Quarterly Journal of Experimental Psychology

Subjects were adapted for 45 s to a 5 cycle per degree grating, tilted 10° from the vertical, and at one of four levels of luminance contrast. Estimates of the slope of the grating, or of a single line which replaced the grating, were obtained before and after the period of adaptation by the subject's setting of a single reference line which was located 3° from the edge of the grating. In Experiment I the fixation area was at the centre of the grating, so that half of the grating fell on each retinal hemifield. The reference line was set to a tilt further from the vertical following the period of adaptation, indicating either a change in the apparent orientation of the grating or the reference line. In Experiment II, where the fixation area was midway between the grating and the reference line, so that line and grating appeared in different hemifields, settings indicated no change in the tilt of the grating. In Experiment III, where the fixation area was again midway between grating and setting line, but where the grating was replaced by a single line after the adaptation period, settings indicated that the line had decreased in apparent tilt. The results of the three experiments indicate that while gratings either do not normalize or do so to an insignificant extent they produce a substantial amount of normalization on a single line. Comparison of the results of Experiments I and II shows that spread of this effect outside the directly adapted area is less across the naso-temporal division of the retina than within the same hemifield.

Two experiments, designed to compare the perception and retention of tachisto-scopic displays of four block capital letters and four simple “nonsense” figures are described. The results show that the letters were much better remembered and suggest that this was mainly due to the ease with which they were verbalized. The nonsense figures usually gave rise either to rapidly fading “iconic” images, or to an unstable kind of mixed imagery which was difficult to describe or remember, but in which inadequate verbalization was often a source of error. Subsidiary experiments illustrate the importance, not only of verbalization, but also of symmetry and simplicity in remembering visual display.

Theories of selective attention differ with respect to the amount of processing alleged to be undergone by non-attended material. “Early” selection theorists have argued that only physical properties of the non-attended material are extracted whereas “late” selection theorists have claimed that all inputs are fully analysed with selection taking place at the output stage.

Recent attempts to investigate these theories have investigated memory for non-attended material. The present experiment was designed to investigate memory for physical and semantic properties of non-attended material. Subjects shadowed words presented aurally and were tested for recall of simultaneously presented visual material. The visual stimuli consisted of either patches of colour or the names of those colours, the former containing only physical properties and the latter requiring semantic processing. Different shadowing conditions were employed in which subjects shadowed either colour names or unrelated words.

Recall of the colours was found to be superior to recall of the colour names and recall of both classes of material was found to be superior when subjects shadowed colour names than when they shadowed unrelated words. The results were interpreted as providing evidence for the existence of a post-iconic visual memory store based primarily on physical properties of the input.

Immediate recognition memory span and short-term forgetting for non-verbal stimuli (“unfamiliar faces”) were investigated in normal subjects and amnesic patients. Surnames were used as a verbal control. It was found that normal subjects had a reliable immediate recognition span of one for faces and that there was no decrement in performance in the retention of three faces over a 30-s interval. Amnesic subjects were impaired on both the immediate memory span task and on the short-term forgetting task. This pattern of results contrasts with those obtained using surnames on which the results were comparable to other verbal S.T.M. tasks. It is suggested that performance on these tasks of recognition memory for faces is determined by L.T.M. processes. The implications for the interpretation of S.T.M. are discussed.

The reaction times (RTs) of 12 subjects were recorded in a design where a visual or auditory warning signal preceded an auditory RT signal by one of four short foreperiods 500, 750, 1000 or 1250 ms long, which occured in a random sequence. For the 16 trials at each foreperiod, with each modality of warning signal, the average of the 2-s long EEG samples following the warning signal was computed so that the record showed the scalp recorded (vertex–-left mastoid) evoked potentials (EPs) to both warning and RT signals, and also the contingent negative variation or expectancy wave occurring during the foreperiod.

Differences between RTs with different foreperiods were not reflected in negatively correlated differences in the amplitude of the RT signal EPs, taking the major positive going deflection between peaks N1 and P2 at mean latencies of 126 and 231 msec after the RT signal. Furthermore RT signal EPs preceded by a warning signal were highly attenuated in amplitude relative to control EPs which were not preceded by a warning signal, whether or not an RT response was required. This was despite the fact that alerted RTs were slightly faster than non-alerted RTs, so that these findings contradict previous findings associating augmented EPs with responding versus not responding and with speeded RTs.

However, it was also found that RT signal EP amplitudes were greater with the more effective modality of warning signal than the less effective, which was consistent with previous findings. The divergence from previous findings when comparing EPs preceded by a warning with those having no prior warning is tentatively accounted for in terms of persisting physiological refractoriness following the warning signal EP.

Children were shown three visually displayed digits. The digits were exposed successively in three windows in such a way, that the left-to-right order never corresponded with the temporal-sequential order. When asked to recall or recognize the digits, normal children responded in terms of temporal order. Deaf, autistic and some subnormal children, recalled or recognized the spatial, i.e. the left-to-right order. The relationship between hearing and/or speech and the temporal ordering of visual displays is discussed.

It was hypothesized that the time course of preparation during a variable interstimulus interval (ISI) of a simple reaction time (RT) experiment was partly determined by the subjective distribution of conditional probabilities of the executive signal (ES). Sixty subjects performed a simple auditory RT task with various ranges of six ISI durations organized in rectangular frequency distributions. In order to give the subjects information about elapsed time during ISI, a recurring time-marking click, the periodicity of which was varied, was introduced during the ISI in one of the three series of trials each subject performed. A strong decreasing RT–-ISI relationship was observed supporting the main hypothesis. However, a clear increase of mean RT over all ISIs combined, was also found. Because these two mixed effects were greatest when the click intervened at the possible times of ES occurrence only, three functions of time-information given by the click are discussed: (a) a reduction of the usual increase of time estimation error with increased ISI; (b) an increase of the subjects knowledge of the ISI range resulting from the discontinuity of the time-marking click which makes easier a discrete time-intervals numbering process; (c) a change of the simple-RT task into a discrimination task.

