Time course of selective attention in clinically depressed young adults: an eye tracking study

Depressed individuals display biased attention for emotional information when stimuli are presented for relatively “long” (e.g., 1 s) durations. The current study examined whether attentional biases are sustained over a much longer period. Specifically, clinically depressed and never depressed young adults simultaneously viewed images from four emotion categories (sad, threat, positive, neutral) for 30 s while line of visual gaze was assessed. Depressed individuals spent significantly more time viewing dysphoric images and less time viewing positive images than their never depressed counterparts. Time course analyses indicated that these biases were maintained over the course of the trial. Results suggest that depressed participants' attentional biases for dysphoric information are sustained for relatively long periods even when other emotional stimuli are present. Mood congruent information-processing biases appear to be a robust feature of depression and may have an important role in the maintenance of the disorder.     

Algorithms and selective attention

Selective attention is hypothesized to be controlled by intentionally chosen algorithms that specify how stimuli are to be processed. These experiments attempted to measure the time to select such algorithms. Subjects were given a two-choice reaction time task with a variety of different possible stimuli. Prior to each trial, subjects viewed a cue under their control that indicated the two possible stimuli for the upcoming trial. During this interval, subjects presumably selected a stimulus identification algorithm appropriate for that pair of letters; the duration of the interval was used as an index of algorithm selection time. The results indicated that selection time increases with the number of alternative algorithms and that algorithms may consist, in part, of perceptual tests to determine which of the two possible stimuli was presented. A specific model of the selection process was proposed to account for the results.     

Semantic control of selective attention

Summary It is argued that at least three modes of information processing should be distinguished: (1) sensory preprocessing; (2) activation and inhibition of knowledge structures, which run parallel and are unlimited in terms of capacity; (3) activated knowledge structures are used to make behavioral decisions. Decision processes are assumed to be sequentially organized because at any moment only one unit of the activated knowledge can be taken into account. Selective attention mainly refers to the third mode of processing. In this paper, potential rules are investigated that may determine what part of the activated knowledge influences making decisions about behavior. An intuitively plausible speculation about a rule of this kind is that activated knowledge is taken into account in the order of its activation level. Certain phenomena in selective attention are related to the operation of the rule, and some data are presented that seem to favor the validity of the rule's operation in the processing of multi-element visual displays.     

Time course of selective attention to face regions in social anxiety: eye-tracking and computational modelling

ABSTRACT

We investigated the time course of selective attention to face regions during judgment of dis/approval by low (LSA) and high (HSA) social anxiety undergraduates (with clinical levels on questionnaire measures). The viewers’ gaze direction was assessed and the stimulus visual saliency of face regions was computed, for video-clips displaying dynamic facial expressions. Social anxiety was related to perception of disapproval from faces with an ambiguous smile (i.e. with non-happy eyes), but not those with congruent happy eyes and a smile. HSA observers selectively looked earlier at the eye region, whereas LSA ones preferentially looked at the smiling mouth. Consistently, gaze allocation was less related to visual saliency of the smile for HSA than for LSA viewers. The attentional bias towards the less salient eye region – thus opposing the automatic capture by the smile – suggests that it is strategically driven in HSA individuals, possibly aimed at detecting negative evaluators.     

Temporal contextual cuing of visual attention

Previous research has shown how spatial attention is guided to a target location, but little is understood about how attention is allocated to an event in time. The authors introduce a paradigm to manipulate the sequential structure of visual events independent of responses. They asked whether this temporal context could be implicitly learned and used to guide attention to a relative point in time or location, or both, in space. Experiments show that sequentially structured event durations, event identities, and spatiotemporal event sequences can guide attention to a point in time as well as to a target event's identity and location. Cuing was found to rely heavily on the element immediately preceding the target, although cuing from earlier items also was evident. Learning was implicit in all cases. These results show that the sequential structure of the visual world plays an important role in guiding visual attention to target events.     

Temporal aspects of selective masking

In two experiments, rows of random letter sequences were presented for 100 ms and were patterned masked at varying delays after display offset. In Experiment I recall was probed by visual partial report cues, while auditory probes were employed in Experiment II. Compared to no-masking control conditions, the masking stimulus had a selective effect at the different positions of the rows. The masking stimulus produced the largest decrements in recall of letters from the centre positions of the displays but had a minimal effect on performance at either end of the rows. Furthermore, it was demonstrated that improvements in recall were limited to the centre positions of the rows at increased delays of mask. Subsidiary analyses revealed that processing of the end letters of the displays terminates shortly after display offset while processing of the centre letters continues for at least 500 ms. The results are consistent with the notion that processing of multi-letter arrays commences at the ends of the rows and that the selective masking effect reflects the order of processing of the contents of iconic memory. However, these results were evident only in Experiment II which employed auditory partial report cues. When the partial report cues were visual, there were no effects of masking and minimal increases in performance at increased delays of mask. The discrepant results of the two experiments are discussed in terms of process interruption caused by obligatory attention to the partial report cues.     

