Annual Activity Report 2010

Populations with Developmental and/or Acquired Limitations in Symbolic Functioning

4. Equivalence relations and the construction of symbolic repertoires in pre-verbal populations

The Institute has been studying two pre-verbal populations: Human infants and pre-lingually deaf children (with or without cochlear implantation).

4A. Development of Symbolic Function in Infants: Pre-requisites for stimulus equivalence and emergent mapping

Studies of stimulus equivalence in human infants may provide essential information about the onthogenesis of symbolic behavior and language. Human infants pose phenomenal challenges for long-term experimental investigation of behavioral processes. It is extremely difficult to maintain their behavior (and the infants themselves) for long periods in controlled settings. It is also very difficult to establish the behaviors to be investigated. To investigate stimulus equivalence in human infants it is necessary first to establish baselines of identity and arbitrary matching to sample. These way stations were “conquered” in recent studies of the Institute (Gil, Oliveira, & McIlvane, in press). This line of investigation has produced the identification of optimal (or at least much improved) conditions and parameters of reinforcement, session duration, number of trials, and mastery criteria. Implementation of these conditions diminished experimental variability and yielded systematic and replicable data in the study of simple discrimination, discrimination reversal, identity conditional discrimination, generalized identity matching to sample, and arbitrary conditional discrimination, in children in the age range from 15 to 24 months.

4B: Fast Mapping Strategies in Toddler-Age Children

Fast mapping (relating for the first time an unfamiliar word to a novel object – that is, an arbitrary matching task) has been observed in children as young as 17 to 24 months (Oliveira & Gil, in preparation; the master’s dissertation of Garcia, 2010). In order to investigate this basic behavioral process the Instute has developed new experimental preparations, some of which can be easily implemented in playing settings.

Older children, aged from 24 to 30 months, showed fast mapping or learning by exclusion in the presence of nonsense words simulating adjectives (properties), verbs (actions) and names, thus extending the generality of data: the basic behavioral processes involved in learning arbitrary relations between words and events independ of the particular world aspect to which the words are to be related (Costa, de Souza, & McIlvane, paper in preparation). This is an important contribution for the scientific analysis of processes of language acquisition in children with typical development, and may also be useful for planning preventive interventions with children at risk for delays in language acquisition.

4C: Relational Learning in Newly Hearing Children

A study published just before the beginning of the Institute established the approach in this area, by developing effective procedures to establish auditory-visual equivalences in prelingually deaf children with cochlear implantation. The results showed the incorporation of auditory stimuli into previously formed equivalence classes of visual stimuli, and the formation of new auditory-visual equivalence classes. Direct and systematic replications of this study have been conducted aiming to extend the results to a larger population, in a broader age range (Almeida-Verdu, Bevilacqua, de Souza, & Souza, in press; Almeida-Verdu, Matos, Battaglini, Bevilacqua, & de Souza, submitted).

A recent doctoral dissertation (Golfeto, 2010) showed auditory learning sets by prelingually deaf children with cochlear implant and outlined a “curriculum” to teach them to hear and to speak. The study also evaluated listening comprehesion of spoken sentences, reading of printed sentences and generalized recombination of sentence elements (Golfeto & de Souza, submitted). The curriculum will be evaluated with a larger number of children; the ultimate goal will be to implement a “virtual” laboratory for auditory rehabilitation, through which teaching procedures will be readly acessed through the internet, for application by parents and speech therapists.

At the same time, a new software was developed by members of the Institute from UFPA (Moraes, Souza, & Monteiro, 2011) and tests are underway to assess its utility in providing systematic auditory stimulation for post-lingually deaf persons with recent cochlear implants. In this case, the main role of rehabilitation is to teach the person to recognize, through the implant, speech sounds that they already know and rehabilitation efforts can begin soon after the implant. The software and the stimulation procedures will also be assessed with prelingually deaf children, after implant.

An important parallel development of the research in cochlear implant was the development of procedures to measure the auditory threshold of implanted children (da Silva, de Souza, Bevilacqua, Kimura, & Lopes Jr., in press; da Silva, de Souza, Bevilacqua, Kimura, & Lopes Jr., under review);

 

5: Relational Learning in Basic Academics

5.1. Procedures based on stimulus equivalence can establish sight-reading (Sidman & Tailby, 1982). Stimulus equivalence procedures can be scheduled in effective ways to produce recombinative generalization and generalized reading, as documented in previous work of this group. The Institute developed a computerized reading program (Learning to read and spell in small steps) to teach basic reading skills to children with typical development and poor school performance. Children submitted to the program learn generalized reading and spelling.

One extension of this work was the application of the program by parents of children with intellectual disabilities; the parents were prepared to supervise their children while they worked with the computer (the master’s thesis of Benitez, 2011; Benitez, & Domeniconi, submitted). At the end of the program the children were reading novel words and the parents reported an improvement in their interactions with their children.

The main tasks in original teaching program are matching to sample (relating spoken words to printed words and relating the same spoken words to the corresponding pictures). However, other tasks could be effective as well and it is important to evaluate them empirically, to increase the variety of teaching alternatives. A recent study evaluated the formation of equivalence classes after teaching simple discrimination between words with specific differential consequences for each word (the master’s thesis of Zaine, 2011).

5.2 (1) The Institute developed and evaluated a battery of tasks for assessment of pre-arithmetic behaviors, which will be important as a diagnostic tool (Gualberto, Aloi, & Carmo, in press).

5.2 (2) One study demonstrated the efficacy of equivalence based instruction for the emergence of mathematical relations involving rational numbers (Santos, Cameschi, & Hanna, in press).

 

6: Extensions to Neurobehavioral Science

6.1. Laboratory-Derived Neuropsychological Methodology.

The project designed to develop a mini-battery of neuropsychological tests for children with developmental limitations (e.g., preschool children, children with intellectual disabilities, etc.) that does not rely on syntactically-complex verbal instructions is underway. The battery is designed also for adaptation to nonhuman primates, an extension that will be useful also in collaborations between the University Federal do Pará and the UMMS. The battery has tests for 1) sustained attention, 2) shifts in attention (executive functioning), 3) immediate and delayed memory, and 4) matching- and nonmatching to sample. Data thus far show that these tests can be used effectively with typically developing children in the 3-5 year age range. Data from the children with intellectual disabilities are also promising, but further work is indicated to adapt the methods for use with totally nonverbal children. Subsequent work will be targeted at reaching nonverbal children reliably via implementing a variety of stimulus control shaping methods that have been developed for this population in laboratory research conducted at UMMS and collaborating universities within the INCT-ECCE network.

6.2 Translational Studies of Neurobehavioral Effects of Mercury Exposure. This project is a collaboration between UMMS and UFPA researchers who will study the effects of mercury exposure on children in gold-mining areas of Brazil and in a nonhuman primate model. The work was funded by the US National Institute of Environmental Health Sciences. The funding subcontract was issued to UFPA to support the Brazilian collaborators working on the project. Concerning the nonhuman primate model, the first study is underway and was designed to evaluate short-term memory. Two adult Cebus apella were exposed to a delayed matching procedure, with a gradual increase in the delay between the removal of the sample stimulus and the subsequent presentation of the comparison stimuli. When the performance was disturbed by the increase in the delay, increasing the intertrial interval was effective in restoring the accuracy. So far one subject has maintained high accuracy in 10 arbitrary relations, under delays of 9.5 s; other Cebus has shown high accuracy in 9 identity-matching relations with delays of 14 s.