A developmental comparison of identity and equivalence conservations

The developmental priority of identity conservation as contrasted with equivalence conservation theorized by Elkind (1967) was investigated using quantity and number conservation tasks. Subjects were 60 four-, five-, and six-year-old children of middle socioeconomic class background. All children received a battery of tasks which included qualitative identity, quantitative identity, and equivalence conservation of quantity and number problems. For the quantity battery, under the without justification condition, conditional probabilities and significant performance differences in the mean number of trials passed indicated that the order of acquisition of quantity tasks did conform to the hypothesized sequence: qualitative identity, quantitative identity, and equivalence conservation. No significant performance differences for number concepts were noted for both justification and without justification conditions. Scalogram analyses performed upon the combined quantity number task array indicated a scale or quasi-scale in the predicted order of difficulty. It was concluded that identity concepts develop prior to equivalence concepts when the content area is quantity conservation. In contrast, clear-cut conclusions cannot be made about number conservation.     

A disconfirmation of the quantitative identity-quantitative equivalence sequence

Sixty-four kindergarten children received tests of quantitative identity and quantitative equivalence for the conservations of number and continuous quantity. Two types of identity trials were included: a standard version using a single stimulus, and a modified version which paralleled the equivalence task in its use of two stimuli. In addition, half of the children were asked two questions on each trial (one preceding and one following the transformation), whereas half were asked only the post-transformation question. Neither the number of stimuli used nor the number of questions asked had any effect on performance. In contrast to some previous reports, tests of quantitative identity were no easier than tests of quantitative equivalence. It was concluded that the identity-equivalence décalage, if it exists at all, is less important than previous authors have claimed.     

The developmental relationship between identity and equivalence conservation

Hooper's (1969a) finding that identity conservation develops prior to equivalence conservation was investigated using a more stringent within-subject design. Seventy-two kindergarten, first, and second graders were given three conservation tasks: (1) Identity, (2) Equivalence 1, in which the perceptual cues were comparable to those in Identity, and (3) Equivalence 2, the traditional Piagetian conservation task. Each task was administered under two levels of transformation. No significant differences in performance as a function of level of transformation, type of equivalence task, or sex of S were found, but first and second grade Ss performed better than kindergarten Ss. Eighty-six percent of the sample conserved in an all-or-none fashion, and 7 Ss (10%) passed equivalence while failing identity, thus contradicting the developmental priority of identity conservation.     

Attention to important versus trivial tasks and salience of fatigue-related symptoms for coronary prone individuals

The present study tested the hypothesis that individuals with the Type A coronary prone behavior pattern focus their attention more on important tasks, and less on trivial tasks than do Type B's. The study used a paradigm in which some subjects worked on math problems (important task) and rated intervening mood items (trivial task), whereas others rated mood items they were to memorize (important task) and worked on intervening math problems (trivial task). All subjects were later tested on recall of mood items. Results indicated that Type A's performed better on math problems and recalled more fatigue-related mood items when the task was important than when it was trivial; for Type B subjects, there was no difference in the number of math problems solved correctly or number of mood items recalled between important and trivial task conditions. Moreover, Type A's reported greater fatigue when mood recall was the important task than when math was the important task, whereas fatigue ratings of Type B's did not differ across these conditions. The findings suggest that Type A's suppress their attention to fatigue-related symptoms only when symptoms are not the objects of focus.     

The effects of a memory aid on three types of conservation judgments

Twelve boys and 12 girls at each of 3 ages (4, 5, and 6 years) were tested on three types of conservation judgments (qualitative, quantitative, and equivalence) on both continuous and discontinuous substances. Half of the subjects were provided a memory aid while the other half were not. Conservation ability was determined both with and without verbal justification. The memory aid increased the number of equivalence conservation responses only when verbal justification was not required. The number of subjects conserving on each of the three tasks varied as a function of the scoring criteria used. Type of materials, sex, and age effects were found. The role of transitive inferences and memory in the equivalence conservation task was discussed. Inconsistencies in previous research due to different scoring techniques were noted.     