Cerebral hemispheres and selective attention

The present paper is intended to discuss critically the integration model of the functional interhemispheric relation that has become dominant in neuropsychology with the development, in the last two decades, of split-brain studies.While the split-brain research has undoubtedly produced new experimental methodologies, the current theorizing in this area has been contrastingly conservative. The present paper examines some of its basic assumptions, in particular that the corpus callosum is an association pathway devoted to interhemispheric transmission of information, and that the disconnected cerebral hemispheres function in a parallel way. It is shown that these assumptions have only low consistency both with split-brain behavior and with the normal organization of the fore-brain connectivity.In the early seventies, theoretical novelty has emerged from another research field with Kinsbourne's interpretation of laterality effects in normal man. His concept of asymmetrical hemispheric arousal is shown to be supported, with some reservations, by evidence in this field. But this dynamical concept has a more general value and there are signs that current ideas about the functional relation between the cerebral hemispheres are presently deeply transformed.     

Effects of location, frequency region, and time course of selective attention on auditory scene analysis

Often, the sound arriving at the ears is a mixture from many different sources, but only 1 is of interest. To assist with selection, the auditory system structures the incoming input into streams, each of which ideally corresponds to a single source. Some authors have argued that this process of streaming is automatic and invariant, but recent evidence suggests it is affected by attention. In Experiments 1 and 2, it is shown that the effect of attention is not a general suppression of streaming on an unattended side of the ascending auditory pathway or in unattended frequency regions. Experiments 3 and 4 investigate the effect on streaming of physical gaps in the sequence and of brief switches in attention away from a sequence. The results demonstrate that after even short gaps or brief switches in attention, streaming is reset. The implications are discussed, and a hierarchical decomposition model is proposed.     

Disambiguating ambiguous figures by selective attention

The present study was designed to investigate the hypothesis that the formation of a given percept of an ambiguous figure results from focusing attention on a focal area that contains features significant for this percept but not for the alternative one. Two such focal areas were designated for the two competing interpretations of the bird/plane and duck/rabbit ambiguous figures. Detecting a letter following the figure was faster when the letter appeared in the focal area of the perceived interpretation than in the focal area of the alternative one. Furthermore, directing attention to a given focal area shortly before the presentation of the figure increased the likelihood of forming the corresponding interpretation rather than the alternative one. Results suggest that maintaining different interpretations of the same ambiguous figure is mediated by focusing attention on different parts of the figure.     

Tactile selective attention and temporal masking

The presentation of a nontarget stimulus to one fingerpad interferes with the identification of a target stimulus presented to a second fingerpad. This interference has been attributed to a failure of selective attention and, more specifically, to the nontarget’s eliciting a competing response. In the present study, the temporal interval between the target and nontarget was varied to determine the extent to which a nontarget primes a competing response. The results showed more interference when the nontarget was presented after the target than when it was presented before the target. Although still consistent with a response-competition explanation, this result offered no support for a priming explanation. The function relating the amount of interference to the temporal separation between the target and nontarget was similar to the functions obtained in studies of temporal masking, and this prompted a second experiment in which temporal masking was examined. These results, obtained with stimuli presented to the same fingerpad, indicate that response competition may be a major factor in temporal masking and that similar processes are involved in temporal masking and selective attention.     

Stimules configuration in selective attention tasks

The possibility that perceptual configuration of stimulus elements impairs the ability to attend selectively to individual elements was tested with two-element stimuli, constructed by placing two curved lines in close proximity. Ss rapidly classified series of these stimuli which could differ on both elements or on only one with the second held constant. It was hypothesized that if the two elements formed a configuration, then Ss should have difficulty attending selectively to the element relevant for classification while filtering information from the other element. This result was obtained in one experiment with both stimulus elements oriented vertically, and it is concluded that these stimuli were perceived as unanalyzed, nominally related shapes. In another experiment, with one stimulus element oriented horizontally, selective attention to the relevant element was possible.     

