Stimulus complexity,free looking time,and inspective exploration

Fourteen Ss rated 59 objects on a seven point complexity scale. From these ratings 10 objects were chosen at the high, middle, and low levels of complexity, and 35 mm slides were made of these 30 objects. Fifteen Ss manipulated and inspected each of the objects for as long as they wished and a second group of 15 Ss viewed slides of the objects for as long as they wished. Analysis of the time scores from these two groups revealed that both inspective manipulation time and free looking time increased as a function of stimulus complexity. Inspective manipulation time was greater than free looking time except at the low complexity level.     

Insensitivity to stimulus validity in human pavlovian conditioning

Four experiments investigated the role of information value, or stimulus validity, in human electrodermal conditioning. Conditioned stimuli (CSs) were long, variable duration (10-50-sec) slides or sounds, the unconditioned stimulus (US) was shock, and the primary measures were change in tonic skin conductance level and self-report expectancy of shock. In Experiment 1 electrodermal responding to a target stimulus was marginally lower in a blocking group than in a superconditioning group. This difference failed to occur in Experiment 2, despite increased sensitivity of the electrodermal measure. Explicit instructions to pay attention to the relationship between each stimulus and shock improved learning, but did not lead to group differences (Experiment 3). In Experiment 4 expectancy ratings in a blocking group were lower than in an overshadowing group, but no electrodermal differences occurred. The results were interpreted in terms of non-additive learning processes such as occasion-setting, in addition to a general lack of transfer of learning about a stimulus from one context to another (element to compound or vice versa). It was suggested that sensitivity to stimulus validity might be observed if conditioning were embedded in a causally familiar task, as in contingency judgement research.     

Effects of task difficulty on subsequent preference for visual complexity.

Ss rated on a 1 to 13 Likert scale their preference for four environmental scenes which differed in complexity. Ss were then given 30 sec. to solve each of 10 3-, 5-, or 7-letter single-solution anagrams. Finally the Ss rated four new slides which were of the same complexity level as the slides seen during the first session. Change scores were calculated by subtracting the preference ratings at each complexity level during the first session from the rating at the corresponding complexity level during the second session. The Anagram Complexity X Slide Complexity interaction was significant: the complexity of the slides showing the most positive change scores was inversely related to the complexity of the anagrams attempted. The results were discussed in terms of optimal level of stimulation theories.     

Visual stimuli in distraction strategies for increasing pain tolerance

Recent experimental studies in pain control have questioned the value of pleasant affect in strategies employing distraction. It appears that pleasant affect may have been systematically confounded with task complexity or novelty in past research that found pleasant imagery or slides effective in increasing pain tolerance with the cold pressor test. The present study was a follow-up to a study conducted by this author (Greenstein, 1984) in which unpleasant slides had significantly increased pain tolerance above pleasant slide level. In the present study, 69 college students (35 females, 34 males) rated either the pleasant or unpleasant slides used in the original study on their perceived pleasantness, complexity, and uniqueness (novelty). Results indicated that the unpleasant slides were rated significantly more complex (P<0.001) and unique (P<0.001) than the pleasant slides. Additionally, as in the earlier study, ratings of the unpleasant slides on pleasantness deviated significantly farther from neutrality than did ratings of the pleasant slides (t=5.04,P<0.001). Thus the unpleasant slides were also perceived as being more significant (i.e., pertinent) than were the pleasant slides. The results indicate that affect was confounded with other stimulus characteristics in the Greenstein (1984) pain control study and probably in a significant number of other studies as well. Researchers are cautioned to control for the stimulus characteristics of visual distraction strategies used in pain control studies. The assumption that pleasantness,per se, contributes to strategy effectiveness is no longer tenable; future research must demonstrate an independent effect. Further, the implication that stimulus significance may increase the effectiveness of distraction strategies opens up a potentially fruitful avenue of research in pain control.     

Dimensions in the perception of architecture:I. Identification and interpretation of dimensions of similarity

Pairwise similarity-dissimilarity ratings of 20 slides of buildings representing major architectural styles were subjected to an INDSCAL analysis. Four major similarity dimensions were identified. Subsequently, the stimuli were rated on two batteries of scales: (1) collative and affective ratings, and (2) stylistic and technical ratings. Canonical correlations and redundancy indices revealed close relations between the multidimensional stimulus locations and the scale and factor spaces. The findings of the three experiments suggest that the four principal dimensions in the perception of architecture appear to be (1)Clarity, (2)Hedonic Tone/Arousal, (3) Uncertainty, and (4) Familiarity.     

