A cross-sequential analysis of developmental differences in speed of visual information processing

Development of processing speed was examined in three backward masking studies. The first verified the central nature of backward masking for children aged 8 and 11 years and for adults. The second suggested that task requirements were equivalent for children similar to those in Study 1, and that age differences in performance were not attributable to nonprocessing variables. The main cross-sequential study estimated speed of processing in 80 children (approximately 6 years to 13 years) and young adults using an inspection time task. Target exposure duration was varied to establish the time required to achieve a high level of discriminative accuracy. Estimates of processing speed increased until about 11-13 years of age; beyond this, the trend was less obvious, and it is possible that inspection time asymptotes at around the onset of adolescence. Performance improvement after 1 year could not be explained as resulting from practice since improvement among controls over a period of 2 weeks was significantly less. Correlations between estimates of inspection time made up to 2 years apart found the measure to be reliable.     

Measures of timed performance and intelligence

The question of an association between IQ and measures of timed performance derived from inspection time and reaction time was examined in a sample of 182 adults and by reanalyzing data involving 48 adults from a previously published study. Multiple regression analysis found that measures of timed performance accounted for as much as 25% of IQ variance in the normal population, but that the inclusion of borderline and mildly retarded subjects resulted in much higher correlation coefficients because of the markedly less efficient performance of these persons in tasks of this kind. This outcome raised doubts about the validity of combining data from retarded and nonretarded subjects. Results ran counter to claims that tasks of the kind used are largely uninfluenced by cognitive variables, so that findings are not necessarily explained satisfactorily in terms of a mental speed factor. It was concluded that these measures of timed performance do not, at this time, provide a basis from which a reliable culture-fair measure of intelligence might be devised.     

Stimulus- or response-induced excitation. A comparison of the behavior of introverts and extraverts

The tendency to inspect visual material (slides) rather than to respond by pressing a key in an attempt to move on to the next slide, was compared among introverts and extraverts. As predicted from Brebner and Cooper (1974): (1) extraverts inspected the stimuli for a shorter time before making their first response, (2) extraverts made more responses at a faster rate than introverts did, and (3) extraverts produced a significantly higher proportion of runs of accelerating responses.     

The effect of a low rate of regular signals upon the reaction times of introverts and extraverts

In an RT (reaction time) task involving responding to infrequent, regular signals, extraverts produced higher proportions of missed signals and lengthened RT's than introverts did. This result was only obtained after some time on task and is evidence that inhibitory states are formed more rapidly in extraverted subjects under low stimulation conditions. In a more extended version of the task, mean RT was found to be longer in extraverted than introverted subjects in the second half of the experiment though there was no significant difference between the groups in the first half. These findings are complementary to data from previous studies showing that extraverts generate stronger inhibitory potential in continuous responding tasks, or that their characteristic arousal level may be lower than that of introverted subjects. The need to distinguish between the different explanatory constructs is discussed and a simple model amalgamating the major theoretical positions is outlined.     

Visual field differences in verbal tasks: Effects of task familiarity and sex of subject

Four experiments using normal subjects investigated differences in magnitude of the right visual field (RVF) superiority as a function of word material (frequency and concreteness/imageability status), nonword letter strings (some of which were homophonic with nonpresented real words), and type of task (overt naming or lexical decision with discriminatory manual responses) as well as sex of the subject and the subject's familiarity with the material. Both latency and error measures showed that RVF superiority was more consistent when overt naming was required and with male subjects. For female subjects engaged in lexical decisions, a left visual field (LVF) superiority was often apparent, especially in the first half of an experimental sequence; when actually naming the items aloud, they showed field asymmetries similar to males. Except from an analysis of errors, there was little evidence to support differential right hemisphere mediation of high frequency concrete/imageable materials. It is suggested that in females, right hemisphere space normally reserved for visuospatial processing may have been invaded by secondary speech mechanisms. These mechanisms appear to operate at an essentially lexical level and may act in a supportive or auxiliary capacity for difficult or unfamiliar material; they seem to be equally concerned with both phonological and graphological processing and may account for the well-known female superiority in verbal tasks and inferiority in visuospatial tasks. Other findings are discussed such as the degree of consistency of the field differences, both for the same subjects and for the same stimulus materials under different task requirements and experimental conditions.     

