Target-size influences on reaction time with movement time controlled

The variable that affect motor programming time may be studied by changing the nature of the response and measuring the subsequent changes in reaction time (RT). One notion of motor programming suggests that aiming responses with reduced target size and/or increased target amplitude require more "complex" motor programs that require longer RTs. In a series of five experiments which movement time (MT) was experimentally varied target size neither influences RT when the movement amplitude was 2 or 30 cm nor when the target sizes differed by as much as a factor of 16:1. Increasing the movement amplitude from 15 to 30 cm also had no influence on RT. Movement time, however, did affect RT, with 200-msec movements having longer RTs than 120-msec movements. Target size and movement amplitude did not appear to be factors that influence programming time or program complexity.     

The quantitative measure of pattern representation in images using orientation-specific color aftereffects

A quantitative method is developed for assessing the quality of pattern information in imagery, using the magnitude of color aftereffects as an objective index. Subjects were given instructions to project imagined bar patterns of particular width and orientation onto adapting color fields, in such a manner as to simulate standard conditions for establishing the McCollough effect. Our control procedures indicate that the resulting orientation-specific complementary color aftereffects cannot be attributed to the conditioning of particular directions of eye scanning movements to color processing during adaptation, or to other possible sources of experimental bias. Furthermore, subjects who rated themselves prior to the adaptation procedure as having relatively vivid imagery showed significantly larger aftereffects than those who reported having relatively low imagery. These results not only provide an important confirmation of our earlier finding that imagination can replace physical pattern information in the formation of basic color-feature associations in the human visual system, but also demonstrate that these aftereffects can provide a practical measure of the fidelity of pattern representation in visual images.     

Ambiversion: characteristics of midrange responders on the Introversion-Extraversion continuum

Sixty-nine midrange responders on the Introversion-Extroversion (IE) scale of the Eysenck Personality Questionnaire (EPQ) were given an experimental measure to assess tendency toward ambivalence (i.e., both strongly introverted and strongly extraverted responses) vs. moderation (i.e., midrange responses), and degree of importance given to IE types of activities. The participants were divided into those showing ambivalence vs. those showing moderate responses, and into those reporting high vs. low importance of such activities. As was predicted, the ambivalent group showed significantly higher scores on the neuroticism scale of the EPQ, while the low importance group tended to show more psychoticism, but not to a significant degree. Both of the midrange scores were unrelated to the Bem Sex Role Inventory. Based on the findings, at least two groups are posited in the midrange of the IE dimension: an ambivalent group with mixed strong introversive and extraversive tendencies, and an ambiverted group with midrange scores.     

Homesickness in preadolescent and adolescent girls: risk factors, behavioral correlates, and sequelae.

Examined homesickness in 117 girls ages 8 to 16 during a 2-week stay at summer camp. (Homesickness is the distress or impairment caused by an actual or anticipated separation from home. It is characterized by acute longing and preoccupying thoughts of home and attachment objects.) Elevated preseparation levels of homesickness, high expectations of homesickness, negative separation attitudes, low decision control, and little previous separation experience predicted in-camp levels of homesickness. During the separation, homesickness was associated with insecure interpersonal attitudes, negative initial impressions of the novel environment, high perceived distance from home, and low perceived control. Female surrogate caregivers rated homesick girls as having lower social status and more somatic complaints, social problems, and externalizing behavior than less homesick girls. Although the prevalence, intensity, and longitudinal course of homesickness in girls did not differ from analogous samples of boys, girls' profile of risk factors, correlates, and sequelae is unique in its mixed behavioral presentation and small correlations with age and experience.     

Flanker recall and the flanker validity effect may reflect different attentional processes

High flanker recall in the correlated flanker task suggests a failure of selective attention. We used a dissociation approach to examine the role of attentional processing of the flankers’ identities in the flanker validity effect (FVE). In three experiments, flanker recall decreased as flanker duration decreased, but the FVE was not affected by flanker duration. Masking also produced a dissociation, in that masking decreased flanker recall but the FVE was not affected. Examination of on-line flanker identification suggested that flanker recall was an adequate measure of attentional processing of the flankers’ identities on most trials. The results suggest that attentional processing of the flankers’ identities is not related to the magnitude of the FVE and is not necessary for it to obtain. Because there is a failure of selective attention, the dissociations suggest that flanker recall and the FVE may reflect different attentional processes.     

Summary knowledge of results for skill acquisition: support for the guidance hypothesis

Summary knowledge of results (KR) involves the presentation KR for each of a set of trials (e.g., 10) only after the last trial in the set has been completed. Earlier, Lavery (1962) showed that, relative to providing KR after each trial, a 20-trial summary KR was detrimental to performance in a practice phase with KR present but was beneficial for a no-KR retention test. Using a relatively simple ballistic-timing task, we examined summary lengths of 1 (essentially KR after every trial), 5, 10, and 15 trials, searching for an inverted-U relationship between summary length and retention performance as predicated by a guidance hypothesis for KR. During acquisition when KR was present and being manipulated, all groups showed improvements in performance across practice, while increased summary lengths generally depressed performance. However, in a delayed no-KR retention test, there was an inverse relation between the summary length in acquisition and absolute constant error on the retention test. A guidance hypothesis is favored to explain how, relative to immediate KR, long KR summaries can provide detrimental effects in acquisition while enhancing retention performance.