In defence of iconic memory

According to a model of visual information-processing which originated with Sperling (1960), and which currently enjoys wide acceptance, the contents of brief alphanumeric displays are initially held in a high-capacity fast-decay visual-information store (“iconic memory”). Some of these items are subsequently transferred to a more durable form of storage; the remaining non-transferred items are lost. Observers can select which items are to be transferred on the basis of physical characteristics of the items (such as colour, location, size, shape or brightness).

This model has recently been attacked by Holding (1970, 1971, 1972, 1973), sometimes by claiming that iconic memory does not exist, and at other times by claiming that transfer from iconic memory cannot be selectively controlled by the observer. We argue in this paper that Holding's criticisms are incorrect, and that, even if they were correct, the experiment we report would not be open to objections he has raised concerning previous studies of iconic memory. Despite this, evidence fully supporting the orthodox model was obtained, and we therefore conclude that this model remains tenable.     

The non-occurrence of a stimulus as a signal

Two groups of rats were rewarded for pressing a panel following a varying number of bar presses; a signal following the bar press indicated whether or not a panel press would be rewarded if made before the next bar press. For one group the signal indicating reward was a flash of light, for the other it was the non-occurrence of the flash (in the latter case the flash thus signalled non-reward). The first group learned to withold panel presses except when reward was signalled, but the second group did not. This result is related to the “feature positive effect” of Jenkins and Sainsbury (1970), in which pigeons failed to withold pecks at a negative stimulus display when it was the same as the positive display except for the addition of a distinctive feature.     

LEVEL OF ACTIVATION AND GOAL-DIRECTED BEHAVIOUR: The effect of chlorpromazine on aggressive, achievement oriented, and affiliation oriented verbal responses

The purpose was to investigate the effect of chlorpromazine on verbal response contents in sentence completion tests. 30 male subjects participated in two chlorpromazine and one placebo session. It was found that the amount of aggressive, achievement and affiliation oriented responses was significantly reduced as an effect of drug intake. The results are discussed on the basis of the theories of conflict motivation and of arousal.     

Memory access: The effects of fact-oriented versus problem-oriented acquisition

This study examined the effects of similarity between the processing of acquisition and the processing of test materials on performance in a problem solving task. Previous work by Perfetto, Bransford, and Franks (1983) demonstrated that uninformed subjects’ failure to utilize relevant acquisition information in a later problem solving task is the result of a failure to spontaneously access such information. The present study demonstrated that spontaneous access can be enhanced when both acquisition and test materials are processed in a similar manner, that is, in a problem-oriented manner. Furthermore, the present findings indicate that the processing similarity leading to enhanced access is specific to particular acquisition and test items, rather than a general problem solving set induced at acquisition and the subsequent testing situation. Results are interpreted within a transfer-appropriate processing perspective.     

Labeling and family resemblance in the discrimination of polymorphous categories by pigeons

Two experiments examined whether pigeons discriminate polymorphous categories on the basis of a single highly predictive feature or overall similarity. In the first experiment, pigeons were trained to discriminate between categories of photographs of complex real objects. Within these pictures, single features had been manipulated to produce a highly salient texture cue. Either the picture or the texture provided a reliable cue for discrimination during training, but in probe tests, the picture and texture cues were put into conflict. Some pigeons showed a significant tendency to discriminate on the basis of the picture cue (overall similarity or family resemblance), whereas others appeared to rely on the manipulated texture cue. The second experiment used artificial polymorphous categories in which one dimension of the stimulus provided a completely reliable cue to category membership, whereas three other dimensions provided cues that were individually unreliable but collectively provided a completely reliable basis for discrimination. Most pigeons came under the control of the reliable cue rather than the unreliable cues. A minority, however, came under the control of single dimensions from the unreliable set. We conclude that cue salience can be more important than cue reliability in determining what features will control behavior when multiple cues are available.     

Contextual effects in a metaphor verification task

The verbal transformation effect, an auditory illusion in which physically invariant repetitive verbal input undergoes perceptual transformation, has traditionally been interpreted as a speech-specific phenomenon. Experiment 1 showed that the effect is not limited to speech, but occurs in non-speech categories such as music and other complex everyday sounds, with transformations being comparable in nature and number to those in speech. Experiment 2 provided evidence for an alternative, broader-based view of the phenomenon, involving spreading activation through a multidimensional associative network of mental representations, by demonstrating that creating or activating pre-existing links between a single complex non-verbal stimulus and other representations by priming led to an increase in transformations.     

Development, gender equality, and suicide rates

A component of the United Nations Development Programme Human Development Index which measures longevity was negatively associated -.55 with suicide rates in 37 nations for men; the correlation with the suicide sex ratio was also negative (r = -.59). Women's access to social, political, and economic power in a subsample of 26 nations, summarized in the UNDP's Gender Empowerment Measure, was positively correlated with suicide rates (r = .36 for both women and men). UNDP measures of attainment in literacy and income showed no individual relationship with suicide rates. In a multiple regression model, life expectancy was negatively related, and the Gender-related Development index was positively related, to suicide rates.     

Should there be a three-strikes rule against pure discovery learning? The case for guided methods of instruction

The author's thesis is that there is sufficient research evidence to make any reasonable person skeptical about the benefits of discovery learning--practiced under the guise of cognitive constructivism or social constructivism--as a preferred instructional method. The author reviews research on discovery of problem-solving rules culminating in the 1960s, discovery of conservation strategies culminating in the 1970s, and discovery of LOGO programming strategies culminating in the 1980s. In each case, guided discovery was more effective than pure discovery in helping students learn and transfer. Overall, the constructivist view of learning may be best supported by methods of instruction that involve cognitive activity rather than behavioral activity, instructional guidance rather than pure discovery, and curricular focus rather than unstructured exploration.     

Genetic and environmental influences on pubertal development: longitudinal data from Finnish twins at ages 11 and 14

To study sources of individual differences in pubertal development, the authors fit a sex-limitation common factor model to data reported, at ages 11 and 14 years, by 1,891 twin pairs on items that comprise the Pubertal Development Scale (PDS; A. C. Petersen, L. Crockett, M. Richards, & A. Boxer, 1988). The model divides variation into a general pubertal factor and item-specific variation and, in addition, decomposes it into constituent sources. In both boys and girls, genetic influences made the largest contribution to variance common to PDS items. Genetic and nonshared environmental factors accounted for variation specific to PDS items in boys, whereas for girls, common environmental influences were added for growth spurt and menarcheal status. For both common and item-specific variation, genetic effects were partially sex specific. Subsidiary analyses found accelerated maturation in both boys and girls who at age 14 were reared in father-absent homes.