A psychophysical theory of intensity proportions, joint presentations, and matches.

Empirically testable assumptions relate 3 psychophysical primitives: presentations of pairs of physical intensities (e.g., pure tones of the same frequency and phase to the 2 ears or 2 successive tones to both ears); a respondent's ordering of such signal pairs by perceived intensity (e.g., loudness); and judgments about 2 pairs of stimuli being related as some proportion (numerical factor, as in magnitude production). Explicit behavioral assumptions lead to 2 families of psychophysical functions, one corresponding to unbiased joint presentations and the other to biased ones. Under an invariance assumption, the psychophysical functions in the unbiased case are approximate power functions, and those in the biased case are exact power functions. A number of testable predictions are made. The mathematics involved draws from publications in utility theory and mathematics but with a reinterpretation of the primitives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative activation of stimulus representations restores lost salience: Implications for perceptual learning.

In 3 experiments, rats received preexposure to presentations of a compound flavor BX. The effective salience of B was then tested by assessing its ability to interfere with the aversion controlled by another flavor or the tendency to drink a saline solution after the induction of a salt need. It was found that the effective salience of B was maintained when during preexposure, presentations of BX alternated with presentations of X alone. This was true both when BX was presented as a simultaneous compound (Experiment 1) and as a serial compound (X→B; Experiments 2 and 3); salience was not maintained when the serial compound took the form B→X (Experiments 2 and 3a). It was argued that the salience of B declines during preexposure but is restored when presentations of X are able to activate the representation of B by way of the associative X-B link. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serial modules in parallel: The psychological refractory period and perfect time-sharing.

The authors describe ACT-R/perceptual-motor (ACT-R/PM), an integrated theory of cognition, perception, and action that consists of the ACT-R production system and a set of perceptual-motor modules. Each module (including cognition) is essentially serial, but modules run in parallel with one another. ACT-R/PM can model simple dual tasks such as the psychological refractory period (PRP), including subtle results previously explained with executive process interactive control (EPIC, D. E. Meyer & D. E. Kieras, 1997a). The central difference between the theories is that EPIC's productions can fire in parallel, whereas in ACT-R/PM, they are serial. Results from three PRP-like experiments with more demanding cognitive requirements indicate that cognitive processing for the 2 tasks need not overlap. ACT-R's activation-based retrieval processes are critical in accounting for the timing of these tasks and for explaining the dual-task performance decrement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual learning in flavor aversion: Evidence for learned changes in stimulus effectiveness.

Rats were exposed to the compound flavors AX and BX, presented in alternation, and to CX on a separate block of trials. Generalization to BX after aversion conditioning with AX was less than to CX. An equivalent effect was found when the nature of the common element was changed after preexposure but not when the common element was omitted during preexposure, during conditioning and test, or both. Rats conditioned with X alone again showed less aversion to BX than to CX; similarly, rats conditioned with a novel flavor (Y) showed less aversion to BY than to CY. These effects support the proposal that intermixed preexposure to AX and BX enhances the perceptual effectiveness of their unique features, A and B. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning effects in the block design task: A stimulus parameter-based approach.

Learning effects were assessed for the block design (BD) task, on the basis of variation in 2 stimulus parameters: perceptual cohesiveness (PC) and set size uncertainty (U). Thirty-one nonclinical undergraduate students (19 female) each completed 3 designs for each of 4 varied sets of the stimulus parameters (high-PC/high-U, high-PC/low-U, low-PC/high-U, and low-PC/low-U), ordered randomly within a larger set of designs with mixed stimulus characteristics. Regression analyses revealed significant, although modest, learning effects in all conditions. Negative-logarithmic learning slopes (growth factors) were greatest for high-U/high-PC designs and smallest for low-U/low-PC designs. Comparison of these slopes with known Wechsler Adult Intelligence Scale (3rd ed.; D. Wechsler, 1997; and 4th ed.; D. Wechsler, 2008) BD subtest gain scores demonstrated that presenting novel test items matched on stimulus parameters in multiple administrations reduced learning effects compared with the repeated use of the same test items. The results suggest that repeated administration of novel test items of the BD subtest, matched for PC and U, would result in more accurate assessments of changes in examinees’ abilities over time than would the use of the same items. Difficulties inherent in implementing this method are also discussed. (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)     

A set of conditions for a consistent recovery of a subliminal stimulus.

