Learning to ignore distracters

Eye tracking has indicated that older and young adults process distracters similarly when reading single sentences. The present study extended this approach by presenting short paragraphs, sentence by sentence. Eye tracking measures included reading times per word, and the duration of the first fixation and total fixations to the distracters and target words. Comprehension was tested following each paragraph, and recognition of distracters and target words was assessed. The results indicated that young adults were able to learn to ignore the distracters as they read through the paragraphs, whereas older adults were less successful at learning to ignore the distracters.     

Learning to ignore: Acquisition of sustained attentional suppression

We examined whether the selection mechanisms committed to the suppression of ignored stimuli can be modified by experience to produce a sustained, rather than transient, change in behavior. Subjects repeatedly ignored the shape of stimuli, while attending to their color. On subsequent attention to shape, there was a robust and sustained decrement in performance that was selective to when shape was ignored across multiple-colortarget contexts, relative to a single-color-target context. Thus, amount of time ignored was not sufficient to induce a sustained performance decrement. Moreover, in this group, individual differences in initial color target selection were associated with the subsequent performance decrement when attending to previously ignored stimuli. Accompanying this sustained decrement in performance was a transfer in the locus of suppression from an exemplar (e.g., a circle) to a feature (i.e., shape) level of representation. These data suggest that learning can influence attentional selection by sustained attentional suppression of ignored stimuli.     

Learning to use functional rules in inference tasks

Abstract.— Earlier studies have established that subjects perform less well in inference tasks with nonlinear rules than in tasks with linear rules, and that one source of the lower level of performance in nonlinear tasks is that the subjects cannot utilize a nonlinear rule as well as they utilize a linear rule. The three experiments in this paper investigate whether utilization of a nonlinear rule can be improved by training. The results show that there is some improvement with training, but the improvement could not be attributed to feedback, or to the learning of specific cue and criterion values. Cognitive feedback did not produce higher performance than ordinary outcome feedback.     

Learning to ignore irrelevant stimuli: Variations within and between displays

Pigeons were exposed to stimuli differing in orientation. Some birds received both horizontal and vertical on every trial; others received two horizontals on some trials and two verticals on other trials. These stimuli were irrelevant, i.e., did not predict reliably the availability of reinforcement. When required to learn a discrimination between horizontal and vertical, the birds that had experienced the stimulus variation within each display learned more slowly. This was true whether the test problem was a simultaneous or a successive discrimination. It is argued that this result implies that animals will actively learn to ignore stimuli that are irrelevant.     

Learning diphone-based segmentation

This paper reconsiders the diphone-based word segmentation model of Cairns, Shillcock, Chater, and Levy (1997) and Hockema (2006), previously thought to be unlearnable. A statistically principled learning model is developed using Bayes' theorem and reasonable assumptions about infants' implicit knowledge. The ability to recover phrase-medial word boundaries is tested using phonetic corpora derived from spontaneous interactions with children and adults. The (unsupervised and semi-supervised) learning models are shown to exhibit several crucial properties. First, only a small amount of language exposure is required to achieve the model's ceiling performance, equivalent to between 1 day and 1 month of caregiver input. Second, the models are robust to variation, both in the free parameter and the input representation. Finally, both the learning and baseline models exhibit undersegmentation, argued to have significant ramifications for speech processing as a whole.     

Preferential processing of target features in texture segmentation

In five experiments, observers were required to detect a texture target and/or identify the orientation of elements composing target and nontarget regions. They were significantly worse at discerning the orientation of nontarget regions than at detecting target presence (Experiment 1). On the other hand, accuracy of identifying target orientation was found to be near 100% (Experiment 2). When observers were required only to identify surround orientation (Experiment 3), accuracy was diminished on target-present trials relative to that on target-absent trials. The superiority of target processing and the interference produced by target presence on surround processing were demonstrated in unpracticed observers (Experiment 4). In Experiment 5, it was found that information regarding target presence is available before information regarding feature values of the target. These findings are consistent with a model of visual attention and search that incorporates a fast generalized difference operator and a slower feature comparison process.     

