Sustained Readiness Task
In the sustained readiness task (SRT) subjects are required to monitor the succession of presentations of a simple stimulus (red square) and respond as fast as possible at each stimulus onset. The rather long and random inter-trial-intervals (ITI) and the absence of external stimulation other than the red square, make it difficult for the subject to stay alerted (Klemmer, 1957). As such, response latencies are known to increase with fatigue and sedative effects.
The SRT task is only asking for a simple response to each appearance of the same red square without the need to discriminate between different stimuli (Donders, 1969). The SRT task is focusing on decrease in response speed when subjects monitor a simple unpredictable stimulus over an extended period of time. In contrast, vigilance tasks focus primarily on the decrement of discriminating between signal and noise (Davies & Parasuraman, 1982).
The sustained readiness task is an alternative way to measure the concept of sustained attention. Vigilance tasks require the subject to detect a specific target stimulus among non critical distractor stimuli (noise). It typically takes a long test period (20min – 60min) until there is a decline in subject performance in form of false alarms to non-targets or missed targets. This makes it difficult to measure vigilance in context of clinical trials which only provide limited time for cognitive assessments. But increase of RT is typically also observed in those vigilance task even before the subject begins missing targets.
Parasuraman et al. describe techniques to accelerate the decrease in performance by using lower target probabilities or introducing target conditions that induced working memory load (Parasuraman, 1979). But then the nature of the task becomes more of a continuous performance task where subjects have to perform over a prolonged time at a rather high level. These tasks are very stimulating and perceived as challenging by subjects, which makes it more difficult to discover subtle differences in general alertness since subjects feel motivated and compensate. With lower target rates, the re-test reliability deteriorates since with fewer targets fewer measurements of hit and miss are available.
For this reason, the sustained readiness task can be seen as method to measure performance decreases within a rather short time interval that relate to general state of arousal and subjective state of feeling tired and not energetic.
Davies, D. R., & Parasuraman, R. (1982). The psychology of vigilance. London: Academic Press.
Donders, F. C. (1969). Over de snelheid van psychische processen [On the speed of psychological processes]. In W. Koster (Ed.), Attention and Performance: II (Original work published 1868). Amsterdam: North-Holland.
Klemmer, T.E. (1975). Journal of Experimental Psychology, Vol 54, No. 3, 1957.
Parasuraman R. Memory load and event rate control sensitivity decrements in sustained attention. Science. 1979;205:924–927.
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Kazi ya utayari wa kudumu (SRT) - Wanafunzi wanaohusika na kazi ya utayari wa kudumu (SRT) wanahitajika kufuatilia mfululizo wa maonyesho ya kichocheo rahisi (square nyekundu) na kujibu haraka iwezekanavyo kwa kila kichocheo. Kwa sababu ya muda mrefu na random inter-trial intervals (ITI) na kukosekana kwa stimulation nje isipokuwa mraba nyekundu, kufanya ni vigumu kwa ajili ya mtu kukaa makini (Klemmer, 1957). Kama vile, majibu latencies ni inayojulikana kuongeza na uchovu na athari sedative. SRT ni kazi ya kuomba tu kwa majibu rahisi kwa kila kuonekana kwa mraba wa rangi nyekundu bila haja ya kutofautisha kati ya vichocheo tofauti. SRT ni kazi ya kupunguza kasi ya majibu wakati watu wanaangalia kichocheo rahisi cha muda mrefu. Kwa upande mwingine, kazi za tahadhari zinazingatia hasa kupungua kwa kutofautisha kati ya ishara na kelele (Davies & Parasuraman, 1982). Kazi ya utayari endelevu ni njia mbadala ya kupima dhana ya tahadhari endelevu. Kazi za tahadhari zinahitaji mtihani kugundua kichocheo maalum cha lengo kati ya vichocheo visivyo muhimu vya kuharibu (sauti). Kwa kawaida inachukua kipindi kirefu cha mtihani (20 min - 60 min) hadi kutakuwa na kupungua kwa utendaji wa somo katika fomu ya kengele bandia kwa malengo yasiyo ya malengo au malengo yaliyopotezwa. Hii inafanya kuwa vigumu kupima tahadhari katika muktadha wa majaribio ya kliniki ambayo hutoa tu muda mdogo kwa ajili ya tathmini ya utambuzi. Lakini ongezeko la RT ni kawaida pia kuchunguzwa katika wale kazi tahadhari hata kabla ya somo huanza kukosa malengo. Parasuraman et al. Utafiti wa kumbukumbu za kazi (parasuraman) Lakini hali ya kazi hiyo inakuwa ya kuendelea, ambapo watu wanaofanya kazi hiyo kwa muda mrefu na kwa kiwango cha juu. Kazi hizi ni stimulating sana na kuonekana kama changamoto na masomo, ambayo inafanya kuwa vigumu zaidi kugundua tofauti ndogo katika tahadhari ya jumla, kwa kuwa masomo kujisikia motisha na fidia. Pamoja na viwango vya chini vya lengo, kuegemea kwa majaribio upya huharibika kwani na malengo machache vipimo vichache vya hit na miss zinapatikana. Kwa sababu hii, kazi ya utayari wa kudumu inaweza kuonekana kama njia ya kupima kupungua kwa utendaji ndani ya muda mfupi wa muda ambao unahusiana na hali ya jumla ya kuamsha na hali ya kibinafsi ya kujisikia uchovu na si nguvu. Davies, D. R., na Parasuraman, R. (1982). Saikolojia ya tahadhari. London: Academic Press. Donders, F. C. (1969). Zaidi ya kasi ya michakato ya kisaikolojia. Katika W. Koster (Ed. (Kumbuka: Utafiti wa kwanza ulichapishwa mnamo 1868) Amsterdam: Holland ya Kaskazini. Klemmer, T. E. (1975). - Utafiti wa Jarida la Saikolojia ya Majaribio, Vol. 3 (KJV) 1957 Parasuraman R. Memory mzigo na tukio kiwango cha kudhibiti nyeti decreases katika makini endelevu. Sayansi. 1979;205:924927. < start=""104.9" dur=""0.5""> Idadi ya majaribio ya kawaida