El uso de Internet en las PYMES

5.1 Introduction

Following on from the previous chapter which explored the role o f temporal order in duration, the present chapter takes this matter a stage further by examining the notion of the temporal structure inherent in an interval. As discussed in chapter 2, the idea that the internal temporal organisation of events could offer cues to interval duration is attributable to social psychological and ‘ecological’ traditions within psychology. In chapter 3 it was argued that temporal order in narrative form (temporal coherence) may function as a general organising scheme for information processing such that intervals of different temporal structure would be experienced as different in length. According to the Kintsch and van Dijk (1978) model of text comprehension this would reflect different degrees o f overlap between macropropositions within a working memory buffer (see chapter 2). It seems plausible that any attenuation of attention or working memory capacity is likely to limit on-line text processing such that differences in temporal coherence will result in different amounts of information being processed. In terms of attentional accounts of psychological time, the more processing resources that are allocated to the narrative, the less accurate should be the resulting time estimation.

Certainly, poor recall of narrative information is common after severe brain injury, which might lead to expectations of a concomitant reduction in timing accuracy. However, time experience for periods up to one minute appears to depend on short-term retention and rehearsal processes (Richards, 1973; Williams et al. 1989; Kinsboume & Hicks, 1990; Nichelli et al , 1993) and may be experienced by memory-impaired subjects fairly accurately. Thus one might expect the influence of temporal coherence as an organising framework for information processing to be evident only for intervals which exceed working memory capacity.

The present investigation was undertaken to explore the relation between temporal structure, information processing and the experience o f duration. In order to distinguish between the temporal coherence of events in an interval and memory for the constituent events (which may itself be affected by intrinsic temporality), a prospective time estimation paradigm was employed. This permits the effects of interval content on memory to be assessed separately from the effects of content on experienced duration.

5.2 Method

Two versions of an auditory-verbal recall task from the Adult Memory and Information Processing Battery (AMIPB, Coughlan & Hollows, 1985) were administered in the study. Although presented as parallel forms of the same task, normative data suggest that (at least for the 46-75 age group) one story, “Peter Williams” is slightly more difficult than the other, “Angela Harper.” Temporal coherence of the passages was analysed in terms of the temporal congruity of each statement, ie. the degree to which succeeding statements reflected the order of actions to which they referred. The stories are already divided into scorable segments or tokens, each of which, for the present analysis was designated as congruent if the token referred to an action which had immediately followed the act referred by the preceding token. The token was designated as

incongruent if its referent act did not follow directly from the previous statement. An comparative analysis of the two passages (abbreviated to AH and PW) in this way reveals contrasting temporal properties such that the AH narrative is approximately 80% temporally congruent, whereas the PW story exhibits only about 20% temporal congruity.

Subjects

As in the previous chapter two groups of closed head-injured subjects were employed in this study. They were designated as severe (N=15) and very severe (N=14) in accordance with the PTA cut-off of 12 weeks discussed in chapter 4. The subjects were matched for age and present intellectual status on the WAIS-R and constituted approximately the

same sample who were employed in the previous investigation. Although both groups comprised individuals who had sustained very severe brain injuries, they were differentiated in terms of clinical presentation and injury severity as defined by length of PTA. Thus the more severe of the two groups was associated with prolonged post- traumatic confusion and behavioural problems. This latter group could not undertake the NART reliably and were therefore matched on current WAIS-R performance only. The inclusion of orthopaedic controls is particularly important as some research suggests that accident victims are likely to suffer task-irrelevant concerns which may impede working memory (Richardson & Snape,1984). The clinical details of the subject groups are summarised in table 5.1 below.

Orthopaedic Controls Severely head injured Very severely head injured Age (yrs.months) 42.1 (15.6) 38.3 (14.4) 37.3 (10.4) Sex (M;F) 8:7 13:2 14:0

Months post injury - 9.1 (7.6) 67.6 (58.1) *

PTA (weeks) - 7.0 (7.2) 42.8 (4.5) **

NART-IQ 107.5 (9.8) 102.4 (8.2) -

WAIS-R FSIQ - 83.6 (9.9) 75.4 (9.1)

Table 5.1 Summarv of clinical characteristics of subjects (means and SD.s)

* v < 0.01. * * < 0 .0 0 1

Procedure

The subjects were adminstered the Peter Williams and Angela Harper stories from the AMIPB, as part of a more comprehensive neuropsychological assessment. The only departure from the standard administration instructions was that subjects were told that

they would be asked at the end of the story, how long it had taken to read the passage out to them. Thus the emphasis was on prospective time estimation, assessing how time was experienced during the task. Participants were reminded that they would also be asked to recall as many details from the passage that they could remember. In order to facilitate performance among the more severely impaired subjects, they were told that it was not necessary that they try to recall information in the order in which it was presented. The stories were administered at least thirty minutes apart, and in quasi-random order across subjects. The subject always provided a time estimate before recalling information from the narratives.

5.3 Results

The clinical characteristics of the three subject groups are summarised in table 5.1. There were no significant differences in age between the groups. The controls and the severely head injured group were equivalent in premorbid intellectual ability, as indicated by the re-standardised NART. In addition, the two head injured samples were functioning within the same range on current WAIS-R IQ. As reported in previous chapters, although all head-injured subjects sustained very severe injuries, two groups are discernible in terms of the magnitude of PTA (/ = 9.21 (df,28) p < .001) with the more severely disturbed group also being tested significantly later after their injury {t = 3.34 (df,28)/7<.01).