Misremembering a familiar object: Mnemonic illusion,not drawing bias

It was reported by Jones (1990) that the design of British coins is systematically misremembered. Although the Queen's head in fact faces right, most people draw it facing left. It is possible, however, that the origin of this phenomenon does not reside in memory but instead in a leftward drawing bias. Two experiments of the three reported here tested this hypothesis. In Experiment 1, British participants attempted to recall the direction of the Queen's head but responded verbally instead of pictorially. The results were similar to those of Jones and thus contradict the hypothesis that misremembering of the Queen's head is caused by a leftward drawing bias. In Experiment 2, Canadian participants attempted to draw a Canadian coin. Leftward misremembering was not observed in this case. Thus the hypothesized importance of a leftward drawing bias was again not supported. Instead, the results provided support for the schema explanation of the Queen's Head memory illusion proposed by Jones. The results of Experiment 3, which compared memory for British coins and stamps, further bolstered this conclusion.     

A developmental evaluation of the role of word shape in word recognition

Fourth- and seventh-grade children and college-age adults proofread passages typed either in lowercase or in all capital letters. Words were misspelled by deleting one of four letters, s, c, k, or p, that have similar features in lowercase and uppercase. Proofreading errors decreased with age and increasing reading ability, but all of the subjects were sensitive to changes in word shape--they missed more words with deletions of s or c than k or p in the lowercase passage but not in the all-capitals passage. These findings indicate that word shape is an important variable in recognizing familiar words, even for young readers.     

The role of syllabic and orthographic properties of letter cues in solving word fragments

The present research examined the role of phonological and orthographic properties of cues in mediating the retrieval of words from the mental lexicon. The task required subjects to resolve fragmented words when provided with semantically related cues (e.g., spiteful:---DIC----). Phonological properties of the letter cues were manipulated such that the letters either corresponded to the syllables (e.g., DIC in vindictive) or nonsyllables (NDI) in the word. Orthographic properties of the letter cues were manipulated by selecting letter groups that either co-occurred frequently in the language or did not. In two experiments, results revealed little or no effect of the phonological variable (syllables) but a reliable effect of the orthographic variable (letter-cue frequency). Letter cues with a low frequency of co-occurrence in the language led to better completion of the fragmented words. We interpret these findings as support for models of lexical representation that are based on orthographic properties (e.g., Seidenberg & McClelland, 1989) rather than those based on phonological constraints.     

Output and retrieval interference in the missing-number task

Three experiments are reported that represent a reexamination of the missing-number method (Buschke, 1963b) of estimating short-term memory span. The missing-number task involved presenting a random sequence of all but one of the numbers of a known reference set and asking subjects to identify the missing number. Experiment 1 introduced a modified missing-number task that included two missing items and two choices made by the subject. With a large decline in performance for the second choice relative to the first, it is possible that only the second choice was subject to output or retrieval interference. An alternative explanation is that subjects output the number with the weakest memory representation as their first response. By postcuing subjects to report their two choices in a forward or backward sequence, Experiment 2 provided evidence against the importance of output interference and support either for the importance of retrieval interference or for the "weakest-first" hypothesis. However, with a paradigm that replaced only correctly identified missing numbers, a prediction that subjects would select the number with the weakest memory representation as their first response was not confirmed in Experiment 3. Instead, retrieval interference was implicated to explain the first-choice superiority found in Experiments 1 and 3. The results were interpreted in terms of the TODAM model of Murdock (1982, 1987, in press).     

Effects of preliminary perceptual output on neuronal activity of the primary motor cortex.

Observations of single neurons in the primary motor cortex of 1 monkey provided evidence that preliminary perceptual information reaches the motor system before perceptual analysis is complete. Neurons were recorded during a task in which 1 stimulus was assigned to a wrist flexion response and another was assigned to wrist extension. Two stimuli were assigned to a no-go response; each was visually similar to either the flexion or the extension stimulus. When a no-go stimulus was presented, neurons responded with weaker versions of the discharge patterns exhibited to the visually similar stimulus requiring a movement, suggesting that neurons receive partial perceptual information favoring that movement. Functionally separable neuronal populations were identified, and differences in the activations of these provide evidence about the functional effects of preliminary perceptual output on movement control processes.     

Rapid Automatized Naming and gesture by normal and language-impaired children

This study investigates whether language-impaired (LI) children show deficits in rapid automatized naming and whether RAN performance is specific to verbal output (or to rapid motor output in general). A total of 67 LI and 54 age-matched control children were tested with the Rapid Automatized Naming (RAN) test (Denckla & Rudel, 1976) and with a manual version of the RAN (RAN-manual) in which subjects were required to provide a nonverbal, pantomime response. Subjects also completed tests of rapid oral and manual sequencing skills and standardized tests of reading ability. Each subject was tested at 4, 6, and 8 years old. The results showed that LI children perform significantly poorer on both versions of the RAN than age-matched controls. Correlations between RAN scores and tests of reading ability were significant for normal and LI subjects and were particularly high for 8-year-old LI children. RAN-manual scores also correlated with 8-year-old LI children's reading scores. Further, RAN and RAN-manual scores for the LI children correlated significantly with these children's manual sequencing abilities, whereas this was not the case for the control subjects. These findings suggest that LI children's rapid sequential processing deficits are not limited to verbal output, but also generalize to other motoric domains.     

Contributions of subjective-tone to tone-phoneme identification

We measured subjective-tone identification thresholds evoked by acoustically filtered complex tones and compared them to Mandarin-Chinese tone-phoneme identification thresholds previously measured under the same filtering conditions. Tone phonemes were identified at intensities below subjective-tone identification thresholds, suggesting subjective tone is not necessary for tone-phoneme identification. Lower subjective-tone thresholds evoked by resolved harmonics rather than unresolved harmonics were consistent with pattern recognition theories of pitch perception.The authors thank Donald Gans and Richard Klich for all their help.