Acquisition and transfer of skilled performance: Are visual discrimination skills stimulus specific?

The authors examine how the difficulty of initial training influences the acquisition and transfer of both stimulus-specific knowledge and strategic knowledge not tied to specific stimuli. Participants were asked to discriminate between random polygon stimuli. The order of exposure to very similar and less similar discriminations was varied, in which difficulty of discriminations was defined by the similarity of the stimuli being discriminated. Participants were then transferred to making discriminations between a completely novel set of random polygons. Exposure to discriminations between highly similar stimuli led to eventually faster and more accurate discriminations and superior transfer performance on novel stimuli. The results are explained by a theory of skill acquisition that includes both stimulus-specific knowledge and strategic knowledge that is driven by exposure to specific stimuli, but is not stimulus specific. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Dissociation of visual and auditory pattern discrimination functions within the cat's temporal cortex

In ablation-behavior experiments performed in adult cats, a double dissociation was demonstrated between ventral posterior suprasylvian cortex (vPS) and temporo-insular cortex (TI) lesions on complex visual and auditory tasks. Lesions of the vPS cortex resulted in deficits at visual pattern discrimination, but not at a difficult auditory discrimination. By contrast, TI lesions resulted in profound deficits at discriminating complex sounds, but not at discriminating visual patterns. This pattern of dissociation of deficits in cats parallels the dissociation of deficits after inferior temporal versus superior temporal lesions in monkeys and humans.     

Changes of auditory word discrimination induced by inversion of the visual field.

Examined auditory discrimination in normal hospital staff members during induced visual conflict. Discrimination of words accompanied by background noise was measured at 6 speech-signal-noise intensity levels during preexperimental (normal vision), experimental (inverted vision), and postexperimental (normal vision) periods. A control condition (no inverted vision) served as a check for the possible effects of practice or fatigue. Significant losses of word discrimination occurred only in the inverted vision condition. Discrimination losses occurred at all intensity levels in which speech was accompanied by noise, prior to walking in the inverted vision condition, following a walking period, and after removal of inversion eyepieces. Results are attributed to a process of visually induced conflict in which Ss were unable to decenter the altered contents of vision. Affinities between reports of induced alterations of experience and pathological alterations of experience are discussed. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cortical lesions and auditory discrimination.

Reviews studies investigating the effects of lesions of the auditory cortex upon auditory discriminations. Discriminations studied include frequency, intensity, duration and other temporal cues, complex spectral differences, and changes in temporal patterning. Factors determining the effectiveness of lesions are (a) size and completeness of lesion, (b) whether the lesion involved 1 or both hemispheres, (c) nature of the testing procedure, (d) size of the signal differences to be discriminated, and (e) nature of the discrimination. In view of the numerous factors, comparison of different studies is often difficult because of confounding. In terms of the factors listed above, (a) patterning changes, in which signals are not changed but merely rearranged in order of presentation, suffer more than do tasks involving the detection of new signals or the recognition of different signals; and (b) discrimination tasks requiring recognition suffer more than do tasks requiring only the detection of a new signal. It appears probable that the nature of the discrimination task interacts with the locus of the lesion and that failures on different types of tasks reflect different deficits. (58 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The temporal dynamics of a visual discrimination: The role of stimulus comparison and opponent processes.

The influence of trial spacing on simple conditioning is well established: When successive reinforced conditioned stimulus, CS+, trials are separated by a short interval (massed training), conditioned responding emerges less rapidly than when such trials are separated by longer intervals (spaced training). This study examined the influence of trial spacing on the acquisition of an appetitive visual discrimination in rats. Experiments 1 and 2 established that massed training facilitates the acquisition of such discriminations. The results of subsequent experiments demonstrated that this trial-spacing effect reflects the proximity of nonreinforced, CS-, trials to preceding (Experiment 3) and signaled (Experiment 4) presentations of the reinforcer. Experiment 5 showed that the facilitation of discrimination learning with massed training reflected an effect on learning rather than performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rhinal cortex lesions produce mild deficits in visual discrimination learning for an auditory secondary reinforcer in rhesus monkeys.