First-grade boys' responses to a new task following noncontingent feedback

Sixty-four first-grade boys trained on a two-choice discrimination task received positive feedback either contingent upon their correct responses or in the same amount but noncontingently. Each child was then asked to choose between two alternate ways of accumulating pennies. He could solve problems and earn pennies for correct responses to a contingent task, or he could collect pennies at the same rate by remaining passive. The purpose of this research was to determine if the usual effects of noncontingent feedback would transfer from a simple training procedure to a different contingent task. It was found that the total amount of time spent at the passive alternative did not differ between training conditions. However, a significantly greater number of noncontingently trained children did choose the passive alternative early during testing; these children either gave all of their time to the passive alternative or, very shortly after attempting the task, switched to the passive response. When the noncontingently trained children did choose to work actively during testing, their performance reflected ineffective problem-solving strategies. These results suggest that even when conditions change, experience with prior noncontingent feedback disrupts the ability to utilize contingent information.     

The effects of restraint and noncontingent preshock on subsequent escape learning in the rat

Three experiments investigated the effects of restraint and of inescapable fixed duration preshocks on subsequent shuttlebox escape-from-shock learning. Fixed-intensity preshock, random-intensity preshock, and no-preshock conditions were included in each experiment. In Experiment 1, restraining the rat in a harness prior to escape training retarded escape acquisition. There was no effect of preshock. In Experiment 2, both restraint and high fixed-intensity (1.0 mA) preshock retarded escape acquisition, when escape training occurred either immediately or 24 hr after preshock. In Experiment 3, movement was punished by positively correlating preshock intensity with the rat's movement; this treatment retarded escape conditioning. No effects were found for low fixed-intensity or random-intensity preshock nor for a condition in which movement was rewarded during preshock. The retarding effects of restraint and certain types of preshock were explained in terms of interfering instrumental responses.     

The roles of event contingencies and reinforcement in human autoshaping and omission responding

Four experiments were conducted to test those features deemed to play an important role in the acquisition and/or maintenance of autoshaping and omission responding with human subjects, viz., event contingencies, reinforcement, stimulus generalization, the type of CS employed, conditioned reinforcement, and response topography. One important aspect of these studies is that the boundary conditions were made to resemble those pertaining to the majority of nonhuman animal studies, i.e., magazine training followed by paired CS-US presentations. The results demonstrated the importance of CS-UR or, alternatively, CS-US contiguity together with generalization and a response-reinforcer contingency for autoshaped response initiation and maintenance, respectively. The conditioned reinforcing effect of CS offset appears to play a part in generating and maintaining some responding during omission training, especially during a response-terminated CS procedure. Similar response topography was observed when the form of the UR was compared to that of the CR or autoshaped response. Taken as a whole the results of these experiments with humans are directly comparable to results previously reported using a wide variety of nonhuman animals.     

Anterior-posterior interhemispheric differences in the loci of lesions producing visual hemineglect

Five neuropsychological tests designed to measure the presence and severity of visual hemineglect were given to 101 patients with clearly defined unilateral lesions. Of these, visual hemineglect was present in 28 out of a total of 56 left brain damaged (LBD) patients and in 20 out of 45 right brain damaged (RBD) patients. The incidence of hemineglect in these groups did not differ significantly, but the severity of hemineglect was greater in the RBD group than in the LBD group. However, the two groups were found to differ significantly with respect to the loci of the lesions most likely to result in hemineglect. In the RBD group most patients with hemineglect had posterior lesions, and in the LBD group most patients with hemineglect had anterior lesions. Possible reasons for this were discussed first from the point of view of an inattention hypothesis and second in terms of the effects the lateralization of language representation might have on the representation of spatial functions.     

