The psychophysics of iconic storage

Some simple models of iconic storage, based on the persisting responses of photoreceptors, were tested in two experiments. Substantial changes in such physical parameters as adapting luminance, stimulus luminance, and stimulus contrast produced little or no change in the duration of partial-report performance. This is at odds with most receptoral models. It seems unlikely that any model based on receptoral persistence can accommodate the results, thus forcing one to locate the icon beyond the receptors and probably beyond the retina as a whole.     

Target duration effects on iconic memory: the confounding role of changing stimulus dimensions

Observers' accuracy in detecting a narrow spatial gap between two brief, luminous rectangles presented successively was determined within a two-alternative, forced-choice procedure. This successive-field task requires iconic memory, because the information (rectangle position) in the two presentations must be combined for successful gap detection. On this task, the effect of varying the duration of the first rectangle was systematically investigated over several target luminance levels and for several ISI conditions between rectangles. At the long ISI conditions (100 and 300 ms), the effects of increasing stimulus duration was to improve performance. However, at the brief ISI condition (20 ms), increasing stimulus duration initially depressed task performance. It was found that, with practice, this initial performance drop largely disappeared, and the beneficial influence of increasing target duration was again obtained. These results are discussed in terms of (a) a proposed retinal locus for the iconic memory involved and (b), at a more general level, the potentially distracting role of changing stimulus dimensions on a task employing transient stimuli as in the present study.     

Components of the laterality effect in letter recognition: Asymmetries in iconic storage

A partial report procedure and a backward masking paradigm were employed to explore lateral asymmetries in components of letter recognition. Stimulus displays were displaced off-centre into the left visual field (LVF) or the right visual field (RVF). Visual field differences in the effect of a delayed backward mask indicated an RVF superiority in the rate of read-out or encoding. Comparison of masked and unmasked full report also yielded estimates of iconic persistence. The persistence of these peripheral displays was surprisingly brief, although it was significantly longer in the LVF (₅₇ ms) than in the RVF (₃₄ ms). Precueing by colour and by location produced a larger partial report advantage in the RVF, reflecting a superiority in selective sampling. With postcueing no partial report effect was obtained at any delay, and this failure was attributed to the briefness of the iconic persistence.     

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.     

Amount of stimulus exploration and preference as differential functions of stimulus complexity

Two sets of photographic slides, one made up of scenes from the geographic environment, the other of works of non-representational modern art, were scaled for complexity by obtaining judges’ ratings of amount of variation present on several specified stimulus attributes. Fourteen slides defining a sevenpoint scale of complexity were selected from each set and given to college students to obtain measures of (a) amount of exploratory behavior (number of times S chose to expose each slide briefly), and (b) preference (evaluative ratings on a seven-point scale). In accordance with prediction, the former measure emerged as a linearly increasing function of complexity, while the relationship between complexity and preference was curvilinear, reaching a maximum at an intermediate level of complexity. The results are related to Berlyne’s distinction between specific and diversive stimulus exploration, and implications for the study of aesthetics are discussed.     

Frequency,complexity, and clarity as covariates of observer reliability

Factors affecting interobserver agreement (reliability) with a comprehensive coding system in the naturalistic observation of children were examined. Data from 117 pairs of observations on 35 children and their families were examined with respect to reliability and three possible covariates: response frequency, observation complexity, and code definition clarity. Analysis of results strongly supported response frequency as a positive covariate of interobserver agreement. Complexity was found to negatively covary with interobserver agreement. The relationship between code clarity and reliability was in the predicted direction but failed to obtain statistical significance. Implications for observer training and data collection in observational studies are discussed.An earlier version of this article was prepared for presentation at The Association for the Advancement of Behavior Therapy, Atlanta, Georgia, December 1977.     

Some functional properties of iconic storage in retarded and nonretarded subjects

Four experiments, which examine some functional properties of iconic storage in mildly retarded subjects, are reported. Experiments I and III demonstrated that retardates report about three items, or one item less than normal subjects, after a single brief tachistoscopic exposure and that this span of attention was independent of size of array. Both normal and retarded groups reported more items correctly when arrays were arranged on two lines. Experiment II determined that exposure durations up to 250 msec did not influence the number of items reported by either group. Experiment IV compared the form of decay for both groups by cuing report of each of seven positions at five poststimulus delays. The presence of the typical W-shaped curve for both groups at all delays permitted the inference that items in iconic storage decay together rather than individually. Although quantitative differences existed between groups, in no case did intelligence interact with the manipulated variables. The results were discussed in relation to control processes and structural features within an information processing model of memory.     

Note on preference for stimulus complexity across the life-span

Preference for stimulus complexity across the life-span was investigated with 175 females ranging in age from 17 to 72 yr. of age. Preference for complexity appeared to be age-invariant and monotonic function. Relationships to previous findings are discussed.     

A theory of intelligence: I. span and the complexity of stimulus control

A theory of intelligence is couched in stimulus-response terms, bridging the gap between S-R and cognitive psychology. The chief theoretical concepts are span ability (a capacity notion), response string (sequentially cued responses), and complexity of stimulus control (task complexity). Span is equated with the ability to respond appropriately when several cues are conjunctively relevant for correct performance (complex stimulus control). So defined, span is consistently and broadly related to many aspects of intelligent behavior.     

