Adolescents' time spent viewing television

This study examined the amount of time adolescents spend viewing television. Findings indicated that adolescents viewed television 147 minutes per day, or an average of 17 1/4 hours per week. Employment of mother significantly affected the time adolescents spend viewing television. Sex of adolescent, age of father, mother, and adolescent, education of father and mother, income of family, and day of week were not significant factors. Adolescents watched television with another family member 65% of the total viewing time, but were unlikely to engage in other activities at the same time.     

Auditory processing and perceptual abilities of “organic” and “functional” stutterers

The present investigation was undertaken to determine whether significant differences in auditory processing and perceptual abilities exist between (1) stutterers as a supposedly homogeneous group when compared with controls, (2) two differentiated subgroups of stutterers, and (3) either of the stuttering subgroups when separately compared with controls. Dichotic listening and masking level difference (MLD) tasks were administered to the two groups of school-age stutterers and an age-matched nonstuttering control group. Stuttering subjects were differentiated into “organic” and “functional” subgroups on the basis of neuropsychological test performances. Organic stutterers performed significantly poorer than did controls on one MLD experimental condition. Functional stutterers performed more like control subjects than like organic stutterers.     

Changes in learning about aversive nonreward accounts for ontogeny of paradoxical appetitive reward effects in the rat pup: a mathematical model (DMOD) integrates results

Baby rats do not show any paradoxical appetitive reward effects (e.g., faster extinction following partial than continuous reinforcement, contrast effects when large and small rewards are given) until they are at least 12-14 days old, but can learn to pattern when reward and nonreward are alternated (e.g., Amsel, 1986). These results have been puzzling, but are now successfully integrated by DMOD (Daly MODification of Rescorla and Wagner's [1972] mathematical model; Daly & Daly, 1982). It was assumed that young rats do not have the capacity to learn about aversive nonreward but slowly gain this ability between 12 and 26 days (1 parameter reflecting the rate of conditioning of aversive nonreward, beta 1 for Vav, is increased from 0 to .15 beginning at 12 days). This theoretical integration has implications for understanding behavioral and neurological development of altricial organisms, and effects of neurological damage and toxic substances.     

Lexicality and phonological similarity: a challenge for the retrieval-based account of serial recall?

The retrieval-based account of serial recall (Saint-Aubin & Poirier, 2000) attributes lexicality, phonological similarity, and articulatory suppression effects to a process where long-term representations are used to reconstruct degraded phonological traces. Two experiments tested this assumption by manipulating these factors in the recall of four- and five-item lists of words and non-words. Lexicality enhanced item recall (IR), but only affected position accuracy (PA) for five-item lists under suppression. Phonological similarity influenced both words and non-words, and produced impaired PA in silent and suppressed conditions. Consistent with the retrieval-based account, words and non-words of high word-likeness appear subject to redintegration. However, some findings, like suppression not reducing the phonological similarity impairment in suppressed conditions, present challenges for the retrieval-based account and other models of serial recall.     

Using Brief Functional Analysis to Select Interventions for Oral Reading

Reading interventions were applied in a brief multielement format to examine their effectiveness at improving the oral reading fluency of three students referred for reading problems. Although each student had different profiles across experimental analyses, effective interventions were identified and a mini-replication confirmed the pattern of results in each case.     

A computer simulation/mathematical model of learning: Extension of DMOD from appetitive to aversive situations

The computer simulation/mathematical model called DMOD, which can simulate over 35 different phenomena in appetitive discrete-trial and simple free-operant situations, has been extended to include aversive discrete-trial situations. Learning (V) is calculated using a three-parameter equation \(\Delta V = \alpha \beta (\lambda - \bar V)\) (see Daly & Daly, 1982; Rescorla & Wagner, 1972). The equation is applied to three possible goal events in the appetitive (e.g., food) case and to three in the aversive (e.g., shock) case. The original goal event can be present, absent, or reintroduced; in the appetitive situation, these events condition approach (Vap), avoidance (Vav), and courage (Vcc), respectively. In the aversive situation, the events condition avoidance (Vav*), approach (Vap*), and cowardice (Vcc*), respectively. The model was developed in simple learning situations and subsequently was applied to complex situations. It can account for such diverse phenomena as contrast effects after reward shifts, greater persistence following partial than following continuous reinforcement, and a preference for predictable appetitive and predictable aversive events. Application of the aversive version of the model to “reward” shifts is described.     

Preference for unpredictable food rewards occurs with high proportion of reinforced trials or alcohol if rewards are not delayed

Organisms typically prefer situations where reward and nonreward are predictable rather than unpredictable. Although many theories can account for this result (e.g., information theory and delay-reduction theory), a recently developed mathematical model (DMOD) also predicts that subjects prefer the unpredictable reward situation under conditions that substantially decrease aversiveness of unpredictable nonreward (Daly & Daly, 1982). Because a high proportion of reinforced trials (lenient schedule) and alcohol injections decrease aversive conditioning, these variables were tested with rats in five E-maze experiments. A choice to one side of the maze resulted in a stimulus uncorrelated with reward outcome (unpredictable situation). A choice to the other side resulted in stimuli correlated with reward and nonreward (predictable situation). The stimuli were not visible until after the choice was made. A lenient reinforcement schedule resulted in preference for the unpredictable reward situation if rewards were not delayed. Alcohol resulted in preference for the unpredictable reward situation if a medium five-pellet reward was given. A lenient reinforcement schedule combined with an alcohol injection resulted in faster acquisition of the preference for the unpredictable reward situation than did a lenient schedule combined with a saline control injection. These results pose a major challenge to most theories, yet were predicted by DMOD.