Effects of differential reinforcement and task difficulty on preschoolers' compliance with teacher instructions

Preschool children in day schools were given instructions to complete certain tasks. Four tasks were given of two types and two levels of difficulty. In each condition compliance with at most one instruction (one task) was reinforced. In two similar experiments, with six children, general results were: compliance with easy tasks was maintained without reinforcement when any task compliance was reinforced; compliance for hard tasks remained high only when that specific task was reinforced. Thus, generalization of compliance with instructions varied with task difficulty. The setting and procedure for both studies were designed to reduce possible coercive features of laboratory studies of generalized performance. Results show generalized performance can occur under naturalistic conditions. The effect of effort, as a response characteristic affecting generalized performance, is discussed.     

The logical and empirical bases of conservation judgements

It is argued that conservation judgements are based on a particular combination of logical necessity and empirical belief. The empirical belief is that a given transformation will not alter a particular quantity (Elkind's conservation of identity). The logical aspect is a transitive deductive argument containing an initial equivalence of two quantities and the conservation of identity belief as premises which lead to the conclusion of maintained equivalence (Elkind's conservation of equivalence). In two experiments, it is shown that conservation of identity beliefs can be manipulated in subjects who have long since developed the capacity for transitive deductive inference. Untrained 10 year olds were unaware of how sublimation acts to alter certain quantities over particular transformations of shape. And untrained adults incorrectly believed that both the area and perimeter of a closed figure would be conserved over transformations which elongated the figure. Both groups of subjects could be trained in the correct conservation of identity beliefs and this affected their conservation of equivalence judgements in predicted ways. It is suggested that the locical aspect of conservation is developmentally stable and that the empirical aspect varies widely across problems and individuals because of its dependence on relevant experience.     

The effects of task and practice on search for invisibly displaced objects

The ability to successfully search for an invisibly displaced object is frequently assumed to relate to the emergence of mental representation at around 2 years of age. However, little is known about what is actually being measured in the typical “stage 6” object permanence search task. Two studies examined the effects of task factors and practice on invisible displacements and systematic search tasks to show that simple variations in ways of hiding an object change the child's ability to find it. Experiment 1 compared two common methods of presenting invisible displacements items to 36 children, approximately 2 years of age. One task was significantly easier than the other, despite the fact that they contained identical items that varied only in their order of presentation. Experiment 2 tested the effects of short-term practice on 18- and 24-month-olds' success on invisible displacements trials and on two systematic search tasks. Results indicate that too little practice inhibited performance in 18-month-olds, but that practice beyond an optimum level did not further affect their scores. In contrast, 24-month-olds continued to benefit from increased practice until they reached the maximum possible score. The findings are interpreted to mean that invisible displacements tasks may require only sensorimotor search strategies rather than representation. The findings also have implications for (a) research that attempts to relate object permanence to other variables and (b) programs that use object permanence as an assessment or screening measure.     

Using what children know to improve their learning

Eighty children from three to seven years of age were tested on two forms of a matrix task, one of which was designed to take into account children's limited problem solving skills. The tasks involved seriating nine items (geometric shapes or birds) across two dimensions in a 3 × 3 matrix. The children were required to replace items that had been removed from a matrix board, to reproduce the entire matrix when all items had been removed from the board, and to transpose the matrix, that is, to reproduce the same spatial relations between the items, rotated ninety degrees. Results showed that children performed better when tested using common materials than when they were given standard materials. Furthermore, a greater percentage of children were able to complete the tasks and were able to respond correctly on the first trial of the tasks when using common materials (bird families) than when using the standard geometric shapes. The results were discussed in terms of task variables that influence children's performance and the problems resulting from generating theories of children's cognitive competence based on their performance in specific situations.     