Learning complex rules in probabilistic inference tasks

Abstract.— A hypothesis-sampling theory for rule learning predicts that only those rules that are available for sampling can be learned. Earlier results show that subjects have a very limited set of hypotheses about rules relating scaled cue and criterion variables, consisting mainly of linear and symmetric quadratic functions, but not of complex functions, such as J-shaped rules. Tasks requiring the use of such rules should, therefore, not be learned. The results of the present experiment show, however, that subjects are able to find J-shaped relations. The results were interpreted to mean that subjects are able to construct hypotheses, and that they are not limited to sampling of hypotheses from a preestablished set of possible hypotheses.     

On the interference of task-irrelevant hue variation on texture segmentation.

Although natural images often include discordant information about object boundaries, the majority of research on texture segmentation has involved variation along a single dimension, e.g. colour, orientation, size. In this study, we examined orientation-based texture segmentation in the presence and absence of task-irrelevant colour variation. Previously, it had been shown that orientation-based texture segmentation was impaired if the elements, normally of one colour, were randomly allocated one of two colours (Morgan et al, 1992 Proceedings of the Royal Society of London, Series B 248 291-295). We found that this interference disappeared, however, when the spatial pattern of the colour variation was regular, as opposed to random, and when the elements were randomly positioned. We consider four models of how relevant and irrelevant texture information might combine to produce the interference effect, with special regard to these new findings. None of the models could account for the dependency of the interference effect on the spatial arrangement of colour and orientation in the texture. We suggest that inter-element separation and spatial-frequency selectivity are critical variables in the interference effect.     

Learning and hypothesis testing in probabilistic inference tasks

The relation between learning of probabilistic inference tasks and the availability of correct hypotheses for the tasks in individual subjects was investigated in two experiments. The results showed that having the correct hypotheses as measured before learning the tasks was neither a sufficient nor a necessary condition for learning the task. It was concluded that the hypothesis measurements are not reliable enough to allow predictions on an individual level. The results also showed that subjects have not only the four basic functions: positive linear, negative linear, U-shaped and inversely U-shaped, in their hypothesis hierarchies but also J-shaped functions. That the subjects can leam such functions is thus no discodinnation of the hypotheses sampling conception of learning as assumed in earlier studies.     

Allocating time to future tasks: The effect of task segmentation on planning fallacy bias

The scheduling component of the time management process was used as a "paradigm" to investigate the allocation of time to future tasks. In three experiments, we compared task time allocation for a single task with the summed time allocations given for each subtask that made up the single task. In all three, we found that allocated time for a single task was significantly smaller than the summed time allocated to the individual subtasks. We refer to this as the segmentation effect. In Experiment 3, we asked participants to give estimates by placing a mark on a time line, and found that giving time allocations in the form of rounded close approximations probably does not account for the segmentation effect. We discuss the results in relation to the basic processes used to allocate time to future tasks and the means by which planning fallacy bias might be reduced.     

Learning procedures and goal specificity in learning and problem-solving tasks

This experiment set out to examine the influence of two task variables (instructional procedure and goal specificity) on learning and problem-solving performance. A 2 × 2 between-subjects design was used. Twenty-four undergraduate students were asked to think aloud as they learned eight Word for Windows text editing operations, each implemented as a keyboard shortcut. Two instructional procedures were used, instructions presented either as lists or as paired statements. ''List'' groups required fewer trials than ''pairs'' groups to learn the operations, and relied more extensively upon rehearsal procedures, while ''pairs'' groups tended to use elaborative inference more frequently. Analyses of problem-solving solution times revealed no differences between the groups, although the no-goal groups tended to complete the tasks faster than the goal groups. Verbal protocols indicated that ''list'' groups tended to rely upon phonological cues to recover operation names, and made more phonological errors in recovering operation names. ''Pairs'' groups recalled more about the functions of the operations than the ''list'' groups. We conclude that different instructional procedures may lead to subtle, but important, differences in how information is encoded, represented, and recovered, and that individuals who perform to similar standards may not share the same understanding of the task in question.     