Fear decrement to anxiety hierarchy items—Effects of stimulus intensity

The effects of hierarchy item intensity and duration of presentation on intra-item fear decrement were assessed with regard to systematic desensitization. Forty-eight color slides of snakes were scaled and ranked for anxiety value with the psychophysical technique of magnitude estimation by 30 female snake phobics using two response methods: verbal report and a non-verbal report instrument, the hand dynamometer. Seven test slides, spanning the scale range, were shown for 257 sec to 42 additional subjects who rated their fear level on 10 separate occasions using the hand dynamometer and verbal report. For all slides significant fear decrement occurred as a function of duration and the fear decrement across time was greater for slides of higher intensity. Negative exponential functions with similar slopes were found to fit the data for each of the slides, indicating that for each slide the same percentage of the total amount of fear decrement was lost per unit of time. The implications of these results and techniques are discussed for desensitization theory, research and therapeutic procedure.     

Quantifying aggression: Effects of identity of stimulus

A test for children's insight into relations between behaviour and aggressive emotion showed that kindergarten children showed an increase in ratings of emotion corresponding to an increase in aggressive behaviour (positive relation), and that an increase in ratings of emotions corresponding to a decrease in aggression-related behaviour (negative relation) was shown by seven- and nine-year-old children. Cognition of relations between aggressive emotion and behaviour seemed to be developed earlier than cognition of relations between intention and behaviour as observed in a previous study. Results from the test also indicated that the magnitude of emotion ratings differed in identity (same stimulus person) and non-identity (differed stimulus persons) stimulus conditions.     

Looking time: The effects of stimulus complexity and familiarity

During a 10 min. stimulus familiarization period, three groups of 60 Ss each received either 0, 10, or 20 sec. of familiarization on each of 30 experimental stimuli: 10 each of low, medium, and high stimulus complexity. All Ss then viewed the experimental stimuli in a second task, during which they could look at each stimulus for as long as they wished (free looking). For half the Ss in each group, free looking was administered immediately after the familiarization period. The remaining Ss received free looking 48 hr. later. The results replicated earlier research which has shown that free looking time is inversely related to stimulus familiarity, and directly related to stimulus complexity. Unlike earlier findings, the data suggested that with a 48 hr. delay between familiarization and free looking, a stimulus can, at least partially, recover from the decrement in looking time produced by 10 sec. of familiarization.     

前额叶神经振荡活动反映了稳固的刺激冲突和反应冲突

为考察典型Flanker任务中练习对刺激冲突和反应冲突的影响,本研究采用练习范式记录被试完成2:1字母Flanker任务时的行为和脑电数据。行为结果发现,练习对这两类冲突无显著影响。神经震荡能量结果发现,前额叶theta能量随练习而显著减弱,这暗示刺激-反应之间的联结因练习而提升;前额叶alpha能量差异不随练习而变化,这可能反映了Flanker任务中稳定的刺激冲突和反应冲突加工机制。因此,本研究揭示了典型Flanker任务中刺激冲突和反应冲突的稳定特征。     

Effects of stimulus complexity on mental rotation rate of polygons

Both spatial and propositional theories of imagery predict that the rate at which mental images can be rotated is slower the more complex the stimulus. Four experiments (three published and one unpublished) testing that hypothesis found no effect of complexity on rotation rate. It is argued that despite continued methodological improvements, subjects in the conditions of greater complexity may have found it sufficient to rotate only partial images, thereby vitiating the prediction. The two experiments reported here are based on the idea of making the discriminative response sufficiently difficult so as to force the rotation of complete images. The first one scaled the similarity between standard polygons and certain systematically mutated versions. From the ratings so obtained, two levels of perceived similarity, high and low, were defined and served as separate conditions in a response-time, image rotation experiment. The second experiment tested the complexity hypothesis by examining the effect of similarity on rotation rates and its interaction with levels of complexity. The results support the complexity hypothesis, but only for the highly similar stimuli. Rotation times were also generally slower for high as compared with low similarity. It is argued that these results arise because subjects rotate incomplete images when the stimuli are not very similar.     

A visual object stimulus database with standardized similarity information

Although many visual stimulus databases exist, none has data on item similarity levels for multiple items of each kind of stimulus. We present such data for 50 sets of grayscale object photographs. Similarity measures between pictures in each set (e.g., 25 different buttons) were collected using a similarity-sorting method (Goldstone, Behavior Research Methods Instruments & Computers, 26(4):381–386, 1994). A validation experiment used data from 1 picture set and compared responses from standard pairwise measures. This showed close agreement. The similarity-sorting measures were then standardized across picture sets, using pairwise ratings. Finally, the standardized similarity distances were validated in a recognition memory experiment; false alarms increased when targets and foils were more similar. These data will facilitate memory and perception research that needs to make comparisons between stimuli with a range of known target–foil similarities.     