Effectiveness of social reinforcement as a function of contingent and noncontingent satiation

The social satiation effect is the inverse relation between the availability of a social stimulus and its subsequent efficacy in a reinforcing role. According to a suggested cognitive-interactive theory, the satiation effect is mediated by children's attributions of contingency between their own behavior and the experimenter's actions in the satiation treatments. Perceived contingencies depend, at least to an extent, on actual contingencies, and it was therefore predicted that a satiation effect would be observed only for groups presented in the satiation treatment with noncontingent social stimuli but not for groups presented with contingent stimuli. Middle-class 5- and 7-year-old children were subjected to a 10-min waiting period in which the stimulus word “Yafeh” (“good” in English) was presented 2 or 20 times, contingently or noncontingently. They were then given a 75-trial binary discrimination test: correct responses were reinforced with “Yafeh”. The hypothesis was confirmed in the analysis of variance. However, the predicted difference between the slopes of the contingency and noncontingency conditions was found clearly only in the older sample, while the younger children were more influenced by the number of social stimuli presented in the treatment (satiation) and less influenced by the method of stimulus presentation.     

Feature-processing deficits following brain injury. I. Overselectivity in recognition memory for compound stimuli

A previous experiment (S. Wayland & J.E. Taplin, 1982, Brain and Language, 16, 87-108) demonstrated that aphasic subjects had particular difficulty performing a categorization task, which for normals involves abstraction of a prototype from a set of patterns and sorting of other patterns with reference to this prototype. This study extended the investigation to a recognition memory task similarly organized in categorical structure. The aim was to replicate the previous findings and to delineate the precise nature of aphasics' difficulties with such tasks. Aphasics were again found to be aberrant in performing this task in comparison with normal subjects, nonaphasic brain-injured control subjects also demonstrating a departure from normality. The results suggest that the problem for brain-injured subjects is one of overselectivity in terms of the features of the stimuli to which they respond rather than a difficulty with prototype abstraction itself.     

Can group differences in hemispheric asymmetry be inferred from behavioral laterality indices?

A large and often contradictory literature purports to demonstrate different patterns—or at least different degrees—of hemispheric specialization across various groups of people. Schizophrenics, dyslexies, stutterers, musicians, Orientals, Jews, and many other groups have been alleged to display idiosyncratic laterality patterns. An examination of this literature reveals three important problems. First the groups concerned are rarely homogeneous. This makes it difficult to know which group characteristics, if any, are responsible for the observed differences. Second, most behavioral laterality indices are of low reliability making group differences highly unstable. Third, the validity of many behavioral laterality indices has not been substantiated. Because of these problems, it is concluded that caution should be exercised in using and interpreting laterality measures to make between-group comparisons. For now at least, group differences in laterality cannot be inferred.     

Biasing evaluations to appear unbiased: A self-presentational paradox

Subjects interviewed a confederate posing as a job applicant. In a 2 × 2 factorial design, half the subjects were insulted by the confederate at the end of the interview and half were not insulted. Half the subjects were observed by the experimenter during the final phase of the interview and evaluated the confederate publicly. The remaining subjects were unobserved during the interview and evaluated the confederate anonymously. As predicted, subjects who were publicly insulted were more favorable toward the confederate than were subjects who were privately insulted. Within the public/insult condition, subjects scoring high on Snyder's (1974, Journal of Personality and Social Psychology, 30, 526–537) self-monitoring scale were more favorable toward the confederate than were subjects scoring low on this scale. The positivity bias occurred only on highly subjective ratings, which are most prone to the appearance of bias. The results are discussed in terms of the subjects' desire to avoid the appearance of bias by biasing their evaluations.     

Acquired and developmental spelling dyslexia

Two cases of acquired spelling dyslexia and one case of developmental spelling dyslexia are described along with accounts of their performance on various psycholinguistic tasks. It is argued that there is some evidence that spelling dyslexia may exist in developmental form but that parallels are difficult to draw because of the very different histories of child and adult cases. It is also suggested that features of surface dyslexia exist in at least a proportion of spelling dyslexic cases and that this may be influenced by level of premorbid reading skill.     