On the inability to ignore touch when responding to vision in the crossmodal congruency task

We investigated the extent to which people can selectively ignore distracting vibrotactile information when performing a visual task. In Experiment 1, participants made speeded elevation discrimination responses (up vs. down) to a series of visual targets presented from one of two eccentricities on either side of central fixation, while simultaneously trying to ignore task-irrelevant vibrotactile distractors presented independently to the finger (up) vs. thumb (down) of either hand. Participants responded significantly more slowly, and somewhat less accurately, when the elevation of the vibrotactile distractor was incongruent with that of the visual target than when they were presented from the same (i.e., congruent) elevation. This crossmodal congruency effect was significantly larger when the visual and tactile stimuli appeared on the same side of space than when they appeared on different sides, although the relative eccentricity of the two stimuli within the hemifield (i.e., same vs. different) had little effect on performance. In Experiment 2, participants who crossed their hands over the midline showed a very different pattern of crossmodal congruency effects to participants who adopted an uncrossed hands posture. Our results suggest that both the relative external location and the initial hemispheric projection of the target and distractor stimuli contribute jointly to determining the magnitude of the crossmodal congruency effect when participants have to respond to vision and ignore touch.     

Learning disability as related to infrequent punishment and limited participation in delay of reinforcement tasks

By comparing for learning disabled and control children parental frequency ratings of physical punishment and of completing household tasks, this experiment tested the hypothesis that parental indulgence is associated with learning disorders. Referral children with learning problems (N=18), matched on grade and sex with those in two control groups, were rated significantly lower on both measures than were either the students referred for other reasons or the nonreferred students. The infrequent punishment suggests that some children have learning problems because of a failure to acquire adequate response inhibition tendencies, which are necessary to control inappropriate behaviors resulting from the ineffective classroom positive reinforcement system. Furthermore, the lower responsibility index suggests some of their academic problems result from limited experiences functioning under delayed reinforcement.     

Perception of object shape and texture in human newborns: evidence from cross-modal transfer tasks

The present research investigates newborn infants' perceptions of the shape and texture of objects through studies of the bi-directionality of cross-modal transfer between vision and touch. Using an intersensory procedure, four experiments were performed in newborns to study their ability to transfer shape and texture information from vision to touch and from touch to vision. The results showed that cross-modal transfer of shape is not bi-directional at birth. Newborns visually recognized a shape previously held but they failed to tactually recognize a shape previously seen. In contrast, a bi-directional cross-modal transfer of texture was observed. Taken together, the results suggest that newborn infants, like older children and adults, gather information differently in the visual and tactile modes, for different object properties. The findings provide evidence for continuity in the development of mechanisms for perceiving object properties.     

Failures to ignore entirely irrelevant distractors: the role of load

In daily life (e.g., in the work environment) people are often distracted by stimuli that are clearly irrelevant to the current task and should be ignored. In contrast, much applied distraction research has focused on task interruptions by information that requires a response and therefore cannot be ignored. Moreover, the most commonly used laboratory measures of distractibility (e.g., in the response-competition and attentional-capture paradigms), typically involve distractors that are task relevant (e.g., through response associations or location). A series of experiments assessed interference effects from stimuli that are entirely unrelated to the current task, comparing the effects of perceptual load on task-irrelevant and task-relevant (response competing) distractors. The results showed that an entirely irrelevant distractor can interfere with task performance to the same extent as a response-competing distractor and that, as with other types of distractors, the interfering effects of the irrelevant distractors can be eliminated with high perceptual load in the relevant task. These findings establish a new laboratory measure of a form of distractibility common to everyday life and highlight load as an important determinant of such distractibility.     