Human evaluative conditioning: Order of stimulus presentation

In an experiment designed to demonstrate evaluative conditioning, subjects were shown 48 pictures of sculptures that they rated on a scale with 21 categories (?10 to +10). Then, the two most liked pictures (L) were paired with pictures from the categories ?1, 0, or +1 (N). In contrast to prior experiments, subjects were given either forward conditioning (N-L) or backward conditioning (L-N) trials but not both. Four other neutral stimuli were paired with each other (N-N) and acted as control stimulus pairs. After conditioning, the stimuli were rated a second time. There was a statistically significant difference in evaluative ratings showing a change of the evaluative tone of the previously neutral stimuli in a positive direction only after forward conditioning. This finding is inconsistent with results of prior experiments and challenges the assumption of Martin and Levey (1987) that evaluative conditioning is different from human classical conditioning.     

Complexity,response competition,and preference

In an attempt to resolve disagreements about the events underlying repeated exposure to a stimulus and the affective consequences of these events, two experiments examined psychological complexity and response competition (two measures of the uncertainty produced by a stimulus) as related to each other and to liking and goodness of meaning ratings of Chinese characterlike stimuli. In Experiment 1, 60 undergraduates' mean latency of first free association to the stimuli (response competition) increased as a perfect monotonic function of the number of lines constituting them (psychological complexity). In Experiment 2, ratings of liking by 40 undergraduates were highest for stimuli associated with an intermediate level of uncertainty (psychological complexity and response competition). Thus it was speculated that a moderate number of stimulus exposures (reducing uncertainty to an intermediate level) is preferable to an indefinitely large number of exposures (reducing uncertainty to a minimal level). The finding of no relationship between rated goodness of stimulus meaning and uncertainty was judged to be consistent with Stang's (1974) hypothesis that characteristically observed increases in rated goodness with increasing stimulus exposures (decreasing uncertainty) are a result of subject intuitions rather than an effect of decreasing uncertainty.     

Return of fear in a human differential conditioning paradigm caused by a stimulus change after extinction

In a human fear conditioning experiment, 32 participants were trained in a differential conditioning procedure with geometrical shapes as CS+ and CS- (four presentations each), and an electric shock as US. Measures of conditioned responding were skin conductance response (SCR) and retrospective US-expectancy ratings. For half of the participants (Generalization Group, GG), the subsequent extinction phase consisted of four nonreinforced presentations of generalization stimuli (GS+ and GS-). Participants from the Extinction control Group received an equal amount of nonreinforced presentations of the CSs. Finally, all participants were tested with the original CSs. The results from both measures clearly show an increase in the size of the discrimination upon the stimulus change after extinction in the GG. Because this pattern is not observed in the Extinction control Group, extinction performance appears to be somehow restricted to the perceptual characteristics of the extinction stimulus. Interestingly, the size of the conditioned SCR discrimination in the GG is not influenced by the stimulus change after acquisition. This observation points to a differential impact of stimulus change after acquisition vs. extinction treatment. The findings are discussed from the theoretical perspective of renewal and the clinical perspective of Return of Fear.     

Multidimensional normative ratings for the International Affective Picture System

The purpose of the present investigation was to replicate and extend the International Affective Picture System norms (Ito, Cacioppo, & Lang, 1998; Lang, Bradley, & Cuthbert, 1999). These norms were developed to provide researchers with photographic slides that varied in emotional evocation, especially arousal and valence. In addition to collecting rating data on the dimensions of arousal and valence, we collected data on the dimensions of consequentiality, meaningfulness, familiarity, distinctiveness, and memorability. Furthermore, we collected ratings on the primary emotions of happiness, surprise, sadness, anger, disgust, and fear. A total of 1,302 participants were tested in small groups. The participants in each group rated a subset of 18 slides on 14 dimensions. Ratings were obtained on 703 slides. The means and standard deviations for all of the ratings are provided. We found our valence ratings to be similar to the previous norms. In contrast, our participants were more likely to rate the slides as less arousing than in the previous norms. The mean ratings on the remaining 12 dimensions were all below the midpoint of the 9-point Likert scale. However, sufficient variability in ratings across the slides indicates that selecting slides on the basis of these variables is feasible. Overall, the present ratings should allow investigators to use these norms for research purposes, especially in research dealing with the interrelationships among emotion and cognition. The means and standard deviations for emotions may be downloaded as an Excel spreadsheet from www.psychonomic.org/archive.     

