John J. Shaughnessy

Further evidence on the MP-DP effect in free-recall learning

In Experiment 1, rate and frequency of presentation, concrete and abstract words, and imagery instructions were manipulated along with MP and DP schedules in a long free-recall list, presented for one trial. Large differences between MP and DP were found, but none of the other variables except frequency interacted with MP-DP. In Experiment 2, various forms of MP and DP patternings were used with all words presented four times. Recall was predictable by the number of distributed points within the patterns. In Experiment 3, S paced himself through a long list of words presented on slides. The usual MP-DP differences in recall were present, and parallel differences were observed in exposure times. The difference in MP and DP recall was greater than could be accounted for by differences in exposure time. All experiments showed recall to be related to the input position of the words.

A double-blind histamine placebo—controlled trial of polymerized whole grass for immunotherapy of grass allergy

Twenty-six patients were recruited for a study of the safety and efficacy of immunotherapy with IPG. They were randomly assigned to two groups based on skin test titrations to grass allergens. One group was treated in a double-blind fashion before the 1982 grass season with 12 weekly injections totaling approximately 48,000 PNU, and the other group was treated with 12 weekly injections of caramelized glucose histamine placebo. Daily symptom and medication score sheets were completed by all patients each day of the grass season. Blocking antibody rose ninefold in the IPG group (p less than 0.007) but was unchanged in the placebo group. There was no significant change in IgE against rye grass group I in either the IPG or the placebo group. Symptom-score mean in the IPG group was 217 +/- 71 (S.E.M.), statistically lower (p less than 0.02) than the mean in the placebo group 496 +/- 117 (S.E.M.). There were no systemic reactions and only minor local reactions. There was no change in routine laboratory tests in either group. Although two prior studies with grass allergen immunotherapy reported efficacy, these studies did not use symptom-score analysis. This is the first double-blind, histamine placebo-controlled study of grass immunotherapy that demonstrates efficacy by symptom-score index evaluation. IPG is a safe, clinically effective, and potentially cost-effective therapy for grass pollinosis.

Persistence of efficacy after a brief course of polymerized ragweed allergen: A controlled study☆

Immunotherapy with PRW has been demonstrated to be safe and effective. To determine whether the efficacy would remain in successive ragweed seasons without further therapy, a trial was conducted comparing PRW to histamine placebo therapy in patients that had received courses of PRW previously. Those patients were also compared to previously untreated ragweed-sensitive patients. In a double-blind fashion, 21 previously treated patients were treated before the 1982 ragweed season with four injections of PRW therapy, whereas 21 previously treated patients were treated with four injections of placebo therapy. An additional control group of 21 previously untreated ragweed-sensitive patients received no injections. Daily symptom and medication score sheets were completed by patients each day of the ragweed season. Blocking antibody rose elevenfold with treatment (p less than 0.0001) in the PRW group. There was a statistically significant difference in symptom score mean between untreated patients (1007 +/- 174) and previously treated patients whether they received supplemental injections (554 +/- 180) (p less than 0.01) or whether they did not (650 +/- 168) (p less than 0.03). In summary the efficacy of 15 injections of PRW immunotherapy persists at least several years without need for supplemental immunotherapy.

A double-blind placebo-controlled trial of polymerized whole grass administered in an accelerated dosage schedule for immunotherapy of grass pollinosis☆

Forty-four patients were entered into a study of the efficacy and safety of individually polymerized grass (IPG) immunotherapy with an accelerated dosage schedule. Patients were paired on the basis of cutaneous end point titrations to timothy, orchard, and Bermuda grass-pollen extracts. In a double-blind manner, one patient in each pair was treated in nine weekly visits with 13 injections that totaled 24,000 PNU of each grass to which the patient had cutaneous reactivity. The other patient in each pair received caramelized glucose histamine placebo. Symptom and medication score sheets were completed by 33 patients each day of the grass season. Blocking antibody rose significantly in the IPG-treated group but was unchanged in the placebo-treated group. By Wilcoxon paired signed-rank test, the symptom medication scores in the IPG-treated group were significantly lower than those in the placebo-treated group. There were no systemic reactions and no clinically significant changes in routine laboratory tests in either group. In summation, this study demonstrates the safety, immunogenicity, and efficacy of IPG therapy in an accelerated dosage schedule for treatment of grass pollinosis.

A Recognition Test of Vocabulary Using Signal-Detection Measures and Some Correlates of Word and Nonword Recognition.

Abstract In the first of three experiments, university undergraduates were presented a list of 300 words and 100 nonwords in two sessions. Their confidence that an item was a word was indicated for each item on a 6-point scale. This experiment demonstrated the feasibility of creating a recognition test of vocabulary. In Expeiment II, 100 items were chosen to form a subtest, and the subtest was cross-validated on a new sample of subjects. The tests in Experiments I and II were scored using signal-detection measures. The primary criterion, SAT (verbal) scores, correlated approximately .60 with the test scores. In Experiment III subjects scaled the words and nonwords for four psychological attributes. These were submitted to a stepwise regression with the confidence ratings from Experiment I as the dependent variable. It was concluded that associability. frequency, orthography, and pronounceability all may be components of word recognition. However, only frequency was found to be a significant predictor of the confidence of recognition of nonwords.

