Experimental analyses of gene-brain-behavior relations: some notes on their application.

The fields of genetics and neuroscience are yielding findings useful in understanding complex behavior-environment relations. We believe that these developments in interdisciplinary basic research are of interest to applied behavior analysts because of the long history of basic findings being used by the readership of the Journal of Applied Behavior Analysis to improve everyday human activities. An awareness of contemporary developments in a range of basic research disciplines may facilitate the systematic replication of those functional relations in applied settings. In this context, we selectively review papers published in the Journal of the Experimental Analysis of Behavior and other basic research journals that relate to gene-brain-behavior relations.     

Biomechanical analyses of prolonged handwriting in subjects with and without perceived discomfort

Since wrist-joint position affects finger muscle length and grip strength, we studied its biomechanical relevance in prolonged handwriting. We recruited participants from young adults, aged 18–24, and separated them into control (n = 22) and in-pain (n = 18) groups, based whether or not they experience pain while handwriting. The participants then performed a writing task for 30 min on a computerized system which measured their wrist-joint angle and documented their handwriting kinematics. The in-pain group perceived more soreness and had a less-extended wrist joint, longer on-paper time, and slower stroke velocity compared to control group. There was no significant difference in handwriting speed and quality between the two groups. The wrist extension angle significantly correlated with perceived soreness. Ergonomic and biomechanical analyses provide important information about the handwriting process. Knowledge of pen tip movement kinematics and wrist-joint position can help occupational therapists plan treatment for individuals with handwriting induced pain.     

Speed analyses of stimulus equivalence.

The functional substitutability of stimuli in equivalence classes was examined through analyses of the speed of college students'' accurate responding. After training subjects to respond to 18 conditional relations, subjects'' accuracy and speed of accurate responding were compared across trial types (baseline, symmetry, transitivity, and combined transitivity and symmetry) and nodal distance (one- through five-node transitive and combined transitive and symmetric relations). Differences in accuracy across nodal distance and trial type were significant only on the first tests of equivalence, whereas differences in speed were significant even after extended testing. Response speed was inversely related to the number of nodes on which the tested relations were based. Significant differences in response speed were also found across trial types, except between transitivity and combined trials. To determine the generality of these comparisons, three groups of subjects were included: An instructed group was given an instruction that specified the interchangeability of stimuli related through training; a queried group was queried about the basis for test-trial responding: and a standard group was neither instructed nor queried. There were no significant differences among groups. These results suggest the use of response speed and response accuracy to measure the strength of matching relations.     

Symptoms of prosopagnosia in intoxicated subjects.

Two experiments were made to test whether a blood ethanol concentration of about 1 g ethanol per kg blood influences the ability to recognize faces which were shown 24 hours earlier. 18 subjects who saw the faces for the first time when sober and whose task it was to recognize the faces when under the influence of alcohol, recognized the faces significantly less frequently than controls. The controls saw the faces for the first time when sober and their task was to recognize the faces later when also in a sober state. When 20 sober subjects had to recognize faces which they had seen 24 hours earlier under the influence of alcohol, they recognized the faces significantly less frequently than controls. 18 subjects to whom visual forms were shown when under the influence of alcohol and who had to recognize these forms 24 hours later when sober again performed like subjects who had to recognize faces under identical experimental conditions. Subjects who saw the forms, however, in a sober state and who had to recognize these forms when intoxicated performed significantly better than subjects who had to recognize faces under identical experimental conditions. In additional experiments, it was shown that alcohol did not influence ability to compare simultaneously presented faces. Intoxicated subjects' reduced abilities to recognize faces is regarded as a symptom of prosopagnosia since it cannot be explained by a reduced ability to recognize forms or to compare faces.     

Genetic analyses of focal aspects of infant temperament.

The authors explored the genetic and environmental underpinnings of individual differences in temperament with a sample of 604 3- to 16-month-old infant twins and their parents. Mothers completed Rothbart's Infant Behavior Questionnaire (IBQ), and a subsample of 140 9-month-old twins participated in behavioral assessment of temperament in the laboratory as well. For IBQ Smiling and Laughter and Duration of Orienting, both additive genetic and shared environmental effects were needed to best represent the data. Shared environmental effects fully accounted for cotwin similarity for IBQ Soothability, and conversely, additive genetic effects fully accounted for cotwin similarity for the IBQ Distress to Limitations, Distress to Novelty, and Activity Level scales. With the subsample, the authors fit a multivariate model to mother report, father report, and lab measures of stranger distress and found that genetic influences were most important for the covariation among these measures.     

Dot counting by brain damaged subjects.

In this study, we examine how brain damaged adults (aphasics, right-brain lesioned subjects (RBD), and demented subjects) perform a basic education skill: determining the cardinality of different sets of objects (dots). The RBD subjects encountered more difficulty with the spatial correspondence components of the task (correct pointing to the dots), while the aphasics experienced more difficulty with the verbal components (the production of the correct number-word sequence). The deficit evidenced by the demented patients was less systematic. However, qualitative analyses of patients' behavior suggested an organization that tended to minimize the impact of their cognitive deficits on the object-counting task, and an analysis of their counting indicates that the basic counting principles proposed by Gelman (1982) and Fuson (1988) may be preserved.     

Underestimation of length by subjects in motion.