Counterintuitive and alternative moves choice in the Water Jug task

MOVE problems, like the Tower of London (TOL) or the Water Jug (WJ) task, are planning tasks that appear structurally similar and are assumed to involve similar cognitive processes. Carder et al. [Carder, H.P., Handley, S.J., & Perfect, T.J. ( 2004). Deconstructing the Tower of London: Alternative moves and conflict resolution as predictors of task performance. The Quarterly Journal of Experimental Psychology 57a, 8, 1459-1483] showed that one predictor of TOL performance was the number of alternative move choices there were at a given point in the solution. In two experiments an individual move experienced on the WJ task was manipulated (perceptually consistent/counterintuitive) along with the number of alternative moves there were to choose between. A verification paradigm was employed in which participants made speeded judgements about the correctness of a move. Results showed performance was consistent with the application of a perceptual strategy accompanied by a process involving the evaluation of non-redundant alternative moves. These are discussed in the context of recent research that has examined the impact of executive dysfunction on Water Jug performance [Colvin, M.K., Dunbar, K., & Grafman, J. (2001). The effects of frontal lobe lesions on goal achievement in the Water Jug task. Journal of Cognitive Neuroscience, 13, 1129-1147].     

Recognition memory for single items and for associations is similarly impaired following damage to the hippocampal region

The formation of new associations between items is critical for establishing episodic memories. It has been suggested that the hippocampus is essential for creating such associations but is not involved, or is much less involved, in memory for single items. In Experiment 1, we tested controls and amnesic patients with bilateral lesions thought to be limited primarily to the hippocampal region in both single-item and associative recognition memory tasks. In the single-item task, a conventional recognition memory task was administered in which participants studied either houses or faces and were tested for their ability to recognize the individual items. In the associative task, participants studied paired pictures of houses and faces with instructions that encouraged associating the two stimuli, and were tested for their ability to recognize the specific pairings that were presented at study. Like the controls, the amnesic patients performed more poorly on the associative task. Relative to the controls, the amnesic patients were impaired to a similar extent on the single-item and associative tasks. In Experiment 2, the performance of the amnesic patients was improved by increasing the number of presentations of the study lists (eight presentations instead of one). On both the single-item and associative tests, the performance of the amnesic patients after eight presentations was now identical to the performance of the controls who had been given only one presentation of the study list. Thus, the associative condition was not disproportionally difficult for the amnesic patients. These results are consistent with the idea that the hippocampus is similarly involved in single-item and associative memory.     

Selective interference with verbal short-term memory for serial order information: A new paradigm and tests of a timing-signal hypothesis

Many recent computational models of verbal short-term memory postulate a separation between processes supporting memory for the identity of items and processes supporting memory for their serial order. Furthermore, some of these models assume that memory for serial order is supported by a timing signal. We report an attempt to find evidence for such a timing signal by comparing an “item probe” task, requiring memory for items, with a “list probe” task, requiring memory for serial order. Four experiments investigated effects of irrelevant speech, articulatory suppression, temporal grouping, and paced finger tapping on these two tasks. In Experiments 1 and 2, irrelevant speech and articulatory suppression had a greater detrimental effect on the list probe task than on the item probe task. Reaction time data indicated that the list probe task, but not the item probe task, induced serial rehearsal of items. Phonological similarity effects confirmed that both probe tasks induced phonological recoding of visual inputs. Experiment 3 showed that temporal grouping of items during list presentation improved performance on the list probe task more than on the item probe task. In Experiment 4, paced tapping had a greater detrimental effect on the list probe task than on the item probe task. However, there was no differential effect of whether tapping was to a simple or a complex rhythm. Overall, the data illustrate the utility of the item probe/list probe paradigm and provide support for models that assume memory for serial order and memory for items involve separate processes. Results are generally consistent with the timing-signal hypothesis but suggest further factors that need to be explored to distinguish it from other accounts.     