Visual selective attention with virtual barriers

Previous studies have shown that interference effects in the flanker task are reduced when physical barriers (e.g., hands) are placed around rather than below a target flanked by distractors. One explanation of this finding is the referential coding hypothesis, whereby the barriers serve as reference objects for allocating attention. In five experiments, the generality of the referential coding hypothesis was tested by investigating whether interference effects are modulated by the placement of virtual barriers (e.g., parentheses). Modulation of flanker interference was found only when target and distractors differed in size and the virtual barriers were beveled wood-grain objects. Under these conditions and those of previous studies, the author conjectures that an impression of depth was produced when the barriers were around the target, such that the target was perceived to be on a different depth plane than the distractors. Perception of depth in the stimulus display might have led to referential coding of the stimuli in three-dimensional (3-D) space, influencing the allocation of attention beyond the horizontal and vertical dimensions. This 3-D referential coding hypothesis is consistent with research on selective attention in 3-D space that shows flanker interference is reduced when target and distractors are separated in depth.     

Temporal course of perceived auditory duration

A series of experiments explored the temporal course of the perceived duration of an auditory stimulus. A backward recognition masking paradigm was utilized, in which the subject was to determine which of two target durations was presented on a given trial. The target tone was followed, after a variable silent intertone interval, by a masking tone which could assume one of three possible durations. Identification of the long target was found to improve consistently with increases in the intertone interval. In contrast, identification of the short target was as accurate at the short as at the long intertone intervals. Blocking the intertone interval across experimental sessions eliminated these differences between the two target tones. Performance on both the long and the short target tones improved monotonically with increases in the intertone interval. When masking tone duration was randomized within an experimental session, identification of the long (short) target was most accurate with the longer (shorter) masking tone. Blocking the duration of the masking tone across experimental sessions eliminated the effect of the duration of the mask, but did not alter any of the other results. A model, proposed to account for the results, assumes that the percept of target duration grows over time, and can be terminated by the onset of the masking tone. The masking tone also acts to lengthen the perceived duration of the target tone, and this lengthening is a direct function of the duration of the masking tone.     

Shadowing and monitoring for selective attention

Although shadowing has been assumed to hold attention strongly (e.g. Hochberg, 1970) this has not been demonstrated, and the incidence of errors and intrusions suggest that it is not as powerful a technique as might have been supposed. An alternative, simpler, technique would be monitoring, but Kahneman (1970) maintains that selectivity fails in the absence of a continuous response. The experiments here compare the shadowing and monitoring tasks when attentional selectivity was required, and when it was not required, and indicate that similar attentional strategies operate during the monitoring and shadowing of brief messages. The shadowing paradigm is criticized in terms of an interaction between the relative resemblance of the stimuli and the shadowing voice. It is not demonstrated that an absolute interaction takes place, but more importantly that relatively greater interference is apparent when the shadower's voice and the stimuli to be shadowed are similar than when they are distinct. It is suggested that low target detections in the unattended message may be an artifact of the processing requirements of the shadowing task.     

Perceptual grouping and visual selective attention

The present study demonstrates that incongruent distractor letters at a constant distance from a target letter produce more response competition and negative priming when they share a target’s color than when they have a different color. Moreover, perceptual grouping by means of color, attenuated the effects of spatial proximity. For example, when all items were presented in the same color, near distractors produced more response competition and negative priming than far distractors (Experiment 3A). However, when near distractors were presented in a different color and far distractors were presented in the same color as the target, the response competition × distractor proximity interaction was eliminated and the proximity × negative priming interaction was reversed (Experiment 3B). A final experiment demonstrated that distractors appearing on the same object as a selected target produced comparable amounts of response competition and negative priming whether they were near or far from the target. This suggests that the inhibitory mechanisms of visual attention can be directed to perceptual groups/objects in the environment and not only to unsegmented regions of visual space.     

Age-related decrement in auditory selective attention

Young (n = 30), middle-aged (n = 32), and old (n = 28) adults repeated (shadowed) words presented to the left ear at 60 words per minute with and without distracter words presented to the other ear. Dichotic shadowing error rate increased with age. An attempt to eliminate the age effect by adjusting for age differences in monaural shadowing errors, fluid intelligence, and pure-tone hearing loss did not succeed. When the analyses were confined to subjects who made no monaural shadowing errors, dichotic shadowing errors still increased linearly with age. These results showed that there are selective-attention deficits in older adults that cannot be accounted for by the uncertainty of the target location.