3 experimental groups of 10 Ss, each with their corresponding controls, were given mathematical problems in a tachistoscope as a supraliminal stimulus. At a level established by a pretest group, the experimental groups received subliminal answers to the problems. Group 1 attempted to solve the problems, Group 2 to guess at the answers, and Group 3 to select their answers from dual possibilities on a given list. A significant tendency was found in Groups 1 and 2 to repeat various subliminally projected digits in their answers, without the answers directly affecting their computational processes. Group 3 selected the projected answers significantly over the correct answers. The need for a positive relationship between supra- and subliminal stimuli as well as the relevancy of the task to the Ss' present activity was also observed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An Exemplar Account of the Bow and Set-Size Effects in Absolute Identification.

The extended generalized context model for response times (K. Lamberts, 2000) was designed to account for choice proportions and response times in perceptual categorization. In this article, the hypothesis that the model also offers an account of accuracy and response times in absolute identification was investigated. The model was applied to the data from 2 absolute identification experiments and provided a good account of the bow and the set-size effects in accuracy and response time data from individual participants, including the response time distributions for individual stimuli. The model applications demonstrated that exemplar-based process models offer a viable account of absolute identification data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"What matters in implicit task sequence learning: Perceptual stimulus features, task sets, or correlated streams of information?" Correction to Weiermann et al. (2010).

Reports an error in "What matters in implicit task sequence learning: Perceptual stimulus features, task sets, or correlated streams of information" by Brigitte Weiermann, Josephine Cock and Beat Meier (Journal of Experimental Psychology: Learning, Memory, and Cognition, 2010[Nov], Vol 36[6], 1492-1509). Two figures appearing on pages 1500 and 1502 contained incorrect labels for the x-axis of the control condition (ranran). The correct versions of Figure 3 and Figure 4 are provided in the erratum. (The following abstract of the original article appeared in record 2010-22281-001.) Implicit task sequence learning may be attributed to learning the order of perceptual stimulus features associated with the task sequence, learning a series of automatic task set activations, or learning an integrated sequence that derives from 2 correlated streams of information. In the present study, our purpose was to distinguish among these 3 possibilities. In 4 separate experiments, we replicated and extended a previous study by Heuer, Schmidtke, and Kleinsorge (2001). The presence or absence of a sequence of tasks, as well as that of a sequence of different task-to-response mappings, was manipulated independently within experiments. Evidence of implicit sequence learning was found only when correlated sequences of tasks and mappings were present. No sequence learning effects were found when only a single task sequence or a single mapping sequence was present, even when the structure of the single sequence was identical to the structure of the integrated sequence of task-mapping combinations. These results suggest that implicit task sequence learning is not dependent on either perceptual learning of stimulus features or automatic task-set activation per se. Rather, it appears to be driven by correlated streams of information. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Semantic effects in naming perceptual identification but not in delayed naming: Implications for models and tasks.

Previous research has demonstrated that the subjective danger and usefulness of words affect lexical decision times. Usually, an interaction is found: Increasing danger predicts faster reaction times (RTs) for words low on usefulness, but increasing danger predicts slower RTs for words high on usefulness. The authors show the same interaction with immediate auditory naming. The interaction disappeared with a delayed auditory naming control experiment, suggesting that it has a perceptual basis. In an attempt to separate input (signal to ear) from output (brain to muscle) processes in word recognition, the authors ran 2 auditory perceptual identification experiments. The interaction was again significant, but performance was best for words high on both danger and usefulness. This suggests that initial demonstrations of the interaction were reflecting an output approach/withdraw response conflict induced by stimuli that are both dangerous and useful. The interaction cannot be characterized as a tradeoff of speed versus accuracy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of a subliminal food stimulus on verbal responses.

To what extent can subliminal stimulation be used to influence human behavior? This study involving 105 college freshmen attempts to isolate and study a few of the possible variables. "The experimental group saw a classroom movie with the word 'beef' superimposed in flashes of –1??? of a second every seven seconds; the control group just saw the movie. It was found that, compared to the control Ss, the experimental Ss (a) did not show increased verbal references to the stimulus word; (b) did not choose the stimulus object in a multiple choice situation (though sex differences were significant); but (c) did rate themselves significantly more hungry. It was also found that hours of food deprivation did not influence any of these relationships. 15 refs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exemplar and prototype models revisited: Response strategies, selective attention, and stimulus generalization.

J. D. Smith and colleagues (J. P. Minda & J. D. Smith, 2001; J. D. Smith & J. P. Minda, 1998, 2000; J. D. Smith, M. J. Murray, & J. P. Minda, 1997) presented evidence that they claimed challenged the predictions of exemplar models and that supported prototype models. In the authors' view, this evidence confounded the issue of the nature of the category representation with the type of response rule (probabilistic vs deterministic) that was used. Also, their designs did not test whether the prototype models correctly predicted generalization performance. The present work demonstrates that an exemplar model that includes a response-scaling mechanism provides a natural account of all of Smith et al's experimental results. Furthermore, the exemplar model predicts classification performance better than the prototype models when novel transfer stimuli are included in the experimental designs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differences in gradients of stimulus generalization as a function of psychiatric disorder.

