Perception without awareness in a dichoptic viewing situation

One way of investigating perception without awareness is to utilize the phenomenon of binocular rivalry. The dichoptic viewing situation can be so arranged that a stimulus may be above identification level (when presented alone) but masked by contiguous stimulation, i.e. a brighter image to the other eye. This experimental situation was used to replicate an experiment of Smith et al. (1959) which claimed to demonstrate that differences in meaning between words registered below recognition threshold could affect associated conscious thoughts. In the two experiments reported here, a neutral face was paired with affect words presented subliminally and subjects were asked to rate its expression using a forced-choice indicator. Additional controls to those of Smith et al. were used. In Expt. I it was established that words presented outside of awareness had an effect on semantically related judgements, which was at least as great as that with the same words presented supraliminally. In Expt. II this was confirmed and it was found that increasing the similarity of contour between critical and control words of different meaning suggested differences between subliminal and supraliminal sessions. Responses tended to be meaning-related in the former and structure-related in the latter. It was suggested that the experiments have relevance to current theories of selective attention.     

Factors predicting success and failure in the first-year examinations of medical and dental courses

Entrants to medical and dental courses in London University were given questionnaires covering aspects of study organization, attitudes towards the course, and approach to studying. Two factors were identified with a significant relation to examination performance at the end of the first year, a general study organization factor and performance at the GCE advanced level examination. The first was a stronger predictor than the second. However these factors only demonstrated a limited ability to identify students who failed the first year of the course, so can at best enable a modest improvement in selecting students who will pass, or in identifying students in need of counselling during the course. Some differences were found between results for the two samples and possible reasons for these are discussed.     

Differential effects of noise and incentives on learning.

Three experiments are reported. In the first, monetary incentives improved the learning of nonsense words in response to colours only when the test order was the same as presentation order. In the second, incentives increased the recall of spatial location which served as an additional retrieval cue for nonsense words. In the third, noise was used to manipulate arousal. Noise during learning produced a significant decline in recall of locations for nonsense words. The results suggest that incentives increase attentional capacity, while noise does not. Previous results showing that noise increases the use of order cues are discussed and it is suggested that noise induces a type of learning which depends on order cues. Existing hypotheses about the nature of this process are noted but it is argued that further work is needed to select between them.     

The interaction of word frequency and stimulus quality in the lexical decision task: Now you see it, now you don't

Two experiments are reported that examined the joint effects of word frequency and stimulus quality in the context of a lexical decision task. In the first experiment the interval between response to a stimulus and onset of the next stimulus was 0.8 sec, and the effect of the two factors was additive. In the second this interval was 3.3 sec, and the effect of reducing stimulus quality was greater for infrequent words than for frequent words. This is similar to the result of Norris (1984). The inability of current models of word recognition to explain this finding is discussed.     

Noise effects on rehearsal rate in short term serial order memory

Three experiments are reported which were designed to test the hypothesis that the rate of rehearsal during noise is slower than that under quiet conditions. The first experiment measured directly the rate of articulation while subjects either read or rehearsed a set of five consonants. It was shown that while the rate of articulation when reading aloud did not differ under the two noise levels [65 dB(C) and 85 dB(C)], rate of articulation during overt rehearsal in loud noise was significantly slower than under quiet conditions. In Experiment II a similar effect was demonstrated where words were required to be read or rehearsed; here it was shown that the greatest impairment due to noise was on the rate of rehearsal of words of long spoken length.

The third experiment showed that loud noise impaired recall performance more markedly for a set of words of long spoken length presented early on in the sequence than for a set of shorter words, even though both sets were equal in the number of syllables and phonemes they contained.

It was concluded that in verbal memory tasks where rote rehearsal of the to-be-remembered material is the predominant strategy for enhancing trace duration, noise may affect memory performance by slowing down the rehearsal rate.     

Earwitness testimony 2. Voices,faces and context

Two factors relevant to voice recognition were investigated in the study reported here: the effect on memory for a voice of the presence of a face or personal information about the speaker, and the effects of the re-presentation of this information as contextual cues at test. Recognition memory for the briefly heard voice of a stranger was superior in conditions where the face of the speaker was absent. Presence of the additional contextual cues at test had no effects on recognition performance. Theoretical and forensic applications of the findings are discussed in terms of face-recognition models and witness line-up design. The sensitivity of voice memory measures to the different types of experimental design is also considered. © 1997 John Wiley & Sons, Ltd.     

Influences of test expectations on memory-processing strategies

In a series of four experiments, recall and recognition performance were examined following recall and recognition instructions. It was found that recall-instructed subjects produced significantly better performance than recognition-instructed subjects on tests of ordered and free recall of words, particularly on the early part of the list (Experiments 1 and 2). The results of two further experiments suggest that this is mediated by differences occurring at input, and is due to increased rehearsal by subjects expecting a recall test (Experiments 3 and 4).     

A note on relations between trait and state measures of arousal

Analysis of Eysenck Personality Inventory measures of personality and measures of mood obtained by the Nowlis Mood Adjective Check List revealed four main factors. Neuroticism was associated with a cluster of mood variables related to anxiety and depression and extraversion to a cluster related to self -confidence, but not to activation. Implications for the use of these measures in cognitive and other research are indicated.     

Relations between approaches to studying and note-taking behaviour in lectures

Copies of notes taken during a lecture were obtained from first-year psychology students, and the relations examined between measures derived from these (the number of points recorded, the number of words written, and the number of words per point) and a number of variables measuring personality and approach to studying. Three variables were found to be related to the measures derived from the notes: older students, those scoring high on strategic learning (strategy component) and those scoring high on surface learning (motivational component), both measured by questions derived from Biggs (1979), produced longer notes and recorded more of the important points in the lecture. The results suggest that relations between approaches to studying and specific study behaviour are not straightforward and require more detailed investigation.     

Visual search in typically developing toddlers and toddlers with Fragile X or Williams syndrome

Visual selective attention is the ability to attend to relevant visual information and ignore irrelevant stimuli. Little is known about its typical and atypical development in early childhood Experiment 1 investigates typically developing toddlers' visual search for multiple targets on a touch-screen. Time to hit a target, distance between successively touched items, accuracy and error types revealed changes in 2- and 3-year-olds' vulnerability to manipulations of the search display. Experiment 2 examined search performance by toddlers with Fragile X syndrome (FXS) or Williams syndrome (WS). Both of these groups produced equivalent mean time and distance per touch as typically developing toddlers matched by chronological or mental age; but both produced a larger number of errors. Toddlers with WS confused distractors with targets more than the other groups; while toddlers with FXS perseverated on previously found targets. These findings provide information on how visual search typically develops in toddlers, and reveal distinct search deficits for atypically developing toddlers.