Cued shifts of attention and memory encoding in partial report: A dual-task approach

This study explores how cued shifts of visual attention and rapid encoding of visual information relate to limited-capacity processing mechanisms. Three experiments were conducted placing a partial-report task within a dual-task paradigm. Experiments 1 and 2 involved a simple speeded visual discrimination (Task 1) and then an unspeeded partial-report task (Task 2). Generally, Task 2 accuracy declined as the temporal overlap between the two tasks increased. In addition, in Experiment 1, varying the number of items in the partial-report display had an effect on performance regardless of overlap. In contrast, in Experiment 2, varying the type of probe had an effect only at long task overlap. The generality of the interference effect was tested in Experiment 3 using an auditory discrimination as Task 1. Again, Task 2 accuracy declined as the temporal overlap between the two tasks increased. In all cases, the observed interference had the properties of a processing bottleneck. It is argued that encoding information into memory and response selection for the first task both require general-purpose processing. The results are discussed in terms of the functional relationship between attention and memory.     

Metacognitive development of deaf children: lessons from the appearance-reality and false belief tasks

'Theory of mind' development is now an important research field in deaf studies. Past research with the classic false belief task has consistently reported a delay in theory of mind development in deaf children born of hearing parents, while performance of second-generation deaf children is more problematic with some contradictory results. The present paper is aimed at testing the metacognitive abilities of deaf children on two tasks: the appearance-reality paradigm designed by Flavell, Flavell and Green (1983) and the classic false belief inference task (Wimmer & Perner, 1983; Hogrefe, Wimmer & Perner, 1986). Twenty-eight second-generation deaf children, 60 deaf children of hearing parents and 36 hearing children, aged 5 to 7, were tested and compared on three appearance-reality and three false belief items. Results show that early exposure to language, be it signed or oral, facilitates performance on the two theory of mind tasks. In addition, native signers equal hearing children in the appearance-reality task while surpassing them on the false belief one. The differences of performance patterns in the two tasks are discussed in terms of linguistic and metarepresentational development.     

Enumeration versus multiple object tracking: the case of action video game players

Here, we demonstrate that action video game play enhances subjects' ability in two tasks thought to indicate the number of items that can be apprehended. Using an enumeration task, in which participants have to determine the number of quickly flashed squares, accuracy measures showed a near ceiling performance for low numerosities and a sharp drop in performance once a critical number of squares was reached. Importantly, this critical number was higher by about two items in video game players (VGPs) than in non-video game players (NVGPs). A following control study indicated that this improvement was not due to an enhanced ability to instantly apprehend the numerosity of the display, a process known as subitizing, but rather due to an enhancement in the slower more serial process of counting. To confirm that video game play facilitates the processing of multiple objects at once, we compared VGPs and NVGPs on the multiple object tracking task (MOT), which requires the allocation of attention to several items over time. VGPs were able to successfully track approximately two more items than NVGPs. Furthermore, NVGPs trained on an action video game established the causal effect of game playing in the enhanced performance on the two tasks. Together, these studies confirm the view that playing action video games enhances the number of objects that can be apprehended and suggest that this enhancement is mediated by changes in visual short-term memory skills.     

Variables for designing cube folding tasks influencing sixth-graders' performance

This study investigated whether the three variables of task form, squares carried, and figural complexity, for designing cube folding tasks, affect sixth graders' cube folding performance. Two task forms were used to develop two versions of “cube folding test.” Each version was designed based on two levels of squares carried and three levels of figural complexity, and contained 18 multiple-choice items. The sample included 107 boys and 92 girls with an average age of 12.04 years who were randomly assigned to complete one of the two versions. A linear mixed model was carried out with three factors: task forms, squares carried, and figural complexity, in which squares carried and figural complexity were “within-subjects” factors, and task form was the “between-subjects” factor. The results showed the interaction effect of squares carried and task form, and the main effect of figural complexity, which differentiated the difficulty in cube folding tasks.     

