Retention and transfer of morse code reception skill by novices: part-whole training.

The training of composite skills requiring differential responding to a large set of stimuli raises issues about how to break down the whole task into parts and which parts should be trained first. Components of Morse code reception skill were identified, separated, and used to test whether initial training on a difficult part was more effective than initial training on an easy part. Initial training on a difficult subset of stimuli and on a difficult subtask both yielded disadvantages rather than the advantage implied by recent findings with different tasks. Incremental training should begin with the part yielding the most effective strategic skills, which appear to depend on characteristics of the task. In both present experiments, easy initial training led to adoption of an effective unitization strategy for representing codes. The hypothesis that procedural reinstatement at delayed testing leads to better retention was supported and extended.

Cross-modality priming between odors and odor-congruent words.

It is well known that the Stroop effect is subject to influence by same-modality primes, but the possibility of cross-modal priming effects is unclear. Smell is a fundamental sensory system that is assumed to have potent cross-modality priming effects. We might expect the presence of a specific odor to interfere with performance on Stroop cards containing odor-congruent words. Forty participants, half of whom were primed with an unpleasant odor and half with a pleasant odor, were examined with modified Stroop cards containing pleasant and unpleasant descriptive words. A significant Stroop card by odor group interaction was found, indicating that the presence of an odor interferes with the performance on an odor-congruent Stroop card. These findings demonstrate cross-modality priming between olfaction and vision.

Effects of cortical polarization on mental arithmetic.

A biofeedback procedure was used to influence participants' cortical polarity before the presentation of single digit multiplication problems. To ensure that participants could solve the problems by direct memory retrieval of arithmetic facts, only nine different multiplication problems were used, and participants received extensive pre-experimental practice on these problems. After biofeedback training, cortical positivity before problem presentation was associated with faster response initiation times, a measure of mental calculation time, for correctly solved problems and with more multiplication errors than cortical negativity. Response execution time, a measure of motor speed, was not affected by cortical polarity. The shift in positivity from the amplitude of the slow cortical potential (SCP) before problem presentation to the amplitude of the positive slow wave (pSW) after problem presentation was less in positivity-required compared to negativity-required trials, mainly because of the manipulation of SCP starting points by biofeedback. We assume that cortical positivity is associated with direct retrieval of arithmetic facts, more precisely with the inhibition of incorrect answers. Cortical positivity before task presentation results in a reduced positive shift, a sign of less inhibition before answer production. The effect of less inhibition during positivity-required trials is to produce faster responses and more errors. The opposite might to be true of cortical negativity.

Some tests of an identical elements model of basic arithmetic skills.

Two experiments tested an identical elements model of the organization of basic arithmetic skills (T. C. Rickard, A. F. Healy, & L. E. Bourne, 1994). This model assumes a distinct abstract representation for each unique combination of the basic elements (i.e., the operands and the required operation) of a problem. Participants practiced multiplication and division problems and were then tested on various altered versions of these problems. Experiment 1 confirmed the prediction of no positive transfer when the presented elements of a test problem do not exactly match those of a practice problem. Experiment 2 confirmed the prediction that there is complete transfer when the elements of the test problem match exactly with those of a practice problem. Experiment 2 also confirmed that there is both perceptually specific and nonspecific speed-up with practice. Implications for number processing and arithmetic are discussed.

Neurophysiological correlates of mental arithmetic.

Thirteen subjects were extensively trained on nine multiplication problems varying in difficulty. Practice was associated with a reaction time speed up and an attenuation of the problem size effect. The introduction of previously unpracticed problems led to a performance rebound to pretraining levels, indicating practice specificity. The eventrelated potentials were characterized by a late positive complex, followed by a positive slow wave. Offset latency of positive slow wave and preresponse amplitude at parietal electrodes showed practice specificity effects that systematically changed with practice and problem size, indicating an association with the load imposed on working memory. The peak of the late positive complex probably reflects task learning or adaptation effects because it was attenuated by practice predominantly at frontal electrodes, showed no practice specificity, and was not affected by problem size.

Brain potentials during mental arithmetic: effects of extensive practice and problem difficulty.