The effects of stimulus complexity on the preattentive processing of self-generated and nonself voices: An ERP study

The ability to differentiate one’s own voice from the voice of somebody else plays a critical role in successful verbal self-monitoring processes and in communication. However, most of the existing studies have only focused on the sensory correlates of self-generated voice processing, whereas the effects of attentional demands and stimulus complexity on self-generated voice processing remain largely unknown. In this study, we investigated the effects of stimulus complexity on the preattentive processing of self and nonself voice stimuli. Event-related potentials (ERPs) were recorded from 17 healthy males who watched a silent movie while ignoring prerecorded self-generated (SGV) and nonself (NSV) voice stimuli, consisting of a vocalization (vocalization category condition: VCC) or of a disyllabic word (word category condition: WCC). All voice stimuli were presented as standard and deviant events in four distinct oddball sequences. The mismatch negativity (MMN) ERP component peaked earlier for NSV than for SGV stimuli. Moreover, when compared with SGV stimuli, the P3a amplitude was increased for NSV stimuli in the VCC only, whereas in the WCC no significant differences were found between the two voice types. These findings suggest differences in the time course of automatic detection of a change in voice identity. In addition, they suggest that stimulus complexity modulates the magnitude of the orienting response to SGV and NSV stimuli, extending previous findings on self-voice processing.     

Observing behavior in the albino rat: a within-subjects' comparison of increasing levels of visual complexity.

54 male CD strain Charles River albino rats were tested for complexity preference using a non-locomotor response. Each subject was presented an array of photographic slides containing an incremental series of complexity elements, i.e., 1, 2, 5 and 25 elements. All photographic slides were randomized both within and across subjects. Each photographic slide of each level of complexity was repeated three times. Results of an analysis of covariance, with luminance as the covariate, showed that cummulative viewing time increased with an increase in stimulus complexity. The relationship between looking and level of complexity was shown to be different when covariance procedures were used than without them.     

Ratings of Emotional Response to Pictorial Stimuli: Positive and Negative Affect Dimensions

The purpose of this study was to investigate the structure of emotional responses to pictorial stimuli within the affective space defined by orthogonal dimensions of positive affect (PA) and negative affect (NA). College student participants (N = 151) viewed 60 color photographic slides from the International Affective Picture System (Lang, Bradley, & Cuthbert, 1995) and rated their emotional responses to each slide using the Positive and Negative Affect Schedule (Watson, Clark, & Tellegen, 1988). Consistent with prediction, affective reactions to pleasant slides were characterized as high in PA, and low in NA. Unpleasant slides produced elevations on the NA scale, but contrary to expectation, also produced elevated ratings of PA, with the magnitude of PA scale scores increasing systematically with NA scale scores. The results suggest an interesting divergence between the structure of pictorially elicited affective reactions and that of ad hoc mood states. Directions for future research are discussed in relation to the unique properties of the slide viewing paradigm.     

Eye movements and a dynamic stimulus situation

Two experiments were conducted to investigate performance with and without voluntary eye movements in a dynamic stimulus situation. Experiment I used a combined tracking and prediction task. Level of training, complexity of the signal, and visual region sampled were the variables of interest. Experiment II manipulated the same variables in only the prediction task. Thus, the amount of attention allotted to the prediction task was varied between experiments. The d' measure indicated that under peripheral vision instructions accuracy on the prediction task was the same as under foveal vision instructions provided that: (1) the level of task complexity was low, (2) the subjects were well trained, and (3) only the prediction task was performed, or in the dual task situation only visual regions near the fovea were sampled. All other combinations of the variables resulted in a lower performance scores under peripheral vision instructions. Results are interpreted within the framework of current theories of the functional visual field.     

Effects of stimulus context on magnitude estimations and category ratings of perceived loudness--the spacing of intensity intervals

Effects of stimulus context on magnitude estimations and on category ratings were examined for a range of stimulus intensities of a 1-kHz tone. The stimuli were distributed in equal-interval steps of energy so they formed a perceptual cluster of high-intensity tones with a perceptual outlier at the lowest intensity. According to the Invariance Principle, the shape of the response function should not be affected by the distribution of stimulus intensities. However, neither magnitude estimations nor category ratings yielded the linear functions predicted from the Invariance Principle when plotted on log-log axes. Instead, both procedures yielded concave-upward response functions for the group data as well as for the individual data sets of the six subjects. Moreover, unlike previous reports of a nonlinear relationship, we found a linear relationship between magnitude estimations and category ratings. Rather than implying an equivalence of the underlying sensory scales, however, our results may imply subjects used a similar attention strategy for both procedures. We consider some theoretical suggestions, including an attention-band concept, for modification of a multistage stimulus-response (S-R) transformation model.