Memory-monitoring accuracy as influenced by the distribution of retrieval practice

An experiment was done to determine whether retrieval practice improved judgment-of-learning (JOL) accuracy when degree of learning was controlled. Fifty undergraduate students were asked to learn a long list of unrelated facts, with critical items presented either once or four times. The repetitions of critical items were retrieval prompts for half of the subjects (study-test) and additional study presentations (study-only) for the other half of the subjects. The subjects made JOL ratings after the last occurrence of critical items. Immediately after the study list, they were given a cued-recall test. Recall was comparable for once-presented items and repeated items across the two groups, but JOL accuracy was higher for repeated items in the study-test group. These results confirm that retrieval practice enhances JOL accuracy even when degree of learning is controlled.

Long-Term Retention and the Spacing Effect in Free-Recall and Frequency Judgments.

In 2 experiments undergraduate students were presented with a long list of words in which items were repeated varying numbers of times according to either a massed presentation (MP) schedule or a distributed presentation (DP) schedule. Following list presentation, subjects were given either a frequency-judgment test (Experiment I) or a free-recall test (Experiment II). In both experiments, the retention test was given either immediately after or 24 hours after list presentation. As expected, on the immediate test MP items were judged to have occurred less frequently and they were recalled more poorly than DP items. On the delayed frequency judgment test, the spacing effect was slightly (though not significantly) smaller, and these results were considered to be consistent with the prevailing notion that MP items are more poorly registered in memory. The results of the delayed free-recall test, however, were less consistent with this explanation in that there was no difference in the recall of twice-presented MP and DP items. In a list presented for study, the successive occurrences of a repeated item may appear either in adjacent or nonadjacent list positions. Repeated items whose successive occurrences appear in adjacent positions are referred to as massed-presentation (MP) items, while those repeated in nonadjacent positions are referred to as distributed-presentation (DP) items. It has been consistently shown that, on tests of retention given immediately after presentation of the study list, MP items are more poorly recalled (e.g., Shaughnessy, Zimmerman, and Underwood, 1972) and are judged to have occurred less frequently (e.g., Underwood, 1969) than are DP items. Hintzman (1974) has provided a recent review of both the empirical findings and the proposed theoretical explanations related to this so-called spacing effect in free-recall and frequency judgments. Somewhat surprisingly, very little attention has been given to the study of the spacing effect in long-term tests of retention. Ciccone and Brels

On the independence of judged frequencies for items presented in successive lists

In an experiment examining retroactive interference effects in a frequency-judging task, all Ss were presented with a list of words occurring varying numbers of times according to either a massed- or distributed-practive (MP or DP) schedule. They were then asked to judge how often each word had occurred. Following this, Ss were given one of four types of second tasks a second list with different items followed by a frequency-judging task for that list (Condition New): a second list with items repeated from the first list but with different frequencies for each item, while either maintaining items as either MP or DP items (Condition Same) or switching MP items to DP, and vice versa (Condition Reverse): followed by a frequency-judging task for the second-list frequencies only: or a puzzle task for the amount of time required for second-list presentation and judgment in the other conditions (Condition None). Finally, all Ss were asked to recall List 1 frequencies, List 2 frequencies were less discriminable in Conditions Same and Reverse than in Condition New. Recall of List 1 frequencies, however, was not different for these three groups, but was poorer than in List 2 frequency judgments were not independent of List 1 frequencies.

The retention of frequency information for categorized lists

In two experiments subjects were presented a list containing words which occurred with varying frequencies. Some of the words were conceptually related. Frequency judgments for the items were taken either immediately or after 1 week. In both experiments the presence of items conceptually related to a given test item produced an overestimation of frequency. This overestimation was greater for test items presented twice than for test items presented five times. This was interpreted in terms of a loss of discrimination between presented frequency and frequency accrued through displaced rehearsals. Support for this position was given in the finding that test items presented before other instances conceptually related to them were overestimated more than were test items presented after the other instances related to them.

The spacing effect in the learning of word pairs

Following the presentation of a single list of word pairs consisting of a three-letter word on the left and a five-letter word on the right, groups of 64 Ss each were asked to recall the (a) three-letter words, (b) five-letter words, (c) intact pairs, or (d) five-letter words with the three-letter words provided. Two types of repeated pairs were presented, one in which the same three- and five-letter words were repeated together (same pairs) and one in which the same five-letter word was repeated with different three-letter words (different pairs). For half of the Ss in each recall group, the repetitions of a pair containing a given five-letter word were massed (MP); for the other half, the repetitions were distributed (DP). Recall of MP same pairs and the eomponents of these pairs was consistently poorer than that of DP same pairs. Recall of the repeated component of the different pairs was also poorer under MP than under DP. The results were interpreted as supportive of an attenuation-of-attention explanation of the spacing effect.