Recent behavioral investigations indicate that the processes underlying mental arithmetic change systematically with practice from deliberate, conscious calculation to automatic, direct retrieval of answers from memory [Bourne, L.E.Jr. and Rickard, T.C., Mental calculation: The development of a cognitive skill, Paper presented at the Interamerican Congress of Psychology, San Jose, Costa Rica, 1991: Psychol. Rev., 95 (1988) 492-527]. Results reviewed by Moscovitch and Winocur [In: The handbook of aging and cognition, Erlbaum, Hillsdale, NJ, 1992, pp. 315-372] suggest that consciously controlled processes are more dependent on frontal lobe function than are automatic processes. It is appropriate, therefore to determine whether transitions in the locus of primary brain activity occur with practice on mental calculation. In this experiment, we examine the relationship between characteristics of event-related brain potentials (ERPs) and mental arithmetic. Single-digit mental multiplication problems varying in difficulty (problem size) were used, and subjects were trained on these problems for four sessions. Problem-size and practice effects were reliably found in behavioral measures (RT). The ERP was characterized by a pronounced late positivity after task presentation followed by a slow wave, and a negativity during response indication. These components responded differentially to the practice and problem-size manipulations. Practice mainly affected topography of the amplitude of positivity and offset latency of slow wave, and problem-size mainly offset latency of slow wave and pre-response negativity. Fronto-central positivity diminished from session to session, and the focus of positivity centered finally at centro-parietal regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term repetition effects for motoric and perceptual procedures.

Two experiments examined the relationship between implicit and explicit measures of memory for information encoded in a motoric task, called data entry. In both experiments, subjects entered lists of digit sequences with a computer keypad. They were retested on the same task after a delay of up to 1 month. At retention, implicit memory for the digit lists was evidenced by faster entry of old relative to new lists in both experiments. In Experiment 1, subjects were able to discriminate old from new lists. Recognition memory of old lists was better after than before entering the lists. In Experiment 2, perceptual and motoric contributions to the old/new difference in typing speed were isolated by means of a transfer paradigm. The results showed that the entry-speed advantage for the old lists was due to the separate reinstatement at the retention test of both perceptual and motoric procedures encoded earlier. Implicit and explicit measures of memory were found to be dependent rather than independent. The findings from this study are interpreted within a framework of memory based on procedural reinstatement.

Identification of letters in the predesignated target paradigm: a word superiority effect for the common word the.

The size of the perceptual unit used in reading was addressed using the predesignated target paradigm. Sixteen subjects viewed the following stimuli in random order: the words tee, the, tie, and toe; the nonwords eet, eht, eit, and eot; and the letters e, h, i, and o. Subjects fixated on the location of the center letter and identified the letter as e, h, i, or o, alternatives which were known to them at the onset. A word superiority effect was obtained for the common word the but not for the less common words tee, tie, and toe. The word superiority effect was attributable to bias rather than discriminability: Subjects exhibited a bias to perceive the words in this experiment as the (i.e., there was a bias to perceive h in the t e stimulus presentations). These results suggest that the common word the is processed in reading units that are larger than the letter, and that the system is biased to perceive common rather than uncommon words in data-limited conditions.

Facilitating text memory with additional processing opportunities in rapid sequential reading.

Previous research indicates that during conventional reading, readers pause at particular loci within a text, presumably for the purpose of higher level processing and integration. If such pausing is necessary for efficient text comprehension and memory, then providing readers with equivalent processing opportunities with strategically placed pauses in rapid sequential visual presentation (RSVP) text displays should facilitate comprehension and memory. Three experiments are reported in which various time parameters of RSVP displays are manipulated. The results indicate that memory for specific text is facilitated when additional processing time is provided. However, how and where the additional time is distributed within a text, over broad limits, is not important. We use a method of text memory assessment that is not typically used in RSVP research and that is more sensitive to text presentation manipulations than the commonly used multiple-choice questions. This fill-in-the-blank technique also provides evidence that memory representations for texts are structured as meaningful subsentence units.

Thought disorder and schizophrenia: isolating and timing a mental event.

This study explored the ability of nonparanoid schizophrenic, paranoid schizophrenic, and mixed psychiatric control (manics and schizoaffectives) patients to perform on two types of conceptual, speeded inference (SI) tasks, which differ in type of abstraction process required. The subjects (N = 30) were grouped into high and low levels of thought dysfunction, as measured by the Whitaker Index of Schizophrenic Thinking (WIST). There were no differences among the three clinical groups on the conceptual, SI tasks. Reaction times differed reliably across the two SI tasks. High-WIST subjects were impaired on SI accuracy. Significant impairment in accuracy was demonstrated by high-WIST time and error groups on the more complex SI tasks. Information processing deficit was demonstrated in terms of encoding phase and reaction time in problem-solving of the three diagnostic groups as a function of WIST levels.