Aspiration, but not neurotoxic, lesions of the amygdala impair performance on a visual discrimination learning task in which an auditory secondary reinforcer signals which of 2 stimuli will be reinforced with food. Because aspiration lesions of the amygdala interrupt projections of the rhinal cortex traveling close to the amygdala, it was hypothesized that damage to the rhinal cortex would severely impair learning in this task. Rhesus monkeys (Macaca mulatta) were trained to solve visual discrimination problems based on an auditory secondary reinforcer, were given lesions of the rhinal cortex or the perirhinal cortex alone, and were then retested. The monkeys displayed a reliable, albeit mild, deficit in postoperative performance. It is concluded that the aspiration lesions of the amygdala that produced a severe impairment did so because they interrupted connections of temporal cortical fields beyond the rhinal cortex that are also involved in learning in this task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Independent dimension-weighting mechanisms for visual selection and stimulus identification.

Observers respond faster when the task-relevant perceptual dimension (e.g., color) repeats across consecutive trials relative to when it changes. Such dimension repetition benefits (DRBs) occur in different tasks, from singleton feature search to feature discrimination of a stimulus presented on its own. Here, we argue that the DRBs observed in different tasks originate from distinct mechanisms: preselective weighting of dimension-specific feature contrast signals and, respectively, postselective stimulus processing. The multiple-weighting-systems hypothesis predicts significant DRBs across trials of different tasks that share the same weighting mechanism, but not across tasks involving different mechanisms. Experiments 1, 2, and 3 examined DRBs across localization and detection tasks (both involving feature contrast computations); across detection and identification tasks (which presumably involved different weighting systems); and across identification and discrimination tasks (both involving stimulus identification). As expected, significant DRBs were observed across different tasks in Experiments 1 and 3, but not in Experiment 2. These findings support the multiple-weighting-systems hypothesis. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Comparative potency of tactile, auditory, and visual stimulus repetition in eliciting activated forebrain EEG in the rabbit.

Examined whether certain modalities of stimulation are more effective than others in eliciting immobility-related, atropine-sensitive neocortical low-voltage fast activity and hippocampal rhythmical slow activity from the rabbit. Four Dutch belt male rabbits were used in a series of studies in which the number of stimulus presentations; stimulus modality; interstimulus interval; or drug treatment—saline, atropine sulfate (60 mg/kg, ip), and low-dose pentobarbital—were varied. More pronounced activation and less pronounced habituation followed tactile than auditory and visual stimulation. It is suggested that atropine-sensitive EEG activity may be importantly involved in the central programming, initiation, and guidance of movement. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Children's memory for auditory and visual information on television.

Examined the relationship between children's cognitive processing of video and audio information on TV. 96 5-yr-olds viewed a videotaped segment of Sesame Street followed by comprehension and recognition tests. Ss viewed experimental segments in which (a) the audio and video tracks were from the same segment (A/V match), (b) the audio and video tracks were not from the same segment (A/V mismatch), (c) the video track was presented alone, or (d) the audio track was presented alone. This design allowed unconfounded comparisons of modality-specific processing. In the A/V mismatch condition, memory for audio information was reduced more than memory for video information. However, comprehension and recognition of audio information was similar in the audio-only and A/V match conditions. Results suggest that in regular TV programs, the video information does not interfere with processing the audio information but is more salient and memorable than the audio material. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Invariance of perceptual spaces and perceptual separability of stimulus dimensions

This article reports an extension of a paradigm for studying processing of perceptual dimensions. The paradigm is the complete identification task with a feature-complete factorial design (FCFD) of stimuli providing data for multidimensional signal detection analyses. The extension uses blocks of trials with subsets of the FCFD stimulus set, allowing estimation of various d's for inferring perceptual separability (PS) of dimensions and for disambiguating stimulus configurations when PS fails. Results of 4 experiments found the following: PS of arc curvature and line orientation in a discrimination task (Experiment 1), increasing PS failure in detection of horizontal and vertical lines (Experiment 2a), 45 degrees and 135 degrees (Experiment 2b), and 50 degrees and 60 degrees oblique lines (Experiment 2c). In each experiment, corresponding d's remained equivalent across blocks with different stimulus subsets.     

Generalized auditory same-different discrimination by pigeons.