Feature-processing deficits following brain injury. II. Classification learning, categorical decision making, and feature production

The claim that overselectivity in feature processing underlies the disorders that aphasics display in processing both visual and verbal material was directly tested by exploring the relationships between the behavior of brain-injured subjects on three experimental tasks: classification learning, categorical decision making, and feature production. From each of these tests a score selected as being indicative of overselective responding was entered into a principal components analysis, together with measures of visual recognition and memory, visual reasoning, naming skills, and severity of aphasia. This analysis supported the assumption that feature-processing disability is a specific and separable deficit, although related both to naming ability and to severity of aphasia. The relevance of the overselectivity hypothesis to naming difficulties following brain injury is discussed.     

Individual differences in aggressive responses to attack: Internal-external locus of control and field dependence-independence

Two experiments assessed the effect of individual differences on aggression. In both studies subjects were exposed to opponents in the competitive reaction time task who decreased the intensity of their attack from high to low, remained constantly moderate in their attack, or increased the intensity of their attack from low to high. In the first experiment Internal Locus of Control subjects consistently set high intensity shocks in response to high intensity attack and low shocks in response to mild attack. External subjects showed relatively minor variations in their aggressive responses to varying intensities of attack. In the second experiment field-independent subjects set more intense shocks than field-dependent subjects only in the Decreasing attack condition.     

Power and speed components of individual differences in letter matching

Several previous studies have reported a correlation (typically around −.30) between standardized verbal ability test scores and name identity minus physical identity reaction times (NI-PI) in a letter-matching task. This correlation has usually been thought to reflect the mutual dependence of both measures on long-term memory access time. The present research was designed to assess Carroll's (1981) suggestions that: (a) NI — PI may not be the optimal formula for predicting standardized test scores from letter matching data, and (b) NI — PI may actually be related to the speed rather than the power component of standardized tests. Fifty-one subjects previously tested with a standardized reading test participated in letter-matching and word-reading tasks. The latter tasks required subjects to read words and specially constructed pseudowords. Power and speed measures were derived from the word-reading tasks and the standardized test on theoretical grounds (and supported by a principal components analysis). The results supported both of Carroll's contentions. NI — PI reaction time was related more to speed than power and the NI — PI statistic (as usually used) was not the optimum formula for predicting standardized test scores.     

Switching pauses in cooperative and competitive conversations

The effects of three variables (conversation type, turn completeness, and sexual composition of the interacting dyad) on switching pause durations was investigated. Conversation type was represented by two categories of conversation: cooperative and competitive. A cooperative conversation is one in which participants cooperate in floor apportionment, while a competitive conversation is one in which the participants compete for the floor. Turn completeness has two levels and refers to the presence or absence of a turn-yielding signal in the utterance immediately preceding a switching pause. Three dyad compositions, male-male, female-female, and male-female were used, with six dyads in each category. The subjects participated in four conversations, two friendly chats and two arguments, on various topics. The switching pauses in competitive conversations were shorter than those in cooperative conversations. Furthermore, conversation type had a significant effect on the switching pause length following imcomplete utterances.     

Hemispheric differences in picture-word interference

In a picture-word version of the Stroop task, 30 right-handed subjects were tested under each of six conditions in which a picture alone or a picture plus a word were presented to the left, the right, or both hemispheres. In two additional conditions the picture was presented to the right hemisphere and the word was simultaneously presented to the left hemisphere, or vice versa. For all conditions, subjects were instructed to name the picture only, as rapidly as possible. Picture naming times were significantly slower for the conditions in which the pictures were accompanied by words than in the respective picture alone conditions. Moreover, simultaneous presentation of a picture and a word to both hemispheres resulted in greater interference (slower picture naming times) than did the simultaneous presentation of the picture and the word to either the left hemisphere alone or the right hemisphere alone. The latter two conditions, in turn, resulted in significantly more interference than did the simultaneous presentation of the picture to one hemisphere and the word to the other hemisphere. This pattern of results suggests that the Stroop effect obtained under normal circumstances is in large part a function of the interference caused by the simultaneous processing of items in the same hemisphere. In contrast to hemispheric differences reported for the color-word Stroop task, the effect of presenting a picture and word simultaneously to the right hemisphere did not differ reliably from that of presenting a picture and word to the left hemisphere. The failure to replicate this aspect of the color-word Stroop is attributed to differences in the abilities of the two hemispheres to process the respective target items (the color or the picture) of the two tasks.