Long-term memory for concepts in a California sea lion (<Emphasis Type="Italic">Zalophus californianus</Emphasis>)

An adult California sea lion (Zalophus californianus) with extensive experience in performing discrimination learning tasks was tested to evaluate her long-term memory for two previously learned concepts. An associative concept, that of equivalence classification, was retested after a retention interval of approximately 1 year. The sea lion had originally shown emergent equivalence classification with nonsimilarity-based classes of stimuli in a simple discrimination repeated-reversal procedure as well as in a matching-to-sample procedure. The 1-year memory test revealed no decrement in classification performance in either procedure. A relational concept, that of generalized identity matching, was retested after approximately 10 years. The sea lion had originally received trial-and-error exemplar training with identity matching-to-sample problems prior to transferring the concept to novel stimulus configurations. In the 10-year memory test, the sea lion immediately and reliably applied the previously established identity concept to familiar and novel sets of matching problems. These are the first reports of long-term conceptual memory in a nonprimate species. The experimental findings are consistent with a variety of observations of sea lions in natural settings, which indicate that natal sites, feeding areas, and individuals may be remembered over long periods of time. Electronic Supplementary Material is available if you access this article at http://dx.doi.org/10.1007/s10071-002-0153-8. On that page (frame on the left side), a link takes you directly to the supplementary material. Electronic Publication     

Enhanced discrimination in autism

Children with autism are superior to typically developing children at visual search tasks (O'Riordan, Plaisted, Driver, & Baron-Cohen, in press; Plaisted, O'Riordan, & Baron-Cohen, l998b). This study investigates the reasons for this phenomenon. The performance of children with autism and of typically developing children was compared on a series of visual search tasks to investigate two related problems. The first issue was whether the critical determinant of search rate in children is the discriminability of the display items, as it is in normal adults. The second question investigated was whether the superior performance of individuals with autism on visual search tasks is due to an enhanced ability to discriminate between display items. The results demonstrated that discriminability is the rate-determining factor for children with and without autism, replicating earlier findings with normal adults, and that children with autism have an enhanced ability to discriminate between display items. Thus, it seems that an enhanced ability to discriminate between display items underlies superior visual search in autism.     

Conceptual Combinations and Subsequent Creativity

Conceptual combination has been advocated as an important component of creativity, but relatively little research has investigated its importance. Two experiments were designed to extend previous research on the relationship between performance on conceptual combination tasks and subsequent performance on creativity tasks. Both experiments involved the generation of category exemplars and manipulated the type of conceptual combination experience and whether the items presented were related or unrelated to one another. In the first experiment, this was followed by a brainstorming task (divergent thinking) and in the second experiment by a creative problem solving task (convergent thinking). Contrary to expectations, the condition that required conceptual combinations did not enhance the generation of the number and originality of exemplars. As predicted, exposure to unrelated items led to more original products than related ones. The conceptual combination task with related items was predictive of performance on the creative problem solving task but not the divergent thinking task. Performance on the divergent task was related to the generation of exemplars for unrelated items. These results suggest that the conceptual combination task taps creative problem solving rather than divergent creativity.     

The value of relative-time-spent ratings in task-oriented job analysis

Recent studies have called for the abandonment of the relative-time-spent scale in task inventories. This recommendation is based on findings that the job profile created with the scale data is highly correlated with the profile created from a much simpler “Do you perform this task?” checklist. We examined this issue using 3 inventories and 42 jobs (N=2252). Profile correlations were computed on only the tasks actually performed by incumbents to avoid possibly inflated rs due to including irrelevant tasks. The specificity of task inventory items was proposed as an explanation for the high correlation between the two job profiles. Specificity of items was examined by looking at both the type (job duties versus tasks) and the amount (number of items in job profile and average number of items relevant to each job) of items used in the inventory. Correlations between time spent and checklist profiles were in the .80's and .90's regardless of the number of irrelevant tasks or the specificity of tasks. We agree with previous military research and conclude that the relative-time-spent scale has limited incremental utility beyond a dichotomous checklist.