Three pigeons were trained in a successive same/different (S/D) procedure using compound auditory stimuli (pitch/timbre combinations). Using a go/no-go procedure, pigeons successfully learned to discriminate between sequences of either all same (AAAA...or BBBB...) or all different (ABCD...) sequences consisting of 12 sounds. Both pitch and timbre were subsequently established as controlling dimensions. Transfer tests with novel stimuli revealed a generalized basis for the discrimination (novel pitch/timbre combinations, novel pitches, novel instruments, and complex natural & man-made sounds). These results indicate for the first time that pigeons can learn generalized same/different discriminations in a nondominant modality. When combined with earlier visual results, they support a qualitative similarity among birds and primates in their capacity to judge this type of fundamental stimulus relation across different modalities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotional state and the use of stimulus dimensions in judgment.

Previous studies have demonstrated that, when they are emotional, individuals are more likely to attend to emotional stimuli. However, such work has not established that individuals attend to the emotional dimensions of complex stimuli or that such changes in focus of attention affect judgments. In the present experiments a multidimensional scaling analysis was used to assess the weights that happy, sad, and neutral-emotion participants gave to emotional and nonemotional dimensions of face stimuli in judgments of similarity. Compared to neutral-emotion participants, those in emotional states gave more weight to the emotional dimension of the faces, less weight to other face dimensions, and rated pairs of faces that expressed the same emotion as more similar. Emotion-congruent dimension use was also observed in one experiment. Results are discussed with respect to emotional response categories (P. M. Niedenthal & J. B. Halberstadt, 1995), the tendency for stimuli to cohere as categories on the basis of the emotional response they elicit in the perceiver. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Short-term memory for the timing of auditory and visual signals.

Short-term memory for the timing of irregular sequences of signals has been said to be more accurate when the signals are auditory than when they are visual. No support for this contention was obtained when the signals were beeps vs flashes (Exps 1 and 3) nor when they were sets of spoken vs typewritten digits (Exps 4 and 5). On the other hand, support was obtained both for beeps vs flashes (Exps 2 and 5) and for repetitions of a single spoken digit vs repetitions of a single typewritten digit (Exp 6) when the Ss silently mouthed a nominally irrelevant item during sequence presentation. Also, the timing of sequences of auditory signals, whether verbal (Exp 7) or nonverbal (Exps 8 and 9), was more accurately remembered when the signals within each sequence were identical. The findings are considered from a functional perspective. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensory integration of auditory and visual information.

In exp. I with 3 male and 1 female o, the bisensory recognition of simultaneously presented auditory and visual verbal information was measured as a function of auditory and visual recognition. It is shown that bisensory performance is superior to performance predicted by a model that assumes the 2 modalities are processing the information independently. Instead integrative processing is suggested. In previous studies using theory of signal detectability (tsd), independent processing of bisensory presentations of mathematically equivalent stimuli has been shown. Present results suggest that the mathematically equated stimuli in those studies were not cognitively equivalent. Exp. Ii with 3 male os lends support to this notion by (a) using verbal information in a tsd paradigm, and (b) showing that when the stimuli are equivalent the results are consistent with a model in which bisensory processing occurs integratively on a common decision axis. However, when the stimuli to each mode are not equivalent, results are consistent with a model in which bisensory processing occurs independently on separate decision axes. (french summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cardiac orienting and auditory discrimination in 6-wk-old infants.

A series of 3 experiments with 32 6-wk-old infants studied heart rate and sucking in response to changes in acoustic stimuli. Exp I used a conventional discrete trials paradigm to present trains of synthetic speech syllables, Exp II used a no-delay paradigm to present nonspeech stimuli (tone frequencies). Overall analysis of cardiac data indicated that discriminative capacities in 6-wk-olds can be revealed by changes in heart rate and that this discrimination is better demonstrated using a no-delay (rather than a discrete trials) paradigm. It is suggested that direction of this rate change may provide information about differences in processing, since cardiac responses to changes in synthetic speech syllables was accelerative (possibly a defensive or startle reaction) while responses to changes in tone frequency were decelerative (possibly an orienting index). Findings reveal a consistent absence of sucking responses, indicating that heart rate responses to changes in acoustic stimulation can occur independently of sucking in 6-wk-olds. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal interval discrimination thresholds depend on perceived synchrony for audio-visual stimulus pairs.