An histidine-devoid but otherwise balanced amino acid mixture depressed food intake from 2 hr after its gastric intubation. It induced conditioned aversion to an odour incorporated in a protein-free diet presented for 6 h following intubation. In other rats, a balanced amino acid mixture established conditioned preference for odour presented in the same diet for 6 h following intubation. The degree of preference was considerably less than the degree of aversion.

A series of 10 tone stimuli was presented to rats at intervals of 1/4, 1/2, 1, 1 1/2, 2, 2 1/2, or 3 min or 24 h. The next day a test tone was presented and the distraction to this measured. There was less habituation (i.e. greater distraction) at shorter inter-stimulus intervals, but this effect asymptoted at 2 min and thereafter there was no further increase in habituation, even with inter-stimulus intervals of 24 h. A second independent variable was the stimulus duration which did not affect the rate of habituation, nor did it interact in any way with the inter-stimulus interval.

This study is concerned with the recognition and recall of semantically ambiguous words (homographs) presented in a semantic context. Changing the semantic context lowered test scores relative to test conditions both without context and with the same semantic context. This effect was found to obtain in both recognition and recall. The results are discussed in terms of the role of retrieval in recognition and recall.

The effects of item familiarity in memory have been variously ascribed to differences in storage or retrieval efficiency, response availability, and response bias. The experiments reported here attempted to discriminate between these explanations, using a model of the response process based on signal-detection theory. Memory for English surnames varying in frequency of occurrence was tested under free recall and recognition conditions. In both conditions, common names appeared more often among the incorrect responses, reflecting a response bias in their favour; but storage and/or retrieval of these names, as measured by the parameter d′, was less efficient than for uncommon ones. The finding of similar results in recognition and recall shows that the effect remains even when differences in response availability are removed by the use of a probe.

In the Stroop test it is found that the presence of words interferes with the task of naming colours. The usual account of this phenomenon is that the names of words are more readily obtained than are the names of colours and that the production of the latter is interfered with by the spontaneous occurrence of the former. Treisman and Fearnley (1969) have suggested a modification of the usual account such that stress is laid on the correspondence between the nature of the response (“verbal”) and that feature of a stimulus which will dominate. The present experiments seem to demonstrate that the data which Treisman and Fearnley use in support of their claim can be attributed to the strategy which their subjects adopted in their task. Some further observations are made concerning the different levels at which comparisons can be made between two stimuli.

A monocular lens mounted behind a stimulus screen was used to monitor fixation in a tachistoscopic recognition task. This technique was found superior to the often used “sideview technique” and as accurate as the method involving identification of a fixation stimulus. It was found that the “telescope technique” is preferable in those studies where presentation of a fixation stimulus might interfere with recognition or report of the experimental stimulus.

The effect of different types of competing auditory tasks on laterality differences in visual perception was investigated. Right-handed subjects were presented with digits which occurred randomly in the left or right visual fields. They responded vocally to previously specified digits in a go, no-go reaction time situation. In the absence of any competing auditory task, digits presented in the right visual field were processed more quickly. This visual field difference in reaction time was in the same direction while subjects performed a secondary musical task. However, when a secondary verbal task had to be performed, digits in the left visual field received faster responses. The results support the view that the right hemisphere is capable of some language functions, and that hemispheric differences in performance have at their basis a quantitative asymmetry, which can be reversed even in normal subjects by overloading their limited capacity.

Ten-year-old children who were shown pictures of objects immediately preceded by the object's name recalled the material no better than those exposed to the names of the stimuli alone. Both conditions yielded significantly poorer retention than those in which pictures alone were presented or pictures followed by their names. A second study replicated this result. In addition this demonstrated, by a picture and name recognition task, that the effects could not be due to subjects in the “name prior to picture” condition ignoring the pictorial component. These results were interpreted as contradicting the “double encoding” explanation of the superiority of pictures to names in free recall. Parallel visual and verbal encoding of a pictured object does not facilitate retention unless the verbal cue is actively elicited from the subject by the stimulus. The implications of this result for other studies which have employed either simultaneous or sequential presentation of pictures and names are briefly discussed.

Auditory temporal psychometric functions were obtained for forward masking, backward masking, and for combined forward and backward masking for the case of an impulsive signal in white noise. Temporal psychometric functions show a large interaction between forward masking and backward masking when evaluated against an independence model of performance. The results are not consistent with the concept of a sharp rectangular temporal integrating period (“moment”) to account for the interaction.

In auditory memory span experiments an extra word presented at the end of the list impairs performance on the last few items even though it is completely redundant; delaying this stimulus suffix past the time when an additional memory item would have occurred–-so that the rate of presentation is retarded for the suffix–-reduces the magnitude of the performance impairment. One account of this pattern of results is that during presentation of the items the subject adjusts periodic bursts of attention to the regular cadence of new information. Since an immediate suffix is in time with this cadence and a delayed suffix not, the larger effect of the former is explained without appeal to any process dependent on real time. In the present study the stimulus items were presented in an arhythmic manner with interstimulus intervals ranging from 100 to 900 ms on a random basis. Under these conditions the same effect of delaying the suffix was observed as is typical of rhythmic stimulus presentation; therefore, the rhythm hypothesis for the effect is not supported.