Word length effects are not due to proactive interference

In immediate serial recall short words are better recalled than long words. The word length effect has become pivotal in the development of short-term memory models. The current research tests one explanation of the word length effect; that it is related to proactive interference (PI). We report two experiments in which the relationship is directly tested. In the first experiment we show that word length effects can be observed over the first few trials in an experiment and that the effect shows itself primarily in the number of omissions made. In the second experiment we simultaneously test for PI and word length effects. Strong word length effects were present but there was little evidence for PI influencing either overall levels of recall or the word length effect. In short, no empirical support was found for PI as an explanation of the word length effect.     

Word length and phonological similarity effects in simple,complex, and delayed serial recall tasks: Implications for working memory

Some current models of working memory argue that a passive short-term store is not involved in more dynamic working memory tasks. Other models argue that standard short-term memory and working memory tasks rely on common storage facilities. We examine these issues by exploring two signature effects of passive short-term storage in simple span, complex span, and Brown-Peterson tasks. The finding that all three tasks show word length and phonological similarity effects suggests that common processes or storage mechanisms are involved in all tasks. The implications for models of working memory are discussed.     

Lexicality and phonological similarity: A challenge for the retrieval‐based account of serial recall?

The retrieval‐based account of serial recall () 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.     

Is spoken duration a sufficient explanation of the word length effect?

The word length effect is one of the cornerstones of trace decay plus rehearsal models (TDR) of memory. Words of long spoken duration take longer to rehearse than words of short spoken duration and as such suffer more decay and are thus less well recalled. The current experiment manipulates both syllable length and spoken duration within words of fixed syllable length in an aim to test the assumptions of the TDR model. Our procedures produced robust effects of both syllable length and spoken duration in four measures of the time it takes to pronounce the different types of words. Serial recall for the same materials produced robust syllable effects, but no duration effects.     

Conflicting social paradigms of human freedom and the problem of justification

In recent work, Rawls, Nozick, and the ‘democratic‐socialist’ theory of Markovi? and Gould, attempt to ground rival models of just economic relations on the basis of conflicting interpretations of human freedom. Beginning with a philosophical conception of humans as essentially free beings, each derives a different system of basic rights and freedoms: (1) the familiar democratic civil and political rights of citizenship in the West (Rawls); (2) the classical bourgeois market freedoms ‐ ‘life, liberty, and property’ (Nozick); and (3) democratic socialist rights of self‐management of the work‐place (Gould and Markovi?). I argue that each of these theorists implicitly assumes a different but ungrounded ’social paradigm of human agency’ concerning the particular forms of human choice which are singled out as most important for a free, human life. None of these theories contains the methodological resources for showing why the forms of human agency it ‘emancipates’ are more important than the forms it suppresses or ignores. In order to overcome this impasse and provide a way of evaluating such rival paradigms of free agency, I elaborate a methodology based on the idea that a free society must provide its members with ‘equality in the social bases of self‐respect’. I use this methodology to argue that all three of the above conceptions are blind to problems of human agency, freedom, and dignity posed by the modern phenomena of welfare dependency, unemployment, and a self‐stultifying division of labor.     

The Treatment of Hard-Core Voluntary Drug Addict Patients

The complete population of adolescents in a residential and day-treatment program over a 4-year period, 532 youths, served in two studies. Along with residential and day-treatment settings, predictive variables of interest were the number of hours spent in group, individual, and family therapy. A total of 227 adolescents qualified for Study 1 which found a reduction of rates of criminal charges from pre- to posttreatment. Study 1 also found that hours in group therapy explained the most variance in the reduction in rates of criminal charges, followed closely by hours in individual therapy. Hours in family therapy was not a significant predictor. A total of 430 adolescents qualified for Study 2, which found that residential treatment was associated with greater reductions in adult correctional commitments than day treatment. Implications stress the need for further research examining the relationships between therapeutic components of residential treatment and behavioral outcomes.     

Patterns of Aggression in Parents and their Children

In this research, we examined children's awareness of inconsistencies in messages that are meaningful for children, instructions for games. In the first experiment, kindergarten (n = 25) and second- (n = 25) and fourth-grade (n = 26) children were individually read the instructions for two games, each of which included two inconsistent statements. Chi-square analyses yielded a significant effect for grade for one game (p < .05) and a marginally significant effect for a second game (p < .10). In a second experiment, second- (n = 40), fourth- (n = 40), and sixth-grade (n = 40) children were read the instructions for two games, each of which included two statements that were inconsistent. An analysis of variance demonstrated that with an increase in grade, there was a significant increase (p < .001) in awareness that a message contained an inconsistency. The analysis also indicated that the subjects were more willing (p < .08) to question an adult than they were to question a child about an inconsistency. Moreover, a regression analysis indicated that awareness of inconsistencies in the rules for games was significantly related to memory (p < .001) and to one's ability to note inconsistencies in shorter, simpler messages (p < .001).     

Effect of Age and Gender in the Control of Elbow Flexion Movements

In previous studies of rapid elbow movements in young healthy men, characteristic task-dependent changes in the patterns of muscle activation when movement speed or distance was varied have been reported. In the present study, the authors investigated whether age or gender is associated with changes in the patterns of muscle activity previously reported in young men. Arm movements of 10 healthy older and 10 healthy younger participants (5 men and 5 women in each group) were studied. Surface electromyograms (EMGs) from agonist (biceps) and antagonist (triceps) muscles, kinematic and kinetic parameters, as well as anthropometric and strength measures were recorded. All 4 groups of participants showed similar task- (distance or speed) dependent changes in biphasic EMG activity. Similar modulation of the initial rate of rise of the EMG, integrated agonist and antagonist EMG activity, as well as their relative timing were observed in all 4 groups. Those results suggest that older individuals of both genders retain the control strategies for elbow movements used by young individuals. Despite the qualitative similarities in the patterns of muscle activation, the men moved more quickly than the women, and younger participants moved more quickly than older participants. Those performance differences could not be explained in terms of differences in body size and strength alone.     

Spinal Cord Circuits

Over the past decade, research at three different levels of sensorimotor control has revealed a degree of complexity that challenges traditional hypotheses regarding servocontrol of individual muscles: (a) The connectivity of spinal circuits is much more divergent and convergent than expected. (b) The normal and reflex-induced recruitment of individual muscles and compartments of muscles is more finely controlled than was noted previously. (c) The mechanical interactions among linked skeletal segments and their often multiarticular muscles are neither simple nor intuitively obvious. We have developed a mathematical model of the cat hind limb that permits us to examine the influence of individual muscles on posture and gait. We have used linear quadratic control theory to predict the optimal distribution of feedback from a hypothetical set of proprioceptors, given different assumptions about the behavioral goals of the animal. The changes in these predictions that result from changes in the structure and control objectives of the model may provide insights into the functions actually performed by the various circuits in the spinal cord.