Audio-visual stimulus pairs presented at various relative delays, are commonly judged as being “synchronous” over a range of delays from about ?50 ms (audio leading) to +150 ms (video leading). The center of this range is an estimate of the point of subjective simultaneity (PSS). The judgment boundaries, where “synchronous” judgments yield to a predominance of “asynchronous” judgments, usually include physical synchrony, or the point of objective simultaneity (POS). When the POS is used as a standard in a delay discrimination paradigm, thresholds tend to be asymmetric; that is, smaller on the audio-leading side than on the video-leading side of the standard. We replicated this finding using different stimulus types, and standards distributed within and beyond the synchrony judgment boundaries. Thresholds were symmetric near the center of the synchrony range (PSS), but showed opposite patterns of asymmetry as the standard approached either of the two synchrony judgment boundaries. That is, apparent synchrony shows a type of categorical perception in that discriminations within the synchrony category are difficult, but those near the category boundary are easy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Same–different texture discrimination in pigeons: Testing competing models of discrimination and stimulus integration.

The choice behavior of 6 pigeons performing a multidimensional same-different texture discrimination was examined. On each trial, they had to choose among 2 choice hoppers depending on whether a color, shape, or redundant (color and shape) target signal was present or not in a textured stimulus. Receiver operating characteristic (ROC) curves were produced by variations in the a priori signal presentation probabilities across conditions. Quantitative analyses of these ROC curves were used to evaluate different competing theories of discrimination (signal detection vs. high-threshold-default response models) and information integration (independent observations, additive integration, unidimensional models). The results suggested the structure of the pigeons' choice behavior in this same different discrimination was best described by an unequal variance signal detection model involving a unidimensional evidence variable (e.g., degree of difference). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integrality/separability of stimulus dimensions and multidimensional generalization in pigeons.

The authors present a quantitative framework for interpreting the results of multidimensional stimulus generalization experiments in animals using concepts derived from the geometrical approach to human cognition. The authors apply the model to the analysis of stimulus generalization data obtained from pigeons trained with different sets of stimuli varying along two orthogonal dimensions. Separable pigeons were trained with stimuli varying along the dimensions of circle size and line tilt, dimensions found to be separable in previous human research; integral pigeons were trained with stimuli varying along two dimensions of rotation in depth, dimensions that are intuitively integral and which hold special interest for theories of object recognition. The model accurately described the stimulus generalization data, with best fits to the City-Block metric for separable pigeons and to the euclidean metric for integral pigeons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Salient-features coding in the translation between orthogonal stimulus and response dimensions.

Stimulus-response compatibility effects typically are attributed to translation processes. However, studies of compatibility effects obtained with orthogonal stimulus and response arrangements have attributed such effects to mechanisms other than translation processes. The present study evaluated whether recent theoretical advances regarding cognitive coding render a translation-based account viable for orthogonal stimulus-response arrangements. Across all experiments, a preference was shown for the mapping of up-to-right and down-to-left. This preference occurred regardless of whether the response set was manual or vocal, unimanual or bimanual, and whether the stimuli were spatial or symbolic. The results are consistent with the general literature on stimulus-response compatibility, which places the locus of most compatibility phenomena in translation processes. Moreover, the results support the notion that these translation processes operate according to a salient-features coding principle. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detecting anxiety and defensiveness from visual and auditory cues

Defensive individuals have been shown to differ from nondefensive individuals on a number of physiological and behavioral measures. We report two studies on observers' inferences of defensiveness, and the contribution of communication channels in the inference of defensiveness. Observers judged high and low state anxious segments of high and low trait anxious defensive and nondefensive individuals. Accurate assessments were made of (a) defensiveness, (b) state anxiety, and (c) trait anxiety: Individuals with higher levels of each variable were perceived as more anxious compared with the lower level. Effects for defensiveness and state anxiety were greater in audio-only segments, while effects for trait anxiety were greater in video-only segments. Inferences of defensiveness were greater at higher levels of state anxiety and trait anxiety. Low trait anxious defensive individuals were perceived as more anxious than the true low trait anxious. Results for defensiveness and trait anxiety were replicated in Study 2, and observers' perceptions of state anxiety matched individuals' self-reports: Defensive individuals with maximal differences between high and low state anxiety were seen as more anxious in high state anxiety, while defensive individuals with minimal differences between high and low state anxiety were regarded as less anxious in high state anxiety.