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Biomedical subjects

M C Potter

Publications and source records attributed to M C Potter.

11 recordsLinked to original sources
PubMed1992

Visual and phonological codes in repetition blindness.

Repetition blindness (RB) is the inability to detect or recall a repeated word in rapid serial visual presentation. The role of visual versus phonological (name) similarity in RB was examined. RB was found for single letters, whether printed in the same or different cases, and for single digits, whether represented verbally (nine), as arabic numerals (9), or in a mixture of the 2 formats. Hence, visual similarity is not necessary to produce RB. RB was obtained between homophonic pairs (won/one), showing that phonological similarity is sufficient to produce RB, although visual identity also contributes to RB. It is proposed that RB results when the codes used for initial registration of the targets in short-term memory are similar. This initial code may be predominantly visual or predominantly phonological.

Humans↗
PubMed1990

Repetition blindness: levels of processing.

Repetition blindness (RB) is the failure to detect or recall repetitions of words in rapid serial visual presentation. Experiment 1 showed that synonym pairs are not susceptible to RB. In Experiments 2 and 3, RB was still found when one occurrence of the word was part of a compound noun phrase. In Experiment 4, homonyms produced RB if they were spelled identically (even if pronounced differently) but not if spelled differently and pronounced the same. Similarly spelled but otherwise unrelated word pairs appeared to generate RB (Experiment 5), but Experiment 6 produced an alternative account. Experiments 7 and 8 demonstrated that repeated letters are susceptible to RB only when displayed individually, not as part of two otherwise different words. It is concluded that RB can occur at either an orthographic (possibly morphemic) level or a case-independent letter level, depending on which unit (words or single letters) is the focus of processing.

Adult↗
PubMed1989

Repetition blindness: the effects of stimulus modality and spatial displacement.

Repetition blindness (Kanwisher, 1986, 1987) is the failure to detect repetitions of words in lists presented in rapid serial visual presentation (RSVP). Two questions were investigated in the present study. First, if repetition blindness is not found with auditory presentation, it would support a specifically visual account of the effect. Second, if displacement of the two instances in visual space eliminates repetition blindness, it would suggest that repetition blindness is restricted to instances in which identical stimuli are distinguished soley by temporal differences. In Experiment 1, the subjects omitted second occurrences of repeated words in verbatim recall of rapid sentences presented visually (in RSVP), but not auditorily (using compressed speech), indicating that repetition blindness is a modality-specific phenomenon. In Experiments 2 and 3, repetition blindness was observed even when two occurrences of a written word were presented in different locations, showing that distinct locations do not guarantee token individuation. The results are discussed within a model that distinguishes between processes of type recognition and token individuation.

Attention↗
PubMed1986

Pictures in sentences: understanding without words.

To understand a sentence, the meanings of the words in the sentence must be retrieved and combined. Are these meanings represented within the language system (the lexical hypothesis) or are they represented in a general conceptual system that is not restricted to language (the conceptual hypothesis)? To evaluate these hypotheses, sentences were presented in which a pictured object replaced a word (rebus sentences). Previous research has shown that isolated pictures and words are processed equally rapidly in conceptual tasks, but that pictures are markedly slower than words in tasks requiring lexical access. The lexical hypothesis would therefore lead one to expect that rebus sentences will be relatively difficult, whereas the conceptual hypothesis would predict that rebus sentences would be rather easy. Sentences were shown using rapid serial visual presentation (RSVP) at a rate of 10 or 12 words per second. With one set of materials (Experiments 1 and 2), readers took longer to judge the plausibility of rebus sentences than all-word sentences, although the accuracy of judgment and of recall were similar for the two formats. With two new sets of materials (Experiments 3 and 5), rebus and all-word sentences were virtually equivalent except in one circumstance: when a picture replaced the noun in a familiar phrase such as seedless grapes. In contrast, when the task required overt naming of the rebus picture in a sentence context, latency to name the picture was markedly longer than to name the corresponding word, and the appropriateness of the sentence context affected picture naming but not word naming (Experiment 4). The results fail to support theories that place word meanings in a specialized lexical entry. Instead, the results suggest that the lexical representation of a noun or familiar noun phrase provides a pointer to a nonlinguistic conceptual system, and it is in that system that the meaning of a sentence is constructed.

Adolescent↗
PubMed1976

Short-term conceptual memory for pictures.

Three converving procedures were used to determine whether pictures presented in a rapid sequence at rates comparable to eye fixations are understood and then quickly forgotten. In two experiments, sequences of 16 color photographs were presented at rates of 113, 167, or 333 msec per picture. In one group, subjects were given an immediate test of recognition memory for the pictures and in other groups they searched for a target picture. Even when the target had only been specified by a title (e.g., a boat) detection of a target was strikingly superior to recognition memory. Detection was slightly but significantly better for pictured than named targets. In a third experiment pictures were presented for 50, 70, 90 or 120 msec preceded and followed by a visual mask; at 120 msec recognition memory was as accurate as detection had been. The results, taken together with those in 1969 of Potter and Levy for slower rates of sequential presentation, suggest that on the average a scene is understood and so becomes immune to ordinary visual masking within about 100 msec but requires about 300 msec of further processing before the memory representation is resistant to conceptual masking from a following picture. Possible functions of a short-term conceptual memory, such as the control of eye fixations, are discussed.

Concept Formation↗
PubMed1975

Meaning in visual search.

Viewers briefly glimpsed pictures presented in a sequence at rates up to eight per second. They recognized a target picture as accurately and almost as rapidly when they knew only its meaning given by a name (for example, a boat) as when they had seen the picture itself in advance.

Adult↗