peripheral cues; and (3) the letter-discrimination task with central cues at a short (200 msec) SOA. RT costs and benefits increased with age only for SOAs greater than 200 msec with central cueing in the discrimination task. In general, the efficiency of cue-based shifts of visuospatial attention appears relatively resistant to the effects of adult age up to 79 years. When an age effect was found, RT costs and benefits increased steadily across all age decades, the correlation with age being 0.25 and 0.38 for the 500 and 2000 msec SOAs, respectively. The findings suggest a qualitative difference in the influence of normal adult aging and effects of dementia noted in previous studies; normal aging has only a weak influence on voluntary attention shifts, whereas dementia affects both voluntary and involuntary modes of attention shifting.