Chronic alcoholism in males: cognitive deficit as a function of age of onset, age, and duration.

Performance on a cognitive rule-learning task was studied in detoxified alcoholics having early/late onset and short-/long-term drinking histories, and in matched nonalcoholic controls. There were pronounced cognitive deficits in early onset and long-term alcoholics. Impairment was severest in the early onset group, even though they were on the average 15 years younger than the late onset group. Early onset alcoholics were relatively more impaired on both the abstract and the verbal Shipley measures. This group also manifested a relative deficit in ability to show positive transfer across problems. Chronicity of alcoholism also interfered with acquisition of an abstract relationship between concrete stimulus attributes. Age negatively influenced ability to perform abstractions, but not commonly tested verbal skills. The findings suggest that an early onset of alcoholism, regardless of duration of problem drinking, is particularly predictive of cognitive impairment.

Cognitive and electrophysiologic parameters during ascending and descending limbs of the blood alcohol curve.

This study examined the effects of acute alcohol ingestion and prior success or failure upon cognitive performance of 40 healthy, non-alcoholic subjects, during both the ascending and descending limbs of the blood alcohol curve. Measures of physiological arousal were made with frontal/laryngeal electromyographic and skin conductance response level parameters. Major findings were: (1) cognitive performance was impaired by alcohol ingestion; (2) autonomic arousal was significantly greater after alcohol than after placebo; (3) number and amplitude of skin response were greater on the ascending than on the descending limb; (4) the anticipated effects of failure on cognitive performance were ameliorated by alcohol; and (5) differential effects of alcohol on the psychophysiological parameters were demonstrated.

Conscious attentional demands of encoding and retrieval from long-term memory.

The importance of allocating conscious attention to encoding and retrieval from long-term memory was investigated. Encoding, retrieval, and reactivation hypotheses were tested. College students were shown schematic faces in a secondary task and numerical problems as a primary task. The primary task was imposed both when the faces were encoded on study trials and when they were retrieved on recognition test trials. Difficulty of the primary task (easy vs. hard) was varied on both study and test trials. The easy problems permitted conscious attention to be given to the secondary faces whereas the hard problems prevented such allocation. Instructions about encoding the faces (incidental vs. intentional) were given to different groups. The degree of conscious attention that was allocated to the faces on study trials was assessed by means of interference, intention, and retrospection criteria of attended processing. Recognition of the faces was better when subjects allocated conscious attention to encoding than when they did not, in consistent support of the encoding hypothesis. The data ruled out a reactivation explanation. Finally, at times, paying special attention at retrieval improved recognition performance, providing weak support for the retrieval hypothesis.

Stimulus-rule interactions in concept verification.

The difficulty of learning a conceptual rule has been shown to depend upon the stimulus attributes which that rule conjoins. For what appear to be separable attributes, the disjunctive rule is easier than the conjunctive. In contrast, for what appear to be integrable attributes, the conjunctive rule is easier. This paper reports six experiments designed to determine whether the integrality of stimulus attributes affects the speed of verification of the stimulus, as positive or negative, with respect to a given conjunctive or disjunctive concept. The pattern of reaction times is not consistent with the result of rule-learning experiments and does not support an integrality hypothesis. Verification times seem to be more a function of the perceptual salience of the relevant attributes of the concept. Thus, a perceptual-integrality hypothesis is an unlikely explanation of rule learning results.

Limits to conceptual rule-learing by schizophrenic patients.

Two studies of conceptual rule-learning by 36 hospitalized psychiatric patients revealed that (a) while all were clinically diagnosed as schizophrenic, they differed widely in their ability to discover abstract rules; (b) the Whitaker Index of Schizophrenic Thinking (WIST) strongly predicted the patients' ability to learn and to apply a conceptual rule; and (c) regardless of severity of conceptual impairment, the patients were unaffected by modest levels of externally generated irrelevant information as presented through the modality of vision. Deficits in abstractive ability, when they exist, are believed to be due to a schizophrenic patient's inability to prevent task-irrelevant information that originates in long-term memory from spilling into and despoiling the operations of working memory.