On the basis of the "Dollard and Miller… principle that 'increasing the strength of the drive raises the entire gradient of generalization… ' [and that]… such emotional states as fear, anxiety, and guilt can acquire the properties of a drive… . The present research investigates the hypotheses that there are differences in the shape of the SG gradients among psychotic, neurotic, and control Ss… . The results indicate that (a) the psychotics showed more generalization than the nonpsychotics; (b) the neurotics showed less… than the psychotics, but did not differ from the controls; and (c) the brain-damaged Ss showed more generalization than the nonpsychotics, but they did not differ from the psychotics." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual recognition as a function of anxiety, motivation, and the testing situation.

The hypothesis was made that degree of anxiety and motivation would influence S's performance on tasks measuring skill in discovering objects embedded in a stimulus field, particularly as the situation was structured to be stressful or not. Ss low in anxiety and high in motivation performed significantly better than Ss high in anxiety but with low motivation. In the nonstressful situation, Ss low in anxiety and motivation performed significantly poorer than their counterparts. It is recommended, therefore, that situational task variables be considered as crucial factors in analysing behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditioned reinstatement of drug-seeking behavior with a discrete compound stimulus classically conditioned with intravenous cocaine.

The present study investigated the ability of a light and tone (LT) compound stimulus paired with cocaine infusions to reinstate cocaine-seeking behavior. Rats were trained to self-administer cocaine in the presence or absence of the LT during daily 3-hr sessions (maintenance). During Maintenance Days 5 and 10, rats underwent classical conditioning, whereby passive cocaine infusions were paired with either short-delayed, random, or no presentations of an LT. After extinction sessions, rats underwent test sessions in which the LT was presented in a noncontingent or response-contingent manner to measure conditioned cocaine-seeking behavior. The results demonstrated that response-contingent LT presentations significantly increased cocaine-seeking behavior and that the LT trained in a classical conditioning format transferred to an operant secondary reinforcer. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reaction time as a function of manifest anxiety and stimulus intensity.

"The present study was designed to investigate the relative increase in drive of anxious and nonanxious individuals as a function of different intensities of stimulation… The results indicated that both an increase in manifest anxiety and an increase in stimulus intensity were effective in increasing the speed of reaction during training, and in raising the height of the temporal gradient of response strength; neither factor was effective in steepening the slope of the gradient." 17 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Feature-sampling and random-walk models of individual-stimulus recognition.

Traditional process models of old-new recognition have not addressed differences in accuracy and response time between individual stimuli. Two new process models of recognition are presented and applied to response time and accuracy data from 3 old-new recognition experiments. The 1st model is derived from a feature-sampling account of the time course of categorization, whereas the 2nd model is a generalization of a random-walk model of categorization. In the experiments, a new technique was used, which yielded reliable individual-stimulus data through repeated presentation of structurally equivalent items. The results from the experiments showed reliable differences in accuracy and response times between stimuli. The random-walk model provided the better account of the results from the 3 experiments. The implications of the results for process models of recognition are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reaction time and response amplitude as a function of anxiety and stimulus intensity.

"The present study was concerned with reaction time and response amplitude as a function of C S intensity and anxiety (Taylor scale). 5 presentations of 2 auditory stimuli varying only in intensity were given to each of 22 anxious and 22 nonanxious Ss. Increased intensity resulted in significant increases in amplitude and speed of reaction. Mean amplitude scores of the anxious group were significantly greater than those of the nonanxious group. A significant interaction was found between anxiety and intensity… . Significant sex differences were found on both measures. The results were discussed in terms of competing implicit response tendencies." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of cross-modal and intramodal division of attention on perceptual implicit memory.

Extant results motivate 3 hypotheses on the role of attention in perceptual implicit memory. The first proposes that only intramodal manipulations of attention reduce perceptual priming. The second attributes reduced priming to the effects of distractor selection operating in a central bottleneck process. The third proposes that manipulations of attention only affect priming via disrupted stimulus identification. In Experiment 1, a standard cross-modal manipulation did not disrupt priming in perceptual identification. However, when study words and distractors were presented synchronously, cross-modal and intramodal distraction reduced priming. Increasing response frequency in the distractor task produced effects of attention regardless of target-distractor synchrony. These effects generalized to a different category of distractors arguing against domain-specific interference. The results support the distractor-selection hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)