Short article one's own face is hard to ignore

One's own face possesses two properties that make it prone to grab attention: It is a face, and, in addition, it is a self-referential stimulus. The question of whether the self-face is actually an especially attention-grabbing stimulus was addressed by using a face-name interference paradigm. We investigated whether interference from a flanking self-face on the processing of a target classmate's name was stronger than interference from a classmate's flanking face on the processing of one's own name as the target. In a control condition a third familiar face served as the flanker for both decisions from the participant's own name and from the classmate's name. The presentation of the self-face as a flanker produced significantly more interference on the identification of a classmate's name than the presentation of that classmate's face did on the identification of one's own name. This result was due to the interfering power of the self-face and not to a particular resistance of one's name to interfering facial stimuli. We argue that the emotional value or the high familiarity of one's own face may explain its attention-grabbing property.     

Short article one's own face is hard to ignore

One's own face possesses two properties that make it prone to grab attention: It is a face, and, in addition, it is a self-referential stimulus. The question of whether the self-face is actually an especially attention-grabbing stimulus was addressed by using a face–name interference paradigm. We investigated whether interference from a flanking self-face on the processing of a target classmate's name was stronger than interference from a classmate's flanking face on the processing of one's own name as the target. In a control condition a third familiar face served as the flanker for both decisions from the participant's own name and from the classmate's name. The presentation of the self-face as a flanker produced significantly more interference on the identification of a classmate's name than the presentation of that classmate's face did on the identification of one's own name. This result was due to the interfering power of the self-face and not to a particular resistance of one's name to interfering facial stimuli. We argue that the emotional value or the high familiarity of one's own face may explain its attention-grabbing property.     

Learning and generalization of piagetian tasks by mentally retarded students

70 mentally retarded students, successfully taught to conserve number and substance in the Piagetian sense, resisted attempts at extinction but were unable to generalize to other conservation tasks.     

Templates for rejection: configuring attention to ignore task-irrelevant features

Theories of attention are compatible with the idea that we can bias attention to avoid selecting objects that have known nontarget features. Although this may underlie several existing phenomena, the explicit guidance of attention away from known nontargets has yet to be demonstrated. Here we show that observers can use feature cues (i.e., color) to bias attention away from nontarget items during visual search. These negative cues were used to quickly instantiate a template for rejection that reliably facilitated search across the cue-to-search stimulus onset asynchronies (SOAs), although negative cues were not as potent as cues that guide attention toward target features. Furthermore, by varying the search set size we show a template for rejection is increasingly effective in facilitating search as scene complexity increases. Our findings demonstrate that knowing what not to look for can be used to configure attention to avoid certain features, complimenting what is known about setting attention to select certain target features.     

Preattentive texture segmentation: The role of line terminations,size, and filter wavelength

The texel pair represents a dilemma in texture discrimination because, despite having the same component orientations, discrimination is still possible (Julesz, 1981), showing a performance asymmetry. Other possible element properties that could influence this task are line terminations, closure, and the size of these elements. We found that line terminators are critical for the task; however, results from double-task experiments indicated that terminator-based discrimination requires the use of attention. When attention is not available for the task, “size” of the elements (with the considered slightly larger) seems to be critical for this discrimination and for the asymmetric performance. To generalize the concept of “size” to textures in general, further experiments were performed with textures of different-sized elements. Results showed, as past literature has indicated, that there is a performance asymmetry, with the larger of the elements being more visible when in the foreground. This asymmetry was additionally shown to reverse itself (i.e., the smaller element became the more visible) as the scale of the elements increased (while interelement distance remained fixed). A filter analysis was developed in order to measure the apparent size of these elements within textures (texsize), defined as the response weighted average of the filter wavelength, $\bar \lambda $ , for a group of elements. The calculation of $\bar \lambda $ was attained by introducing a nonlinearity after the second stage of filtering (or spatial averaging of filter responses). This analysis showed high correlation between the texture with the larger $\bar \lambda $ and the more visible texture. On the basis of this correlation, a wavelength-dependent noise is proposed, having more internal noise for low-spatial-frequency filters and less for high-spatial-frequency filters.