Alcohol-induced state-dependent learning: Differentiating stimulus and storage hypotheses

State-dependent effects of alcohol have been demonstrated in animals and man. Most studies have used tasks for which accurate performance typically requires that stimulus input was adequately stored initially and that the items were retrieved at the time of testing. Thus an alcohol-induced decrement in performance could be due to impaired storage, impaired retrieval, or both. The purpose of this experiment was to distinguish between stimulus and storage hypotheses of state-dependent learning (SDL). Sixteen subjects were used in a 2×2 design in which the task involved the learning and recall of a 19-item ‘route’ map. During initial learning, all subjects were sober. Immediately after learning, half the subjects were given a moderate dose of alcohol. Twenty-four hours later, all subjects were tested for recall under the same or different conditions. Greater retention was found for those subjects whose drug states were the same in memory storage/consolidation and retrieval. Thus an alcohol state effective during the memory consolidation interval following acquisition appears to be a sufficient condition for producing SDL. In this context, SDL might be better termed state-dependent memory storage and retrieval. The implications of these results for the aetiology and treatment of alcohol dependence are discussed.     

The processing of multidimensional information from iconic storage: perceptual independence and comparative rates of decay

Using selection by location, the probe technique was applied to alphabetic and 2-dimensional position information. The purpose was to examine (a) the nature of iconic decay, and (b) whether, or not, both types of information are processed independently, when processed simultaneously. Positioning performance gained more benefit from partial report than identify performance, but decay rates were the same for both types of information. Data indicated the existence of perceptual interaction, but no response interaction, when both types of information were processed jointly. The perceptual interaction was attributed to an inverse relationship between structural stimulus complexity and clarity of iconic storage.     

Duration of visible persistence in relation to stimulus complexity

Visible persistence refers to the phenomenal impression that a stimulus is still present after its offset. A dispute exists whether visible persistence is due to temporal sluggishness in the visual pathway (neural hypothesis) or whether it is a byproduct of information-extraction processes under cognitive control (process hypothesis). This was investigated by manipulating stimulus complexity in five temporal integration experiments and one recognition memory experiment. According to the process hypothesis, complex stimuli should persist longer than simple stimuli because they require more information extraction. This prediction was not confirmed; in all six experiments, complexity was found to have no reliable effect on the duration of visible persistence. By contrast, and in accordance with earlier findings, complexity was shown to have a significant effect on a short-lived, nonvisible form of memory known as schematic persistence. This pattern of results supports two major conclusions: First, that the effects of complexity reported in earlier research were probably on schematic—rather than visible—persistence; and second, that visible persistence must be regarded as a residual neural trace of an extinguished stimulus, rather than as a byproduct of information-extraction processes.     

Indirect evidence and the poverty of the stimulus: the case of anaphoric one

It is widely held that children's linguistic input underdetermines the correct grammar, and that language learning must therefore be guided by innate linguistic constraints. Here, we show that a Bayesian model can learn a standard poverty-of-stimulus example, anaphoric one , from realistic input by relying on indirect evidence, without a linguistic constraint assumed to be necessary. Our demonstration does, however, assume other linguistic knowledge; thus, we reduce the problem of learning anaphoric one to that of learning this other knowledge. We discuss whether this other knowledge may itself be acquired without linguistic constraints.     

Age differences in within-session habituation of exploratory behavior: effects of stimulus complexity

The effects of age on the habituation of exploratory behavior of 8-month- and 28-month-old male C57BL/NNia mice were examined under three different stimulus complexity conditions. Increases in the degree of stimulus complexity resulted in an attenuation of between-session habituation and an initial disruption of within-session habituation by 8-month-old mice. Although increases in stimulus complexity also resulted in an increase in the overall level of exploration by aged mice, stimulus complexity was not found to have a systematic effect on between- or within-session habituation by aged mice. No between-session habituation was observed in aged mice under any of the stimulus complexity conditions. Further, aged mice exhibited significant within-session increases, rather than decreases, in exploration under each stimulus complexity condition. This disruption of within-session habituation in aged mice was found to persist over four daily test sessions. In view of the specific patterns of exploration by aged mice, the disruption of within-session habituation was attributed to age-related differences in reactivity to the arousal-inducing properties of novel stimuli.     

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.     

Structural complexity and the quality of stepfather-stepchild relationships

This research examined the effects of structural complexity and sex of stepchild on the quality of stepfather-stepchild relationships. Sixteen simple stepfather families (the wife had custody of a child from a previous marriage, but the stepfather has no biological children) and 16 complex stepfather families (the wife had custody of a child from a previous marriage, and the stepfather was a noncustodial biological parent) with half of each type (N = 8) having a male and half having a female, 9-12-year-old target child participated in a multimethod-multimeasure assessment of the stepfather-stepchild relationship. Families were recruited from marriage license records, and data collection was accomplished in a single three-and-a-half-hour home visit. Dependent variables included: (a) questionnaire measures of love and detachment relationship dimensions independently obtained from parents, stepparents, and (step)children, and (b) proportions of positive and negative stepparent and stepchild communication behaviors derived from videotaped interaction tasks. Findings revealed that simple and complex stepfather families did not differ on any questionnaire or behavioral measures. Girls, however, engaged in a lower proportion of positive verbal and greater proportion of negative problem-solving behaviors toward their stepfathers than boys did. Stepfathers did not differ on proportions of communication behaviors emitted toward boys and girls. No sex-of-child differences were obtained on the questionnaire measures. Directions for future research on structural complexity and stepfather families are discussed.