To check a prior observation, in the present experiment, subjects made estimates of the lengths of both the guidelines and the spaces between guidelines on automotive highways so the magnitude of the illusion could be more accurately determined. Ten males and ten females were individually tested at 0 and 60 mph. At 60 mph, spaces were estimated with an error of 85%; lines were estimated with an error of 72%. Combining data for both stimuli, an error of 78% results, which corresponds to underestimation by a factor of 4.67. This illusory effect is considerably greater than that of the moon illusion, considered by many the most powerful of the classical illusions.     

Dichotic word-perception of aphasic and normal subjects.

The present investigation examined the role of the right cerebral hemisphere in linguistic perception following a left cerebral insult which had resulted in aphasia. Auditory dichotic procedures were utilized to investigate the ear-preferences of 30 aphasic Ss, grouped relative to the amount of time since the onset of left cerebral insult, and a group of 10 normal control Ss. An oral-response task and a pointing-response task were given. Statistical analyses showed a significant left-ear preference for aphasic Ss who were more than 6 mo. post-cerebral insult; however, Ss less than 6 mo. post-cerebral insult did not demonstrate a significant ear-preference under auditory dichotic stimulation. In contrast, a significant right-ear preference was noted for the normal controls. Significant differences were not shown for the aphasic or control groups on the oral and pointing tasks.     

Pseudomemory in hypnotized and task-motivated subjects.

Highly hypnotizable hypnotized (H; n = 16) and task-motivated (TM; n = 13) subjects received pseudomemory suggestions (see Orne, 1979). TM subjects reported being more awake and motivated than did H subjects and were more likely to pass the target noise suggestion. However, 69% of subjects in both conditions who passed the noise suggestion reported pseudomemories. Pseudomemory rate (for H subjects, 69% and for TM subjects, 46%) was not reduced by informing subjects that they could distinguish reality and fantasy in a state of deep concentration. At final inquiry, after deep concentration, pseudomemories remained stable (for H subjects, 75% and for TM subjects, 54%). As predicted, H subjects reported more unsuggested noises and more pseudomemories of novel noises than did TM subjects. Subjects who reported pseudomemories were more confident in the accuracy of their memories than were subjects who reported that the suggested noises were imagined.     

Evolutionary versus prototype analyses of the concept of disorder.

The harmful dysfunction (HD) analysis of the concept of disorder (J. C. Wakefield, 1992a) holds that disorders are harmful failures of internal mechanisms to perform their naturally selected functions. S. O. Lilienfeld and L. Marino (1995) proposed instead that disorder is a Roschian prototype concept without defining properties. Against the HD analysis, they argued that many disorders are not failures of naturally selected functions because they are either designed reactions (e.g., fever) or failures of functions that are not naturally selected (e.g., reading disorder). The HD analysis is defended here against these and other objections and compared with the Roschian account. It is argued that the objections are based on conceptual confusions and can be turned around to provide strong new support for the HD analysis. A series of conceptual experiments demonstrates the superior explanatory power of the HD analysis and disconfirms the Roschian account.     

Economic stress and suicide: multilevel analyses. Part 1: Aggregate time-series analyses of economic stress and suicide

Of the research on health and economic stress, the approach that has produced the strongest findings has been the aggregate time-series analysis of unemployment and suicide rates. A review of the literature indicates that this aggregate work has been disputed on both methodological and interpretive grounds. To address these issues, two studies of the relationship between economic stress and suicide were conducted on the same population. The first, reported in this paper (Part 1), replicated the aggregate time-series work with improvements in method, using monthly data for 1975-1982 for Los Angeles. A second study (reported in Part 2) combined aggregate economic indicators with individual-level measures of stressful events, symptoms, and suicidal ideation.     

Correspondence between outcomes of brief and extended functional analyses.

We compared results obtained from 50 sets of functional analysis data from assessments of self-injurious behavior (SIB), 35 of which showed clear response patterns and 15 of which were undifferentiated, with those obtained from two abbreviated methods of assessment: (a) a brief functional analysis, consisting of the first session of each condition from the full functional analysis, and (b) a within-session analysis, in which data from the brief analysis were regraphed to show minute-by-minute changes in response rates during a session. Results indicated that outcomes of the brief and within-session analyses corresponded with those of the full functional analyses in 66.0% and 68.0% of the cases, respectively. Further examination of results indicated a tendency for the brief analysis to identify a large proportion of positive cases (both true and false positives) and for the within-session analysis to identify a large proportion of negative cases (true and false negatives).     

Cue selection in verbal discrimination learning of retarded subjects.

A series of experiments was conducted to examine cue function in trigram verbal discrimination learning by retarded subjects. The issue was to determine the factors that control attention in this type of learning situation. The two variables of chief interest were trigram meaningfulness and reinforcement history. The major general conclusion was that retarded subjects employ complex cue selection strategies in solving a verbal discrimination involving compound verbal stimuli. Major findings were as follows: (a) Retarded subjects exhibit a response bias in favor of words over nonsense trigrams; (b) relatively little active cue selection based on meaningfulness was observed; (c) a compound stimulus discrimination was more difficult to learn than a discrimination involving single verbal stimuli; (d) compound and single stimuli may be processed differently in original discrimination learning; (e) cue position probably controls attention in compound discrimination learning; and (f) a frequency theory of verbal discrimination learning is supported by these data.